From aff48baa34c033318ad322ecbf2e4bcd891b29ca Mon Sep 17 00:00:00 2001 From: Avi Kivity Date: Sun, 5 Dec 2010 18:56:11 +0200 Subject: [PATCH] KVM: Fetch guest cr3 from hardware on demand Instead of syncing the guest cr3 every exit, which is expensince on vmx with ept enabled, sync it only on demand. [sheng: fix incorrect cr3 seen by Windows XP] Signed-off-by: Sheng Yang Signed-off-by: Avi Kivity --- arch/x86/include/asm/kvm_host.h | 2 ++ arch/x86/kvm/kvm_cache_regs.h | 2 ++ arch/x86/kvm/svm.c | 5 +++++ arch/x86/kvm/vmx.c | 18 ++++++++++++------ arch/x86/kvm/x86.c | 2 ++ 5 files changed, 23 insertions(+), 6 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 6268f6ce6434..95f026be8b5e 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -117,6 +117,7 @@ enum kvm_reg { enum kvm_reg_ex { VCPU_EXREG_PDPTR = NR_VCPU_REGS, + VCPU_EXREG_CR3, }; enum { @@ -533,6 +534,7 @@ struct kvm_x86_ops { struct kvm_segment *var, int seg); void (*get_cs_db_l_bits)(struct kvm_vcpu *vcpu, int *db, int *l); void (*decache_cr0_guest_bits)(struct kvm_vcpu *vcpu); + void (*decache_cr3)(struct kvm_vcpu *vcpu); void (*decache_cr4_guest_bits)(struct kvm_vcpu *vcpu); void (*set_cr0)(struct kvm_vcpu *vcpu, unsigned long cr0); void (*set_cr3)(struct kvm_vcpu *vcpu, unsigned long cr3); diff --git a/arch/x86/kvm/kvm_cache_regs.h b/arch/x86/kvm/kvm_cache_regs.h index a6bf8db326f5..3377d53fcd36 100644 --- a/arch/x86/kvm/kvm_cache_regs.h +++ b/arch/x86/kvm/kvm_cache_regs.h @@ -75,6 +75,8 @@ static inline ulong kvm_read_cr4_bits(struct kvm_vcpu *vcpu, ulong mask) static inline ulong kvm_read_cr3(struct kvm_vcpu *vcpu) { + if (!test_bit(VCPU_EXREG_CR3, (ulong *)&vcpu->arch.regs_avail)) + kvm_x86_ops->decache_cr3(vcpu); return vcpu->arch.cr3; } diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index a7b04c0bd7a5..25bd1bc5aad2 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -1327,6 +1327,10 @@ static void svm_decache_cr0_guest_bits(struct kvm_vcpu *vcpu) { } +static void svm_decache_cr3(struct kvm_vcpu *vcpu) +{ +} + static void svm_decache_cr4_guest_bits(struct kvm_vcpu *vcpu) { } @@ -3871,6 +3875,7 @@ static struct kvm_x86_ops svm_x86_ops = { .get_cpl = svm_get_cpl, .get_cs_db_l_bits = kvm_get_cs_db_l_bits, .decache_cr0_guest_bits = svm_decache_cr0_guest_bits, + .decache_cr3 = svm_decache_cr3, .decache_cr4_guest_bits = svm_decache_cr4_guest_bits, .set_cr0 = svm_set_cr0, .set_cr3 = svm_set_cr3, diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 141956ebf794..1896cada805f 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -180,6 +180,7 @@ static int init_rmode(struct kvm *kvm); static u64 construct_eptp(unsigned long root_hpa); static void kvm_cpu_vmxon(u64 addr); static void kvm_cpu_vmxoff(void); +static void vmx_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3); static DEFINE_PER_CPU(struct vmcs *, vmxarea); static DEFINE_PER_CPU(struct vmcs *, current_vmcs); @@ -1866,6 +1867,13 @@ static void vmx_decache_cr0_guest_bits(struct kvm_vcpu *vcpu) vcpu->arch.cr0 |= vmcs_readl(GUEST_CR0) & cr0_guest_owned_bits; } +static void vmx_decache_cr3(struct kvm_vcpu *vcpu) +{ + if (enable_ept && is_paging(vcpu)) + vcpu->arch.cr3 = vmcs_readl(GUEST_CR3); + __set_bit(VCPU_EXREG_CR3, (ulong *)&vcpu->arch.regs_avail); +} + static void vmx_decache_cr4_guest_bits(struct kvm_vcpu *vcpu) { ulong cr4_guest_owned_bits = vcpu->arch.cr4_guest_owned_bits; @@ -1909,6 +1917,7 @@ static void ept_update_paging_mode_cr0(unsigned long *hw_cr0, unsigned long cr0, struct kvm_vcpu *vcpu) { + vmx_decache_cr3(vcpu); if (!(cr0 & X86_CR0_PG)) { /* From paging/starting to nonpaging */ vmcs_write32(CPU_BASED_VM_EXEC_CONTROL, @@ -3756,11 +3765,6 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu) if (vmx->emulation_required && emulate_invalid_guest_state) return handle_invalid_guest_state(vcpu); - /* Access CR3 don't cause VMExit in paging mode, so we need - * to sync with guest real CR3. */ - if (enable_ept && is_paging(vcpu)) - vcpu->arch.cr3 = vmcs_readl(GUEST_CR3); - if (exit_reason & VMX_EXIT_REASONS_FAILED_VMENTRY) { vcpu->run->exit_reason = KVM_EXIT_FAIL_ENTRY; vcpu->run->fail_entry.hardware_entry_failure_reason @@ -4077,7 +4081,8 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu) ); vcpu->arch.regs_avail = ~((1 << VCPU_REGS_RIP) | (1 << VCPU_REGS_RSP) - | (1 << VCPU_EXREG_PDPTR)); + | (1 << VCPU_EXREG_PDPTR) + | (1 << VCPU_EXREG_CR3)); vcpu->arch.regs_dirty = 0; vmx->idt_vectoring_info = vmcs_read32(IDT_VECTORING_INFO_FIELD); @@ -4344,6 +4349,7 @@ static struct kvm_x86_ops vmx_x86_ops = { .get_cpl = vmx_get_cpl, .get_cs_db_l_bits = vmx_get_cs_db_l_bits, .decache_cr0_guest_bits = vmx_decache_cr0_guest_bits, + .decache_cr3 = vmx_decache_cr3, .decache_cr4_guest_bits = vmx_decache_cr4_guest_bits, .set_cr0 = vmx_set_cr0, .set_cr3 = vmx_set_cr3, diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 6e50314d64fb..fa708c9a7437 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -667,6 +667,7 @@ int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3) if (unlikely(!gfn_to_memslot(vcpu->kvm, cr3 >> PAGE_SHIFT))) return 1; vcpu->arch.cr3 = cr3; + __set_bit(VCPU_EXREG_CR3, (ulong *)&vcpu->arch.regs_avail); vcpu->arch.mmu.new_cr3(vcpu); return 0; } @@ -5583,6 +5584,7 @@ int kvm_arch_vcpu_ioctl_set_sregs(struct kvm_vcpu *vcpu, vcpu->arch.cr2 = sregs->cr2; mmu_reset_needed |= kvm_read_cr3(vcpu) != sregs->cr3; vcpu->arch.cr3 = sregs->cr3; + __set_bit(VCPU_EXREG_CR3, (ulong *)&vcpu->arch.regs_avail); kvm_set_cr8(vcpu, sregs->cr8); -- GitLab