| Message ID | 5cf935068a9539146e033276b6d9a6c9b1e42119.1617804573.git.viremana@linux.microsoft.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Hyper-V nested virt enlightenments for SVM | expand |
Vineeth Pillai <viremana@linux.microsoft.com> writes: > Enlightened MSR-Bitmap as per TLFS: > > "The L1 hypervisor may collaborate with the L0 hypervisor to make MSR > accesses more efficient. It can enable enlightened MSR bitmaps by setting > the corresponding field in the enlightened VMCS to 1. When enabled, L0 > hypervisor does not monitor the MSR bitmaps for changes. Instead, the L1 > hypervisor must invalidate the corresponding clean field after making > changes to one of the MSR bitmaps." > > Enable this for SVM. > > Related VMX changes: > commit ceef7d10dfb6 ("KVM: x86: VMX: hyper-v: Enlightened MSR-Bitmap support") > > Signed-off-by: Vineeth Pillai <viremana@linux.microsoft.com> > --- > arch/x86/kvm/svm/svm.c | 27 +++++++++++++++++++++++++++ > 1 file changed, 27 insertions(+) > > diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c > index 6287cab61f15..3562a247b7e8 100644 > --- a/arch/x86/kvm/svm/svm.c > +++ b/arch/x86/kvm/svm/svm.c > @@ -646,6 +646,27 @@ static bool msr_write_intercepted(struct kvm_vcpu *vcpu, u32 msr) > return !!test_bit(bit_write, &tmp); > } > > +#if IS_ENABLED(CONFIG_HYPERV) > +static inline void hv_vmcb_dirty_nested_enlightenments(struct kvm_vcpu *vcpu) > +{ > + struct vmcb *vmcb = to_svm(vcpu)->vmcb; > + > + /* > + * vmcb can be NULL if called during early vcpu init. > + * And its okay not to mark vmcb dirty during vcpu init > + * as we mark it dirty unconditionally towards end of vcpu > + * init phase. > + */ > + if (vmcb && vmcb_is_clean(vmcb, VMCB_HV_NESTED_ENLIGHTENMENTS) && > + vmcb->hv_enlightenments.hv_enlightenments_control.msr_bitmap) > + vmcb_mark_dirty(vmcb, VMCB_HV_NESTED_ENLIGHTENMENTS); vmcb_is_clean() check seems to be superfluous, vmcb_mark_dirty() does no harm if the bit was already cleared. > +} > +#else > +static inline void hv_vmcb_dirty_nested_enlightenments(struct kvm_vcpu *vcpu) > +{ > +} > +#endif > + > static void set_msr_interception_bitmap(struct kvm_vcpu *vcpu, u32 *msrpm, > u32 msr, int read, int write) > { > @@ -677,6 +698,9 @@ static void set_msr_interception_bitmap(struct kvm_vcpu *vcpu, u32 *msrpm, > write ? clear_bit(bit_write, &tmp) : set_bit(bit_write, &tmp); > > msrpm[offset] = tmp; > + > + hv_vmcb_dirty_nested_enlightenments(vcpu); > + > } > > void set_msr_interception(struct kvm_vcpu *vcpu, u32 *msrpm, u32 msr, > @@ -1135,6 +1159,9 @@ static void hv_init_vmcb(struct vmcb *vmcb) > if (npt_enabled && > ms_hyperv.nested_features & HV_X64_NESTED_ENLIGHTENED_TLB) > hve->hv_enlightenments_control.enlightened_npt_tlb = 1; > + > + if (ms_hyperv.nested_features & HV_X64_NESTED_MSR_BITMAP) > + hve->hv_enlightenments_control.msr_bitmap = 1; > } > #else > static inline void hv_init_vmcb(struct vmcb *vmcb)
On 07/04/21 16:41, Vineeth Pillai wrote: > > +#if IS_ENABLED(CONFIG_HYPERV) > +static inline void hv_vmcb_dirty_nested_enlightenments(struct kvm_vcpu *vcpu) > +{ > + struct vmcb *vmcb = to_svm(vcpu)->vmcb; > + > + /* > + * vmcb can be NULL if called during early vcpu init. > + * And its okay not to mark vmcb dirty during vcpu init > + * as we mark it dirty unconditionally towards end of vcpu > + * init phase. > + */ > + if (vmcb && vmcb_is_clean(vmcb, VMCB_HV_NESTED_ENLIGHTENMENTS) && > + vmcb->hv_enlightenments.hv_enlightenments_control.msr_bitmap) > + vmcb_mark_dirty(vmcb, VMCB_HV_NESTED_ENLIGHTENMENTS); > +} In addition to what Vitaly said, can svm->vmcb really be NULL? If so it might be better to reorder initializations and skip the NULL check. Paolo
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 6287cab61f15..3562a247b7e8 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -646,6 +646,27 @@ static bool msr_write_intercepted(struct kvm_vcpu *vcpu, u32 msr) return !!test_bit(bit_write, &tmp); } +#if IS_ENABLED(CONFIG_HYPERV) +static inline void hv_vmcb_dirty_nested_enlightenments(struct kvm_vcpu *vcpu) +{ + struct vmcb *vmcb = to_svm(vcpu)->vmcb; + + /* + * vmcb can be NULL if called during early vcpu init. + * And its okay not to mark vmcb dirty during vcpu init + * as we mark it dirty unconditionally towards end of vcpu + * init phase. + */ + if (vmcb && vmcb_is_clean(vmcb, VMCB_HV_NESTED_ENLIGHTENMENTS) && + vmcb->hv_enlightenments.hv_enlightenments_control.msr_bitmap) + vmcb_mark_dirty(vmcb, VMCB_HV_NESTED_ENLIGHTENMENTS); +} +#else +static inline void hv_vmcb_dirty_nested_enlightenments(struct kvm_vcpu *vcpu) +{ +} +#endif + static void set_msr_interception_bitmap(struct kvm_vcpu *vcpu, u32 *msrpm, u32 msr, int read, int write) { @@ -677,6 +698,9 @@ static void set_msr_interception_bitmap(struct kvm_vcpu *vcpu, u32 *msrpm, write ? clear_bit(bit_write, &tmp) : set_bit(bit_write, &tmp); msrpm[offset] = tmp; + + hv_vmcb_dirty_nested_enlightenments(vcpu); + } void set_msr_interception(struct kvm_vcpu *vcpu, u32 *msrpm, u32 msr, @@ -1135,6 +1159,9 @@ static void hv_init_vmcb(struct vmcb *vmcb) if (npt_enabled && ms_hyperv.nested_features & HV_X64_NESTED_ENLIGHTENED_TLB) hve->hv_enlightenments_control.enlightened_npt_tlb = 1; + + if (ms_hyperv.nested_features & HV_X64_NESTED_MSR_BITMAP) + hve->hv_enlightenments_control.msr_bitmap = 1; } #else static inline void hv_init_vmcb(struct vmcb *vmcb)
Enlightened MSR-Bitmap as per TLFS: "The L1 hypervisor may collaborate with the L0 hypervisor to make MSR accesses more efficient. It can enable enlightened MSR bitmaps by setting the corresponding field in the enlightened VMCS to 1. When enabled, L0 hypervisor does not monitor the MSR bitmaps for changes. Instead, the L1 hypervisor must invalidate the corresponding clean field after making changes to one of the MSR bitmaps." Enable this for SVM. Related VMX changes: commit ceef7d10dfb6 ("KVM: x86: VMX: hyper-v: Enlightened MSR-Bitmap support") Signed-off-by: Vineeth Pillai <viremana@linux.microsoft.com> --- arch/x86/kvm/svm/svm.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+)