Re: [PATCH 0/8] KVM: SEV-ES: fixes for string I/O emulation

Paolo Bonzini
2021-10-21T17:47:55Z

On 13/10/21 18:56, Paolo Bonzini wrote:
> This series, namely patches 1 and 8, fix two bugs in string I/O
> emulation for SEV-ES:
>
> - first, the length is completely off for "rep ins" and "rep outs"
> operation of size > 1. After setup_vmgexit_scratch, svm->ghcb_sa_len
> is in bytes, but kvm_sev_es_string_io expects the number of PIO
> operations.
>
> - second, the size of the GHCB buffer can exceed the size of
> vcpu->arch.pio_data. If that happens, we need to go over the GHCB
> buffer in multiple passes.
>
> The second bug was reported by Felix Wilhelm. The first was found by
> me by code inspection; on one hand it seems *too* egregious so I'll be
> gladly proven wrong on this, on the other hand... I know I'm bad at code
> review, but not _that_ bad.

Ping.

Paolo