Re: [PATCH v9 07/13] KVM: guest_memfd: Add flag to remove from direct map

From: Sean Christopherson <seanjc@google.com>
To: Rick P Edgecombe <rick.p.edgecombe@intel.com>
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Subject: Re: [PATCH v9 07/13] KVM: guest_memfd: Add flag to remove from direct map
Date: Fri, 16 Jan 2026 07:41:02 -0800	[thread overview]
Message-ID: <aWpcDrGVLrZOqdcg@google.com> (raw)
In-Reply-To: <4781ba9c5d16394cdd785d008cf2a2d81c5cda35.camel@intel.com>

On Fri, Jan 16, 2026, Rick P Edgecombe wrote:
> On Fri, 2026-01-16 at 15:02 +0000, Nikita Kalyazin wrote:
> > > TDX does some clearing at the direct map mapping for pages that
> > > comes from gmem, using a special instruction. It also does some
> > > clflushing at the direct map address for these pages. So I think we
> > > need to make sure TDs don't pull from gmem fds with this flag.
> > 
> > Would you be able to give a pointer on how we can do that?  I'm not
> > very familiar with the TDX code.
> 
> Uhh, that is a good question. Let me think.

Pass @kvm to kvm_arch_gmem_supports_no_direct_map() and then return %false if
it's a TDX VM.