From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 07/10] KVM: VMX: Add proper cache tracking for CR0
Date: Fri, 1 May 2020 21:32:31 -0700 [thread overview]
Message-ID: <20200502043234.12481-8-sean.j.christopherson@intel.com> (raw)
In-Reply-To: <20200502043234.12481-1-sean.j.christopherson@intel.com>
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 <sean.j.christopherson@intel.com>
---
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 dbf7d3f2edbc..55c8f78bc9e8 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,
@@ -1091,7 +1092,6 @@ 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 921a539bcb96..ff2d0e9ca3bc 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 e09f7e8b961f..e185368a2d32 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1524,10 +1524,6 @@ 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;
@@ -3993,7 +3989,6 @@ 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 31316cffb427..0cb0c347de04 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -2202,6 +2202,12 @@ 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);
@@ -2905,14 +2911,6 @@ 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;
@@ -3002,6 +3000,7 @@ 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);
@@ -7782,7 +7781,6 @@ 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 39d0f32372e7..5f3f141d7254 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)
--
2.26.0
next prev parent reply other threads:[~2020-05-02 4:33 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-02 4:32 [PATCH 00/10] KVM: x86: Misc anti-retpoline optimizations Sean Christopherson
2020-05-02 4:32 ` [PATCH 01/10] KVM: x86: Save L1 TSC offset in 'struct kvm_vcpu_arch' Sean Christopherson
2020-05-02 4:32 ` [PATCH 02/10] KVM: nVMX: Unconditionally validate CR3 during nested transitions Sean Christopherson
2020-05-02 4:32 ` [PATCH 03/10] KVM: x86: Make kvm_x86_ops' {g,s}et_dr6() hooks optional Sean Christopherson
2020-05-04 13:19 ` Paolo Bonzini
2020-05-02 4:32 ` [PATCH 04/10] KVM: x86: Split guts of kvm_update_dr7() to separate helper Sean Christopherson
2020-05-02 4:32 ` [PATCH 05/10] KVM: nVMX: Avoid retpoline when writing DR7 during nested transitions Sean Christopherson
2020-05-02 4:32 ` [PATCH 06/10] KVM: VMX: Add proper cache tracking for CR4 Sean Christopherson
2020-05-02 4:32 ` Sean Christopherson [this message]
2020-05-02 4:32 ` [PATCH 08/10] KVM: VMX: Add anti-retpoline accessors for RIP and RSP Sean Christopherson
2020-05-02 4:32 ` [PATCH 09/10] KVM: VMX: Move nested EPT out of kvm_x86_ops.get_tdp_level() hook Sean Christopherson
2020-05-02 4:32 ` [PATCH 10/10] KVM: x86/mmu: Capture TDP level when updating CPUID Sean Christopherson
2020-05-04 13:25 ` [PATCH 00/10] KVM: x86: Misc anti-retpoline optimizations Paolo Bonzini
2020-05-04 15:09 ` Sean Christopherson
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