[PATCH 18/33] KVM: MMU: Remove invlpg interception

Avi Kivity
2007-01-04T16:07:07Z

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-atKUWr5tajBWk0Htik3J/w@public.gmane.org>

Index: linux-2.6/drivers/kvm/mmu.c
===================================================================
--- linux-2.6.orig/drivers/kvm/mmu.c
+++ linux-2.6/drivers/kvm/mmu.c
@@ -767,10 +767,6 @@ static int nonpaging_page_fault(struct k
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

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
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(
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

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;
Index: linux-2.6/drivers/kvm/kvm_main.c
===================================================================
--- linux-2.6.orig/drivers/kvm/kvm_main.c
+++ linux-2.6/drivers/kvm/kvm_main.c
@@ -943,10 +943,6 @@ static unsigned long get_segment_base(st

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;
}

Index: linux-2.6/drivers/kvm/kvm.h
===================================================================
--- linux-2.6.orig/drivers/kvm/kvm.h
+++ linux-2.6/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;
Index: linux-2.6/drivers/kvm/svm.c
===================================================================
--- linux-2.6.orig/drivers/kvm/svm.c
+++ linux-2.6/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) |
Index: linux-2.6/drivers/kvm/vmx.c
===================================================================
--- linux-2.6.orig/drivers/kvm/vmx.c
+++ linux-2.6/drivers/kvm/vmx.c
@@ -1059,7 +1059,6 @@ static int vmx_vcpu_setup(struct kvm_vcp
| 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 *vc
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[])(st
[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,