From: Maxim Levitsky <mlevitsk@redhat.com>
To: kvm@vger.kernel.org
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Borislav Petkov <bp@alien8.de>, Bandan Das <bsd@redhat.com>,
linux-kernel@vger.kernel.org (open list),
Joerg Roedel <joro@8bytes.org>, Ingo Molnar <mingo@redhat.com>,
Wei Huang <wei.huang2@amd.com>,
Sean Christopherson <seanjc@google.com>,
linux-kselftest@vger.kernel.org (open list:KERNEL SELFTEST
FRAMEWORK), Maxim Levitsky <mlevitsk@redhat.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Jim Mattson <jmattson@google.com>,
Thomas Gleixner <tglx@linutronix.de>,
x86@kernel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)),
Shuah Khan <shuah@kernel.org>, Wanpeng Li <wanpengli@tencent.com>
Subject: [PATCH 10/14] KVM: x86: nSVM: implement nested LBR virtualization
Date: Tue, 14 Sep 2021 18:48:21 +0300 [thread overview]
Message-ID: <20210914154825.104886-11-mlevitsk@redhat.com> (raw)
In-Reply-To: <20210914154825.104886-1-mlevitsk@redhat.com>
This was tested with kvm-unit-test that was developed
for this purpose.
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
---
arch/x86/kvm/svm/nested.c | 21 +++++++++++++++++++--
arch/x86/kvm/svm/svm.c | 9 +++++++++
arch/x86/kvm/svm/svm.h | 1 +
3 files changed, 29 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index c6f09b591696..aadbff9b6514 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -503,8 +503,19 @@ static void nested_vmcb02_prepare_save(struct vcpu_svm *svm, struct vmcb *vmcb12
vmcb_mark_dirty(svm->vmcb, VMCB_DR);
}
- if (unlikely(svm->vmcb01.ptr->control.virt_ext & LBR_CTL_ENABLE_MASK))
+ if (unlikely(svm->lbrv_enabled && (svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK))) {
+ svm_copy_lbrs(vmcb12, svm->vmcb);
+ /*
+ * TODO: to avoid TOC/TOU race,
+ * make sure that we only pick LBR enable bit from
+ * the guest.
+ */
+ svm->vmcb->save.dbgctl &= LBR_CTL_ENABLE_MASK;
+ svm_update_lbrv(&svm->vcpu);
+
+ } else if (unlikely(svm->vmcb01.ptr->control.virt_ext & LBR_CTL_ENABLE_MASK)) {
svm_copy_lbrs(svm->vmcb01.ptr, svm->vmcb);
+ }
}
static void nested_vmcb02_prepare_control(struct vcpu_svm *svm)
@@ -555,6 +566,9 @@ static void nested_vmcb02_prepare_control(struct vcpu_svm *svm)
svm->vmcb->control.virt_ext = svm->vmcb01.ptr->control.virt_ext &
LBR_CTL_ENABLE_MASK;
+ if (svm->lbrv_enabled)
+ svm->vmcb->control.virt_ext |=
+ (svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK);
nested_svm_transition_tlb_flush(vcpu);
@@ -814,7 +828,10 @@ int nested_svm_vmexit(struct vcpu_svm *svm)
svm_switch_vmcb(svm, &svm->vmcb01);
- if (unlikely(svm->vmcb->control.virt_ext & LBR_CTL_ENABLE_MASK)) {
+ if (unlikely(svm->lbrv_enabled && (svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK))) {
+ svm_copy_lbrs(svm->nested.vmcb02.ptr, vmcb12);
+ svm_update_lbrv(vcpu);
+ } else if (unlikely(svm->vmcb->control.virt_ext & LBR_CTL_ENABLE_MASK)) {
svm_copy_lbrs(svm->nested.vmcb02.ptr, svm->vmcb);
svm_update_lbrv(vcpu);
}
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 981cc9765b95..66f99e8d804c 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -877,6 +877,10 @@ void svm_update_lbrv(struct kvm_vcpu *vcpu)
bool current_enable_lbrv = !!(svm->vmcb->control.virt_ext &
LBR_CTL_ENABLE_MASK);
+ if (unlikely(is_guest_mode(vcpu) && svm->lbrv_enabled))
+ if (unlikely(svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK))
+ enable_lbrv = true;
+
if (enable_lbrv == current_enable_lbrv)
return;
@@ -1006,6 +1010,9 @@ static __init void svm_set_cpu_caps(void)
if (npt_enabled)
kvm_cpu_cap_set(X86_FEATURE_NPT);
+ if (lbrv)
+ kvm_cpu_cap_set(X86_FEATURE_LBRV);
+
/* Nested VM can receive #VMEXIT instead of triggering #GP */
kvm_cpu_cap_set(X86_FEATURE_SVME_ADDR_CHK);
}
@@ -4081,6 +4088,8 @@ static void svm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
svm->nrips_enabled = kvm_cpu_cap_has(X86_FEATURE_NRIPS) &&
guest_cpuid_has(vcpu, X86_FEATURE_NRIPS);
+ svm->lbrv_enabled = lbrv && guest_cpuid_has(vcpu, X86_FEATURE_LBRV);
+
svm_recalc_instruction_intercepts(vcpu, svm);
/* For sev guests, the memory encryption bit is not reserved in CR3. */
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 0c351e9c4d6d..c9a81e18707d 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -161,6 +161,7 @@ struct vcpu_svm {
/* cached guest cpuid flags for faster access */
bool nrips_enabled : 1;
+ bool lbrv_enabled : 1;
u32 ldr_reg;
u32 dfr_reg;
--
2.26.3
next prev parent reply other threads:[~2021-09-14 15:50 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-14 15:48 [PATCH 00/14] nSVM fixes and optional features Maxim Levitsky
2021-09-14 15:48 ` [PATCH 01/14] KVM: x86: nSVM: restore int_vector in svm_clear_vintr Maxim Levitsky
2021-09-23 14:04 ` Paolo Bonzini
2021-09-14 15:48 ` [PATCH 02/14] KVM: x86: selftests: test simultaneous uses of V_IRQ from L1 and L0 Maxim Levitsky
2021-09-23 14:05 ` Paolo Bonzini
2021-09-14 15:48 ` [PATCH 03/14] KVM: x86: nSVM: test eax for 4K alignment for GP errata workaround Maxim Levitsky
2021-09-23 14:05 ` Paolo Bonzini
2021-09-14 15:48 ` [PATCH 04/14] KVM: x86: nSVM: don't copy pause related settings Maxim Levitsky
2021-09-14 15:48 ` [PATCH 05/14] KVM: x86: nSVM: don't copy virt_ext from vmcb12 Maxim Levitsky
2021-09-23 14:06 ` Paolo Bonzini
2021-09-14 15:48 ` [PATCH 06/14] KVM: x86: SVM: don't set VMLOAD/VMSAVE intercepts on vCPU reset Maxim Levitsky
2021-09-23 16:40 ` Paolo Bonzini
2021-09-14 15:48 ` [PATCH 07/14] KVM: x86: SVM: add warning for CVE-2021-3656 Maxim Levitsky
2021-09-23 16:44 ` Paolo Bonzini
2021-10-12 0:21 ` Sean Christopherson
2021-10-11 17:30 ` Xiaoyao Li
2021-10-12 7:51 ` Maxim Levitsky
2021-09-14 15:48 ` [PATCH 08/14] KVM: x86: SVM: add module param to control LBR virtualization Maxim Levitsky
2021-09-14 15:48 ` [PATCH 09/14] KVM: x86: nSVM: correctly virtualize LBR msrs when L2 is running Maxim Levitsky
2021-09-14 15:48 ` Maxim Levitsky [this message]
2021-09-14 15:48 ` [PATCH 11/14] KVM: x86: nSVM: implement nested VMLOAD/VMSAVE Maxim Levitsky
2021-09-14 15:48 ` [PATCH 12/14] KVM: x86: SVM: add module param to control TSC scaling Maxim Levitsky
2021-09-14 15:48 ` [PATCH 13/14] KVM: x86: nSVM: implement nested " Maxim Levitsky
2021-09-14 15:48 ` [PATCH 14/14] KVM: x86: nSVM: support PAUSE filter threshold and count Maxim Levitsky
2021-09-23 16:54 ` [PATCH 00/14] nSVM fixes and optional features Paolo Bonzini
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