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Message-Id: <20211101140324.197921-5-mlevitsk@redhat.com>
Date: Mon, 1 Nov 2021 16:03:22 +0200
From: Maxim Levitsky <mlevitsk@...hat.com>
To: kvm@...r.kernel.org
Cc: Shuah Khan <shuah@...nel.org>,
linux-kselftest@...r.kernel.org (open list:KERNEL SELFTEST FRAMEWORK),
Borislav Petkov <bp@...en8.de>,
Paolo Bonzini <pbonzini@...hat.com>,
linux-kernel@...r.kernel.org (open list:X86 ARCHITECTURE (32-BIT AND
64-BIT)), Joerg Roedel <joro@...tes.org>,
"H. Peter Anvin" <hpa@...or.com>,
Maxim Levitsky <mlevitsk@...hat.com>,
Thomas Gleixner <tglx@...utronix.de>,
Vitaly Kuznetsov <vkuznets@...hat.com>,
Bandan Das <bsd@...hat.com>,
Wanpeng Li <wanpengli@...cent.com>,
Jim Mattson <jmattson@...gle.com>,
Sean Christopherson <seanjc@...gle.com>,
Wei Huang <wei.huang2@....com>,
x86@...nel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)),
Ingo Molnar <mingo@...hat.com>
Subject: [PATCH v2 4/6] KVM: x86: nSVM: implement nested VMLOAD/VMSAVE
This was tested by booting L1,L2,L3 (all Linux) and checking
that no VMLOAD/VMSAVE vmexits happened.
Signed-off-by: Maxim Levitsky <mlevitsk@...hat.com>
---
arch/x86/kvm/svm/nested.c | 35 +++++++++++++++++++++++++++++------
arch/x86/kvm/svm/svm.c | 7 +++++++
arch/x86/kvm/svm/svm.h | 8 +++++++-
3 files changed, 43 insertions(+), 7 deletions(-)
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index eca0f2f41bf30..2dc97cca68f7c 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -119,6 +119,20 @@ static void nested_svm_uninit_mmu_context(struct kvm_vcpu *vcpu)
vcpu->arch.walk_mmu = &vcpu->arch.root_mmu;
}
+static bool nested_vmcb_needs_vls_intercept(struct vcpu_svm *svm)
+{
+ if (!svm->v_vmload_vmsave_enabled)
+ return true;
+
+ if (!nested_npt_enabled(svm))
+ return true;
+
+ if (!(svm->nested.ctl.virt_ext & VIRTUAL_VMLOAD_VMSAVE_ENABLE_MASK))
+ return true;
+
+ return false;
+}
+
void recalc_intercepts(struct vcpu_svm *svm)
{
struct vmcb_control_area *c, *h, *g;
@@ -159,8 +173,17 @@ void recalc_intercepts(struct vcpu_svm *svm)
if (!intercept_smi)
vmcb_clr_intercept(c, INTERCEPT_SMI);
- vmcb_set_intercept(c, INTERCEPT_VMLOAD);
- vmcb_set_intercept(c, INTERCEPT_VMSAVE);
+ if (nested_vmcb_needs_vls_intercept(svm)) {
+ /*
+ * If the virtual VMLOAD/VMSAVE is not enabled for the L2,
+ * we must intercept these instructions to correctly
+ * emulate them in case L1 doesn't intercept them.
+ */
+ vmcb_set_intercept(c, INTERCEPT_VMLOAD);
+ vmcb_set_intercept(c, INTERCEPT_VMSAVE);
+ } else {
+ WARN_ON(!(c->virt_ext & VIRTUAL_VMLOAD_VMSAVE_ENABLE_MASK));
+ }
}
static void copy_vmcb_control_area(struct vmcb_control_area *dst,
@@ -402,10 +425,7 @@ static void nested_save_pending_event_to_vmcb12(struct vcpu_svm *svm,
vmcb12->control.exit_int_info = exit_int_info;
}
-static inline bool nested_npt_enabled(struct vcpu_svm *svm)
-{
- return svm->nested.ctl.nested_ctl & SVM_NESTED_CTL_NP_ENABLE;
-}
+
static void nested_svm_transition_tlb_flush(struct kvm_vcpu *vcpu)
{
@@ -594,6 +614,9 @@ static void nested_vmcb02_prepare_control(struct vcpu_svm *svm)
svm->vmcb->control.virt_ext |=
(svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK);
+ if (!nested_vmcb_needs_vls_intercept(svm))
+ svm->vmcb->control.virt_ext |= VIRTUAL_VMLOAD_VMSAVE_ENABLE_MASK;
+
nested_svm_transition_tlb_flush(vcpu);
/* Enter Guest-Mode */
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 0ae8fa9400902..77fd0922c4060 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1023,6 +1023,9 @@ static __init void svm_set_cpu_caps(void)
if (lbrv)
kvm_cpu_cap_set(X86_FEATURE_LBRV);
+ if (vls)
+ kvm_cpu_cap_set(X86_FEATURE_V_VMSAVE_VMLOAD);
+
/* Nested VM can receive #VMEXIT instead of triggering #GP */
kvm_cpu_cap_set(X86_FEATURE_SVME_ADDR_CHK);
}
@@ -1274,6 +1277,8 @@ static inline void init_vmcb_after_set_cpuid(struct kvm_vcpu *vcpu)
set_msr_interception(vcpu, svm->msrpm, MSR_IA32_SYSENTER_EIP, 0, 0);
set_msr_interception(vcpu, svm->msrpm, MSR_IA32_SYSENTER_ESP, 0, 0);
+
+ svm->v_vmload_vmsave_enabled = false;
} else {
/*
* If hardware supports Virtual VMLOAD VMSAVE then enable it
@@ -4156,6 +4161,8 @@ static void svm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
svm->tsc_scaling_enabled = tsc_scaling && guest_cpuid_has(vcpu, X86_FEATURE_TSCRATEMSR);
svm->lbrv_enabled = lbrv && guest_cpuid_has(vcpu, X86_FEATURE_LBRV);
+ svm->v_vmload_vmsave_enabled = vls && guest_cpuid_has(vcpu, X86_FEATURE_V_VMSAVE_VMLOAD);
+
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 c3d46fdf4b9ad..ec8dd09e41e69 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -161,10 +161,11 @@ struct vcpu_svm {
unsigned int3_injected;
unsigned long int3_rip;
- /* cached guest cpuid flags for faster access */
+ /* optional nested SVM features that are enabled for this guest */
bool nrips_enabled : 1;
bool tsc_scaling_enabled : 1;
bool lbrv_enabled : 1;
+ bool v_vmload_vmsave_enabled : 1;
u32 ldr_reg;
u32 dfr_reg;
@@ -412,6 +413,11 @@ static inline bool gif_set(struct vcpu_svm *svm)
return !!(svm->vcpu.arch.hflags & HF_GIF_MASK);
}
+static inline bool nested_npt_enabled(struct vcpu_svm *svm)
+{
+ return svm->nested.ctl.nested_ctl & SVM_NESTED_CTL_NP_ENABLE;
+}
+
/* svm.c */
#define MSR_INVALID 0xffffffffU
--
2.26.3
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