From: Marc Orr <marcorr@google.com>
To: Peter Gonda <pgonda@google.com>
Cc: kvm list <kvm@vger.kernel.org>,
Paolo Bonzini <pbonzini@redhat.com>,
Sean Christopherson <seanjc@google.com>,
Nathan Tempelman <natet@google.com>,
Brijesh Singh <brijesh.singh@amd.com>,
stable@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH V2] KVM: SEV: Disable KVM_CAP_VM_COPY_ENC_CONTEXT_FROM for SEV-ES
Date: Tue, 14 Sep 2021 12:54:35 -0700 [thread overview]
Message-ID: <CAA03e5HBzp4ttsQ_o8xTmtMNhp9WM0zTUgS_SQViAAhTX5=hTQ@mail.gmail.com> (raw)
In-Reply-To: <20210914190125.3289256-1-pgonda@google.com>
On Tue, Sep 14, 2021 at 12:01 PM Peter Gonda <pgonda@google.com> wrote:
>
> Copying an ASID into new vCPUs will not work for SEV-ES since the vCPUs
> VMSAs need to be setup and measured before SEV_LAUNCH_FINISH. Return an
> error if a users tries to KVM_CAP_VM_COPY_ENC_CONTEXT_FROM from an
> SEV-ES guest. The destination VM is already checked for SEV and SEV-ES
> with sev_guest(), so this ioctl already fails if the destination is SEV
> enabled.
>
> Enabling mirroring a VM or copying its encryption context with an SEV-ES
> VM is more involved and should happen in its own feature patch if that's
> needed. This is because the vCPUs of SEV-ES VMs need to be updated with
> LAUNCH_UPDATE_VMSA before LAUNCH_FINISH. This needs KVM changes because
> the mirror VM has all its SEV ioctls blocked and the original VM doesn't
> know about the mirrors vCPUs.
>
> Fixes: 54526d1fd593 ("KVM: x86: Support KVM VMs sharing SEV context")
>
> V2:
> * Updated changelog with more information and added stable CC.
>
> Signed-off-by: Peter Gonda <pgonda@google.com>
> Cc: Marc Orr <marcorr@google.com>
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Cc: Sean Christopherson <seanjc@google.com>
> Cc: Nathan Tempelman <natet@google.com>
> Cc: Brijesh Singh <brijesh.singh@amd.com>
> Cc: kvm@vger.kernel.org
> Cc: stable@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> ---
> arch/x86/kvm/svm/sev.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
> index 75e0b21ad07c..8a279027425f 100644
> --- a/arch/x86/kvm/svm/sev.c
> +++ b/arch/x86/kvm/svm/sev.c
> @@ -1728,7 +1728,7 @@ int svm_vm_copy_asid_from(struct kvm *kvm, unsigned int source_fd)
> source_kvm = source_kvm_file->private_data;
> mutex_lock(&source_kvm->lock);
>
> - if (!sev_guest(source_kvm)) {
> + if (!sev_guest(source_kvm) || sev_es_guest(source_kvm)) {
> ret = -EINVAL;
> goto e_source_unlock;
> }
> --
> 2.33.0.309.g3052b89438-goog
>
Reviewed-by: Marc Orr <marcorr@google.com>
prev parent reply other threads:[~2021-09-14 19:54 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-14 19:01 [PATCH V2] KVM: SEV: Disable KVM_CAP_VM_COPY_ENC_CONTEXT_FROM for SEV-ES Peter Gonda
2021-09-14 19:12 ` Sean Christopherson
2021-09-14 19:54 ` Marc Orr [this message]
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