Re: [PATCH v2 2/6] x86/HVM: restrict guest-induced WBINVD to cache writeback

[Roger Pau Monné <roger.pau@xxxxxxxxxx>]

On Wed, May 03, 2023 at 11:45:22AM +0200, Jan Beulich wrote:
> We allow its use for writeback purposes only anyway, so let's also carry
> these out that way on capable hardware.

"for writeback purposes only" > is such the case because we cannot
guarantee the guest in which state the cache will be when resuming
from a wbinvd operation, and hence won't be "clean"?

It's my understanding that the same is possible on native, as the CPU
might speculatively pull lines into the cache.  So there's no reason
for an OS to use wbinvd if wbnoinvd is available?

Thanks, Roger.