KVM: x86: accessors for guest registers

As suggested by Avi, introduce accessors to read/write guest registers.
This simplifies the ->cache_regs/->decache_regs interface, and improves
register caching which is important for VMX, where the cost of
vmcs_read/vmcs_write is significant.

[avi: fix warnings]
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

arch/x86/kvm/kvm_cache_regs.h

+#ifndef ASM_KVM_CACHE_REGS_H
+#define ASM_KVM_CACHE_REGS_H
+
+static inline unsigned long kvm_register_read(struct kvm_vcpu *vcpu,
+					      enum kvm_reg reg)
+{
+	if (!test_bit(reg, (unsigned long *)&vcpu->arch.regs_avail))
+		kvm_x86_ops->cache_reg(vcpu, reg);
+
+	return vcpu->arch.regs[reg];
+}
+
+static inline void kvm_register_write(struct kvm_vcpu *vcpu,
+				      enum kvm_reg reg,
+				      unsigned long val)
+{
+	vcpu->arch.regs[reg] = val;
+	__set_bit(reg, (unsigned long *)&vcpu->arch.regs_dirty);
+	__set_bit(reg, (unsigned long *)&vcpu->arch.regs_avail);
+}
+
+static inline unsigned long kvm_rip_read(struct kvm_vcpu *vcpu)
+{
+	return kvm_register_read(vcpu, VCPU_REGS_RIP);
+}
+
+static inline void kvm_rip_write(struct kvm_vcpu *vcpu, unsigned long val)
+{
+	kvm_register_write(vcpu, VCPU_REGS_RIP, val);
+}
+
+#endif

arch/x86/kvm/lapic.c

@@ -32,6 +32,7 @@
 #include <asm/current.h>
 #include <asm/apicdef.h>
 #include <asm/atomic.h>
+#include "kvm_cache_regs.h"
 #include "irq.h"
 
 #define PRId64 "d"
@@ -558,8 +559,7 @@ static void __report_tpr_access(struct kvm_lapic *apic, bool write)
 	struct kvm_run *run = vcpu->run;
 
 	set_bit(KVM_REQ_REPORT_TPR_ACCESS, &vcpu->requests);
-	kvm_x86_ops->cache_regs(vcpu);
-	run->tpr_access.rip = vcpu->arch.rip;
+	run->tpr_access.rip = kvm_rip_read(vcpu);
 	run->tpr_access.is_write = write;
 }
 

arch/x86/kvm/svm.c

@@ -18,6 +18,7 @@
 #include "kvm_svm.h"
 #include "irq.h"
 #include "mmu.h"
+#include "kvm_cache_regs.h"
 
 #include <linux/module.h>
 #include <linux/kernel.h>
@@ -236,13 +237,11 @@ static void skip_emulated_instruction(struct kvm_vcpu *vcpu)
 		printk(KERN_DEBUG "%s: NOP\n", __func__);
 		return;
 	}
-	if (svm->next_rip - svm->vmcb->save.rip > MAX_INST_SIZE)
-		printk(KERN_ERR "%s: ip 0x%llx next 0x%llx\n",
-		       __func__,
-		       svm->vmcb->save.rip,
-		       svm->next_rip);
+	if (svm->next_rip - kvm_rip_read(vcpu) > MAX_INST_SIZE)
+		printk(KERN_ERR "%s: ip 0x%lx next 0x%llx\n",
+		       __func__, kvm_rip_read(vcpu), svm->next_rip);
 
-	vcpu->arch.rip = svm->vmcb->save.rip = svm->next_rip;
+	kvm_rip_write(vcpu, svm->next_rip);
 	svm->vmcb->control.int_state &= ~SVM_INTERRUPT_SHADOW_MASK;
 
 	vcpu->arch.interrupt_window_open = 1;
@@ -581,6 +580,7 @@ static void init_vmcb(struct vcpu_svm *svm)
 	save->dr7 = 0x400;
 	save->rflags = 2;
 	save->rip = 0x0000fff0;
+	svm->vcpu.arch.regs[VCPU_REGS_RIP] = save->rip;
 
 	/*
 	 * cr0 val on cpu init should be 0x60000010, we enable cpu
@@ -615,10 +615,12 @@ static int svm_vcpu_reset(struct kvm_vcpu *vcpu)
 	init_vmcb(svm);
 
 	if (vcpu->vcpu_id != 0) {
-		svm->vmcb->save.rip = 0;
+		kvm_rip_write(vcpu, 0);
 		svm->vmcb->save.cs.base = svm->vcpu.arch.sipi_vector << 12;
 		svm->vmcb->save.cs.selector = svm->vcpu.arch.sipi_vector << 8;
 	}
+	vcpu->arch.regs_avail = ~0;
+	vcpu->arch.regs_dirty = ~0;
 
 	return 0;
 }
@@ -721,23 +723,6 @@ static void svm_vcpu_put(struct kvm_vcpu *vcpu)
 	rdtscll(vcpu->arch.host_tsc);
 }
 
-static void svm_cache_regs(struct kvm_vcpu *vcpu)
-{
-	struct vcpu_svm *svm = to_svm(vcpu);
-
-	vcpu->arch.regs[VCPU_REGS_RAX] = svm->vmcb->save.rax;
-	vcpu->arch.regs[VCPU_REGS_RSP] = svm->vmcb->save.rsp;
-	vcpu->arch.rip = svm->vmcb->save.rip;
-}
-
-static void svm_decache_regs(struct kvm_vcpu *vcpu)
-{
-	struct vcpu_svm *svm = to_svm(vcpu);
-	svm->vmcb->save.rax = vcpu->arch.regs[VCPU_REGS_RAX];
-	svm->vmcb->save.rsp = vcpu->arch.regs[VCPU_REGS_RSP];
-	svm->vmcb->save.rip = vcpu->arch.rip;
-}
-
 static unsigned long svm_get_rflags(struct kvm_vcpu *vcpu)
 {
 	return to_svm(vcpu)->vmcb->save.rflags;
@@ -1139,14 +1124,14 @@ static int nop_on_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
 
 static int halt_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
 {
-	svm->next_rip = svm->vmcb->save.rip + 1;
+	svm->next_rip = kvm_rip_read(&svm->vcpu) + 1;
 	skip_emulated_instruction(&svm->vcpu);
 	return kvm_emulate_halt(&svm->vcpu);
 }
 
 static int vmmcall_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
 {
-	svm->next_rip = svm->vmcb->save.rip + 3;
+	svm->next_rip = kvm_rip_read(&svm->vcpu) + 3;
 	skip_emulated_instruction(&svm->vcpu);
 	kvm_emulate_hypercall(&svm->vcpu);
 	return 1;
@@ -1178,7 +1163,7 @@ static int task_switch_interception(struct vcpu_svm *svm,
 
 static int cpuid_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
 {
-	svm->next_rip = svm->vmcb->save.rip + 2;
+	svm->next_rip = kvm_rip_read(&svm->vcpu) + 2;
 	kvm_emulate_cpuid(&svm->vcpu);
 	return 1;
 }
@@ -1273,9 +1258,9 @@ static int rdmsr_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
 		KVMTRACE_3D(MSR_READ, &svm->vcpu, ecx, (u32)data,
 			    (u32)(data >> 32), handler);
 
-		svm->vmcb->save.rax = data & 0xffffffff;
+		svm->vcpu.arch.regs[VCPU_REGS_RAX] = data & 0xffffffff;
 		svm->vcpu.arch.regs[VCPU_REGS_RDX] = data >> 32;
-		svm->next_rip = svm->vmcb->save.rip + 2;
+		svm->next_rip = kvm_rip_read(&svm->vcpu) + 2;
 		skip_emulated_instruction(&svm->vcpu);
 	}
 	return 1;
@@ -1359,13 +1344,13 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, unsigned ecx, u64 data)
 static int wrmsr_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
 {
 	u32 ecx = svm->vcpu.arch.regs[VCPU_REGS_RCX];
-	u64 data = (svm->vmcb->save.rax & -1u)
+	u64 data = (svm->vcpu.arch.regs[VCPU_REGS_RAX] & -1u)
 		| ((u64)(svm->vcpu.arch.regs[VCPU_REGS_RDX] & -1u) << 32);
 
 	KVMTRACE_3D(MSR_WRITE, &svm->vcpu, ecx, (u32)data, (u32)(data >> 32),
 		    handler);
 
-	svm->next_rip = svm->vmcb->save.rip + 2;
+	svm->next_rip = kvm_rip_read(&svm->vcpu) + 2;
 	if (svm_set_msr(&svm->vcpu, ecx, data))
 		kvm_inject_gp(&svm->vcpu, 0);
 	else
@@ -1723,6 +1708,10 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 	u16 gs_selector;
 	u16 ldt_selector;
 
+	svm->vmcb->save.rax = vcpu->arch.regs[VCPU_REGS_RAX];
+	svm->vmcb->save.rsp = vcpu->arch.regs[VCPU_REGS_RSP];
+	svm->vmcb->save.rip = vcpu->arch.regs[VCPU_REGS_RIP];
+
 	pre_svm_run(svm);
 
 	sync_lapic_to_cr8(vcpu);
@@ -1858,6 +1847,9 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 		load_db_regs(svm->host_db_regs);
 
 	vcpu->arch.cr2 = svm->vmcb->save.cr2;
+	vcpu->arch.regs[VCPU_REGS_RAX] = svm->vmcb->save.rax;
+	vcpu->arch.regs[VCPU_REGS_RSP] = svm->vmcb->save.rsp;
+	vcpu->arch.regs[VCPU_REGS_RIP] = svm->vmcb->save.rip;
 
 	write_dr6(svm->host_dr6);
 	write_dr7(svm->host_dr7);
@@ -1977,8 +1969,6 @@ static struct kvm_x86_ops svm_x86_ops = {
 	.set_gdt = svm_set_gdt,
 	.get_dr = svm_get_dr,
 	.set_dr = svm_set_dr,
-	.cache_regs = svm_cache_regs,
-	.decache_regs = svm_decache_regs,
 	.get_rflags = svm_get_rflags,
 	.set_rflags = svm_set_rflags,
 

arch/x86/kvm/vmx.c

@@ -26,6 +26,7 @@
 #include <linux/highmem.h>
 #include <linux/sched.h>
 #include <linux/moduleparam.h>
+#include "kvm_cache_regs.h"
 
 #include <asm/io.h>
 #include <asm/desc.h>
@@ -715,9 +716,9 @@ static void skip_emulated_instruction(struct kvm_vcpu *vcpu)
 	unsigned long rip;
 	u32 interruptibility;
 
-	rip = vmcs_readl(GUEST_RIP);
+	rip = kvm_rip_read(vcpu);
 	rip += vmcs_read32(VM_EXIT_INSTRUCTION_LEN);
-	vmcs_writel(GUEST_RIP, rip);
+	kvm_rip_write(vcpu, rip);
 
 	/*
 	 * We emulated an instruction, so temporary interrupt blocking
@@ -947,24 +948,19 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 data)
 	return ret;
 }
 
-/*
- * Sync the rsp and rip registers into the vcpu structure.  This allows
- * registers to be accessed by indexing vcpu->arch.regs.
- */
-static void vcpu_load_rsp_rip(struct kvm_vcpu *vcpu)
-{
-	vcpu->arch.regs[VCPU_REGS_RSP] = vmcs_readl(GUEST_RSP);
-	vcpu->arch.rip = vmcs_readl(GUEST_RIP);
-}
-
-/*
- * Syncs rsp and rip back into the vmcs.  Should be called after possible
- * modification.
- */
-static void vcpu_put_rsp_rip(struct kvm_vcpu *vcpu)
+static void vmx_cache_reg(struct kvm_vcpu *vcpu, enum kvm_reg reg)
 {
-	vmcs_writel(GUEST_RSP, vcpu->arch.regs[VCPU_REGS_RSP]);
-	vmcs_writel(GUEST_RIP, vcpu->arch.rip);
+	__set_bit(reg, (unsigned long *)&vcpu->arch.regs_avail);
+	switch (reg) {
+	case VCPU_REGS_RSP:
+		vcpu->arch.regs[VCPU_REGS_RSP] = vmcs_readl(GUEST_RSP);
+		break;
+	case VCPU_REGS_RIP:
+		vcpu->arch.regs[VCPU_REGS_RIP] = vmcs_readl(GUEST_RIP);
+		break;
+	default:
+		break;
+	}
 }
 
 static int set_guest_debug(struct kvm_vcpu *vcpu, struct kvm_debug_guest *dbg)
@@ -2019,6 +2015,7 @@ static int vmx_vcpu_reset(struct kvm_vcpu *vcpu)
 	u64 msr;
 	int ret;
 
+	vcpu->arch.regs_avail = ~((1 << VCPU_REGS_RIP) | (1 << VCPU_REGS_RSP));
 	down_read(&vcpu->kvm->slots_lock);
 	if (!init_rmode(vmx->vcpu.kvm)) {
 		ret = -ENOMEM;
@@ -2072,10 +2069,10 @@ static int vmx_vcpu_reset(struct kvm_vcpu *vcpu)
 
 	vmcs_writel(GUEST_RFLAGS, 0x02);
 	if (vmx->vcpu.vcpu_id == 0)
-		vmcs_writel(GUEST_RIP, 0xfff0);
+		kvm_rip_write(vcpu, 0xfff0);
 	else
-		vmcs_writel(GUEST_RIP, 0);
-	vmcs_writel(GUEST_RSP, 0);
+		kvm_rip_write(vcpu, 0);
+	kvm_register_write(vcpu, VCPU_REGS_RSP, 0);
 
 	/* todo: dr0 = dr1 = dr2 = dr3 = 0; dr6 = 0xffff0ff0 */
 	vmcs_writel(GUEST_DR7, 0x400);
@@ -2139,11 +2136,11 @@ static void vmx_inject_irq(struct kvm_vcpu *vcpu, int irq)
 	if (vcpu->arch.rmode.active) {
 		vmx->rmode.irq.pending = true;
 		vmx->rmode.irq.vector = irq;
-		vmx->rmode.irq.rip = vmcs_readl(GUEST_RIP);
+		vmx->rmode.irq.rip = kvm_rip_read(vcpu);
 		vmcs_write32(VM_ENTRY_INTR_INFO_FIELD,
 			     irq | INTR_TYPE_SOFT_INTR | INTR_INFO_VALID_MASK);
 		vmcs_write32(VM_ENTRY_INSTRUCTION_LEN, 1);
-		vmcs_writel(GUEST_RIP, vmx->rmode.irq.rip - 1);
+		kvm_rip_write(vcpu, vmx->rmode.irq.rip - 1);
 		return;
 	}
 	vmcs_write32(VM_ENTRY_INTR_INFO_FIELD,
@@ -2288,7 +2285,7 @@ static int handle_exception(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 	}
 
 	error_code = 0;
-	rip = vmcs_readl(GUEST_RIP);
+	rip = kvm_rip_read(vcpu);
 	if (intr_info & INTR_INFO_DELIVER_CODE_MASK)
 		error_code = vmcs_read32(VM_EXIT_INTR_ERROR_CODE);
 	if (is_page_fault(intr_info)) {
@@ -2386,27 +2383,25 @@ static int handle_cr(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 	reg = (exit_qualification >> 8) & 15;
 	switch ((exit_qualification >> 4) & 3) {
 	case 0: /* mov to cr */
-		KVMTRACE_3D(CR_WRITE, vcpu, (u32)cr, (u32)vcpu->arch.regs[reg],
-			    (u32)((u64)vcpu->arch.regs[reg] >> 32), handler);
+		KVMTRACE_3D(CR_WRITE, vcpu, (u32)cr,
+			    (u32)kvm_register_read(vcpu, reg),
+			    (u32)((u64)kvm_register_read(vcpu, reg) >> 32),
+			    handler);
 		switch (cr) {
 		case 0:
-			vcpu_load_rsp_rip(vcpu);
-			kvm_set_cr0(vcpu, vcpu->arch.regs[reg]);
+			kvm_set_cr0(vcpu, kvm_register_read(vcpu, reg));
 			skip_emulated_instruction(vcpu);
 			return 1;
 		case 3:
-			vcpu_load_rsp_rip(vcpu);
-			kvm_set_cr3(vcpu, vcpu->arch.regs[reg]);
+			kvm_set_cr3(vcpu, kvm_register_read(vcpu, reg));
 			skip_emulated_instruction(vcpu);
 			return 1;
 		case 4:
-			vcpu_load_rsp_rip(vcpu);
-			kvm_set_cr4(vcpu, vcpu->arch.regs[reg]);
+			kvm_set_cr4(vcpu, kvm_register_read(vcpu, reg));
 			skip_emulated_instruction(vcpu);
 			return 1;
 		case 8:
-			vcpu_load_rsp_rip(vcpu);
-			kvm_set_cr8(vcpu, vcpu->arch.regs[reg]);
+			kvm_set_cr8(vcpu, kvm_register_read(vcpu, reg));
 			skip_emulated_instruction(vcpu);
 			if (irqchip_in_kernel(vcpu->kvm))
 				return 1;
@@ -2415,7 +2410,6 @@ static int handle_cr(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 		};
 		break;
 	case 2: /* clts */
-		vcpu_load_rsp_rip(vcpu);
 		vmx_fpu_deactivate(vcpu);
 		vcpu->arch.cr0 &= ~X86_CR0_TS;
 		vmcs_writel(CR0_READ_SHADOW, vcpu->arch.cr0);
@@ -2426,21 +2420,17 @@ static int handle_cr(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 	case 1: /*mov from cr*/
 		switch (cr) {
 		case 3:
-			vcpu_load_rsp_rip(vcpu);
-			vcpu->arch.regs[reg] = vcpu->arch.cr3;
-			vcpu_put_rsp_rip(vcpu);
+			kvm_register_write(vcpu, reg, vcpu->arch.cr3);
 			KVMTRACE_3D(CR_READ, vcpu, (u32)cr,
-				    (u32)vcpu->arch.regs[reg],
-				    (u32)((u64)vcpu->arch.regs[reg] >> 32),
+				    (u32)kvm_register_read(vcpu, reg),
+				    (u32)((u64)kvm_register_read(vcpu, reg) >> 32),
 				    handler);
 			skip_emulated_instruction(vcpu);
 			return 1;
 		case 8:
-			vcpu_load_rsp_rip(vcpu);
-			vcpu->arch.regs[reg] = kvm_get_cr8(vcpu);
-			vcpu_put_rsp_rip(vcpu);
+			kvm_register_write(vcpu, reg, kvm_get_cr8(vcpu));
 			KVMTRACE_2D(CR_READ, vcpu, (u32)cr,
-				    (u32)vcpu->arch.regs[reg], handler);
+				    (u32)kvm_register_read(vcpu, reg), handler);
 			skip_emulated_instruction(vcpu);
 			return 1;
 		}
@@ -2472,7 +2462,6 @@ static int handle_dr(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 	exit_qualification = vmcs_readl(EXIT_QUALIFICATION);
 	dr = exit_qualification & 7;
 	reg = (exit_qualification >> 8) & 15;
-	vcpu_load_rsp_rip(vcpu);
 	if (exit_qualification & 16) {
 		/* mov from dr */
 		switch (dr) {
@@ -2485,12 +2474,11 @@ static int handle_dr(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 		default:
 			val = 0;
 		}
-		vcpu->arch.regs[reg] = val;
+		kvm_register_write(vcpu, reg, val);
 		KVMTRACE_2D(DR_READ, vcpu, (u32)dr, (u32)val, handler);
 	} else {
 		/* mov to dr */
 	}
-	vcpu_put_rsp_rip(vcpu);
 	skip_emulated_instruction(vcpu);
 	return 1;
 }
@@ -2735,8 +2723,8 @@ static int kvm_handle_exit(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
 	u32 vectoring_info = vmx->idt_vectoring_info;
 
-	KVMTRACE_3D(VMEXIT, vcpu, exit_reason, (u32)vmcs_readl(GUEST_RIP),
-		    (u32)((u64)vmcs_readl(GUEST_RIP) >> 32), entryexit);
+	KVMTRACE_3D(VMEXIT, vcpu, exit_reason, (u32)kvm_rip_read(vcpu),
+		    (u32)((u64)kvm_rip_read(vcpu) >> 32), entryexit);
 
 	/* Access CR3 don't cause VMExit in paging mode, so we need
 	 * to sync with guest real CR3. */
@@ -2922,9 +2910,9 @@ static void vmx_intr_assist(struct kvm_vcpu *vcpu)
 static void fixup_rmode_irq(struct vcpu_vmx *vmx)
 {
 	vmx->rmode.irq.pending = 0;
-	if (vmcs_readl(GUEST_RIP) + 1 != vmx->rmode.irq.rip)
+	if (kvm_rip_read(&vmx->vcpu) + 1 != vmx->rmode.irq.rip)
 		return;
-	vmcs_writel(GUEST_RIP, vmx->rmode.irq.rip);
+	kvm_rip_write(&vmx->vcpu, vmx->rmode.irq.rip);
 	if (vmx->idt_vectoring_info & VECTORING_INFO_VALID_MASK) {
 		vmx->idt_vectoring_info &= ~VECTORING_INFO_TYPE_MASK;
 		vmx->idt_vectoring_info |= INTR_TYPE_EXT_INTR;
@@ -2941,6 +2929,11 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
 	u32 intr_info;
 
+	if (test_bit(VCPU_REGS_RSP, (unsigned long *)&vcpu->arch.regs_dirty))
+		vmcs_writel(GUEST_RSP, vcpu->arch.regs[VCPU_REGS_RSP]);
+	if (test_bit(VCPU_REGS_RIP, (unsigned long *)&vcpu->arch.regs_dirty))
+		vmcs_writel(GUEST_RIP, vcpu->arch.regs[VCPU_REGS_RIP]);
+
 	/*
 	 * Loading guest fpu may have cleared host cr0.ts
 	 */
@@ -3061,6 +3054,9 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 #endif
 	      );
 
+	vcpu->arch.regs_avail = ~((1 << VCPU_REGS_RIP) | (1 << VCPU_REGS_RSP));
+	vcpu->arch.regs_dirty = 0;
+
 	vmx->idt_vectoring_info = vmcs_read32(IDT_VECTORING_INFO_FIELD);
 	if (vmx->rmode.irq.pending)
 		fixup_rmode_irq(vmx);
@@ -3224,8 +3220,7 @@ static struct kvm_x86_ops vmx_x86_ops = {
 	.set_idt = vmx_set_idt,
 	.get_gdt = vmx_get_gdt,
 	.set_gdt = vmx_set_gdt,
-	.cache_regs = vcpu_load_rsp_rip,
-	.decache_regs = vcpu_put_rsp_rip,
+	.cache_reg = vmx_cache_reg,
 	.get_rflags = vmx_get_rflags,
 	.set_rflags = vmx_set_rflags,
 

arch/x86/kvm/x86_emulate.c

@@ -26,6 +26,7 @@
 #define DPRINTF(_f, _a ...) printf(_f , ## _a)
 #else
 #include <linux/kvm_host.h>
+#include "kvm_cache_regs.h"
 #define DPRINTF(x...) do {} while (0)
 #endif
 #include <linux/module.h>
@@ -839,7 +840,7 @@ x86_decode_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
 	/* Shadow copy of register state. Committed on successful emulation. */
 
 	memset(c, 0, sizeof(struct decode_cache));
-	c->eip = ctxt->vcpu->arch.rip;
+	c->eip = kvm_rip_read(ctxt->vcpu);
 	ctxt->cs_base = seg_base(ctxt, VCPU_SREG_CS);
 	memcpy(c->regs, ctxt->vcpu->arch.regs, sizeof c->regs);
 
@@ -1267,7 +1268,7 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
 	if (c->rep_prefix && (c->d & String)) {
 		/* All REP prefixes have the same first termination condition */
 		if (c->regs[VCPU_REGS_RCX] == 0) {
-			ctxt->vcpu->arch.rip = c->eip;
+			kvm_rip_write(ctxt->vcpu, c->eip);
 			goto done;
 		}
 		/* The second termination condition only applies for REPE
@@ -1281,17 +1282,17 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
 				(c->b == 0xae) || (c->b == 0xaf)) {
 			if ((c->rep_prefix == REPE_PREFIX) &&
 				((ctxt->eflags & EFLG_ZF) == 0)) {
-					ctxt->vcpu->arch.rip = c->eip;
+					kvm_rip_write(ctxt->vcpu, c->eip);
 					goto done;
 			}
 			if ((c->rep_prefix == REPNE_PREFIX) &&
 				((ctxt->eflags & EFLG_ZF) == EFLG_ZF)) {
-				ctxt->vcpu->arch.rip = c->eip;
+				kvm_rip_write(ctxt->vcpu, c->eip);
 				goto done;
 			}
 		}
 		c->regs[VCPU_REGS_RCX]--;
-		c->eip = ctxt->vcpu->arch.rip;
+		c->eip = kvm_rip_read(ctxt->vcpu);
 	}
 
 	if (c->src.type == OP_MEM) {
@@ -1768,7 +1769,7 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
 
 	/* Commit shadow register state. */
 	memcpy(ctxt->vcpu->arch.regs, c->regs, sizeof c->regs);
-	ctxt->vcpu->arch.rip = c->eip;
+	kvm_rip_write(ctxt->vcpu, c->eip);
 
 done:
 	if (rc == X86EMUL_UNHANDLEABLE) {
@@ -1793,7 +1794,7 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
 				goto done;
 
 			/* Let the processor re-execute the fixed hypercall */
-			c->eip = ctxt->vcpu->arch.rip;
+			c->eip = kvm_rip_read(ctxt->vcpu);
 			/* Disable writeback. */
 			c->dst.type = OP_NONE;
 			break;
@@ -1889,7 +1890,7 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
 		rc = kvm_set_msr(ctxt->vcpu, c->regs[VCPU_REGS_RCX], msr_data);
 		if (rc) {
 			kvm_inject_gp(ctxt->vcpu, 0);
-			c->eip = ctxt->vcpu->arch.rip;
+			c->eip = kvm_rip_read(ctxt->vcpu);
 		}
 		rc = X86EMUL_CONTINUE;
 		c->dst.type = OP_NONE;
@@ -1899,7 +1900,7 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
 		rc = kvm_get_msr(ctxt->vcpu, c->regs[VCPU_REGS_RCX], &msr_data);
 		if (rc) {
 			kvm_inject_gp(ctxt->vcpu, 0);
-			c->eip = ctxt->vcpu->arch.rip;
+			c->eip = kvm_rip_read(ctxt->vcpu);
 		} else {
 			c->regs[VCPU_REGS_RAX] = (u32)msr_data;
 			c->regs[VCPU_REGS_RDX] = msr_data >> 32;

include/asm-x86/kvm_host.h

@@ -89,7 +89,7 @@ extern struct list_head vm_list;
 struct kvm_vcpu;
 struct kvm;
 
-enum {
+enum kvm_reg {
 	VCPU_REGS_RAX = 0,
 	VCPU_REGS_RCX = 1,
 	VCPU_REGS_RDX = 2,
@@ -108,6 +108,7 @@ enum {
 	VCPU_REGS_R14 = 14,
 	VCPU_REGS_R15 = 15,
 #endif
+	VCPU_REGS_RIP,
 	NR_VCPU_REGS
 };
 
@@ -219,8 +220,13 @@ struct kvm_vcpu_arch {
 	int interrupt_window_open;
 	unsigned long irq_summary; /* bit vector: 1 per word in irq_pending */
 	DECLARE_BITMAP(irq_pending, KVM_NR_INTERRUPTS);
-	unsigned long regs[NR_VCPU_REGS]; /* for rsp: vcpu_load_rsp_rip() */
-	unsigned long rip;      /* needs vcpu_load_rsp_rip() */
+	/*
+	 * rip and regs accesses must go through
+	 * kvm_{register,rip}_{read,write} functions.
+	 */
+	unsigned long regs[NR_VCPU_REGS];
+	u32 regs_avail;
+	u32 regs_dirty;
 
 	unsigned long cr0;
 	unsigned long cr2;
@@ -414,8 +420,7 @@ struct kvm_x86_ops {
 	unsigned long (*get_dr)(struct kvm_vcpu *vcpu, int dr);
 	void (*set_dr)(struct kvm_vcpu *vcpu, int dr, unsigned long value,
 		       int *exception);
-	void (*cache_regs)(struct kvm_vcpu *vcpu);
-	void (*decache_regs)(struct kvm_vcpu *vcpu);
+	void (*cache_reg)(struct kvm_vcpu *vcpu, enum kvm_reg reg);
 	unsigned long (*get_rflags)(struct kvm_vcpu *vcpu);
 	void (*set_rflags)(struct kvm_vcpu *vcpu, unsigned long rflags);