On 28/06/18 00:41, Sean Christopherson wrote:
On Sat, Jun 23, 2018 at 02:35:22AM +0300, Liran Alon wrote:
From: Jim Mattson <jmattson@xxxxxxxxxx>
Haswell and later hardware masks off the irrelevant bits if the guest
access rights fields on vmwrite, storing only the 13 relevant
bits. This masking isn't documented anywhere. When using VMCS
shadowing for these fields, these fields will be masked when written
to the shadow vmcs12. For consistency, mask these fields when the
vmwrite is handled in software.
Is there software that actively relies on this hardware behavior
or is this more of a cosmetic issue, e.g. it causes failures in a
fuzzer or memory checker of some form?
Not that it really matters, but I think it'd be more correct to
model this behavior in the VMREAD path.
Because you think that CPU writes full content to access right field in
VMCS memory
but VMREAD is the one that actually mask the content?
