Merge branch 'kvm-async-pf-int' into HEAD

arch/x86/Kconfig

@@ -802,6 +802,7 @@ config KVM_GUEST
 	depends on PARAVIRT
 	select PARAVIRT_CLOCK
 	select ARCH_CPUIDLE_HALTPOLL
+	select X86_HV_CALLBACK_VECTOR
 	default y
 	help
 	  This option enables various optimizations for running under the KVM

arch/x86/include/asm/idtentry.h

@@ -647,6 +647,10 @@ DECLARE_IDTENTRY_SYSVEC(HYPERVISOR_CALLBACK_VECTOR,	sysvec_acrn_hv_callback);
 DECLARE_IDTENTRY_SYSVEC(HYPERVISOR_CALLBACK_VECTOR,	sysvec_xen_hvm_callback);
 #endif
 
+#ifdef CONFIG_KVM_GUEST
+DECLARE_IDTENTRY_SYSVEC(HYPERVISOR_CALLBACK_VECTOR,	sysvec_kvm_asyncpf_interrupt);
+#endif
+
 #undef X86_TRAP_OTHER
 
 #endif

arch/x86/include/asm/kvm_para.h

@@ -4,6 +4,7 @@
 
 #include <asm/processor.h>
 #include <asm/alternative.h>
+#include <linux/interrupt.h>
 #include <uapi/asm/kvm_para.h>
 
 extern void kvmclock_init(void);

arch/x86/kernel/kvm.c

@@ -9,6 +9,7 @@
 
 #include <linux/context_tracking.h>
 #include <linux/init.h>
+#include <linux/irq.h>
 #include <linux/kernel.h>
 #include <linux/kvm_para.h>
 #include <linux/cpu.h>
@@ -232,16 +233,11 @@ EXPORT_SYMBOL_GPL(kvm_read_and_reset_apf_flags);
 
 noinstr bool __kvm_handle_async_pf(struct pt_regs *regs, u32 token)
 {
-	u32 reason = kvm_read_and_reset_apf_flags();
+	u32 flags = kvm_read_and_reset_apf_flags();
 	bool rcu_exit;
 
-	switch (reason) {
-	case KVM_PV_REASON_PAGE_NOT_PRESENT:
-	case KVM_PV_REASON_PAGE_READY:
-		break;
-	default:
+	if (!flags)
 		return false;
-	}
 
 	rcu_exit = idtentry_enter_cond_rcu(regs);
 	instrumentation_begin();
@@ -254,13 +250,13 @@ noinstr bool __kvm_handle_async_pf(struct pt_regs *regs, u32 token)
 	if (unlikely(!(regs->flags & X86_EFLAGS_IF)))
 		panic("Host injected async #PF in interrupt disabled region\n");
 
-	if (reason == KVM_PV_REASON_PAGE_NOT_PRESENT) {
+	if (flags & KVM_PV_REASON_PAGE_NOT_PRESENT) {
 		if (unlikely(!(user_mode(regs))))
 			panic("Host injected async #PF in kernel mode\n");
 		/* Page is swapped out by the host. */
 		kvm_async_pf_task_wait_schedule(token);
 	} else {
-		kvm_async_pf_task_wake(token);
+		WARN_ONCE(1, "Unexpected async PF flags: %x\n", flags);
 	}
 
 	instrumentation_end();
@@ -268,6 +264,27 @@ noinstr bool __kvm_handle_async_pf(struct pt_regs *regs, u32 token)
 	return true;
 }
 
+DEFINE_IDTENTRY_SYSVEC(sysvec_kvm_asyncpf_interrupt)
+{
+	struct pt_regs *old_regs = set_irq_regs(regs);
+	u32 token;
+	bool rcu_exit;
+
+	rcu_exit = idtentry_enter_cond_rcu(regs);
+
+	inc_irq_stat(irq_hv_callback_count);
+
+	if (__this_cpu_read(apf_reason.enabled)) {
+		token = __this_cpu_read(apf_reason.token);
+		kvm_async_pf_task_wake(token);
+		__this_cpu_write(apf_reason.token, 0);
+		wrmsrl(MSR_KVM_ASYNC_PF_ACK, 1);
+	}
+
+	idtentry_exit_cond_rcu(regs, rcu_exit);
+	set_irq_regs(old_regs);
+}
+
 static void __init paravirt_ops_setup(void)
 {
 	pv_info.name = "KVM";
@@ -311,17 +328,19 @@ static notrace void kvm_guest_apic_eoi_write(u32 reg, u32 val)
 
 static void kvm_guest_cpu_init(void)
 {
-	if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF) && kvmapf) {
-		u64 pa;
+	if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF_INT) && kvmapf) {
+		u64 pa = slow_virt_to_phys(this_cpu_ptr(&apf_reason));
 
 		WARN_ON_ONCE(!static_branch_likely(&kvm_async_pf_enabled));
 
 		pa = slow_virt_to_phys(this_cpu_ptr(&apf_reason));
-		pa |= KVM_ASYNC_PF_ENABLED;
+		pa |= KVM_ASYNC_PF_ENABLED | KVM_ASYNC_PF_DELIVERY_AS_INT;
 
 		if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF_VMEXIT))
 			pa |= KVM_ASYNC_PF_DELIVERY_AS_PF_VMEXIT;
 
+		wrmsrl(MSR_KVM_ASYNC_PF_INT, HYPERVISOR_CALLBACK_VECTOR);
+
 		wrmsrl(MSR_KVM_ASYNC_PF_EN, pa);
 		__this_cpu_write(apf_reason.enabled, 1);
 		pr_info("KVM setup async PF for cpu %d\n", smp_processor_id());
@@ -646,8 +665,10 @@ static void __init kvm_guest_init(void)
 	if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
 		apic_set_eoi_write(kvm_guest_apic_eoi_write);
 
-	if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF) && kvmapf)
+	if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF_INT) && kvmapf) {
 		static_branch_enable(&kvm_async_pf_enabled);
+		alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, asm_sysvec_kvm_asyncpf_interrupt);
+	}
 
 #ifdef CONFIG_SMP
 	smp_ops.smp_prepare_cpus = kvm_smp_prepare_cpus;