arch/x86/kvm/hyperv.c | 12 +-------- arch/x86/kvm/hyperv.h | 6 ++++- arch/x86/kvm/svm/nested.c | 47 ++++++++++++++++++++++++++++----- arch/x86/kvm/svm/svm.c | 3 ++- arch/x86/kvm/svm/svm.h | 16 +++++++---- arch/x86/kvm/svm/svm_onhyperv.h | 12 +++------ 6 files changed, 63 insertions(+), 33 deletions(-)
Enlightened MSR-Bitmap feature implements a PV protocol for L0 and L1
hypervisors to collaborate and skip unneeded updates to MSR-Bitmap.
KVM implements the feature for KVM-on-Hyper-V but it seems there was
a flaw in the implementation and the feature may not be fully functional.
PATCHes 1-2 fix the problem. The rest of the series implements the same
feature for Hyper-V-on-KVM.
Vitaly Kuznetsov (5):
KVM: SVM: Drop stale comment from
svm_hv_vmcb_dirty_nested_enlightenments()
KVM: SVM: hyper-v: Enable Enlightened MSR-Bitmap support for real
KVM: nSVM: Track whether changes in L0 require MSR bitmap for L2 to be
rebuilt
KVM: x86: Make kvm_hv_hypercall_enabled() static inline
KVM: nSVM: Implement Enlightened MSR-Bitmap feature
arch/x86/kvm/hyperv.c | 12 +--------
arch/x86/kvm/hyperv.h | 6 ++++-
arch/x86/kvm/svm/nested.c | 47 ++++++++++++++++++++++++++++-----
arch/x86/kvm/svm/svm.c | 3 ++-
arch/x86/kvm/svm/svm.h | 16 +++++++----
arch/x86/kvm/svm/svm_onhyperv.h | 12 +++------
6 files changed, 63 insertions(+), 33 deletions(-)
--
2.33.1
On 12/20/21 16:21, Vitaly Kuznetsov wrote: > Enlightened MSR-Bitmap feature implements a PV protocol for L0 and L1 > hypervisors to collaborate and skip unneeded updates to MSR-Bitmap. > KVM implements the feature for KVM-on-Hyper-V but it seems there was > a flaw in the implementation and the feature may not be fully functional. > PATCHes 1-2 fix the problem. The rest of the series implements the same > feature for Hyper-V-on-KVM. > > Vitaly Kuznetsov (5): > KVM: SVM: Drop stale comment from > svm_hv_vmcb_dirty_nested_enlightenments() > KVM: SVM: hyper-v: Enable Enlightened MSR-Bitmap support for real > KVM: nSVM: Track whether changes in L0 require MSR bitmap for L2 to be > rebuilt > KVM: x86: Make kvm_hv_hypercall_enabled() static inline > KVM: nSVM: Implement Enlightened MSR-Bitmap feature > > arch/x86/kvm/hyperv.c | 12 +-------- > arch/x86/kvm/hyperv.h | 6 ++++- > arch/x86/kvm/svm/nested.c | 47 ++++++++++++++++++++++++++++----- > arch/x86/kvm/svm/svm.c | 3 ++- > arch/x86/kvm/svm/svm.h | 16 +++++++---- > arch/x86/kvm/svm/svm_onhyperv.h | 12 +++------ > 6 files changed, 63 insertions(+), 33 deletions(-) > Queued 3-5 now, but it would be nice to have some testcases. Paolo
Paolo Bonzini <pbonzini@redhat.com> writes: > On 12/20/21 16:21, Vitaly Kuznetsov wrote: >> Enlightened MSR-Bitmap feature implements a PV protocol for L0 and L1 >> hypervisors to collaborate and skip unneeded updates to MSR-Bitmap. >> KVM implements the feature for KVM-on-Hyper-V but it seems there was >> a flaw in the implementation and the feature may not be fully functional. >> PATCHes 1-2 fix the problem. The rest of the series implements the same >> feature for Hyper-V-on-KVM. >> >> Vitaly Kuznetsov (5): >> KVM: SVM: Drop stale comment from >> svm_hv_vmcb_dirty_nested_enlightenments() >> KVM: SVM: hyper-v: Enable Enlightened MSR-Bitmap support for real >> KVM: nSVM: Track whether changes in L0 require MSR bitmap for L2 to be >> rebuilt >> KVM: x86: Make kvm_hv_hypercall_enabled() static inline >> KVM: nSVM: Implement Enlightened MSR-Bitmap feature >> >> arch/x86/kvm/hyperv.c | 12 +-------- >> arch/x86/kvm/hyperv.h | 6 ++++- >> arch/x86/kvm/svm/nested.c | 47 ++++++++++++++++++++++++++++----- >> arch/x86/kvm/svm/svm.c | 3 ++- >> arch/x86/kvm/svm/svm.h | 16 +++++++---- >> arch/x86/kvm/svm/svm_onhyperv.h | 12 +++------ >> 6 files changed, 63 insertions(+), 33 deletions(-) >> > > Queued 3-5 now, but it would be nice to have some testcases. > Thanks, indeed, I'll try to draft something up, both for nVMX and nSVM. -- Vitaly
On 2/1/22 15:31, Vitaly Kuznetsov wrote:
> Paolo Bonzini <pbonzini@redhat.com> writes:
>
>> On 12/20/21 16:21, Vitaly Kuznetsov wrote:
>>> Enlightened MSR-Bitmap feature implements a PV protocol for L0 and L1
>>> hypervisors to collaborate and skip unneeded updates to MSR-Bitmap.
>>> KVM implements the feature for KVM-on-Hyper-V but it seems there was
>>> a flaw in the implementation and the feature may not be fully functional.
>>> PATCHes 1-2 fix the problem. The rest of the series implements the same
>>> feature for Hyper-V-on-KVM.
>>>
>>> Vitaly Kuznetsov (5):
>>> KVM: SVM: Drop stale comment from
>>> svm_hv_vmcb_dirty_nested_enlightenments()
>>> KVM: SVM: hyper-v: Enable Enlightened MSR-Bitmap support for real
>>> KVM: nSVM: Track whether changes in L0 require MSR bitmap for L2 to be
>>> rebuilt
>>> KVM: x86: Make kvm_hv_hypercall_enabled() static inline
>>> KVM: nSVM: Implement Enlightened MSR-Bitmap feature
>>>
>>> arch/x86/kvm/hyperv.c | 12 +--------
>>> arch/x86/kvm/hyperv.h | 6 ++++-
>>> arch/x86/kvm/svm/nested.c | 47 ++++++++++++++++++++++++++++-----
>>> arch/x86/kvm/svm/svm.c | 3 ++-
>>> arch/x86/kvm/svm/svm.h | 16 +++++++----
>>> arch/x86/kvm/svm/svm_onhyperv.h | 12 +++------
>>> 6 files changed, 63 insertions(+), 33 deletions(-)
>>>
>>
>> Queued 3-5 now, but it would be nice to have some testcases.
Hmm, it fails to compile with CONFIG_HYPERV disabled, and a trivial
#if also fails due to an unused goto label. Does this look good to you?
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index e3759a79d39a..a2b5267b3e73 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -173,9 +173,16 @@ void recalc_intercepts(struct vcpu_svm *svm)
*/
static bool nested_svm_vmrun_msrpm(struct vcpu_svm *svm)
{
+ int i;
+
+ if (!(vmcb12_is_intercept(&svm->nested.ctl, INTERCEPT_MSR_PROT)))
+ return true;
+
+ svm->vmcb->control.msrpm_base_pa = __sme_set(__pa(svm->nested.msrpm));
+
+#if IS_ENABLED(CONFIG_HYPERV)
struct hv_enlightenments *hve =
(struct hv_enlightenments *)svm->nested.ctl.reserved_sw;
- int i;
/*
* MSR bitmap update can be skipped when:
@@ -185,10 +192,8 @@ static bool nested_svm_vmrun_msrpm(struct vcpu_svm *svm)
kvm_hv_hypercall_enabled(&svm->vcpu) &&
hve->hv_enlightenments_control.msr_bitmap &&
(svm->nested.ctl.clean & VMCB_HV_NESTED_ENLIGHTENMENTS))
- goto set_msrpm_base_pa;
-
- if (!(vmcb12_is_intercept(&svm->nested.ctl, INTERCEPT_MSR_PROT)))
return true;
+#endif
for (i = 0; i < MSRPM_OFFSETS; i++) {
u32 value, p;
@@ -213,10 +216,6 @@ static bool nested_svm_vmrun_msrpm(struct vcpu_svm *svm)
}
svm->nested.force_msr_bitmap_recalc = false;
-
-set_msrpm_base_pa:
- svm->vmcb->control.msrpm_base_pa = __sme_set(__pa(svm->nested.msrpm));
-
return true;
}
Thanks,
Paolo
Paolo Bonzini <pbonzini@redhat.com> writes:
> On 2/1/22 15:31, Vitaly Kuznetsov wrote:
>> Paolo Bonzini <pbonzini@redhat.com> writes:
>>
>>> On 12/20/21 16:21, Vitaly Kuznetsov wrote:
>>>> Enlightened MSR-Bitmap feature implements a PV protocol for L0 and L1
>>>> hypervisors to collaborate and skip unneeded updates to MSR-Bitmap.
>>>> KVM implements the feature for KVM-on-Hyper-V but it seems there was
>>>> a flaw in the implementation and the feature may not be fully functional.
>>>> PATCHes 1-2 fix the problem. The rest of the series implements the same
>>>> feature for Hyper-V-on-KVM.
>>>>
>>>> Vitaly Kuznetsov (5):
>>>> KVM: SVM: Drop stale comment from
>>>> svm_hv_vmcb_dirty_nested_enlightenments()
>>>> KVM: SVM: hyper-v: Enable Enlightened MSR-Bitmap support for real
>>>> KVM: nSVM: Track whether changes in L0 require MSR bitmap for L2 to be
>>>> rebuilt
>>>> KVM: x86: Make kvm_hv_hypercall_enabled() static inline
>>>> KVM: nSVM: Implement Enlightened MSR-Bitmap feature
>>>>
>>>> arch/x86/kvm/hyperv.c | 12 +--------
>>>> arch/x86/kvm/hyperv.h | 6 ++++-
>>>> arch/x86/kvm/svm/nested.c | 47 ++++++++++++++++++++++++++++-----
>>>> arch/x86/kvm/svm/svm.c | 3 ++-
>>>> arch/x86/kvm/svm/svm.h | 16 +++++++----
>>>> arch/x86/kvm/svm/svm_onhyperv.h | 12 +++------
>>>> 6 files changed, 63 insertions(+), 33 deletions(-)
>>>>
>>>
>>> Queued 3-5 now, but it would be nice to have some testcases.
>
> Hmm, it fails to compile with CONFIG_HYPERV disabled, and a trivial
> #if also fails due to an unused goto label. Does this look good to you?
>
Hm, it does but honestly I did not anticipate this dependency --
CONFIG_HYPERV is needed for KVM-on-Hyper-V but this feature is for
Hyper-V-on-KVM. Let me take a look tomorrow.
> diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
> index e3759a79d39a..a2b5267b3e73 100644
> --- a/arch/x86/kvm/svm/nested.c
> +++ b/arch/x86/kvm/svm/nested.c
> @@ -173,9 +173,16 @@ void recalc_intercepts(struct vcpu_svm *svm)
> */
> static bool nested_svm_vmrun_msrpm(struct vcpu_svm *svm)
> {
> + int i;
> +
> + if (!(vmcb12_is_intercept(&svm->nested.ctl, INTERCEPT_MSR_PROT)))
> + return true;
> +
> + svm->vmcb->control.msrpm_base_pa = __sme_set(__pa(svm->nested.msrpm));
> +
> +#if IS_ENABLED(CONFIG_HYPERV)
> struct hv_enlightenments *hve =
> (struct hv_enlightenments *)svm->nested.ctl.reserved_sw;
> - int i;
>
> /*
> * MSR bitmap update can be skipped when:
> @@ -185,10 +192,8 @@ static bool nested_svm_vmrun_msrpm(struct vcpu_svm *svm)
> kvm_hv_hypercall_enabled(&svm->vcpu) &&
> hve->hv_enlightenments_control.msr_bitmap &&
> (svm->nested.ctl.clean & VMCB_HV_NESTED_ENLIGHTENMENTS))
> - goto set_msrpm_base_pa;
> -
> - if (!(vmcb12_is_intercept(&svm->nested.ctl, INTERCEPT_MSR_PROT)))
> return true;
> +#endif
>
> for (i = 0; i < MSRPM_OFFSETS; i++) {
> u32 value, p;
> @@ -213,10 +216,6 @@ static bool nested_svm_vmrun_msrpm(struct vcpu_svm *svm)
> }
>
> svm->nested.force_msr_bitmap_recalc = false;
> -
> -set_msrpm_base_pa:
> - svm->vmcb->control.msrpm_base_pa = __sme_set(__pa(svm->nested.msrpm));
> -
> return true;
> }
>
>
>
> Thanks,
>
> Paolo
>
--
Vitaly
On 2/1/22 19:58, Vitaly Kuznetsov wrote: >> Hmm, it fails to compile with CONFIG_HYPERV disabled, and a trivial >> #if also fails due to an unused goto label. Does this look good to you? >> > Hm, it does but honestly I did not anticipate this dependency -- > CONFIG_HYPERV is needed for KVM-on-Hyper-V but this feature is for > Hyper-V-on-KVM. Let me take a look tomorrow. > It's because, without it, the relevant structs are not defined by svm_onhyperv.h. Go ahead and send a new version if you prefer, I can unqueue it (really, just not push to kvm/queue). Paolo
Paolo Bonzini <pbonzini@redhat.com> writes: > On 2/1/22 19:58, Vitaly Kuznetsov wrote: >>> Hmm, it fails to compile with CONFIG_HYPERV disabled, and a trivial >>> #if also fails due to an unused goto label. Does this look good to you? >>> >> Hm, it does but honestly I did not anticipate this dependency -- >> CONFIG_HYPERV is needed for KVM-on-Hyper-V but this feature is for >> Hyper-V-on-KVM. Let me take a look tomorrow. >> > > It's because, without it, the relevant structs are not defined by > svm_onhyperv.h. Go ahead and send a new version if you prefer Should be fixed in v2. I still think it makes sense to keep this KVM-on-Hyper-V and Hyper-V-on-KVM separation as it's really confusing to an unprepared reader. There's still room for improvement in nVMX I believe but it's orthogonal to this nSVM feature. -- Vitaly
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