linux-kernel - Re: [PATCH v4 04/12] KVM: Add capability to discover KVM_GMEM_NO_DIRECT

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Message-ID: <ce3ce109-f38a-4053-808b-5cc75257f3f7@redhat.com>
Date: Tue, 25 Feb 2025 17:55:53 +0100
From: David Hildenbrand <david@...hat.com>
To: Patrick Roy <roypat@...zon.co.uk>, rppt@...nel.org, seanjc@...gle.com
Cc: pbonzini@...hat.com, corbet@....net, willy@...radead.org,
 akpm@...ux-foundation.org, song@...nel.org, jolsa@...nel.org,
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 haoluo@...gle.com, Liam.Howlett@...cle.com, lorenzo.stoakes@...cle.com,
 vbabka@...e.cz, jannh@...gle.com, shuah@...nel.org, kvm@...r.kernel.org,
 linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
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Subject: Re: [PATCH v4 04/12] KVM: Add capability to discover
 KVM_GMEM_NO_DIRECT_MAP support

On 21.02.25 17:07, Patrick Roy wrote:
> Add a capability to let userspace discover whether guest_memfd supports
> removing its folios from the direct map. Support depends on guest_memfd
> itself being supported, but also on whether KVM can manipulate the
> direct map at page granularity at all (possible most of the time, just
> arm64 is a notable outlier where its impossible if the direct map has
> been setup using hugepages, as arm64 cannot break these apart due to
> break-before-make semantics).
> 
> Signed-off-by: Patrick Roy <roypat@...zon.co.uk>
> ---

Not sure how KVM folks handle that, but I suspect we would just want to 
squash that into the previous commit,

-- 
Cheers,

David / dhildenb