| Message ID | 20210707183616.5620-40-brijesh.singh@amd.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | Herbert Xu |
| Headers | show |
| Series | Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support | expand |
On Wed, Jul 07, 2021, Brijesh Singh wrote: > From: Tom Lendacky <thomas.lendacky@amd.com> > > In preparation to support SEV-SNP AP Creation, use a variable that holds > the VMSA physical address rather than converting the virtual address. > This will allow SEV-SNP AP Creation to set the new physical address that > will be used should the vCPU reset path be taken. I'm pretty sure adding vmsa_pa is unnecessary. The next patch sets svm->vmsa_pa and vmcb->control.vmsa_pa as a pair. And for the existing code, my proposed patch to emulate INIT on shutdown would eliminate the one path that zeros the VMCB[1]. That series patch also drops the init_vmcb() in svm_create_vcpu()[2]. Assuming there are no VMCB shenanigans I'm missing, sev_es_init_vmcb() can do if (!init_event) svm->vmcb->control.vmsa_pa = __pa(svm->vmsa); And while I'm thinking of it, the next patch should ideally free svm->vmsa when the the guest configures a new VMSA for the vCPU. [1] https://lkml.kernel.org/r/20210713163324.627647-45-seanjc@google.com [2] https://lkml.kernel.org/r/20210713163324.627647-10-seanjc@google.com > Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> > Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> > --- > arch/x86/kvm/svm/sev.c | 5 ++--- > arch/x86/kvm/svm/svm.c | 9 ++++++++- > arch/x86/kvm/svm/svm.h | 1 + > 3 files changed, 11 insertions(+), 4 deletions(-) > > diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c > index 4cb4c1d7e444..d8ad6dd58c87 100644 > --- a/arch/x86/kvm/svm/sev.c > +++ b/arch/x86/kvm/svm/sev.c > @@ -3553,10 +3553,9 @@ void sev_es_init_vmcb(struct vcpu_svm *svm) > > /* > * An SEV-ES guest requires a VMSA area that is a separate from the > - * VMCB page. Do not include the encryption mask on the VMSA physical > - * address since hardware will access it using the guest key. > + * VMCB page. > */ > - svm->vmcb->control.vmsa_pa = __pa(svm->vmsa); > + svm->vmcb->control.vmsa_pa = svm->vmsa_pa; > > /* Can't intercept CR register access, HV can't modify CR registers */ > svm_clr_intercept(svm, INTERCEPT_CR0_READ); > diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c > index 32e35d396508..74bc635c9608 100644 > --- a/arch/x86/kvm/svm/svm.c > +++ b/arch/x86/kvm/svm/svm.c > @@ -1379,9 +1379,16 @@ static int svm_create_vcpu(struct kvm_vcpu *vcpu) > svm->vmcb01.ptr = page_address(vmcb01_page); > svm->vmcb01.pa = __sme_set(page_to_pfn(vmcb01_page) << PAGE_SHIFT); > > - if (vmsa_page) > + if (vmsa_page) { > svm->vmsa = page_address(vmsa_page); > > + /* > + * Do not include the encryption mask on the VMSA physical > + * address since hardware will access it using the guest key. > + */ > + svm->vmsa_pa = __pa(svm->vmsa); > + } > + > svm->guest_state_loaded = false; > > svm_switch_vmcb(svm, &svm->vmcb01); > diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h > index 9fcfc0a51737..285d9b97b4d2 100644 > --- a/arch/x86/kvm/svm/svm.h > +++ b/arch/x86/kvm/svm/svm.h > @@ -177,6 +177,7 @@ struct vcpu_svm { > > /* SEV-ES support */ > struct sev_es_save_area *vmsa; > + hpa_t vmsa_pa; > struct ghcb *ghcb; > struct kvm_host_map ghcb_map; > bool received_first_sipi; > -- > 2.17.1 >
On 7/20/21 7:20 PM, Sean Christopherson wrote: > On Wed, Jul 07, 2021, Brijesh Singh wrote: >> From: Tom Lendacky <thomas.lendacky@amd.com> >> >> In preparation to support SEV-SNP AP Creation, use a variable that holds >> the VMSA physical address rather than converting the virtual address. >> This will allow SEV-SNP AP Creation to set the new physical address that >> will be used should the vCPU reset path be taken. > > I'm pretty sure adding vmsa_pa is unnecessary. The next patch sets svm->vmsa_pa > and vmcb->control.vmsa_pa as a pair. And for the existing code, my proposed > patch to emulate INIT on shutdown would eliminate the one path that zeros the > VMCB[1]. That series patch also drops the init_vmcb() in svm_create_vcpu()[2]. > > Assuming there are no VMCB shenanigans I'm missing, sev_es_init_vmcb() can do > > if (!init_event) > svm->vmcb->control.vmsa_pa = __pa(svm->vmsa); That will require passing init_event through to init_vmcb and successive functions and ensuring that there isn't a path that could cause it to not be set after it should no longer be used. This is very simple at the moment, but maybe can be re-worked once all of the other changes you mention are integrated. Thanks, Tom > > And while I'm thinking of it, the next patch should ideally free svm->vmsa when > the the guest configures a new VMSA for the vCPU. > > [1] https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flkml.kernel.org%2Fr%2F20210713163324.627647-45-seanjc%40google.com&data=04%7C01%7Cthomas.lendacky%40amd.com%7Cef81e5604f5242262b6908d94bdd5b32%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637624236352681486%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=O3LKXhVLqNuT1PpCNzkjG8Vho7wfMEibFgGbZkoFlMk%3D&reserved=0 > [2] https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flkml.kernel.org%2Fr%2F20210713163324.627647-10-seanjc%40google.com&data=04%7C01%7Cthomas.lendacky%40amd.com%7Cef81e5604f5242262b6908d94bdd5b32%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637624236352681486%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=rn6zZZbGEnN4Hd60Mg3EsPU3fIaoBHdA3jTluiDRvpo%3D&reserved=0 > >> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> >> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> >> --- >> arch/x86/kvm/svm/sev.c | 5 ++--- >> arch/x86/kvm/svm/svm.c | 9 ++++++++- >> arch/x86/kvm/svm/svm.h | 1 + >> 3 files changed, 11 insertions(+), 4 deletions(-) >> >> diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c >> index 4cb4c1d7e444..d8ad6dd58c87 100644 >> --- a/arch/x86/kvm/svm/sev.c >> +++ b/arch/x86/kvm/svm/sev.c >> @@ -3553,10 +3553,9 @@ void sev_es_init_vmcb(struct vcpu_svm *svm) >> >> /* >> * An SEV-ES guest requires a VMSA area that is a separate from the >> - * VMCB page. Do not include the encryption mask on the VMSA physical >> - * address since hardware will access it using the guest key. >> + * VMCB page. >> */ >> - svm->vmcb->control.vmsa_pa = __pa(svm->vmsa); >> + svm->vmcb->control.vmsa_pa = svm->vmsa_pa; >> >> /* Can't intercept CR register access, HV can't modify CR registers */ >> svm_clr_intercept(svm, INTERCEPT_CR0_READ); >> diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c >> index 32e35d396508..74bc635c9608 100644 >> --- a/arch/x86/kvm/svm/svm.c >> +++ b/arch/x86/kvm/svm/svm.c >> @@ -1379,9 +1379,16 @@ static int svm_create_vcpu(struct kvm_vcpu *vcpu) >> svm->vmcb01.ptr = page_address(vmcb01_page); >> svm->vmcb01.pa = __sme_set(page_to_pfn(vmcb01_page) << PAGE_SHIFT); >> >> - if (vmsa_page) >> + if (vmsa_page) { >> svm->vmsa = page_address(vmsa_page); >> >> + /* >> + * Do not include the encryption mask on the VMSA physical >> + * address since hardware will access it using the guest key. >> + */ >> + svm->vmsa_pa = __pa(svm->vmsa); >> + } >> + >> svm->guest_state_loaded = false; >> >> svm_switch_vmcb(svm, &svm->vmcb01); >> diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h >> index 9fcfc0a51737..285d9b97b4d2 100644 >> --- a/arch/x86/kvm/svm/svm.h >> +++ b/arch/x86/kvm/svm/svm.h >> @@ -177,6 +177,7 @@ struct vcpu_svm { >> >> /* SEV-ES support */ >> struct sev_es_save_area *vmsa; >> + hpa_t vmsa_pa; >> struct ghcb *ghcb; >> struct kvm_host_map ghcb_map; >> bool received_first_sipi; >> -- >> 2.17.1 >>
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 4cb4c1d7e444..d8ad6dd58c87 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -3553,10 +3553,9 @@ void sev_es_init_vmcb(struct vcpu_svm *svm) /* * An SEV-ES guest requires a VMSA area that is a separate from the - * VMCB page. Do not include the encryption mask on the VMSA physical - * address since hardware will access it using the guest key. + * VMCB page. */ - svm->vmcb->control.vmsa_pa = __pa(svm->vmsa); + svm->vmcb->control.vmsa_pa = svm->vmsa_pa; /* Can't intercept CR register access, HV can't modify CR registers */ svm_clr_intercept(svm, INTERCEPT_CR0_READ); diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 32e35d396508..74bc635c9608 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -1379,9 +1379,16 @@ static int svm_create_vcpu(struct kvm_vcpu *vcpu) svm->vmcb01.ptr = page_address(vmcb01_page); svm->vmcb01.pa = __sme_set(page_to_pfn(vmcb01_page) << PAGE_SHIFT); - if (vmsa_page) + if (vmsa_page) { svm->vmsa = page_address(vmsa_page); + /* + * Do not include the encryption mask on the VMSA physical + * address since hardware will access it using the guest key. + */ + svm->vmsa_pa = __pa(svm->vmsa); + } + svm->guest_state_loaded = false; svm_switch_vmcb(svm, &svm->vmcb01); diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h index 9fcfc0a51737..285d9b97b4d2 100644 --- a/arch/x86/kvm/svm/svm.h +++ b/arch/x86/kvm/svm/svm.h @@ -177,6 +177,7 @@ struct vcpu_svm { /* SEV-ES support */ struct sev_es_save_area *vmsa; + hpa_t vmsa_pa; struct ghcb *ghcb; struct kvm_host_map ghcb_map; bool received_first_sipi;