Merge tag 'kvmarm-for-v4.18' of...

Merge tag 'kvmarm-for-v4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

KVM/ARM updates for 4.18

- Lazy context-switching of FPSIMD registers on arm64
- Allow virtual redistributors to be part of two or more MMIO ranges

Documentation/virtual/kvm/devices/arm-vgic-v3.txt

@@ -27,16 +27,42 @@ Groups:
       VCPU and all of the redistributor pages are contiguous.
       Only valid for KVM_DEV_TYPE_ARM_VGIC_V3.
       This address needs to be 64K aligned.
+
+    KVM_VGIC_V3_ADDR_TYPE_REDIST_REGION (rw, 64-bit)
+      The attribute data pointed to by kvm_device_attr.addr is a __u64 value:
+      bits:     | 63   ....  52  |  51   ....   16 | 15 - 12  |11 - 0
+      values:   |     count      |       base      |  flags   | index
+      - index encodes the unique redistributor region index
+      - flags: reserved for future use, currently 0
+      - base field encodes bits [51:16] of the guest physical base address
+        of the first redistributor in the region.
+      - count encodes the number of redistributors in the region. Must be
+        greater than 0.
+      There are two 64K pages for each redistributor in the region and
+      redistributors are laid out contiguously within the region. Regions
+      are filled with redistributors in the index order. The sum of all
+      region count fields must be greater than or equal to the number of
+      VCPUs. Redistributor regions must be registered in the incremental
+      index order, starting from index 0.
+      The characteristics of a specific redistributor region can be read
+      by presetting the index field in the attr data.
+      Only valid for KVM_DEV_TYPE_ARM_VGIC_V3.
+
+  It is invalid to mix calls with KVM_VGIC_V3_ADDR_TYPE_REDIST and
+  KVM_VGIC_V3_ADDR_TYPE_REDIST_REGION attributes.
+
   Errors:
     -E2BIG:  Address outside of addressable IPA range
-    -EINVAL: Incorrectly aligned address
+    -EINVAL: Incorrectly aligned address, bad redistributor region
+             count/index, mixed redistributor region attribute usage
     -EEXIST: Address already configured
+    -ENOENT: Attempt to read the characteristics of a non existing
+             redistributor region
     -ENXIO:  The group or attribute is unknown/unsupported for this device
              or hardware support is missing.
     -EFAULT: Invalid user pointer for attr->addr.
 
 
-
   KVM_DEV_ARM_VGIC_GRP_DIST_REGS
   KVM_DEV_ARM_VGIC_GRP_REDIST_REGS
   Attributes:

arch/arm/include/asm/kvm_host.h

@@ -280,6 +280,7 @@ void kvm_mmu_wp_memory_region(struct kvm *kvm, int slot);
 
 struct kvm_vcpu *kvm_mpidr_to_vcpu(struct kvm *kvm, unsigned long mpidr);
 
+static inline bool kvm_arch_check_sve_has_vhe(void) { return true; }
 static inline void kvm_arch_hardware_unsetup(void) {}
 static inline void kvm_arch_sync_events(struct kvm *kvm) {}
 static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {}
@@ -303,8 +304,13 @@ int kvm_arm_vcpu_arch_get_attr(struct kvm_vcpu *vcpu,
 int kvm_arm_vcpu_arch_has_attr(struct kvm_vcpu *vcpu,
 			       struct kvm_device_attr *attr);
 
-/* All host FP/SIMD state is restored on guest exit, so nothing to save: */
-static inline void kvm_fpsimd_flush_cpu_state(void) {}
+/*
+ * VFP/NEON switching is all done by the hyp switch code, so no need to
+ * coordinate with host context handling for this state:
+ */
+static inline void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu) {}
+static inline void kvm_arch_vcpu_ctxsync_fp(struct kvm_vcpu *vcpu) {}
+static inline void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu) {}
 
 static inline void kvm_arm_vhe_guest_enter(void) {}
 static inline void kvm_arm_vhe_guest_exit(void) {}

arch/arm/include/uapi/asm/kvm.h

@@ -91,6 +91,7 @@ struct kvm_regs {
 #define KVM_VGIC_V3_ADDR_TYPE_DIST	2
 #define KVM_VGIC_V3_ADDR_TYPE_REDIST	3
 #define KVM_VGIC_ITS_ADDR_TYPE		4
+#define KVM_VGIC_V3_ADDR_TYPE_REDIST_REGION	5
 
 #define KVM_VGIC_V3_DIST_SIZE		SZ_64K
 #define KVM_VGIC_V3_REDIST_SIZE		(2 * SZ_64K)

arch/arm64/Kconfig

@@ -1130,6 +1130,7 @@ endmenu
 config ARM64_SVE
 	bool "ARM Scalable Vector Extension support"
 	default y
+	depends on !KVM || ARM64_VHE
 	help
 	  The Scalable Vector Extension (SVE) is an extension to the AArch64
 	  execution state which complements and extends the SIMD functionality
@@ -1155,6 +1156,12 @@ config ARM64_SVE
 	  booting the kernel.  If unsure and you are not observing these
 	  symptoms, you should assume that it is safe to say Y.
 
+	  CPUs that support SVE are architecturally required to support the
+	  Virtualization Host Extensions (VHE), so the kernel makes no
+	  provision for supporting SVE alongside KVM without VHE enabled.
+	  Thus, you will need to enable CONFIG_ARM64_VHE if you want to support
+	  KVM in the same kernel image.
+
 config ARM64_MODULE_PLTS
 	bool
 	select HAVE_MOD_ARCH_SPECIFIC

arch/arm64/include/asm/cpufeature.h

@@ -11,9 +11,7 @@
 
 #include <asm/cpucaps.h>
 #include <asm/cputype.h>
-#include <asm/fpsimd.h>
 #include <asm/hwcap.h>
-#include <asm/sigcontext.h>
 #include <asm/sysreg.h>
 
 /*
@@ -510,33 +508,6 @@ static inline bool system_supports_sve(void)
 		cpus_have_const_cap(ARM64_SVE);
 }
 
-/*
- * Read the pseudo-ZCR used by cpufeatures to identify the supported SVE
- * vector length.
- *
- * Use only if SVE is present.
- * This function clobbers the SVE vector length.
- */
-static inline u64 read_zcr_features(void)
-{
-	u64 zcr;
-	unsigned int vq_max;
-
-	/*
-	 * Set the maximum possible VL, and write zeroes to all other
-	 * bits to see if they stick.
-	 */
-	sve_kernel_enable(NULL);
-	write_sysreg_s(ZCR_ELx_LEN_MASK, SYS_ZCR_EL1);
-
-	zcr = read_sysreg_s(SYS_ZCR_EL1);
-	zcr &= ~(u64)ZCR_ELx_LEN_MASK; /* find sticky 1s outside LEN field */
-	vq_max = sve_vq_from_vl(sve_get_vl());
-	zcr |= vq_max - 1; /* set LEN field to maximum effective value */
-
-	return zcr;
-}
-
 #endif /* __ASSEMBLY__ */
 
 #endif

arch/arm64/include/asm/fpsimd.h

@@ -18,6 +18,8 @@
 
 #include <asm/ptrace.h>
 #include <asm/errno.h>
+#include <asm/processor.h>
+#include <asm/sigcontext.h>
 
 #ifndef __ASSEMBLY__
 
@@ -41,6 +43,8 @@ struct task_struct;
 extern void fpsimd_save_state(struct user_fpsimd_state *state);
 extern void fpsimd_load_state(struct user_fpsimd_state *state);
 
+extern void fpsimd_save(void);
+
 extern void fpsimd_thread_switch(struct task_struct *next);
 extern void fpsimd_flush_thread(void);
 
@@ -49,12 +53,27 @@ extern void fpsimd_preserve_current_state(void);
 extern void fpsimd_restore_current_state(void);
 extern void fpsimd_update_current_state(struct user_fpsimd_state const *state);
 
+extern void fpsimd_bind_task_to_cpu(void);
+extern void fpsimd_bind_state_to_cpu(struct user_fpsimd_state *state);
+
 extern void fpsimd_flush_task_state(struct task_struct *target);
+extern void fpsimd_flush_cpu_state(void);
 extern void sve_flush_cpu_state(void);
 
 /* Maximum VL that SVE VL-agnostic software can transparently support */
 #define SVE_VL_ARCH_MAX 0x100
 
+/* Offset of FFR in the SVE register dump */
+static inline size_t sve_ffr_offset(int vl)
+{
+	return SVE_SIG_FFR_OFFSET(sve_vq_from_vl(vl)) - SVE_SIG_REGS_OFFSET;
+}
+
+static inline void *sve_pffr(struct thread_struct *thread)
+{
+	return (char *)thread->sve_state + sve_ffr_offset(thread->sve_vl);
+}
+
 extern void sve_save_state(void *state, u32 *pfpsr);
 extern void sve_load_state(void const *state, u32 const *pfpsr,
 			   unsigned long vq_minus_1);
@@ -63,6 +82,8 @@ extern unsigned int sve_get_vl(void);
 struct arm64_cpu_capabilities;
 extern void sve_kernel_enable(const struct arm64_cpu_capabilities *__unused);
 
+extern u64 read_zcr_features(void);
+
 extern int __ro_after_init sve_max_vl;
 
 #ifdef CONFIG_ARM64_SVE

arch/arm64/include/asm/kvm_asm.h

@@ -30,19 +30,19 @@
 /* The hyp-stub will return this for any kvm_call_hyp() call */
 #define ARM_EXCEPTION_HYP_GONE	  HVC_STUB_ERR
 
-#define KVM_ARM64_DEBUG_DIRTY_SHIFT	0
-#define KVM_ARM64_DEBUG_DIRTY		(1 << KVM_ARM64_DEBUG_DIRTY_SHIFT)
+#ifndef __ASSEMBLY__
+
+#include <linux/mm.h>
 
 /* Translate a kernel address of @sym into its equivalent linear mapping */
 #define kvm_ksym_ref(sym)						\
 	({								\
 		void *val = &sym;					\
 		if (!is_kernel_in_hyp_mode())				\
-			val = phys_to_virt((u64)&sym - kimage_voffset);	\
+			val = lm_alias(&sym);				\
 		val;							\
 	 })
 
-#ifndef __ASSEMBLY__
 struct kvm;
 struct kvm_vcpu;
 

arch/arm64/include/asm/kvm_host.h

@@ -30,6 +30,7 @@
 #include <asm/kvm.h>
 #include <asm/kvm_asm.h>
 #include <asm/kvm_mmio.h>
+#include <asm/thread_info.h>
 
 #define __KVM_HAVE_ARCH_INTC_INITIALIZED
 
@@ -216,8 +217,8 @@ struct kvm_vcpu_arch {
 	/* Exception Information */
 	struct kvm_vcpu_fault_info fault;
 
-	/* Guest debug state */
-	u64 debug_flags;
+	/* Miscellaneous vcpu state flags */
+	u64 flags;
 
 	/*
 	 * We maintain more than a single set of debug registers to support
@@ -238,6 +239,10 @@ struct kvm_vcpu_arch {
 
 	/* Pointer to host CPU context */
 	kvm_cpu_context_t *host_cpu_context;
+
+	struct thread_info *host_thread_info;	/* hyp VA */
+	struct user_fpsimd_state *host_fpsimd_state;	/* hyp VA */
+
 	struct {
 		/* {Break,watch}point registers */
 		struct kvm_guest_debug_arch regs;
@@ -293,6 +298,12 @@ struct kvm_vcpu_arch {
 	bool sysregs_loaded_on_cpu;
 };
 
+/* vcpu_arch flags field values: */
+#define KVM_ARM64_DEBUG_DIRTY		(1 << 0)
+#define KVM_ARM64_FP_ENABLED		(1 << 1) /* guest FP regs loaded */
+#define KVM_ARM64_FP_HOST		(1 << 2) /* host FP regs loaded */
+#define KVM_ARM64_HOST_SVE_IN_USE	(1 << 3) /* backup for host TIF_SVE */
+
 #define vcpu_gp_regs(v)		(&(v)->arch.ctxt.gp_regs)
 
 /*
@@ -394,6 +405,19 @@ static inline void __cpu_init_hyp_mode(phys_addr_t pgd_ptr,
 	kvm_call_hyp(__kvm_set_tpidr_el2, tpidr_el2);
 }
 
+static inline bool kvm_arch_check_sve_has_vhe(void)
+{
+	/*
+	 * The Arm architecture specifies that implementation of SVE
+	 * requires VHE also to be implemented.  The KVM code for arm64
+	 * relies on this when SVE is present:
+	 */
+	if (system_supports_sve())
+		return has_vhe();
+	else
+		return true;
+}
+
 static inline void kvm_arch_hardware_unsetup(void) {}
 static inline void kvm_arch_sync_events(struct kvm *kvm) {}
 static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {}
@@ -420,15 +444,18 @@ static inline void __cpu_init_stage2(void)
 		  "PARange is %d bits, unsupported configuration!", parange);
 }
 
-/*
- * All host FP/SIMD state is restored on guest exit, so nothing needs
- * doing here except in the SVE case:
-*/
-static inline void kvm_fpsimd_flush_cpu_state(void)
+/* Guest/host FPSIMD coordination helpers */
+int kvm_arch_vcpu_run_map_fp(struct kvm_vcpu *vcpu);
+void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu);
+void kvm_arch_vcpu_ctxsync_fp(struct kvm_vcpu *vcpu);
+void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu);
+
+#ifdef CONFIG_KVM /* Avoid conflicts with core headers if CONFIG_KVM=n */
+static inline int kvm_arch_vcpu_run_pid_change(struct kvm_vcpu *vcpu)
 {
-	if (system_supports_sve())
-		sve_flush_cpu_state();
+	return kvm_arch_vcpu_run_map_fp(vcpu);
 }
+#endif
 
 static inline void kvm_arm_vhe_guest_enter(void)
 {

arch/arm64/include/asm/processor.h

@@ -156,7 +156,9 @@ static inline void arch_thread_struct_whitelist(unsigned long *offset,
 /* Sync TPIDR_EL0 back to thread_struct for current */
 void tls_preserve_current_state(void);
 
-#define INIT_THREAD  {	}
+#define INIT_THREAD {				\
+	.fpsimd_cpu = NR_CPUS,			\
+}
 
 static inline void start_thread_common(struct pt_regs *regs, unsigned long pc)
 {
@@ -244,6 +246,17 @@ void cpu_enable_pan(const struct arm64_cpu_capabilities *__unused);
 void cpu_enable_cache_maint_trap(const struct arm64_cpu_capabilities *__unused);
 void cpu_clear_disr(const struct arm64_cpu_capabilities *__unused);
 
+/*
+ * Not at the top of the file due to a direct #include cycle between
+ * <asm/fpsimd.h> and <asm/processor.h>.  Deferring this #include
+ * ensures that contents of processor.h are visible to fpsimd.h even if
+ * processor.h is included first.
+ *
+ * These prctl helpers are the only things in this file that require
+ * fpsimd.h.  The core code expects them to be in this header.
+ */
+#include <asm/fpsimd.h>
+
 /* Userspace interface for PR_SVE_{SET,GET}_VL prctl()s: */
 #define SVE_SET_VL(arg)	sve_set_current_vl(arg)
 #define SVE_GET_VL()	sve_get_current_vl()

arch/arm64/include/asm/thread_info.h

@@ -45,12 +45,6 @@ struct thread_info {
 	int			preempt_count;	/* 0 => preemptable, <0 => bug */
 };
 
-#define INIT_THREAD_INFO(tsk)						\
-{									\
-	.preempt_count	= INIT_PREEMPT_COUNT,				\
-	.addr_limit	= KERNEL_DS,					\
-}
-
 #define thread_saved_pc(tsk)	\
 	((unsigned long)(tsk->thread.cpu_context.pc))
 #define thread_saved_sp(tsk)	\
@@ -117,5 +111,12 @@ void arch_release_task_struct(struct task_struct *tsk);
 				 _TIF_SYSCALL_TRACEPOINT | _TIF_SECCOMP | \
 				 _TIF_NOHZ)
 
+#define INIT_THREAD_INFO(tsk)						\
+{									\
+	.flags		= _TIF_FOREIGN_FPSTATE,				\
+	.preempt_count	= INIT_PREEMPT_COUNT,				\
+	.addr_limit	= KERNEL_DS,					\
+}
+
 #endif /* __KERNEL__ */
 #endif /* __ASM_THREAD_INFO_H */

arch/arm64/include/uapi/asm/kvm.h

@@ -91,6 +91,7 @@ struct kvm_regs {
 #define KVM_VGIC_V3_ADDR_TYPE_DIST	2
 #define KVM_VGIC_V3_ADDR_TYPE_REDIST	3
 #define KVM_VGIC_ITS_ADDR_TYPE		4
+#define KVM_VGIC_V3_ADDR_TYPE_REDIST_REGION	5
 
 #define KVM_VGIC_V3_DIST_SIZE		SZ_64K
 #define KVM_VGIC_V3_REDIST_SIZE		(2 * SZ_64K)

arch/arm64/kernel/fpsimd.c

@@ -37,12 +37,14 @@
 #include <linux/sched/task_stack.h>
 #include <linux/signal.h>
 #include <linux/slab.h>
+#include <linux/stddef.h>
 #include <linux/sysctl.h>
 
 #include <asm/esr.h>
 #include <asm/fpsimd.h>
 #include <asm/cpufeature.h>
 #include <asm/cputype.h>
+#include <asm/processor.h>
 #include <asm/simd.h>
 #include <asm/sigcontext.h>
 #include <asm/sysreg.h>
@@ -118,7 +120,6 @@
  */
 struct fpsimd_last_state_struct {
 	struct user_fpsimd_state *st;
-	bool sve_in_use;
 };
 
 static DEFINE_PER_CPU(struct fpsimd_last_state_struct, fpsimd_last_state);
@@ -159,19 +160,6 @@ static void sve_free(struct task_struct *task)
 	__sve_free(task);
 }
 
-
-/* Offset of FFR in the SVE register dump */
-static size_t sve_ffr_offset(int vl)
-{
-	return SVE_SIG_FFR_OFFSET(sve_vq_from_vl(vl)) - SVE_SIG_REGS_OFFSET;
-}
-
-static void *sve_pffr(struct task_struct *task)
-{
-	return (char *)task->thread.sve_state +
-		sve_ffr_offset(task->thread.sve_vl);
-}
-
 static void change_cpacr(u64 val, u64 mask)
 {
 	u64 cpacr = read_sysreg(CPACR_EL1);
@@ -252,31 +240,24 @@ static void task_fpsimd_load(void)
 	WARN_ON(!in_softirq() && !irqs_disabled());
 
 	if (system_supports_sve() && test_thread_flag(TIF_SVE))
-		sve_load_state(sve_pffr(current),
+		sve_load_state(sve_pffr(&current->thread),
 			       &current->thread.uw.fpsimd_state.fpsr,
 			       sve_vq_from_vl(current->thread.sve_vl) - 1);
 	else
 		fpsimd_load_state(&current->thread.uw.fpsimd_state);
-
-	if (system_supports_sve()) {
-		/* Toggle SVE trapping for userspace if needed */
-		if (test_thread_flag(TIF_SVE))
-			sve_user_enable();
-		else
-			sve_user_disable();
-
-		/* Serialised by exception return to user */
-	}
 }
 
 /*
- * Ensure current's FPSIMD/SVE storage in thread_struct is up to date
- * with respect to the CPU registers.
+ * Ensure FPSIMD/SVE storage in memory for the loaded context is up to
+ * date with respect to the CPU registers.
  *
  * Softirqs (and preemption) must be disabled.
  */
-static void task_fpsimd_save(void)
+void fpsimd_save(void)
 {
+	struct user_fpsimd_state *st = __this_cpu_read(fpsimd_last_state.st);
+	/* set by fpsimd_bind_task_to_cpu() or fpsimd_bind_state_to_cpu() */
+
 	WARN_ON(!in_softirq() && !irqs_disabled());
 
 	if (!test_thread_flag(TIF_FOREIGN_FPSTATE)) {
@@ -291,10 +272,9 @@ static void task_fpsimd_save(void)
 				return;
 			}
 
-			sve_save_state(sve_pffr(current),
-				       &current->thread.uw.fpsimd_state.fpsr);
+			sve_save_state(sve_pffr(&current->thread), &st->fpsr);
 		} else
-			fpsimd_save_state(&current->thread.uw.fpsimd_state);
+			fpsimd_save_state(st);
 	}
 }
 
@@ -598,7 +578,7 @@ int sve_set_vector_length(struct task_struct *task,
 	if (task == current) {
 		local_bh_disable();
 
-		task_fpsimd_save();
+		fpsimd_save();
 		set_thread_flag(TIF_FOREIGN_FPSTATE);
 	}
 
@@ -618,10 +598,8 @@ int sve_set_vector_length(struct task_struct *task,
 	task->thread.sve_vl = vl;
 
 out:
-	if (flags & PR_SVE_VL_INHERIT)
-		set_tsk_thread_flag(task, TIF_SVE_VL_INHERIT);
-	else
-		clear_tsk_thread_flag(task, TIF_SVE_VL_INHERIT);
+	update_tsk_thread_flag(task, TIF_SVE_VL_INHERIT,
+			       flags & PR_SVE_VL_INHERIT);
 
 	return 0;
 }
@@ -765,6 +743,33 @@ void sve_kernel_enable(const struct arm64_cpu_capabilities *__always_unused p)
 	isb();
 }
 
+/*
+ * Read the pseudo-ZCR used by cpufeatures to identify the supported SVE
+ * vector length.
+ *
+ * Use only if SVE is present.
+ * This function clobbers the SVE vector length.
+ */
+u64 read_zcr_features(void)
+{
+	u64 zcr;
+	unsigned int vq_max;
+
+	/*
+	 * Set the maximum possible VL, and write zeroes to all other
+	 * bits to see if they stick.
+	 */
+	sve_kernel_enable(NULL);
+	write_sysreg_s(ZCR_ELx_LEN_MASK, SYS_ZCR_EL1);
+
+	zcr = read_sysreg_s(SYS_ZCR_EL1);
+	zcr &= ~(u64)ZCR_ELx_LEN_MASK; /* find sticky 1s outside LEN field */
+	vq_max = sve_vq_from_vl(sve_get_vl());
+	zcr |= vq_max - 1; /* set LEN field to maximum effective value */
+
+	return zcr;
+}
+
 void __init sve_setup(void)
 {
 	u64 zcr;
@@ -839,7 +844,7 @@ asmlinkage void do_sve_acc(unsigned int esr, struct pt_regs *regs)
 
 	local_bh_disable();
 
-	task_fpsimd_save();
+	fpsimd_save();
 	fpsimd_to_sve(current);
 
 	/* Force ret_to_user to reload the registers: */
@@ -892,31 +897,25 @@ asmlinkage void do_fpsimd_exc(unsigned int esr, struct pt_regs *regs)
 
 void fpsimd_thread_switch(struct task_struct *next)
 {
+	bool wrong_task, wrong_cpu;
+
 	if (!system_supports_fpsimd())
 		return;
+
+	/* Save unsaved fpsimd state, if any: */
+	fpsimd_save();
+
 	/*
-	 * Save the current FPSIMD state to memory, but only if whatever is in
-	 * the registers is in fact the most recent userland FPSIMD state of
-	 * 'current'.
+	 * Fix up TIF_FOREIGN_FPSTATE to correctly describe next's
+	 * state.  For kernel threads, FPSIMD registers are never loaded
+	 * and wrong_task and wrong_cpu will always be true.
 	 */
-	if (current->mm)
-		task_fpsimd_save();
+	wrong_task = __this_cpu_read(fpsimd_last_state.st) !=
+					&next->thread.uw.fpsimd_state;
+	wrong_cpu = next->thread.fpsimd_cpu != smp_processor_id();
 
-	if (next->mm) {
-		/*
-		 * If we are switching to a task whose most recent userland
-		 * FPSIMD state is already in the registers of *this* cpu,
-		 * we can skip loading the state from memory. Otherwise, set
-		 * the TIF_FOREIGN_FPSTATE flag so the state will be loaded
-		 * upon the next return to userland.
-		 */
-		if (__this_cpu_read(fpsimd_last_state.st) ==
-			&next->thread.uw.fpsimd_state
-		    && next->thread.fpsimd_cpu == smp_processor_id())
-			clear_tsk_thread_flag(next, TIF_FOREIGN_FPSTATE);
-		else
-			set_tsk_thread_flag(next, TIF_FOREIGN_FPSTATE);
-	}
+	update_tsk_thread_flag(next, TIF_FOREIGN_FPSTATE,
+			       wrong_task || wrong_cpu);
 }
 
 void fpsimd_flush_thread(void)
@@ -982,7 +981,7 @@ void fpsimd_preserve_current_state(void)
 		return;
 
 	local_bh_disable();
-	task_fpsimd_save();
+	fpsimd_save();
 	local_bh_enable();
 }
 
@@ -1002,14 +1001,33 @@ void fpsimd_signal_preserve_current_state(void)
  * Associate current's FPSIMD context with this cpu
  * Preemption must be disabled when calling this function.
  */
-static void fpsimd_bind_to_cpu(void)
+void fpsimd_bind_task_to_cpu(void)
 {
 	struct fpsimd_last_state_struct *last =
 		this_cpu_ptr(&fpsimd_last_state);
 
 	last->st = &current->thread.uw.fpsimd_state;
-	last->sve_in_use = test_thread_flag(TIF_SVE);
 	current->thread.fpsimd_cpu = smp_processor_id();
+
+	if (system_supports_sve()) {
+		/* Toggle SVE trapping for userspace if needed */
+		if (test_thread_flag(TIF_SVE))
+			sve_user_enable();
+		else
+			sve_user_disable();
+
+		/* Serialised by exception return to user */
+	}
+}
+
+void fpsimd_bind_state_to_cpu(struct user_fpsimd_state *st)
+{
+	struct fpsimd_last_state_struct *last =
+		this_cpu_ptr(&fpsimd_last_state);
+
+	WARN_ON(!in_softirq() && !irqs_disabled());
+
+	last->st = st;
 }
 
 /*
@@ -1026,7 +1044,7 @@ void fpsimd_restore_current_state(void)
 
 	if (test_and_clear_thread_flag(TIF_FOREIGN_FPSTATE)) {
 		task_fpsimd_load();
-		fpsimd_bind_to_cpu();
+		fpsimd_bind_task_to_cpu();
 	}
 
 	local_bh_enable();
@@ -1049,9 +1067,9 @@ void fpsimd_update_current_state(struct user_fpsimd_state const *state)
 		fpsimd_to_sve(current);
 
 	task_fpsimd_load();
+	fpsimd_bind_task_to_cpu();
 
-	if (test_and_clear_thread_flag(TIF_FOREIGN_FPSTATE))
-		fpsimd_bind_to_cpu();
+	clear_thread_flag(TIF_FOREIGN_FPSTATE);
 
 	local_bh_enable();
 }
@@ -1064,29 +1082,12 @@ void fpsimd_flush_task_state(struct task_struct *t)
 	t->thread.fpsimd_cpu = NR_CPUS;
 }
 
-static inline void fpsimd_flush_cpu_state(void)
+void fpsimd_flush_cpu_state(void)
 {
 	__this_cpu_write(fpsimd_last_state.st, NULL);
+	set_thread_flag(TIF_FOREIGN_FPSTATE);
 }
 
-/*
- * Invalidate any task SVE state currently held in this CPU's regs.
- *
- * This is used to prevent the kernel from trying to reuse SVE register data
- * that is detroyed by KVM guest enter/exit.  This function should go away when
- * KVM SVE support is implemented.  Don't use it for anything else.
- */
-#ifdef CONFIG_ARM64_SVE
-void sve_flush_cpu_state(void)
-{
-	struct fpsimd_last_state_struct const *last =
-		this_cpu_ptr(&fpsimd_last_state);
-
-	if (last->st && last->sve_in_use)
-		fpsimd_flush_cpu_state();
-}
-#endif /* CONFIG_ARM64_SVE */
-
 #ifdef CONFIG_KERNEL_MODE_NEON
 
 DEFINE_PER_CPU(bool, kernel_neon_busy);
@@ -1120,11 +1121,8 @@ void kernel_neon_begin(void)
 
 	__this_cpu_write(kernel_neon_busy, true);
 
-	/* Save unsaved task fpsimd state, if any: */
-	if (current->mm) {
-		task_fpsimd_save();
-		set_thread_flag(TIF_FOREIGN_FPSTATE);
-	}
+	/* Save unsaved fpsimd state, if any: */
+	fpsimd_save();
 
 	/* Invalidate any task state remaining in the fpsimd regs: */
 	fpsimd_flush_cpu_state();
@@ -1246,13 +1244,10 @@ static int fpsimd_cpu_pm_notifier(struct notifier_block *self,
 {
 	switch (cmd) {
 	case CPU_PM_ENTER:
-		if (current->mm)
-			task_fpsimd_save();
+		fpsimd_save();
 		fpsimd_flush_cpu_state();
 		break;
 	case CPU_PM_EXIT:
-		if (current->mm)
-			set_thread_flag(TIF_FOREIGN_FPSTATE);
 		break;
 	case CPU_PM_ENTER_FAILED:
 	default:

arch/arm64/kernel/ptrace.c

@@ -44,6 +44,7 @@
 #include <asm/compat.h>
 #include <asm/cpufeature.h>
 #include <asm/debug-monitors.h>
+#include <asm/fpsimd.h>
 #include <asm/pgtable.h>
 #include <asm/stacktrace.h>
 #include <asm/syscall.h>

arch/arm64/kvm/Kconfig

@@ -39,6 +39,7 @@ config KVM
 	select HAVE_KVM_IRQ_ROUTING
 	select IRQ_BYPASS_MANAGER
 	select HAVE_KVM_IRQ_BYPASS
+	select HAVE_KVM_VCPU_RUN_PID_CHANGE
 	---help---
 	  Support hosting virtualized guest machines.
 	  We don't support KVM with 16K page tables yet, due to the multiple

arch/arm64/kvm/Makefile

@@ -19,7 +19,7 @@ kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/psci.o $(KVM)/arm/perf.o
 kvm-$(CONFIG_KVM_ARM_HOST) += inject_fault.o regmap.o va_layout.o
 kvm-$(CONFIG_KVM_ARM_HOST) += hyp.o hyp-init.o handle_exit.o
 kvm-$(CONFIG_KVM_ARM_HOST) += guest.o debug.o reset.o sys_regs.o sys_regs_generic_v8.o
-kvm-$(CONFIG_KVM_ARM_HOST) += vgic-sys-reg-v3.o
+kvm-$(CONFIG_KVM_ARM_HOST) += vgic-sys-reg-v3.o fpsimd.o
 kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/aarch32.o
 
 kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/vgic/vgic.o

arch/arm64/kvm/debug.c

@@ -103,7 +103,7 @@ void kvm_arm_reset_debug_ptr(struct kvm_vcpu *vcpu)
  *
  * Additionally, KVM only traps guest accesses to the debug registers if
  * the guest is not actively using them (see the KVM_ARM64_DEBUG_DIRTY
- * flag on vcpu->arch.debug_flags).  Since the guest must not interfere
+ * flag on vcpu->arch.flags).  Since the guest must not interfere
  * with the hardware state when debugging the guest, we must ensure that
  * trapping is enabled whenever we are debugging the guest using the
  * debug registers.
@@ -111,7 +111,7 @@ void kvm_arm_reset_debug_ptr(struct kvm_vcpu *vcpu)
 
 void kvm_arm_setup_debug(struct kvm_vcpu *vcpu)
 {
-	bool trap_debug = !(vcpu->arch.debug_flags & KVM_ARM64_DEBUG_DIRTY);
+	bool trap_debug = !(vcpu->arch.flags & KVM_ARM64_DEBUG_DIRTY);
 	unsigned long mdscr;
 
 	trace_kvm_arm_setup_debug(vcpu, vcpu->guest_debug);
@@ -184,7 +184,7 @@ void kvm_arm_setup_debug(struct kvm_vcpu *vcpu)
 			vcpu_write_sys_reg(vcpu, mdscr, MDSCR_EL1);
 
 			vcpu->arch.debug_ptr = &vcpu->arch.external_debug_state;
-			vcpu->arch.debug_flags |= KVM_ARM64_DEBUG_DIRTY;
+			vcpu->arch.flags |= KVM_ARM64_DEBUG_DIRTY;
 			trap_debug = true;
 
 			trace_kvm_arm_set_regset("BKPTS", get_num_brps(),
@@ -206,7 +206,7 @@ void kvm_arm_setup_debug(struct kvm_vcpu *vcpu)
 
 	/* If KDE or MDE are set, perform a full save/restore cycle. */
 	if (vcpu_read_sys_reg(vcpu, MDSCR_EL1) & (DBG_MDSCR_KDE | DBG_MDSCR_MDE))
-		vcpu->arch.debug_flags |= KVM_ARM64_DEBUG_DIRTY;
+		vcpu->arch.flags |= KVM_ARM64_DEBUG_DIRTY;
 
 	trace_kvm_arm_set_dreg32("MDCR_EL2", vcpu->arch.mdcr_el2);
 	trace_kvm_arm_set_dreg32("MDSCR_EL1", vcpu_read_sys_reg(vcpu, MDSCR_EL1));

arch/arm64/kvm/fpsimd.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * arch/arm64/kvm/fpsimd.c: Guest/host FPSIMD context coordination helpers
+ *
+ * Copyright 2018 Arm Limited
+ * Author: Dave Martin <Dave.Martin@arm.com>
+ */
+#include <linux/bottom_half.h>
+#include <linux/sched.h>
+#include <linux/thread_info.h>
+#include <linux/kvm_host.h>
+#include <asm/kvm_asm.h>
+#include <asm/kvm_host.h>
+#include <asm/kvm_mmu.h>
+
+/*
+ * Called on entry to KVM_RUN unless this vcpu previously ran at least
+ * once and the most recent prior KVM_RUN for this vcpu was called from
+ * the same task as current (highly likely).
+ *
+ * This is guaranteed to execute before kvm_arch_vcpu_load_fp(vcpu),
+ * such that on entering hyp the relevant parts of current are already
+ * mapped.
+ */
+int kvm_arch_vcpu_run_map_fp(struct kvm_vcpu *vcpu)
+{
+	int ret;
+
+	struct thread_info *ti = &current->thread_info;
+	struct user_fpsimd_state *fpsimd = &current->thread.uw.fpsimd_state;
+
+	/*
+	 * Make sure the host task thread flags and fpsimd state are
+	 * visible to hyp:
+	 */
+	ret = create_hyp_mappings(ti, ti + 1, PAGE_HYP);
+	if (ret)
+		goto error;
+
+	ret = create_hyp_mappings(fpsimd, fpsimd + 1, PAGE_HYP);
+	if (ret)
+		goto error;
+
+	vcpu->arch.host_thread_info = kern_hyp_va(ti);
+	vcpu->arch.host_fpsimd_state = kern_hyp_va(fpsimd);
+error:
+	return ret;
+}
+
+/*
+ * Prepare vcpu for saving the host's FPSIMD state and loading the guest's.
+ * The actual loading is done by the FPSIMD access trap taken to hyp.
+ *
+ * Here, we just set the correct metadata to indicate that the FPSIMD
+ * state in the cpu regs (if any) belongs to current on the host.
+ *
+ * TIF_SVE is backed up here, since it may get clobbered with guest state.
+ * This flag is restored by kvm_arch_vcpu_put_fp(vcpu).
+ */
+void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu)
+{
+	BUG_ON(!current->mm);
+
+	vcpu->arch.flags &= ~(KVM_ARM64_FP_ENABLED | KVM_ARM64_HOST_SVE_IN_USE);
+	vcpu->arch.flags |= KVM_ARM64_FP_HOST;
+	if (test_thread_flag(TIF_SVE))
+		vcpu->arch.flags |= KVM_ARM64_HOST_SVE_IN_USE;
+}
+
+/*
+ * If the guest FPSIMD state was loaded, update the host's context
+ * tracking data mark the CPU FPSIMD regs as dirty and belonging to vcpu
+ * so that they will be written back if the kernel clobbers them due to
+ * kernel-mode NEON before re-entry into the guest.
+ */
+void kvm_arch_vcpu_ctxsync_fp(struct kvm_vcpu *vcpu)
+{
+	WARN_ON_ONCE(!irqs_disabled());
+
+	if (vcpu->arch.flags & KVM_ARM64_FP_ENABLED) {
+		fpsimd_bind_state_to_cpu(&vcpu->arch.ctxt.gp_regs.fp_regs);
+		clear_thread_flag(TIF_FOREIGN_FPSTATE);
+		clear_thread_flag(TIF_SVE);
+	}
+}
+
+/*
+ * Write back the vcpu FPSIMD regs if they are dirty, and invalidate the
+ * cpu FPSIMD regs so that they can't be spuriously reused if this vcpu
+ * disappears and another task or vcpu appears that recycles the same
+ * struct fpsimd_state.
+ */
+void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu)
+{
+	local_bh_disable();
+
+	update_thread_flag(TIF_SVE,
+			   vcpu->arch.flags & KVM_ARM64_HOST_SVE_IN_USE);
+
+	if (vcpu->arch.flags & KVM_ARM64_FP_ENABLED) {
+		/* Clean guest FP state to memory and invalidate cpu view */
+		fpsimd_save();
+		fpsimd_flush_cpu_state();
+	} else if (!test_thread_flag(TIF_FOREIGN_FPSTATE)) {
+		/* Ensure user trap controls are correctly restored */
+		fpsimd_bind_task_to_cpu();
+	}
+
+	local_bh_enable();
+}

arch/arm64/kvm/hyp/debug-sr.c

@@ -163,7 +163,7 @@ void __hyp_text __debug_switch_to_guest(struct kvm_vcpu *vcpu)
 	if (!has_vhe())
 		__debug_save_spe_nvhe(&vcpu->arch.host_debug_state.pmscr_el1);
 
-	if (!(vcpu->arch.debug_flags & KVM_ARM64_DEBUG_DIRTY))
+	if (!(vcpu->arch.flags & KVM_ARM64_DEBUG_DIRTY))
 		return;
 
 	host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context);
@@ -185,7 +185,7 @@ void __hyp_text __debug_switch_to_host(struct kvm_vcpu *vcpu)
 	if (!has_vhe())
 		__debug_restore_spe_nvhe(vcpu->arch.host_debug_state.pmscr_el1);
 
-	if (!(vcpu->arch.debug_flags & KVM_ARM64_DEBUG_DIRTY))
+	if (!(vcpu->arch.flags & KVM_ARM64_DEBUG_DIRTY))
 		return;
 
 	host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context);
@@ -196,7 +196,7 @@ void __hyp_text __debug_switch_to_host(struct kvm_vcpu *vcpu)
 	__debug_save_state(vcpu, guest_dbg, guest_ctxt);
 	__debug_restore_state(vcpu, host_dbg, host_ctxt);
 
-	vcpu->arch.debug_flags &= ~KVM_ARM64_DEBUG_DIRTY;
+	vcpu->arch.flags &= ~KVM_ARM64_DEBUG_DIRTY;
 }
 
 u32 __hyp_text __kvm_get_mdcr_el2(void)

arch/arm64/kvm/hyp/entry.S

@@ -166,46 +166,3 @@ abort_guest_exit_end:
 	orr	x0, x0, x5
 1:	ret
 ENDPROC(__guest_exit)
-
-ENTRY(__fpsimd_guest_restore)
-	// x0: esr
-	// x1: vcpu
-	// x2-x29,lr: vcpu regs
-	// vcpu x0-x1 on the stack
-	stp	x2, x3, [sp, #-16]!
-	stp	x4, lr, [sp, #-16]!
-
-alternative_if_not ARM64_HAS_VIRT_HOST_EXTN
-	mrs	x2, cptr_el2
-	bic	x2, x2, #CPTR_EL2_TFP
-	msr	cptr_el2, x2
-alternative_else
-	mrs	x2, cpacr_el1
-	orr	x2, x2, #CPACR_EL1_FPEN
-	msr	cpacr_el1, x2
-alternative_endif
-	isb
-
-	mov	x3, x1
-
-	ldr	x0, [x3, #VCPU_HOST_CONTEXT]
-	kern_hyp_va x0
-	add	x0, x0, #CPU_GP_REG_OFFSET(CPU_FP_REGS)
-	bl	__fpsimd_save_state
-
-	add	x2, x3, #VCPU_CONTEXT
-	add	x0, x2, #CPU_GP_REG_OFFSET(CPU_FP_REGS)
-	bl	__fpsimd_restore_state
-
-	// Skip restoring fpexc32 for AArch64 guests
-	mrs	x1, hcr_el2
-	tbnz	x1, #HCR_RW_SHIFT, 1f
-	ldr	x4, [x3, #VCPU_FPEXC32_EL2]
-	msr	fpexc32_el2, x4
-1:
-	ldp	x4, lr, [sp], #16
-	ldp	x2, x3, [sp], #16
-	ldp	x0, x1, [sp], #16
-
-	eret
-ENDPROC(__fpsimd_guest_restore)

arch/arm64/kvm/hyp/hyp-entry.S

@@ -113,25 +113,6 @@ el1_hvc_guest:
 
 el1_trap:
 	get_vcpu_ptr	x1, x0
-
-	mrs		x0, esr_el2
-	lsr		x0, x0, #ESR_ELx_EC_SHIFT
-	/*
-	 * x0: ESR_EC
-	 * x1: vcpu pointer
-	 */
-
-	/*
-	 * We trap the first access to the FP/SIMD to save the host context
-	 * and restore the guest context lazily.
-	 * If FP/SIMD is not implemented, handle the trap and inject an
-	 * undefined instruction exception to the guest.
-	 */
-alternative_if_not ARM64_HAS_NO_FPSIMD
-	cmp	x0, #ESR_ELx_EC_FP_ASIMD
-	b.eq	__fpsimd_guest_restore
-alternative_else_nop_endif
-
 	mov	x0, #ARM_EXCEPTION_TRAP
 	b	__guest_exit
 

arch/arm64/kvm/hyp/switch.c

@@ -21,21 +21,25 @@
 
 #include <kvm/arm_psci.h>
 
+#include <asm/cpufeature.h>
 #include <asm/kvm_asm.h>
 #include <asm/kvm_emulate.h>
+#include <asm/kvm_host.h>
 #include <asm/kvm_hyp.h>
 #include <asm/kvm_mmu.h>
 #include <asm/fpsimd.h>
 #include <asm/debug-monitors.h>
+#include <asm/processor.h>
+#include <asm/thread_info.h>
 
-static bool __hyp_text __fpsimd_enabled_nvhe(void)
+/* Check whether the FP regs were dirtied while in the host-side run loop: */
+static bool __hyp_text update_fp_enabled(struct kvm_vcpu *vcpu)
 {
-	return !(read_sysreg(cptr_el2) & CPTR_EL2_TFP);
-}
+	if (vcpu->arch.host_thread_info->flags & _TIF_FOREIGN_FPSTATE)
+		vcpu->arch.flags &= ~(KVM_ARM64_FP_ENABLED |
+				      KVM_ARM64_FP_HOST);
 
-static bool fpsimd_enabled_vhe(void)
-{
-	return !!(read_sysreg(cpacr_el1) & CPACR_EL1_FPEN);
+	return !!(vcpu->arch.flags & KVM_ARM64_FP_ENABLED);
 }
 
 /* Save the 32-bit only FPSIMD system register state */
@@ -92,7 +96,10 @@ static void activate_traps_vhe(struct kvm_vcpu *vcpu)
 
 	val = read_sysreg(cpacr_el1);
 	val |= CPACR_EL1_TTA;
-	val &= ~(CPACR_EL1_FPEN | CPACR_EL1_ZEN);
+	val &= ~CPACR_EL1_ZEN;
+	if (!update_fp_enabled(vcpu))
+		val &= ~CPACR_EL1_FPEN;
+
 	write_sysreg(val, cpacr_el1);
 
 	write_sysreg(kvm_get_hyp_vector(), vbar_el1);
@@ -105,7 +112,10 @@ static void __hyp_text __activate_traps_nvhe(struct kvm_vcpu *vcpu)
 	__activate_traps_common(vcpu);
 
 	val = CPTR_EL2_DEFAULT;
-	val |= CPTR_EL2_TTA | CPTR_EL2_TFP | CPTR_EL2_TZ;
+	val |= CPTR_EL2_TTA | CPTR_EL2_TZ;
+	if (!update_fp_enabled(vcpu))
+		val |= CPTR_EL2_TFP;
+
 	write_sysreg(val, cptr_el2);
 }
 
@@ -318,6 +328,50 @@ static bool __hyp_text __skip_instr(struct kvm_vcpu *vcpu)
 	}
 }
 
+static bool __hyp_text __hyp_switch_fpsimd(struct kvm_vcpu *vcpu)
+{
+	struct user_fpsimd_state *host_fpsimd = vcpu->arch.host_fpsimd_state;
+
+	if (has_vhe())
+		write_sysreg(read_sysreg(cpacr_el1) | CPACR_EL1_FPEN,
+			     cpacr_el1);
+	else
+		write_sysreg(read_sysreg(cptr_el2) & ~(u64)CPTR_EL2_TFP,
+			     cptr_el2);
+
+	isb();
+
+	if (vcpu->arch.flags & KVM_ARM64_FP_HOST) {
+		/*
+		 * In the SVE case, VHE is assumed: it is enforced by
+		 * Kconfig and kvm_arch_init().
+		 */
+		if (system_supports_sve() &&
+		    (vcpu->arch.flags & KVM_ARM64_HOST_SVE_IN_USE)) {
+			struct thread_struct *thread = container_of(
+				host_fpsimd,
+				struct thread_struct, uw.fpsimd_state);
+
+			sve_save_state(sve_pffr(thread), &host_fpsimd->fpsr);
+		} else {
+			__fpsimd_save_state(host_fpsimd);
+		}
+
+		vcpu->arch.flags &= ~KVM_ARM64_FP_HOST;
+	}
+
+	__fpsimd_restore_state(&vcpu->arch.ctxt.gp_regs.fp_regs);
+
+	/* Skip restoring fpexc32 for AArch64 guests */
+	if (!(read_sysreg(hcr_el2) & HCR_RW))
+		write_sysreg(vcpu->arch.ctxt.sys_regs[FPEXC32_EL2],
+			     fpexc32_el2);
+
+	vcpu->arch.flags |= KVM_ARM64_FP_ENABLED;
+
+	return true;
+}
+
 /*
  * Return true when we were able to fixup the guest exit and should return to
  * the guest, false when we should restore the host state and return to the
@@ -334,11 +388,23 @@ static bool __hyp_text fixup_guest_exit(struct kvm_vcpu *vcpu, u64 *exit_code)
 	 * same PC once the SError has been injected, and replay the
 	 * trapping instruction.
 	 */
-	if (*exit_code == ARM_EXCEPTION_TRAP && !__populate_fault_info(vcpu))
+	if (*exit_code != ARM_EXCEPTION_TRAP)
+		goto exit;
+
+	/*
+	 * We trap the first access to the FP/SIMD to save the host context
+	 * and restore the guest context lazily.
+	 * If FP/SIMD is not implemented, handle the trap and inject an
+	 * undefined instruction exception to the guest.
+	 */
+	if (system_supports_fpsimd() &&
+	    kvm_vcpu_trap_get_class(vcpu) == ESR_ELx_EC_FP_ASIMD)
+		return __hyp_switch_fpsimd(vcpu);
+
+	if (!__populate_fault_info(vcpu))
 		return true;
 
-	if (static_branch_unlikely(&vgic_v2_cpuif_trap) &&
-	    *exit_code == ARM_EXCEPTION_TRAP) {
+	if (static_branch_unlikely(&vgic_v2_cpuif_trap)) {
 		bool valid;
 
 		valid = kvm_vcpu_trap_get_class(vcpu) == ESR_ELx_EC_DABT_LOW &&
@@ -350,12 +416,8 @@ static bool __hyp_text fixup_guest_exit(struct kvm_vcpu *vcpu, u64 *exit_code)
 		if (valid) {
 			int ret = __vgic_v2_perform_cpuif_access(vcpu);
 
-			if (ret == 1) {
-				if (__skip_instr(vcpu))
-					return true;
-				else
-					*exit_code = ARM_EXCEPTION_TRAP;
-			}
+			if (ret ==  1 && __skip_instr(vcpu))
+				return true;
 
 			if (ret == -1) {
 				/* Promote an illegal access to an
@@ -368,23 +430,21 @@ static bool __hyp_text fixup_guest_exit(struct kvm_vcpu *vcpu, u64 *exit_code)
 					*vcpu_cpsr(vcpu) &= ~DBG_SPSR_SS;
 				*exit_code = ARM_EXCEPTION_EL1_SERROR;
 			}
+
+			goto exit;
 		}
 	}
 
 	if (static_branch_unlikely(&vgic_v3_cpuif_trap) &&
-	    *exit_code == ARM_EXCEPTION_TRAP &&
 	    (kvm_vcpu_trap_get_class(vcpu) == ESR_ELx_EC_SYS64 ||
 	     kvm_vcpu_trap_get_class(vcpu) == ESR_ELx_EC_CP15_32)) {
 		int ret = __vgic_v3_perform_cpuif_access(vcpu);
 
-		if (ret == 1) {
-			if (__skip_instr(vcpu))
-				return true;
-			else
-				*exit_code = ARM_EXCEPTION_TRAP;
-		}
+		if (ret == 1 && __skip_instr(vcpu))
+			return true;
 	}
 
+exit:
 	/* Return to the host kernel and handle the exit */
 	return false;
 }
@@ -394,7 +454,6 @@ int kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu)
 {
 	struct kvm_cpu_context *host_ctxt;
 	struct kvm_cpu_context *guest_ctxt;
-	bool fp_enabled;
 	u64 exit_code;
 
 	host_ctxt = vcpu->arch.host_cpu_context;
@@ -416,19 +475,14 @@ int kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu)
 		/* And we're baaack! */
 	} while (fixup_guest_exit(vcpu, &exit_code));
 
-	fp_enabled = fpsimd_enabled_vhe();
-
 	sysreg_save_guest_state_vhe(guest_ctxt);
 
 	__deactivate_traps(vcpu);
 
 	sysreg_restore_host_state_vhe(host_ctxt);
 
-	if (fp_enabled) {
-		__fpsimd_save_state(&guest_ctxt->gp_regs.fp_regs);
-		__fpsimd_restore_state(&host_ctxt->gp_regs.fp_regs);
+	if (vcpu->arch.flags & KVM_ARM64_FP_ENABLED)
 		__fpsimd_save_fpexc32(vcpu);
-	}
 
 	__debug_switch_to_host(vcpu);
 
@@ -440,7 +494,6 @@ int __hyp_text __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu)
 {
 	struct kvm_cpu_context *host_ctxt;
 	struct kvm_cpu_context *guest_ctxt;
-	bool fp_enabled;
 	u64 exit_code;
 
 	vcpu = kern_hyp_va(vcpu);
@@ -472,8 +525,6 @@ int __hyp_text __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu)
 		/* And we're baaack! */
 	} while (fixup_guest_exit(vcpu, &exit_code));
 
-	fp_enabled = __fpsimd_enabled_nvhe();
-
 	__sysreg_save_state_nvhe(guest_ctxt);
 	__sysreg32_save_state(vcpu);
 	__timer_disable_traps(vcpu);
@@ -484,11 +535,8 @@ int __hyp_text __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu)
 
 	__sysreg_restore_state_nvhe(host_ctxt);
 
-	if (fp_enabled) {
-		__fpsimd_save_state(&guest_ctxt->gp_regs.fp_regs);
-		__fpsimd_restore_state(&host_ctxt->gp_regs.fp_regs);
+	if (vcpu->arch.flags & KVM_ARM64_FP_ENABLED)
 		__fpsimd_save_fpexc32(vcpu);
-	}
 
 	/*
 	 * This must come after restoring the host sysregs, since a non-VHE

arch/arm64/kvm/hyp/sysreg-sr.c

@@ -196,7 +196,7 @@ void __hyp_text __sysreg32_save_state(struct kvm_vcpu *vcpu)
 	sysreg[DACR32_EL2] = read_sysreg(dacr32_el2);
 	sysreg[IFSR32_EL2] = read_sysreg(ifsr32_el2);
 
-	if (has_vhe() || vcpu->arch.debug_flags & KVM_ARM64_DEBUG_DIRTY)
+	if (has_vhe() || vcpu->arch.flags & KVM_ARM64_DEBUG_DIRTY)
 		sysreg[DBGVCR32_EL2] = read_sysreg(dbgvcr32_el2);
 }
 
@@ -218,7 +218,7 @@ void __hyp_text __sysreg32_restore_state(struct kvm_vcpu *vcpu)
 	write_sysreg(sysreg[DACR32_EL2], dacr32_el2);
 	write_sysreg(sysreg[IFSR32_EL2], ifsr32_el2);
 
-	if (has_vhe() || vcpu->arch.debug_flags & KVM_ARM64_DEBUG_DIRTY)
+	if (has_vhe() || vcpu->arch.flags & KVM_ARM64_DEBUG_DIRTY)
 		write_sysreg(sysreg[DBGVCR32_EL2], dbgvcr32_el2);
 }
 

arch/arm64/kvm/sys_regs.c

@@ -31,7 +31,6 @@
 #include <asm/debug-monitors.h>
 #include <asm/esr.h>
 #include <asm/kvm_arm.h>
-#include <asm/kvm_asm.h>
 #include <asm/kvm_coproc.h>
 #include <asm/kvm_emulate.h>
 #include <asm/kvm_host.h>
@@ -338,7 +337,7 @@ static bool trap_debug_regs(struct kvm_vcpu *vcpu,
 {
 	if (p->is_write) {
 		vcpu_write_sys_reg(vcpu, p->regval, r->reg);
-		vcpu->arch.debug_flags |= KVM_ARM64_DEBUG_DIRTY;
+		vcpu->arch.flags |= KVM_ARM64_DEBUG_DIRTY;
 	} else {
 		p->regval = vcpu_read_sys_reg(vcpu, r->reg);
 	}
@@ -369,7 +368,7 @@ static void reg_to_dbg(struct kvm_vcpu *vcpu,
 	}
 
 	*dbg_reg = val;
-	vcpu->arch.debug_flags |= KVM_ARM64_DEBUG_DIRTY;
+	vcpu->arch.flags |= KVM_ARM64_DEBUG_DIRTY;
 }
 
 static void dbg_to_reg(struct kvm_vcpu *vcpu,
@@ -1441,7 +1440,7 @@ static bool trap_debug32(struct kvm_vcpu *vcpu,
 {
 	if (p->is_write) {
 		vcpu_cp14(vcpu, r->reg) = p->regval;
-		vcpu->arch.debug_flags |= KVM_ARM64_DEBUG_DIRTY;
+		vcpu->arch.flags |= KVM_ARM64_DEBUG_DIRTY;
 	} else {
 		p->regval = vcpu_cp14(vcpu, r->reg);
 	}
@@ -1473,7 +1472,7 @@ static bool trap_xvr(struct kvm_vcpu *vcpu,
 		val |= p->regval << 32;
 		*dbg_reg = val;
 
-		vcpu->arch.debug_flags |= KVM_ARM64_DEBUG_DIRTY;
+		vcpu->arch.flags |= KVM_ARM64_DEBUG_DIRTY;
 	} else {
 		p->regval = *dbg_reg >> 32;
 	}

include/kvm/arm_vgic.h

@@ -28,7 +28,7 @@
 
 #include <linux/irqchip/arm-gic-v4.h>
 
-#define VGIC_V3_MAX_CPUS	255
+#define VGIC_V3_MAX_CPUS	512
 #define VGIC_V2_MAX_CPUS	8
 #define VGIC_NR_IRQS_LEGACY     256
 #define VGIC_NR_SGIS		16
@@ -201,6 +201,14 @@ struct vgic_its {
 
 struct vgic_state_iter;
 
+struct vgic_redist_region {
+	u32 index;
+	gpa_t base;
+	u32 count; /* number of redistributors or 0 if single region */
+	u32 free_index; /* index of the next free redistributor */
+	struct list_head list;
+};
+
 struct vgic_dist {
 	bool			in_kernel;
 	bool			ready;
@@ -220,10 +228,7 @@ struct vgic_dist {
 		/* either a GICv2 CPU interface */
 		gpa_t			vgic_cpu_base;
 		/* or a number of GICv3 redistributor regions */
-		struct {
-			gpa_t		vgic_redist_base;
-			gpa_t		vgic_redist_free_offset;
-		};
+		struct list_head rd_regions;
 	};
 
 	/* distributor enabled */
@@ -311,6 +316,7 @@ struct vgic_cpu {
 	 */
 	struct vgic_io_device	rd_iodev;
 	struct vgic_io_device	sgi_iodev;
+	struct vgic_redist_region *rdreg;
 
 	/* Contains the attributes and gpa of the LPI pending tables. */
 	u64 pendbaser;
@@ -332,7 +338,6 @@ void kvm_vgic_early_init(struct kvm *kvm);
 int kvm_vgic_vcpu_init(struct kvm_vcpu *vcpu);
 int kvm_vgic_create(struct kvm *kvm, u32 type);
 void kvm_vgic_destroy(struct kvm *kvm);
-void kvm_vgic_vcpu_early_init(struct kvm_vcpu *vcpu);
 void kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu);
 int kvm_vgic_map_resources(struct kvm *kvm);
 int kvm_vgic_hyp_init(void);

include/linux/kvm_host.h

@@ -1273,4 +1273,13 @@ static inline long kvm_arch_vcpu_async_ioctl(struct file *filp,
 void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm,
 		unsigned long start, unsigned long end);
 
+#ifdef CONFIG_HAVE_KVM_VCPU_RUN_PID_CHANGE
+int kvm_arch_vcpu_run_pid_change(struct kvm_vcpu *vcpu);
+#else
+static inline int kvm_arch_vcpu_run_pid_change(struct kvm_vcpu *vcpu)
+{
+	return 0;
+}
+#endif /* CONFIG_HAVE_KVM_VCPU_RUN_PID_CHANGE */
+
 #endif

include/linux/sched.h

@@ -1618,6 +1618,12 @@ static inline void clear_tsk_thread_flag(struct task_struct *tsk, int flag)
 	clear_ti_thread_flag(task_thread_info(tsk), flag);
 }
 
+static inline void update_tsk_thread_flag(struct task_struct *tsk, int flag,
+					  bool value)
+{
+	update_ti_thread_flag(task_thread_info(tsk), flag, value);
+}
+
 static inline int test_and_set_tsk_thread_flag(struct task_struct *tsk, int flag)
 {
 	return test_and_set_ti_thread_flag(task_thread_info(tsk), flag);

include/linux/thread_info.h

@@ -60,6 +60,15 @@ static inline void clear_ti_thread_flag(struct thread_info *ti, int flag)
 	clear_bit(flag, (unsigned long *)&ti->flags);
 }
 
+static inline void update_ti_thread_flag(struct thread_info *ti, int flag,
+					 bool value)
+{
+	if (value)
+		set_ti_thread_flag(ti, flag);
+	else
+		clear_ti_thread_flag(ti, flag);
+}
+
 static inline int test_and_set_ti_thread_flag(struct thread_info *ti, int flag)
 {
 	return test_and_set_bit(flag, (unsigned long *)&ti->flags);
@@ -79,6 +88,8 @@ static inline int test_ti_thread_flag(struct thread_info *ti, int flag)
 	set_ti_thread_flag(current_thread_info(), flag)
 #define clear_thread_flag(flag) \
 	clear_ti_thread_flag(current_thread_info(), flag)
+#define update_thread_flag(flag, value) \
+	update_ti_thread_flag(current_thread_info(), flag, value)
 #define test_and_set_thread_flag(flag) \
 	test_and_set_ti_thread_flag(current_thread_info(), flag)
 #define test_and_clear_thread_flag(flag) \

virt/kvm/Kconfig

@@ -54,3 +54,6 @@ config HAVE_KVM_IRQ_BYPASS
 
 config HAVE_KVM_VCPU_ASYNC_IOCTL
        bool
+
+config HAVE_KVM_VCPU_RUN_PID_CHANGE
+       bool

virt/kvm/arm/arm.c

@@ -16,6 +16,7 @@
  * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  */
 
+#include <linux/bug.h>
 #include <linux/cpu_pm.h>
 #include <linux/errno.h>
 #include <linux/err.h>
@@ -41,6 +42,7 @@
 #include <asm/mman.h>
 #include <asm/tlbflush.h>
 #include <asm/cacheflush.h>
+#include <asm/cpufeature.h>
 #include <asm/virt.h>
 #include <asm/kvm_arm.h>
 #include <asm/kvm_asm.h>
@@ -290,7 +292,6 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id)
 
 void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu)
 {
-	kvm_vgic_vcpu_early_init(vcpu);
 }
 
 void kvm_arch_vcpu_free(struct kvm_vcpu *vcpu)
@@ -363,10 +364,12 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 	kvm_vgic_load(vcpu);
 	kvm_timer_vcpu_load(vcpu);
 	kvm_vcpu_load_sysregs(vcpu);
+	kvm_arch_vcpu_load_fp(vcpu);
 }
 
 void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
 {
+	kvm_arch_vcpu_put_fp(vcpu);
 	kvm_vcpu_put_sysregs(vcpu);
 	kvm_timer_vcpu_put(vcpu);
 	kvm_vgic_put(vcpu);
@@ -678,9 +681,6 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
 		 */
 		preempt_disable();
 
-		/* Flush FP/SIMD state that can't survive guest entry/exit */
-		kvm_fpsimd_flush_cpu_state();
-
 		kvm_pmu_flush_hwstate(vcpu);
 
 		local_irq_disable();
@@ -778,6 +778,8 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
 		if (static_branch_unlikely(&userspace_irqchip_in_use))
 			kvm_timer_sync_hwstate(vcpu);
 
+		kvm_arch_vcpu_ctxsync_fp(vcpu);
+
 		/*
 		 * We may have taken a host interrupt in HYP mode (ie
 		 * while executing the guest). This interrupt is still
@@ -1570,6 +1572,11 @@ int kvm_arch_init(void *opaque)
 		return -ENODEV;
 	}
 
+	if (!kvm_arch_check_sve_has_vhe()) {
+		kvm_pr_unimpl("SVE system without VHE unsupported.  Broken cpu?");
+		return -ENODEV;
+	}
+
 	for_each_online_cpu(cpu) {
 		smp_call_function_single(cpu, check_kvm_target_cpu, &ret, 1);
 		if (ret < 0) {

virt/kvm/arm/vgic/vgic-init.c

@@ -44,7 +44,7 @@
  *
  * CPU Interface:
  *
- * - kvm_vgic_vcpu_early_init(): initialization of static data that
+ * - kvm_vgic_vcpu_init(): initialization of static data that
  *   doesn't depend on any sizing information or emulation type. No
  *   allocation is allowed there.
  */
@@ -67,46 +67,6 @@ void kvm_vgic_early_init(struct kvm *kvm)
 	spin_lock_init(&dist->lpi_list_lock);
 }
 
-/**
- * kvm_vgic_vcpu_early_init() - Initialize static VGIC VCPU data structures
- * @vcpu: The VCPU whose VGIC data structures whould be initialized
- *
- * Only do initialization, but do not actually enable the VGIC CPU interface
- * yet.
- */
-void kvm_vgic_vcpu_early_init(struct kvm_vcpu *vcpu)
-{
-	struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
-	int i;
-
-	INIT_LIST_HEAD(&vgic_cpu->ap_list_head);
-	spin_lock_init(&vgic_cpu->ap_list_lock);
-
-	/*
-	 * Enable and configure all SGIs to be edge-triggered and
-	 * configure all PPIs as level-triggered.
-	 */
-	for (i = 0; i < VGIC_NR_PRIVATE_IRQS; i++) {
-		struct vgic_irq *irq = &vgic_cpu->private_irqs[i];
-
-		INIT_LIST_HEAD(&irq->ap_list);
-		spin_lock_init(&irq->irq_lock);
-		irq->intid = i;
-		irq->vcpu = NULL;
-		irq->target_vcpu = vcpu;
-		irq->targets = 1U << vcpu->vcpu_id;
-		kref_init(&irq->refcount);
-		if (vgic_irq_is_sgi(i)) {
-			/* SGIs */
-			irq->enabled = 1;
-			irq->config = VGIC_CONFIG_EDGE;
-		} else {
-			/* PPIs */
-			irq->config = VGIC_CONFIG_LEVEL;
-		}
-	}
-}
-
 /* CREATION */
 
 /**
@@ -167,8 +127,11 @@ int kvm_vgic_create(struct kvm *kvm, u32 type)
 	kvm->arch.vgic.vgic_model = type;
 
 	kvm->arch.vgic.vgic_dist_base = VGIC_ADDR_UNDEF;
-	kvm->arch.vgic.vgic_cpu_base = VGIC_ADDR_UNDEF;
-	kvm->arch.vgic.vgic_redist_base = VGIC_ADDR_UNDEF;
+
+	if (type == KVM_DEV_TYPE_ARM_VGIC_V2)
+		kvm->arch.vgic.vgic_cpu_base = VGIC_ADDR_UNDEF;
+	else
+		INIT_LIST_HEAD(&kvm->arch.vgic.rd_regions);
 
 out_unlock:
 	for (; vcpu_lock_idx >= 0; vcpu_lock_idx--) {
@@ -221,13 +184,50 @@ static int kvm_vgic_dist_init(struct kvm *kvm, unsigned int nr_spis)
 }
 
 /**
- * kvm_vgic_vcpu_init() - Register VCPU-specific KVM iodevs
+ * kvm_vgic_vcpu_init() - Initialize static VGIC VCPU data
+ * structures and register VCPU-specific KVM iodevs
+ *
  * @vcpu: pointer to the VCPU being created and initialized
+ *
+ * Only do initialization, but do not actually enable the
+ * VGIC CPU interface
  */
 int kvm_vgic_vcpu_init(struct kvm_vcpu *vcpu)
 {
-	int ret = 0;
+	struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
 	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
+	int ret = 0;
+	int i;
+
+	vgic_cpu->rd_iodev.base_addr = VGIC_ADDR_UNDEF;
+	vgic_cpu->sgi_iodev.base_addr = VGIC_ADDR_UNDEF;
+
+	INIT_LIST_HEAD(&vgic_cpu->ap_list_head);
+	spin_lock_init(&vgic_cpu->ap_list_lock);
+
+	/*
+	 * Enable and configure all SGIs to be edge-triggered and
+	 * configure all PPIs as level-triggered.
+	 */
+	for (i = 0; i < VGIC_NR_PRIVATE_IRQS; i++) {
+		struct vgic_irq *irq = &vgic_cpu->private_irqs[i];
+
+		INIT_LIST_HEAD(&irq->ap_list);
+		spin_lock_init(&irq->irq_lock);
+		irq->intid = i;
+		irq->vcpu = NULL;
+		irq->target_vcpu = vcpu;
+		irq->targets = 1U << vcpu->vcpu_id;
+		kref_init(&irq->refcount);
+		if (vgic_irq_is_sgi(i)) {
+			/* SGIs */
+			irq->enabled = 1;
+			irq->config = VGIC_CONFIG_EDGE;
+		} else {
+			/* PPIs */
+			irq->config = VGIC_CONFIG_LEVEL;
+		}
+	}
 
 	if (!irqchip_in_kernel(vcpu->kvm))
 		return 0;
@@ -303,13 +303,23 @@ int vgic_init(struct kvm *kvm)
 static void kvm_vgic_dist_destroy(struct kvm *kvm)
 {
 	struct vgic_dist *dist = &kvm->arch.vgic;
+	struct vgic_redist_region *rdreg, *next;
 
 	dist->ready = false;
 	dist->initialized = false;
 
 	kfree(dist->spis);
+	dist->spis = NULL;
 	dist->nr_spis = 0;
 
+	if (kvm->arch.vgic.vgic_model == KVM_DEV_TYPE_ARM_VGIC_V3) {
+		list_for_each_entry_safe(rdreg, next, &dist->rd_regions, list) {
+			list_del(&rdreg->list);
+			kfree(rdreg);
+		}
+		INIT_LIST_HEAD(&dist->rd_regions);
+	}
+
 	if (vgic_supports_direct_msis(kvm))
 		vgic_v4_teardown(kvm);
 }

virt/kvm/arm/vgic/vgic-kvm-device.c

@@ -66,6 +66,7 @@ int kvm_vgic_addr(struct kvm *kvm, unsigned long type, u64 *addr, bool write)
 	int r = 0;
 	struct vgic_dist *vgic = &kvm->arch.vgic;
 	phys_addr_t *addr_ptr, alignment;
+	u64 undef_value = VGIC_ADDR_UNDEF;
 
 	mutex_lock(&kvm->lock);
 	switch (type) {
@@ -84,16 +85,61 @@ int kvm_vgic_addr(struct kvm *kvm, unsigned long type, u64 *addr, bool write)
 		addr_ptr = &vgic->vgic_dist_base;
 		alignment = SZ_64K;
 		break;
-	case KVM_VGIC_V3_ADDR_TYPE_REDIST:
+	case KVM_VGIC_V3_ADDR_TYPE_REDIST: {
+		struct vgic_redist_region *rdreg;
+
 		r = vgic_check_type(kvm, KVM_DEV_TYPE_ARM_VGIC_V3);
 		if (r)
 			break;
 		if (write) {
-			r = vgic_v3_set_redist_base(kvm, *addr);
+			r = vgic_v3_set_redist_base(kvm, 0, *addr, 0);
 			goto out;
 		}
-		addr_ptr = &vgic->vgic_redist_base;
+		rdreg = list_first_entry(&vgic->rd_regions,
+					 struct vgic_redist_region, list);
+		if (!rdreg)
+			addr_ptr = &undef_value;
+		else
+			addr_ptr = &rdreg->base;
 		break;
+	}
+	case KVM_VGIC_V3_ADDR_TYPE_REDIST_REGION:
+	{
+		struct vgic_redist_region *rdreg;
+		u8 index;
+
+		r = vgic_check_type(kvm, KVM_DEV_TYPE_ARM_VGIC_V3);
+		if (r)
+			break;
+
+		index = *addr & KVM_VGIC_V3_RDIST_INDEX_MASK;
+
+		if (write) {
+			gpa_t base = *addr & KVM_VGIC_V3_RDIST_BASE_MASK;
+			u32 count = (*addr & KVM_VGIC_V3_RDIST_COUNT_MASK)
+					>> KVM_VGIC_V3_RDIST_COUNT_SHIFT;
+			u8 flags = (*addr & KVM_VGIC_V3_RDIST_FLAGS_MASK)
+					>> KVM_VGIC_V3_RDIST_FLAGS_SHIFT;
+
+			if (!count || flags)
+				r = -EINVAL;
+			else
+				r = vgic_v3_set_redist_base(kvm, index,
+							    base, count);
+			goto out;
+		}
+
+		rdreg = vgic_v3_rdist_region_from_index(kvm, index);
+		if (!rdreg) {
+			r = -ENOENT;
+			goto out;
+		}
+
+		*addr = index;
+		*addr |= rdreg->base;
+		*addr |= (u64)rdreg->count << KVM_VGIC_V3_RDIST_COUNT_SHIFT;
+		goto out;
+	}
 	default:
 		r = -ENODEV;
 	}
@@ -665,6 +711,7 @@ static int vgic_v3_has_attr(struct kvm_device *dev,
 		switch (attr->attr) {
 		case KVM_VGIC_V3_ADDR_TYPE_DIST:
 		case KVM_VGIC_V3_ADDR_TYPE_REDIST:
+		case KVM_VGIC_V3_ADDR_TYPE_REDIST_REGION:
 			return 0;
 		}
 		break;

virt/kvm/arm/vgic/vgic-mmio-v3.c

@@ -184,12 +184,17 @@ static unsigned long vgic_mmio_read_v3r_typer(struct kvm_vcpu *vcpu,
 					      gpa_t addr, unsigned int len)
 {
 	unsigned long mpidr = kvm_vcpu_get_mpidr_aff(vcpu);
+	struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
+	struct vgic_redist_region *rdreg = vgic_cpu->rdreg;
 	int target_vcpu_id = vcpu->vcpu_id;
+	gpa_t last_rdist_typer = rdreg->base + GICR_TYPER +
+			(rdreg->free_index - 1) * KVM_VGIC_V3_REDIST_SIZE;
 	u64 value;
 
 	value = (u64)(mpidr & GENMASK(23, 0)) << 32;
 	value |= ((target_vcpu_id & 0xffff) << 8);
-	if (target_vcpu_id == atomic_read(&vcpu->kvm->online_vcpus) - 1)
+
+	if (addr == last_rdist_typer)
 		value |= GICR_TYPER_LAST;
 	if (vgic_has_its(vcpu->kvm))
 		value |= GICR_TYPER_PLPIS;
@@ -580,24 +585,32 @@ int vgic_register_redist_iodev(struct kvm_vcpu *vcpu)
 {
 	struct kvm *kvm = vcpu->kvm;
 	struct vgic_dist *vgic = &kvm->arch.vgic;
+	struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
 	struct vgic_io_device *rd_dev = &vcpu->arch.vgic_cpu.rd_iodev;
 	struct vgic_io_device *sgi_dev = &vcpu->arch.vgic_cpu.sgi_iodev;
+	struct vgic_redist_region *rdreg;
 	gpa_t rd_base, sgi_base;
 	int ret;
 
+	if (!IS_VGIC_ADDR_UNDEF(vgic_cpu->rd_iodev.base_addr))
+		return 0;
+
 	/*
 	 * We may be creating VCPUs before having set the base address for the
 	 * redistributor region, in which case we will come back to this
 	 * function for all VCPUs when the base address is set.  Just return
 	 * without doing any work for now.
 	 */
-	if (IS_VGIC_ADDR_UNDEF(vgic->vgic_redist_base))
+	rdreg = vgic_v3_rdist_free_slot(&vgic->rd_regions);
+	if (!rdreg)
 		return 0;
 
 	if (!vgic_v3_check_base(kvm))
 		return -EINVAL;
 
-	rd_base = vgic->vgic_redist_base + vgic->vgic_redist_free_offset;
+	vgic_cpu->rdreg = rdreg;
+
+	rd_base = rdreg->base + rdreg->free_index * KVM_VGIC_V3_REDIST_SIZE;
 	sgi_base = rd_base + SZ_64K;
 
 	kvm_iodevice_init(&rd_dev->dev, &kvm_io_gic_ops);
@@ -631,7 +644,7 @@ int vgic_register_redist_iodev(struct kvm_vcpu *vcpu)
 		goto out;
 	}
 
-	vgic->vgic_redist_free_offset += 2 * SZ_64K;
+	rdreg->free_index++;
 out:
 	mutex_unlock(&kvm->slots_lock);
 	return ret;
@@ -670,22 +683,95 @@ static int vgic_register_all_redist_iodevs(struct kvm *kvm)
 	return ret;
 }
 
-int vgic_v3_set_redist_base(struct kvm *kvm, u64 addr)
+/**
+ * vgic_v3_insert_redist_region - Insert a new redistributor region
+ *
+ * Performs various checks before inserting the rdist region in the list.
+ * Those tests depend on whether the size of the rdist region is known
+ * (ie. count != 0). The list is sorted by rdist region index.
+ *
+ * @kvm: kvm handle
+ * @index: redist region index
+ * @base: base of the new rdist region
+ * @count: number of redistributors the region is made of (0 in the old style
+ * single region, whose size is induced from the number of vcpus)
+ *
+ * Return 0 on success, < 0 otherwise
+ */
+static int vgic_v3_insert_redist_region(struct kvm *kvm, uint32_t index,
+					gpa_t base, uint32_t count)
 {
-	struct vgic_dist *vgic = &kvm->arch.vgic;
+	struct vgic_dist *d = &kvm->arch.vgic;
+	struct vgic_redist_region *rdreg;
+	struct list_head *rd_regions = &d->rd_regions;
+	size_t size = count * KVM_VGIC_V3_REDIST_SIZE;
 	int ret;
 
-	/* vgic_check_ioaddr makes sure we don't do this twice */
-	ret = vgic_check_ioaddr(kvm, &vgic->vgic_redist_base, addr, SZ_64K);
-	if (ret)
-		return ret;
+	/* single rdist region already set ?*/
+	if (!count && !list_empty(rd_regions))
+		return -EINVAL;
 
-	vgic->vgic_redist_base = addr;
-	if (!vgic_v3_check_base(kvm)) {
-		vgic->vgic_redist_base = VGIC_ADDR_UNDEF;
+	/* cross the end of memory ? */
+	if (base + size < base)
 		return -EINVAL;
+
+	if (list_empty(rd_regions)) {
+		if (index != 0)
+			return -EINVAL;
+	} else {
+		rdreg = list_last_entry(rd_regions,
+					struct vgic_redist_region, list);
+		if (index != rdreg->index + 1)
+			return -EINVAL;
+
+		/* Cannot add an explicitly sized regions after legacy region */
+		if (!rdreg->count)
+			return -EINVAL;
 	}
 
+	/*
+	 * For legacy single-region redistributor regions (!count),
+	 * check that the redistributor region does not overlap with the
+	 * distributor's address space.
+	 */
+	if (!count && !IS_VGIC_ADDR_UNDEF(d->vgic_dist_base) &&
+		vgic_dist_overlap(kvm, base, size))
+		return -EINVAL;
+
+	/* collision with any other rdist region? */
+	if (vgic_v3_rdist_overlap(kvm, base, size))
+		return -EINVAL;
+
+	rdreg = kzalloc(sizeof(*rdreg), GFP_KERNEL);
+	if (!rdreg)
+		return -ENOMEM;
+
+	rdreg->base = VGIC_ADDR_UNDEF;
+
+	ret = vgic_check_ioaddr(kvm, &rdreg->base, base, SZ_64K);
+	if (ret)
+		goto free;
+
+	rdreg->base = base;
+	rdreg->count = count;
+	rdreg->free_index = 0;
+	rdreg->index = index;
+
+	list_add_tail(&rdreg->list, rd_regions);
+	return 0;
+free:
+	kfree(rdreg);
+	return ret;
+}
+
+int vgic_v3_set_redist_base(struct kvm *kvm, u32 index, u64 addr, u32 count)
+{
+	int ret;
+
+	ret = vgic_v3_insert_redist_region(kvm, index, addr, count);
+	if (ret)
+		return ret;
+
 	/*
 	 * Register iodevs for each existing VCPU.  Adding more VCPUs
 	 * afterwards will register the iodevs when needed.

virt/kvm/arm/vgic/vgic-v3.c

@@ -419,6 +419,29 @@ int vgic_v3_save_pending_tables(struct kvm *kvm)
 	return 0;
 }
 
+/**
+ * vgic_v3_rdist_overlap - check if a region overlaps with any
+ * existing redistributor region
+ *
+ * @kvm: kvm handle
+ * @base: base of the region
+ * @size: size of region
+ *
+ * Return: true if there is an overlap
+ */
+bool vgic_v3_rdist_overlap(struct kvm *kvm, gpa_t base, size_t size)
+{
+	struct vgic_dist *d = &kvm->arch.vgic;
+	struct vgic_redist_region *rdreg;
+
+	list_for_each_entry(rdreg, &d->rd_regions, list) {
+		if ((base + size > rdreg->base) &&
+			(base < rdreg->base + vgic_v3_rd_region_size(kvm, rdreg)))
+			return true;
+	}
+	return false;
+}
+
 /*
  * Check for overlapping regions and for regions crossing the end of memory
  * for base addresses which have already been set.
@@ -426,41 +449,83 @@ int vgic_v3_save_pending_tables(struct kvm *kvm)
 bool vgic_v3_check_base(struct kvm *kvm)
 {
 	struct vgic_dist *d = &kvm->arch.vgic;
-	gpa_t redist_size = KVM_VGIC_V3_REDIST_SIZE;
-
-	redist_size *= atomic_read(&kvm->online_vcpus);
+	struct vgic_redist_region *rdreg;
 
 	if (!IS_VGIC_ADDR_UNDEF(d->vgic_dist_base) &&
 	    d->vgic_dist_base + KVM_VGIC_V3_DIST_SIZE < d->vgic_dist_base)
 		return false;
 
-	if (!IS_VGIC_ADDR_UNDEF(d->vgic_redist_base) &&
-	    d->vgic_redist_base + redist_size < d->vgic_redist_base)
-		return false;
+	list_for_each_entry(rdreg, &d->rd_regions, list) {
+		if (rdreg->base + vgic_v3_rd_region_size(kvm, rdreg) <
+			rdreg->base)
+			return false;
+	}
 
-	/* Both base addresses must be set to check if they overlap */
-	if (IS_VGIC_ADDR_UNDEF(d->vgic_dist_base) ||
-	    IS_VGIC_ADDR_UNDEF(d->vgic_redist_base))
+	if (IS_VGIC_ADDR_UNDEF(d->vgic_dist_base))
 		return true;
 
-	if (d->vgic_dist_base + KVM_VGIC_V3_DIST_SIZE <= d->vgic_redist_base)
-		return true;
-	if (d->vgic_redist_base + redist_size <= d->vgic_dist_base)
-		return true;
+	return !vgic_v3_rdist_overlap(kvm, d->vgic_dist_base,
+				      KVM_VGIC_V3_DIST_SIZE);
+}
 
-	return false;
+/**
+ * vgic_v3_rdist_free_slot - Look up registered rdist regions and identify one
+ * which has free space to put a new rdist region.
+ *
+ * @rd_regions: redistributor region list head
+ *
+ * A redistributor regions maps n redistributors, n = region size / (2 x 64kB).
+ * Stride between redistributors is 0 and regions are filled in the index order.
+ *
+ * Return: the redist region handle, if any, that has space to map a new rdist
+ * region.
+ */
+struct vgic_redist_region *vgic_v3_rdist_free_slot(struct list_head *rd_regions)
+{
+	struct vgic_redist_region *rdreg;
+
+	list_for_each_entry(rdreg, rd_regions, list) {
+		if (!vgic_v3_redist_region_full(rdreg))
+			return rdreg;
+	}
+	return NULL;
 }
 
+struct vgic_redist_region *vgic_v3_rdist_region_from_index(struct kvm *kvm,
+							   u32 index)
+{
+	struct list_head *rd_regions = &kvm->arch.vgic.rd_regions;
+	struct vgic_redist_region *rdreg;
+
+	list_for_each_entry(rdreg, rd_regions, list) {
+		if (rdreg->index == index)
+			return rdreg;
+	}
+	return NULL;
+}
+
+
 int vgic_v3_map_resources(struct kvm *kvm)
 {
-	int ret = 0;
 	struct vgic_dist *dist = &kvm->arch.vgic;
+	struct kvm_vcpu *vcpu;
+	int ret = 0;
+	int c;
 
 	if (vgic_ready(kvm))
 		goto out;
 
-	if (IS_VGIC_ADDR_UNDEF(dist->vgic_dist_base) ||
-	    IS_VGIC_ADDR_UNDEF(dist->vgic_redist_base)) {
+	kvm_for_each_vcpu(c, vcpu, kvm) {
+		struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
+
+		if (IS_VGIC_ADDR_UNDEF(vgic_cpu->rd_iodev.base_addr)) {
+			kvm_debug("vcpu %d redistributor base not set\n", c);
+			ret = -ENXIO;
+			goto out;
+		}
+	}
+
+	if (IS_VGIC_ADDR_UNDEF(dist->vgic_dist_base)) {
 		kvm_err("Need to set vgic distributor addresses first\n");
 		ret = -ENXIO;
 		goto out;

virt/kvm/arm/vgic/vgic.h

@@ -96,6 +96,13 @@
 /* we only support 64 kB translation table page size */
 #define KVM_ITS_L1E_ADDR_MASK		GENMASK_ULL(51, 16)
 
+#define KVM_VGIC_V3_RDIST_INDEX_MASK	GENMASK_ULL(11, 0)
+#define KVM_VGIC_V3_RDIST_FLAGS_MASK	GENMASK_ULL(15, 12)
+#define KVM_VGIC_V3_RDIST_FLAGS_SHIFT	12
+#define KVM_VGIC_V3_RDIST_BASE_MASK	GENMASK_ULL(51, 16)
+#define KVM_VGIC_V3_RDIST_COUNT_MASK	GENMASK_ULL(63, 52)
+#define KVM_VGIC_V3_RDIST_COUNT_SHIFT	52
+
 /* Requires the irq_lock to be held by the caller. */
 static inline bool irq_is_pending(struct vgic_irq *irq)
 {
@@ -215,7 +222,7 @@ int vgic_v3_probe(const struct gic_kvm_info *info);
 int vgic_v3_map_resources(struct kvm *kvm);
 int vgic_v3_lpi_sync_pending_status(struct kvm *kvm, struct vgic_irq *irq);
 int vgic_v3_save_pending_tables(struct kvm *kvm);
-int vgic_v3_set_redist_base(struct kvm *kvm, u64 addr);
+int vgic_v3_set_redist_base(struct kvm *kvm, u32 index, u64 addr, u32 count);
 int vgic_register_redist_iodev(struct kvm_vcpu *vcpu);
 bool vgic_v3_check_base(struct kvm *kvm);
 
@@ -265,6 +272,39 @@ static inline int vgic_v3_max_apr_idx(struct kvm_vcpu *vcpu)
 	}
 }
 
+static inline bool
+vgic_v3_redist_region_full(struct vgic_redist_region *region)
+{
+	if (!region->count)
+		return false;
+
+	return (region->free_index >= region->count);
+}
+
+struct vgic_redist_region *vgic_v3_rdist_free_slot(struct list_head *rdregs);
+
+static inline size_t
+vgic_v3_rd_region_size(struct kvm *kvm, struct vgic_redist_region *rdreg)
+{
+	if (!rdreg->count)
+		return atomic_read(&kvm->online_vcpus) * KVM_VGIC_V3_REDIST_SIZE;
+	else
+		return rdreg->count * KVM_VGIC_V3_REDIST_SIZE;
+}
+
+struct vgic_redist_region *vgic_v3_rdist_region_from_index(struct kvm *kvm,
+							   u32 index);
+
+bool vgic_v3_rdist_overlap(struct kvm *kvm, gpa_t base, size_t size);
+
+static inline bool vgic_dist_overlap(struct kvm *kvm, gpa_t base, size_t size)
+{
+	struct vgic_dist *d = &kvm->arch.vgic;
+
+	return (base + size > d->vgic_dist_base) &&
+		(base < d->vgic_dist_base + KVM_VGIC_V3_DIST_SIZE);
+}
+
 int vgic_its_resolve_lpi(struct kvm *kvm, struct vgic_its *its,
 			 u32 devid, u32 eventid, struct vgic_irq **irq);
 struct vgic_its *vgic_msi_to_its(struct kvm *kvm, struct kvm_msi *msi);

virt/kvm/kvm_main.c

@@ -2568,8 +2568,13 @@ static long kvm_vcpu_ioctl(struct file *filp,
 		oldpid = rcu_access_pointer(vcpu->pid);
 		if (unlikely(oldpid != current->pids[PIDTYPE_PID].pid)) {
 			/* The thread running this VCPU changed. */
-			struct pid *newpid = get_task_pid(current, PIDTYPE_PID);
+			struct pid *newpid;
 
+			r = kvm_arch_vcpu_run_pid_change(vcpu);
+			if (r)
+				break;
+
+			newpid = get_task_pid(current, PIDTYPE_PID);
 			rcu_assign_pointer(vcpu->pid, newpid);
 			if (oldpid)
 				synchronize_rcu();