This was tested by booting L1,L2,L3 (all Linux) and checking
that no VMLOAD/VMSAVE vmexits happened.
Signed-off-by: Maxim Levitsky <mlevitsk@xxxxxxxxxx>
---
arch/x86/kvm/svm/nested.c | 35 +++++++++++++++++++++++++++++------
arch/x86/kvm/svm/svm.c | 7 +++++++
arch/x86/kvm/svm/svm.h | 12 +++++++++---
3 files changed, 45 insertions(+), 9 deletions(-)
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index aadbff9b6514..29b5d0f85960 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,
@@ -387,10 +410,7 @@ 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)
{
@@ -570,6 +590,9 @@ 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 66f99e8d804c..6504e40e0985 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1013,6 +1013,9 @@ 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);
}
@@ -4090,6 +4093,8 @@ static void svm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
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. */
@@ -4129,6 +4134,8 @@ static void svm_vcpu_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
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index c9a81e18707d..029340a7fbcc 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -159,9 +159,10 @@ struct vcpu_svm {
unsigned int3_injected;
unsigned long int3_rip;
- /* cached guest cpuid flags for faster access */
- bool nrips_enabled : 1;
- bool lbrv_enabled : 1;
+ /* optional nested SVM features that are enabled for this guest */
+ bool nrips_enabled : 1;
+ bool lbrv_enabled : 1;
+ bool v_vmload_vmsave_enabled : 1;
u32 ldr_reg;
u32 dfr_reg;
@@ -409,6 +410,11 @@ 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
