From bd31fe495d0d1a67fe6f44f06dfef637f202241d Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Fri, 1 May 2020 21:32:31 -0700 Subject: [PATCH] KVM: VMX: Add proper cache tracking for CR0 Move CR0 caching into the standard register caching mechanism in order to take advantage of the availability checks provided by regs_avail. This avoids multiple VMREADs in the (uncommon) case where kvm_read_cr0() is called multiple times in a single VM-Exit, and more importantly eliminates a kvm_x86_ops hook, saves a retpoline on SVM when reading CR0, and squashes the confusing naming discrepancy of "cache_reg" vs. "decache_cr0_guest_bits". No functional change intended. Signed-off-by: Sean Christopherson Message-Id: <20200502043234.12481-8-sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini --- arch/x86/include/asm/kvm_host.h | 2 +- arch/x86/kvm/kvm_cache_regs.h | 5 +++-- arch/x86/kvm/svm/svm.c | 5 ----- arch/x86/kvm/vmx/vmx.c | 16 +++++++--------- arch/x86/kvm/vmx/vmx.h | 1 + 5 files changed, 12 insertions(+), 17 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 3e2f582..ad88212 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -167,6 +167,7 @@ enum kvm_reg { NR_VCPU_REGS, VCPU_EXREG_PDPTR = NR_VCPU_REGS, + VCPU_EXREG_CR0, VCPU_EXREG_CR3, VCPU_EXREG_CR4, VCPU_EXREG_RFLAGS, @@ -1092,7 +1093,6 @@ struct kvm_x86_ops { void (*set_segment)(struct kvm_vcpu *vcpu, 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 (*set_cr0)(struct kvm_vcpu *vcpu, unsigned long cr0); int (*set_cr4)(struct kvm_vcpu *vcpu, unsigned long cr4); void (*set_efer)(struct kvm_vcpu *vcpu, u64 efer); diff --git a/arch/x86/kvm/kvm_cache_regs.h b/arch/x86/kvm/kvm_cache_regs.h index 921a539..ff2d0e9 100644 --- a/arch/x86/kvm/kvm_cache_regs.h +++ b/arch/x86/kvm/kvm_cache_regs.h @@ -116,8 +116,9 @@ static inline u64 kvm_pdptr_read(struct kvm_vcpu *vcpu, int index) static inline ulong kvm_read_cr0_bits(struct kvm_vcpu *vcpu, ulong mask) { ulong tmask = mask & KVM_POSSIBLE_CR0_GUEST_BITS; - if (tmask & vcpu->arch.cr0_guest_owned_bits) - kvm_x86_ops.decache_cr0_guest_bits(vcpu); + if ((tmask & vcpu->arch.cr0_guest_owned_bits) && + !kvm_register_is_available(vcpu, VCPU_EXREG_CR0)) + kvm_x86_ops.cache_reg(vcpu, VCPU_EXREG_CR0); return vcpu->arch.cr0 & mask; } diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 805297e..9e24b5b 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -1521,10 +1521,6 @@ static void svm_set_gdt(struct kvm_vcpu *vcpu, struct desc_ptr *dt) mark_dirty(svm->vmcb, VMCB_DT); } -static void svm_decache_cr0_guest_bits(struct kvm_vcpu *vcpu) -{ -} - static void update_cr0_intercept(struct vcpu_svm *svm) { ulong gcr0 = svm->vcpu.arch.cr0; @@ -4002,7 +3998,6 @@ static struct kvm_x86_ops svm_x86_ops __initdata = { .set_segment = svm_set_segment, .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, .set_cr0 = svm_set_cr0, .set_cr4 = svm_set_cr4, .set_efer = svm_set_efer, diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 83e3fe0..a7dca7e 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -2219,6 +2219,12 @@ static void vmx_cache_reg(struct kvm_vcpu *vcpu, enum kvm_reg reg) if (enable_ept) ept_save_pdptrs(vcpu); break; + case VCPU_EXREG_CR0: + guest_owned_bits = vcpu->arch.cr0_guest_owned_bits; + + vcpu->arch.cr0 &= ~guest_owned_bits; + vcpu->arch.cr0 |= vmcs_readl(GUEST_CR0) & guest_owned_bits; + break; case VCPU_EXREG_CR3: if (enable_unrestricted_guest || (enable_ept && is_paging(vcpu))) vcpu->arch.cr3 = vmcs_readl(GUEST_CR3); @@ -2922,14 +2928,6 @@ static void vmx_flush_tlb_guest(struct kvm_vcpu *vcpu) vpid_sync_context(to_vmx(vcpu)->vpid); } -static void vmx_decache_cr0_guest_bits(struct kvm_vcpu *vcpu) -{ - ulong cr0_guest_owned_bits = vcpu->arch.cr0_guest_owned_bits; - - vcpu->arch.cr0 &= ~cr0_guest_owned_bits; - vcpu->arch.cr0 |= vmcs_readl(GUEST_CR0) & cr0_guest_owned_bits; -} - static void ept_load_pdptrs(struct kvm_vcpu *vcpu) { struct kvm_mmu *mmu = vcpu->arch.walk_mmu; @@ -3019,6 +3017,7 @@ void vmx_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0) vmcs_writel(CR0_READ_SHADOW, cr0); vmcs_writel(GUEST_CR0, hw_cr0); vcpu->arch.cr0 = cr0; + kvm_register_mark_available(vcpu, VCPU_EXREG_CR0); /* depends on vcpu->arch.cr0 to be set to a new value */ vmx->emulation_required = emulation_required(vcpu); @@ -7809,7 +7808,6 @@ static struct kvm_x86_ops vmx_x86_ops __initdata = { .set_segment = vmx_set_segment, .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, .set_cr0 = vmx_set_cr0, .set_cr4 = vmx_set_cr4, .set_efer = vmx_set_efer, diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h index 04bb557..298ddef 100644 --- a/arch/x86/kvm/vmx/vmx.h +++ b/arch/x86/kvm/vmx/vmx.h @@ -452,6 +452,7 @@ static inline void vmx_register_cache_reset(struct kvm_vcpu *vcpu) | (1 << VCPU_EXREG_RFLAGS) | (1 << VCPU_EXREG_PDPTR) | (1 << VCPU_EXREG_SEGMENTS) + | (1 << VCPU_EXREG_CR0) | (1 << VCPU_EXREG_CR3) | (1 << VCPU_EXREG_CR4) | (1 << VCPU_EXREG_EXIT_INFO_1) -- 2.7.4