Messages in this thread | | | Date | Tue, 20 Apr 2021 17:24:37 +0000 | From | Sean Christopherson <> | Subject | Re: [PATCH v13 08/12] KVM: X86: Introduce KVM_HC_PAGE_ENC_STATUS hypercall |
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On Tue, Apr 20, 2021, Paolo Bonzini wrote: > On 15/04/21 17:57, Ashish Kalra wrote: > > From: Ashish Kalra <ashish.kalra@amd.com> > > > > This hypercall is used by the SEV guest to notify a change in the page > > encryption status to the hypervisor. The hypercall should be invoked > > only when the encryption attribute is changed from encrypted -> decrypted > > and vice versa. By default all guest pages are considered encrypted. > > > > The hypercall exits to userspace to manage the guest shared regions and > > integrate with the userspace VMM's migration code. > > I think this should be exposed to userspace as a capability, rather than as > a CPUID bit. Userspace then can enable the capability and set the CPUID bit > if it wants. > > The reason is that userspace could pass KVM_GET_SUPPORTED_CPUID to > KVM_SET_CPUID2 and the hypercall then would break the guest.
Right, and that's partly why I was advocating that KVM emulate the MSR as a nop.
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