Messages in this thread | | | Date | Fri, 30 Oct 2020 11:23:14 +0100 | From | Joerg Roedel <> | Subject | Re: [tip: x86/seves] x86/kvm: Add KVM-specific VMMCALL handling under SEV-ES |
| |
On Wed, Oct 28, 2020 at 11:03:05AM -0700, Erdem Aktas wrote: > I might be missing something here but I think what you say is only > correct for the kvm_hypercall4 cases. All other functions use a > smaller number of registers. #VC blindly assumes that all those > registers are used in the vmcall and exposes them.
Right, I think we should fix that in the guest and zero out the unused registers. VMMCALL can come from userspace after all, and the #VC handler does not look at the hypercall numbers.
Further, on the host side KVM will unconditionally read out all 4 registers too, which requires us to set them valid in the GHCB.
Regards,
Joerg
| |