[PATCH] KVM: MMU: Remove invlpg interception

Since we write protect shadowed guest page tables, there is no need to trap
page invalidations (the guest will always change the mapping before issuing
the invlpg instruction).

Signed-off-by: Avi Kivity <avi@qumranet.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/kvm/kvm.h

@@ -158,7 +158,6 @@ struct kvm_vcpu;
 struct kvm_mmu {
 	void (*new_cr3)(struct kvm_vcpu *vcpu);
 	int (*page_fault)(struct kvm_vcpu *vcpu, gva_t gva, u32 err);
-	void (*inval_page)(struct kvm_vcpu *vcpu, gva_t gva);
 	void (*free)(struct kvm_vcpu *vcpu);
 	gpa_t (*gva_to_gpa)(struct kvm_vcpu *vcpu, gva_t gva);
 	hpa_t root_hpa;

drivers/kvm/kvm_main.c

@@ -943,10 +943,6 @@ static unsigned long get_segment_base(struct kvm_vcpu *vcpu, int seg)
 
 int emulate_invlpg(struct kvm_vcpu *vcpu, gva_t address)
 {
-	spin_lock(&vcpu->kvm->lock);
-	vcpu->mmu.inval_page(vcpu, address);
-	spin_unlock(&vcpu->kvm->lock);
-	kvm_arch_ops->invlpg(vcpu, address);
 	return X86EMUL_CONTINUE;
 }
 

drivers/kvm/mmu.c

@@ -767,10 +767,6 @@ static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gva_t gva,
 	return nonpaging_map(vcpu, addr & PAGE_MASK, paddr);
 }
 
-static void nonpaging_inval_page(struct kvm_vcpu *vcpu, gva_t addr)
-{
-}
-
 static void nonpaging_free(struct kvm_vcpu *vcpu)
 {
 	mmu_free_roots(vcpu);
@@ -782,7 +778,6 @@ static int nonpaging_init_context(struct kvm_vcpu *vcpu)
 
 	context->new_cr3 = nonpaging_new_cr3;
 	context->page_fault = nonpaging_page_fault;
-	context->inval_page = nonpaging_inval_page;
 	context->gva_to_gpa = nonpaging_gva_to_gpa;
 	context->free = nonpaging_free;
 	context->root_level = 0;
@@ -895,42 +890,6 @@ static int may_access(u64 pte, int write, int user)
 	return 1;
 }
 
-/*
- * Remove a shadow pte.
- */
-static void paging_inval_page(struct kvm_vcpu *vcpu, gva_t addr)
-{
-	hpa_t page_addr = vcpu->mmu.root_hpa;
-	int level = vcpu->mmu.shadow_root_level;
-
-	++kvm_stat.invlpg;
-
-	for (; ; level--) {
-		u32 index = PT64_INDEX(addr, level);
-		u64 *table = __va(page_addr);
-
-		if (level == PT_PAGE_TABLE_LEVEL ) {
-			rmap_remove(vcpu->kvm, &table[index]);
-			table[index] = 0;
-			return;
-		}
-
-		if (!is_present_pte(table[index]))
-			return;
-
-		page_addr = table[index] & PT64_BASE_ADDR_MASK;
-
-		if (level == PT_DIRECTORY_LEVEL &&
-			  (table[index] & PT_SHADOW_PS_MARK)) {
-			table[index] = 0;
-			release_pt_page_64(vcpu, page_addr, PT_PAGE_TABLE_LEVEL);
-
-			kvm_arch_ops->tlb_flush(vcpu);
-			return;
-		}
-	}
-}
-
 static void paging_free(struct kvm_vcpu *vcpu)
 {
 	nonpaging_free(vcpu);
@@ -951,7 +910,6 @@ static int paging64_init_context_common(struct kvm_vcpu *vcpu, int level)
 	ASSERT(is_pae(vcpu));
 	context->new_cr3 = paging_new_cr3;
 	context->page_fault = paging64_page_fault;
-	context->inval_page = paging_inval_page;
 	context->gva_to_gpa = paging64_gva_to_gpa;
 	context->free = paging_free;
 	context->root_level = level;
@@ -974,7 +932,6 @@ static int paging32_init_context(struct kvm_vcpu *vcpu)
 
 	context->new_cr3 = paging_new_cr3;
 	context->page_fault = paging32_page_fault;
-	context->inval_page = paging_inval_page;
 	context->gva_to_gpa = paging32_gva_to_gpa;
 	context->free = paging_free;
 	context->root_level = PT32_ROOT_LEVEL;

drivers/kvm/svm.c

@@ -497,7 +497,6 @@ static void init_vmcb(struct vmcb *vmcb)
 		/*              (1ULL << INTERCEPT_SELECTIVE_CR0) | */
 				(1ULL << INTERCEPT_CPUID) |
 				(1ULL << INTERCEPT_HLT) |
-				(1ULL << INTERCEPT_INVLPG) |
 				(1ULL << INTERCEPT_INVLPGA) |
 				(1ULL << INTERCEPT_IOIO_PROT) |
 				(1ULL << INTERCEPT_MSR_PROT) |

drivers/kvm/vmx.c

@@ -1059,7 +1059,6 @@ static int vmx_vcpu_setup(struct kvm_vcpu *vcpu)
 			       | CPU_BASED_CR8_LOAD_EXITING    /* 20.6.2 */
 			       | CPU_BASED_CR8_STORE_EXITING   /* 20.6.2 */
 			       | CPU_BASED_UNCOND_IO_EXITING   /* 20.6.2 */
-			       | CPU_BASED_INVDPG_EXITING
 			       | CPU_BASED_MOV_DR_EXITING
 			       | CPU_BASED_USE_TSC_OFFSETING   /* 21.3 */
 			);
@@ -1438,17 +1437,6 @@ static int handle_io(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 	return 0;
 }
 
-static int handle_invlpg(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
-{
-	u64 address = vmcs_read64(EXIT_QUALIFICATION);
-	int instruction_length = vmcs_read32(VM_EXIT_INSTRUCTION_LEN);
-	spin_lock(&vcpu->kvm->lock);
-	vcpu->mmu.inval_page(vcpu, address);
-	spin_unlock(&vcpu->kvm->lock);
-	vmcs_writel(GUEST_RIP, vmcs_readl(GUEST_RIP) + instruction_length);
-	return 1;
-}
-
 static int handle_cr(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 {
 	u64 exit_qualification;
@@ -1636,7 +1624,6 @@ static int (*kvm_vmx_exit_handlers[])(struct kvm_vcpu *vcpu,
 	[EXIT_REASON_EXCEPTION_NMI]           = handle_exception,
 	[EXIT_REASON_EXTERNAL_INTERRUPT]      = handle_external_interrupt,
 	[EXIT_REASON_IO_INSTRUCTION]          = handle_io,
-	[EXIT_REASON_INVLPG]                  = handle_invlpg,
 	[EXIT_REASON_CR_ACCESS]               = handle_cr,
 	[EXIT_REASON_DR_ACCESS]               = handle_dr,
 	[EXIT_REASON_CPUID]                   = handle_cpuid,