Messages in this thread Patch in this message | | | From | Paolo Bonzini <> | Subject | Re: [PATCH v8 13/18] KVM: x86: Introduce new KVM_FEATURE_SEV_LIVE_MIGRATION feature & Custom MSR. | Date | Fri, 4 Dec 2020 12:20:46 +0100 |
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On 05/05/20 23:19, Ashish Kalra wrote: > From: Ashish Kalra <ashish.kalra@amd.com> > > Add new KVM_FEATURE_SEV_LIVE_MIGRATION feature for guest to check > for host-side support for SEV live migration. Also add a new custom > MSR_KVM_SEV_LIVE_MIG_EN for guest to enable the SEV live migration > feature. > > Signed-off-by: Ashish Kalra <ashish.kalra@amd.com> > --- > Documentation/virt/kvm/cpuid.rst | 5 +++++ > Documentation/virt/kvm/msr.rst | 10 ++++++++++ > arch/x86/include/uapi/asm/kvm_para.h | 5 +++++ > arch/x86/kvm/svm/sev.c | 14 ++++++++++++++ > arch/x86/kvm/svm/svm.c | 16 ++++++++++++++++ > arch/x86/kvm/svm/svm.h | 2 ++ > 6 files changed, 52 insertions(+) > > diff --git a/Documentation/virt/kvm/cpuid.rst b/Documentation/virt/kvm/cpuid.rst > index 01b081f6e7ea..0514523e00cd 100644 > --- a/Documentation/virt/kvm/cpuid.rst > +++ b/Documentation/virt/kvm/cpuid.rst > @@ -86,6 +86,11 @@ KVM_FEATURE_PV_SCHED_YIELD 13 guest checks this feature bit > before using paravirtualized > sched yield. > > +KVM_FEATURE_SEV_LIVE_MIGRATION 14 guest checks this feature bit before > + using the page encryption state > + hypercall to notify the page state > + change > + > KVM_FEATURE_CLOCSOURCE_STABLE_BIT 24 host will warn if no guest-side > per-cpu warps are expeced in > kvmclock > diff --git a/Documentation/virt/kvm/msr.rst b/Documentation/virt/kvm/msr.rst > index 33892036672d..7cd7786bbb03 100644 > --- a/Documentation/virt/kvm/msr.rst > +++ b/Documentation/virt/kvm/msr.rst > @@ -319,3 +319,13 @@ data: > > KVM guests can request the host not to poll on HLT, for example if > they are performing polling themselves. > + > +MSR_KVM_SEV_LIVE_MIG_EN: > + 0x4b564d06 > + > + Control SEV Live Migration features. > + > +data: > + Bit 0 enables (1) or disables (0) host-side SEV Live Migration feature. > + Bit 1 enables (1) or disables (0) support for SEV Live Migration extensions. > + All other bits are reserved.
This doesn't say what the feature is or does, and what the extensions are. As far as I understand bit 0 is a guest->host communication that it's properly handling the encryption bitmap.
I applied patches -13, this one a bit changed as follows.
diff --git a/Documentation/virt/kvm/cpuid.rst b/Documentation/virt/kvm/cpuid.rst index cf62162d4be2..7d82d7da3835 100644 --- a/Documentation/virt/kvm/cpuid.rst +++ b/Documentation/virt/kvm/cpuid.rst @@ -96,6 +96,11 @@ KVM_FEATURE_MSI_EXT_DEST_ID 15 guest checks this feature bit before using extended destination ID bits in MSI address bits 11-5.
+KVM_FEATURE_ENCRYPTED_VM_BIT 16 guest checks this feature bit before + using the page encryption state + hypercall and encrypted VM + features MSR + KVM_FEATURE_CLOCKSOURCE_STABLE_BIT 24 host will warn if no guest-side per-cpu warps are expected in kvmclock diff --git a/Documentation/virt/kvm/msr.rst b/Documentation/virt/kvm/msr.rst index e37a14c323d2..02528bc760b8 100644 --- a/Documentation/virt/kvm/msr.rst +++ b/Documentation/virt/kvm/msr.rst @@ -376,3 +376,13 @@ data: write '1' to bit 0 of the MSR, this causes the host to re-scan its queue and check if there are more notifications pending. The MSR is available if KVM_FEATURE_ASYNC_PF_INT is present in CPUID. + +MSR_KVM_ENC_VM_FEATURE: + 0x4b564d08 + + Control encrypted VM features. + +data: + Bit 0 tells the host that the guest is (1) or is not (0) issuing the + ``KVM_HC_PAGE_ENC_STATUS`` hypercall to keep the encrypted bitmap + up to date. diff --git a/arch/x86/include/uapi/asm/kvm_para.h b/arch/x86/include/uapi/asm/kvm_para.h index 950afebfba88..3dda6e416a70 100644 --- a/arch/x86/include/uapi/asm/kvm_para.h +++ b/arch/x86/include/uapi/asm/kvm_para.h @@ -33,6 +33,7 @@ #define KVM_FEATURE_PV_SCHED_YIELD 13 #define KVM_FEATURE_ASYNC_PF_INT 14 #define KVM_FEATURE_MSI_EXT_DEST_ID 15 +#define KVM_FEATURE_ENCRYPTED_VM 16
#define KVM_HINTS_REALTIME 0
@@ -54,6 +55,7 @@ #define MSR_KVM_POLL_CONTROL 0x4b564d05 #define MSR_KVM_ASYNC_PF_INT 0x4b564d06 #define MSR_KVM_ASYNC_PF_ACK 0x4b564d07 +#define MSR_KVM_ENC_VM_FEATURE 0x4b564d08
struct kvm_steal_time { __u64 steal; @@ -136,4 +138,6 @@ struct kvm_vcpu_pv_apf_data { #define KVM_PV_EOI_ENABLED KVM_PV_EOI_MASK #define KVM_PV_EOI_DISABLED 0x0
+#define KVM_ENC_VM_BITMAP_VALID (1 << 0) + #endif /* _UAPI_ASM_X86_KVM_PARA_H */ diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index fa67f498e838..0673531233da 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -1478,6 +1478,17 @@ int svm_page_enc_status_hc(struct kvm *kvm, unsigned long gpa, return 0; }
+void sev_update_enc_vm_flags(struct kvm *kvm, u64 data) +{ + struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info; + + if (!sev_guest(kvm)) + return; + + if (data & KVM_ENC_VM_BITMAP_VALID) + sev->live_migration_enabled = true; +} + int svm_get_page_enc_bitmap(struct kvm *kvm, struct kvm_page_enc_bitmap *bmap) { @@ -1490,6 +1501,9 @@ int svm_get_page_enc_bitmap(struct kvm *kvm, if (!sev_guest(kvm)) return -ENOTTY;
+ if (!sev->live_migration_enabled) + return -EINVAL; + gfn_start = bmap->start_gfn; gfn_end = gfn_start + bmap->num_pages;
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 66f7014eaae2..8ac2c5b9c675 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -2766,6 +2766,9 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr) svm->msr_decfg = data; break; } + case MSR_KVM_ENC_VM_FEATURE: + sev_update_enc_vm_flags(vcpu->kvm, data); + break; case MSR_IA32_APICBASE: if (kvm_vcpu_apicv_active(vcpu)) avic_update_vapic_bar(to_svm(vcpu), data); diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h index 287559b8c5b2..363c3f8d00b7 100644 --- a/arch/x86/kvm/svm/svm.h +++ b/arch/x86/kvm/svm/svm.h @@ -66,6 +66,7 @@ struct kvm_sev_info { int fd; /* SEV device fd */ unsigned long pages_locked; /* Number of pages locked */ struct list_head regions_list; /* List of registered regions */ + bool live_migration_enabled; unsigned long *page_enc_bmap; unsigned long page_enc_bmap_size; }; @@ -504,5 +505,6 @@ int svm_page_enc_status_hc(struct kvm *kvm, unsigned long gpa, unsigned long npages, unsigned long enc); int svm_get_page_enc_bitmap(struct kvm *kvm, struct kvm_page_enc_bitmap *bmap); int svm_set_page_enc_bitmap(struct kvm *kvm, struct kvm_page_enc_bitmap *bmap); +void sev_update_enc_vm_flags(struct kvm *kvm, u64 data);
#endif Paolo
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