Re: [PATCH Part1 RFC v3 16/22] KVM: SVM: Create a separate mapping for the SEV-ES save area

Borislav Petkov
2021-06-14T10:58:34Z

On Wed, Jun 02, 2021 at 09:04:10AM -0500, Brijesh Singh wrote:
> +/* Save area definition for SEV-ES and SEV-SNP guests */
> +struct sev_es_save_area {

Can we agree on a convention here to denote SEV-ES and later
variants VS earlier ones so that you don't have "SEV-ES" in the name
sev_es_save_area but to mean that this applies to SNP and future stuff
too?

What about SEV-only guests? I'm assuming those use the old variant.

Which would mean you can call this

struct prot_guest_save_area

or so, so that it doesn't have "sev" in the name and so that there's no
confusion...

Ditto for the size defines.

> diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
> index 5bc887e9a986..d93a1c368b61 100644
> --- a/arch/x86/kvm/svm/sev.c
> +++ b/arch/x86/kvm/svm/sev.c
> @@ -542,12 +542,20 @@ static int sev_launch_update_data(struct kvm *kvm, struct kvm_sev_cmd *argp)
>
> static int sev_es_sync_vmsa(struct vcpu_svm *svm)

Not SEV-ES only anymore, so I guess sev_snp_sync_vmca() or so.

> - struct vmcb_save_area *save = &svm->vmcb->save;
> + struct sev_es_save_area *save = svm->vmsa;
>
> /* Check some debug related fields before encrypting the VMSA */
> - if (svm->vcpu.guest_debug || (save->dr7 & ~DR7_FIXED_1))
> + if (svm->vcpu.guest_debug || (svm->vmcb->save.dr7 & ~DR7_FIXED_1))
> return -EINVAL;
>
> + /*
> + * SEV-ES will use a VMSA that is pointed to by the VMCB, not
> + * the traditional VMSA that is part of the VMCB. Copy the
> + * traditional VMSA as it has been built so far (in prep
> + * for LAUNCH_UPDATE_VMSA) to be the initial SEV-ES state.

Ditto - nomenclature.

> + */
> + memcpy(save, &svm->vmcb->save, sizeof(svm->vmcb->save));
> +
> /* Sync registgers */
^^^^^^^^^^

typo. Might as well fix while at it.

--
Regards/Gruss,
Boris.