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AHgh+Rqm5zLHW2/2utCRfOTxDEuYHc3S0uamDSOZcStsDOG2s7EFS7NEvtiHMRfZAWNnqxkcHwM=@vger.kernel.org X-Gm-Message-State: AOJu0Ywb+xRr2Mi5vMo05GgdjkjcgS2GgyHoBoq+1u0V/SGJ78/YQX5m 69VWxxm7Il9qj+sQjD0WHrei5vRAPJyeZ4bnGKQRKTqKMv6/xNf37XudUSCK1RjtW19CRbwEKgX C+xJLFg== X-Received: from plpk2.prod.google.com ([2002:a17:903:3da2:b0:2ca:c401:c941]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:903:38cf:b0:2c9:e9c4:82c1 with SMTP id d9443c01a7336-2ccbf051685mr66239695ad.26.1783439881598; Tue, 07 Jul 2026 08:58:01 -0700 (PDT) Date: Tue, 7 Jul 2026 08:58:00 -0700 In-Reply-To: Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260630222607.497895-1-seanjc@google.com> <20260630222607.497895-11-seanjc@google.com> Message-ID: Subject: Re: [PATCH v3 10/12] KVM: SEV: Forcefully invalidate SNP VMSA if its backing gmem page is zapped From: Sean Christopherson To: Michael Roth Cc: Paolo Bonzini , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Ackerley Tng , Hyunwoo Kim , Tom Lendacky , "=?utf-8?B?SsO2cmcgUsO2ZGVs?=" , Fuad Tabba Content-Type: text/plain; charset="us-ascii" On Wed, Jul 01, 2026, Michael Roth wrote: > On Tue, Jun 30, 2026 at 03:26:05PM -0700, Sean Christopherson wrote: > > --- > > arch/x86/include/asm/kvm-x86-ops.h | 2 + > > arch/x86/include/asm/kvm_host.h | 4 ++ > > arch/x86/kvm/mmu/mmu.c | 5 ++ > > arch/x86/kvm/svm/sev.c | 79 +++++++++++++++++++++++++----- > > arch/x86/kvm/svm/svm.c | 2 + > > arch/x86/kvm/svm/svm.h | 2 + > > arch/x86/kvm/x86.c | 6 +++ > > include/linux/kvm_host.h | 1 + > > virt/kvm/guest_memfd.c | 4 ++ > > 9 files changed, 94 insertions(+), 11 deletions(-) > > > ... > > diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h > > index cf7c1a437f38..123e7bf687ef 100644 > > --- a/arch/x86/kvm/svm/svm.h > > +++ b/arch/x86/kvm/svm/svm.h > > @@ -996,6 +996,7 @@ static inline struct page *snp_safe_alloc_page(void) > > { > > return snp_safe_alloc_page_node(numa_node_id(), GFP_KERNEL_ACCOUNT); > > } > > +void sev_snp_reload_vmsa(struct kvm_vcpu *vcpu); > > > > int sev_vcpu_create(struct kvm_vcpu *vcpu); > > void sev_free_vcpu(struct kvm_vcpu *vcpu); > > @@ -1009,6 +1010,7 @@ int sev_dev_get_attr(u32 group, u64 attr, u64 *val); > > extern unsigned int max_sev_asid; > > void sev_handle_rmp_fault(struct kvm_vcpu *vcpu, gpa_t gpa, u64 error_code); > > int sev_gmem_prepare(struct kvm *kvm, kvm_pfn_t pfn, gfn_t gfn, int max_order); > > +void sev_gmem_invalidate_range(struct kvm *kvm, struct kvm_gfn_range *range); > > void sev_gmem_reclaim_memory(kvm_pfn_t start, kvm_pfn_t end); > > int sev_gmem_max_mapping_level(struct kvm *kvm, kvm_pfn_t pfn, bool is_private); > > struct vmcb_save_area *sev_decrypt_vmsa(struct kvm_vcpu *vcpu); > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > > index bc0c3163f4a3..0bb50997c0e3 100644 > > --- a/arch/x86/kvm/x86.c > > +++ b/arch/x86/kvm/x86.c > > @@ -8170,6 +8170,8 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) > > goto out; > > } > > } > > + if (kvm_check_request(KVM_REQ_VMSA_PAGE_RELOAD, vcpu)) > > + kvm_x86_call(reload_vmsa)(vcpu); > > VMSA is SVM/SEV-specific, and while the event/handling might be SEV-specific, It's not just SEV specific, it's SEV-ES+ specific. Splitting hairs, but IMO the distinction matters because while there is a "save area" for SVM and SEV vCPUs, they don't have a dedicated, separata VMSA. > would it make sense to make the kvm_x86_op generic at least? > > 'reload_guest_save_area' maybe? I think I'd prefer to keep the extra-ugly vmsa terminology? We've already bled gory details into common x86, and I don't see an easy way around that. IMO, at that point, any abstraction does more harm than good. E.g. reload_guest_save_area() is more like to be misread as "reload the save state from KVM's vCPU state". Hmm, though by that argument, reload_vmsa_page() would be even better.