[RFC PATCH 0/3] KVM: x86: honor guest memory type

[Paolo Bonzini]

On 14/02/20 23:03, Sean Christopherson wrote:
>> On Fri, Feb 14, 2020 at 1:47 PM Chia-I Wu <olvaffe at gmail.com> wrote:
>>> AFAICT, it is currently allowed on ARM (verified) and AMD (not
>>> verified, but svm_get_mt_mask returns 0 which supposedly means the NPT
>>> does not restrict what the guest PAT can do).  This diff would do the
>>> trick for Intel without needing any uapi change:
>> I would be concerned about Intel CPU errata such as SKX40 and SKX59.
> The part KVM cares about, #MC, is already addressed by forcing UC for MMIO.
> The data corruption issue is on the guest kernel to correctly use WC
> and/or non-temporal writes.

What about coherency across live migration?  The userspace process would
use cached accesses, and also a WBINVD could potentially corrupt guest
memory.

Paolo