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Message-ID: <20230815203653.519297-12-seanjc@google.com>
Date: Tue, 15 Aug 2023 13:36:49 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: Sean Christopherson <seanjc@...gle.com>,
Paolo Bonzini <pbonzini@...hat.com>,
Vitaly Kuznetsov <vkuznets@...hat.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
Zeng Guang <guang.zeng@...el.com>,
Yuan Yao <yuan.yao@...el.com>
Subject: [PATCH v3 11/15] KVM: nSVM: Use KVM-governed feature framework to
track "LBRv enabled"
Track "LBR virtualization exposed to L1" via a governed feature flag
instead of using a dedicated bit/flag in vcpu_svm.
Note, checking KVM's capabilities instead of the "lbrv" param means that
the code isn't strictly equivalent, as lbrv_enabled could have been set
if nested=false where as that the governed feature cannot. But that's a
glorified nop as the feature/flag is consumed only by paths that are
gated by nSVM being enabled.
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
arch/x86/kvm/governed_features.h | 1 +
arch/x86/kvm/svm/nested.c | 23 +++++++++++++----------
arch/x86/kvm/svm/svm.c | 5 ++---
arch/x86/kvm/svm/svm.h | 1 -
4 files changed, 16 insertions(+), 14 deletions(-)
diff --git a/arch/x86/kvm/governed_features.h b/arch/x86/kvm/governed_features.h
index f01a95fd0071..3a4c0e40e1e0 100644
--- a/arch/x86/kvm/governed_features.h
+++ b/arch/x86/kvm/governed_features.h
@@ -11,6 +11,7 @@ KVM_GOVERNED_X86_FEATURE(VMX)
KVM_GOVERNED_X86_FEATURE(NRIPS)
KVM_GOVERNED_X86_FEATURE(TSCRATEMSR)
KVM_GOVERNED_X86_FEATURE(V_VMSAVE_VMLOAD)
+KVM_GOVERNED_X86_FEATURE(LBRV)
#undef KVM_GOVERNED_X86_FEATURE
#undef KVM_GOVERNED_FEATURE
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index 24d47ebeb0e0..f50f74b1a04e 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -552,6 +552,7 @@ static void nested_vmcb02_prepare_save(struct vcpu_svm *svm, struct vmcb *vmcb12
bool new_vmcb12 = false;
struct vmcb *vmcb01 = svm->vmcb01.ptr;
struct vmcb *vmcb02 = svm->nested.vmcb02.ptr;
+ struct kvm_vcpu *vcpu = &svm->vcpu;
nested_vmcb02_compute_g_pat(svm);
@@ -577,18 +578,18 @@ static void nested_vmcb02_prepare_save(struct vcpu_svm *svm, struct vmcb *vmcb12
vmcb_mark_dirty(vmcb02, VMCB_DT);
}
- kvm_set_rflags(&svm->vcpu, vmcb12->save.rflags | X86_EFLAGS_FIXED);
+ kvm_set_rflags(vcpu, vmcb12->save.rflags | X86_EFLAGS_FIXED);
- svm_set_efer(&svm->vcpu, svm->nested.save.efer);
+ svm_set_efer(vcpu, svm->nested.save.efer);
- svm_set_cr0(&svm->vcpu, svm->nested.save.cr0);
- svm_set_cr4(&svm->vcpu, svm->nested.save.cr4);
+ svm_set_cr0(vcpu, svm->nested.save.cr0);
+ svm_set_cr4(vcpu, svm->nested.save.cr4);
svm->vcpu.arch.cr2 = vmcb12->save.cr2;
- kvm_rax_write(&svm->vcpu, vmcb12->save.rax);
- kvm_rsp_write(&svm->vcpu, vmcb12->save.rsp);
- kvm_rip_write(&svm->vcpu, vmcb12->save.rip);
+ kvm_rax_write(vcpu, vmcb12->save.rax);
+ kvm_rsp_write(vcpu, vmcb12->save.rsp);
+ kvm_rip_write(vcpu, vmcb12->save.rip);
/* In case we don't even reach vcpu_run, the fields are not updated */
vmcb02->save.rax = vmcb12->save.rax;
@@ -602,7 +603,8 @@ static void nested_vmcb02_prepare_save(struct vcpu_svm *svm, struct vmcb *vmcb12
vmcb_mark_dirty(vmcb02, VMCB_DR);
}
- if (unlikely(svm->lbrv_enabled && (svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK))) {
+ if (unlikely(guest_can_use(vcpu, X86_FEATURE_LBRV) &&
+ (svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK))) {
/*
* Reserved bits of DEBUGCTL are ignored. Be consistent with
* svm_set_msr's definition of reserved bits.
@@ -734,7 +736,7 @@ static void nested_vmcb02_prepare_control(struct vcpu_svm *svm,
vmcb02->control.virt_ext = vmcb01->control.virt_ext &
LBR_CTL_ENABLE_MASK;
- if (svm->lbrv_enabled)
+ if (guest_can_use(vcpu, X86_FEATURE_LBRV))
vmcb02->control.virt_ext |=
(svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK);
@@ -1065,7 +1067,8 @@ int nested_svm_vmexit(struct vcpu_svm *svm)
if (!nested_exit_on_intr(svm))
kvm_make_request(KVM_REQ_EVENT, &svm->vcpu);
- if (unlikely(svm->lbrv_enabled && (svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK))) {
+ if (unlikely(guest_can_use(vcpu, X86_FEATURE_LBRV) &&
+ (svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK))) {
svm_copy_lbrs(vmcb12, vmcb02);
svm_update_lbrv(vcpu);
} else if (unlikely(vmcb01->control.virt_ext & LBR_CTL_ENABLE_MASK)) {
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 7cecbb58c60f..de40745bc8a6 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1032,7 +1032,7 @@ void svm_update_lbrv(struct kvm_vcpu *vcpu)
struct vcpu_svm *svm = to_svm(vcpu);
bool current_enable_lbrv = svm->vmcb->control.virt_ext & LBR_CTL_ENABLE_MASK;
bool enable_lbrv = (svm_get_lbr_vmcb(svm)->save.dbgctl & DEBUGCTLMSR_LBR) ||
- (is_guest_mode(vcpu) && svm->lbrv_enabled &&
+ (is_guest_mode(vcpu) && guest_can_use(vcpu, X86_FEATURE_LBRV) &&
(svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK));
if (enable_lbrv == current_enable_lbrv)
@@ -4290,8 +4290,7 @@ static void svm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
kvm_governed_feature_check_and_set(vcpu, X86_FEATURE_NRIPS);
kvm_governed_feature_check_and_set(vcpu, X86_FEATURE_TSCRATEMSR);
-
- svm->lbrv_enabled = lbrv && guest_cpuid_has(vcpu, X86_FEATURE_LBRV);
+ kvm_governed_feature_check_and_set(vcpu, X86_FEATURE_LBRV);
/*
* Intercept VMLOAD if the vCPU mode is Intel in order to emulate that
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index b3fdaab57363..45cbbdeac3a3 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -259,7 +259,6 @@ struct vcpu_svm {
bool soft_int_injected;
/* optional nested SVM features that are enabled for this guest */
- bool lbrv_enabled : 1;
bool pause_filter_enabled : 1;
bool pause_threshold_enabled : 1;
bool vgif_enabled : 1;
--
2.41.0.694.ge786442a9b-goog
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