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KVM: x86: nSVM: implement nested LBR virtualization

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This was tested with kvm-unit-test that was developed
for this purpose.

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20220322174050.241850-3-mlevitsk@redhat.com>
[Copy all of DEBUGCTL except for reserved bits. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Maxim Levitsky 2022-03-22 19:40:46 +02:00 committed by Paolo Bonzini
parent 1d5a1b5860
commit d20c796ca3
3 changed files with 28 additions and 4 deletions
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20
arch/x86/kvm/svm/nested.c
View File

@ -588,8 +588,18 @@ static void nested_vmcb02_prepare_save(struct vcpu_svm *svm, struct vmcb *vmcb12
vmcb_mark_dirty(vmcb02, VMCB_DR);
}
if (unlikely(vmcb01->control.virt_ext & LBR_CTL_ENABLE_MASK))
if (unlikely(svm->lbrv_enabled && (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.
*/
svm_copy_lbrs(vmcb02, vmcb12);
vmcb02->save.dbgctl &= ~DEBUGCTL_RESERVED_BITS;
svm_update_lbrv(&svm->vcpu);
} else if (unlikely(vmcb01->control.virt_ext & LBR_CTL_ENABLE_MASK)) {
svm_copy_lbrs(vmcb02, vmcb01);
}
}
static void nested_vmcb02_prepare_control(struct vcpu_svm *svm)
@ -651,6 +661,9 @@ 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)
vmcb02->control.virt_ext |=
(svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK);
if (!nested_vmcb_needs_vls_intercept(svm))
vmcb02->control.virt_ext |= VIRTUAL_VMLOAD_VMSAVE_ENABLE_MASK;
@ -919,7 +932,10 @@ int nested_svm_vmexit(struct vcpu_svm *svm)
svm_switch_vmcb(svm, &svm->vmcb01);
if (unlikely(vmcb01->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, vmcb02);
svm_update_lbrv(vcpu);
} else if (unlikely(vmcb01->control.virt_ext & LBR_CTL_ENABLE_MASK)) {
svm_copy_lbrs(vmcb01, vmcb02);
svm_update_lbrv(vcpu);
}

9
arch/x86/kvm/svm/svm.c
View File

@ -62,8 +62,6 @@ MODULE_DEVICE_TABLE(x86cpu, svm_cpu_id);
#define SEG_TYPE_LDT 2
#define SEG_TYPE_BUSY_TSS16 3
#define DEBUGCTL_RESERVED_BITS (~(0x3fULL))
static bool erratum_383_found __read_mostly;
u32 msrpm_offsets[MSRPM_OFFSETS] __read_mostly;
@ -878,6 +876,10 @@ 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;
@ -4012,6 +4014,7 @@ static void svm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
guest_cpuid_has(vcpu, X86_FEATURE_NRIPS);
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);
@ -4765,6 +4768,8 @@ static __init void svm_set_cpu_caps(void)
if (vls)
kvm_cpu_cap_set(X86_FEATURE_V_VMSAVE_VMLOAD);
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);

3
arch/x86/kvm/svm/svm.h
View File

@ -236,6 +236,7 @@ struct vcpu_svm {
bool nrips_enabled : 1;
bool tsc_scaling_enabled : 1;
bool v_vmload_vmsave_enabled : 1;
bool lbrv_enabled : 1;
u32 ldr_reg;
u32 dfr_reg;
@ -486,6 +487,8 @@ static inline bool nested_npt_enabled(struct vcpu_svm *svm)
/* svm.c */
#define MSR_INVALID 0xffffffffU
#define DEBUGCTL_RESERVED_BITS (~(0x3fULL))
extern bool dump_invalid_vmcb;
u32 svm_msrpm_offset(u32 msr);