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Mon, 1 Sep 2025 14:30:03 +0000 (UTC) X-Farcaster-Flow-ID: 24b98d19-0a60-4c24-a3c6-c81ad810034e Received: from EX19D015EUB001.ant.amazon.com (10.252.51.114) by EX19MTAEUB001.ant.amazon.com (10.252.51.26) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.2562.17; Mon, 1 Sep 2025 14:30:02 +0000 Received: from EX19D015EUB004.ant.amazon.com (10.252.51.13) by EX19D015EUB001.ant.amazon.com (10.252.51.114) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.2562.20; Mon, 1 Sep 2025 14:30:01 +0000 Received: from EX19D015EUB004.ant.amazon.com ([fe80::2dc9:7aa9:9cd3:fc8a]) by EX19D015EUB004.ant.amazon.com ([fe80::2dc9:7aa9:9cd3:fc8a%3]) with mapi id 15.02.2562.020; Mon, 1 Sep 2025 14:30:01 +0000 From: "Roy, Patrick" To: "david@redhat.com" CC: "ackerleytng@google.com" , "Manwaring, Derek" , "Thomson, Jack" , "Kalyazin, Nikita" , "kvm@vger.kernel.org" , "kvmarm@lists.linux.dev" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , "pbonzini@redhat.com" , "Roy, Patrick" , "rppt@kernel.org" , "seanjc@google.com" , "tabba@google.com" , "vbabka@suse.cz" , "will@kernel.org" , "Cali, Marco" Subject: Re: [PATCH v5 05/12] KVM: Documentation: describe GUEST_MEMFD_FLAG_NO_DIRECT_MAP Thread-Topic: [PATCH v5 05/12] KVM: Documentation: describe GUEST_MEMFD_FLAG_NO_DIRECT_MAP Thread-Index: AQHcG0zmqnuL2jS1NUKSUglbGWh4mA== Date: Mon, 1 Sep 2025 14:30:01 +0000 Message-ID: <20250901143000.5017-1-roypat@amazon.co.uk> References: <786503d6-e58d-412a-a17b-f5e4e481c3fe@redhat.com> In-Reply-To: <786503d6-e58d-412a-a17b-f5e4e481c3fe@redhat.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Thu, 2025-08-28 at 11:27 +0100, David Hildenbrand wrote:=0A= > On 28.08.25 11:39, Roy, Patrick wrote:=0A= >> Signed-off-by: Patrick Roy =0A= >> ---=0A= >> Documentation/virt/kvm/api.rst | 5 +++++=0A= >> 1 file changed, 5 insertions(+)=0A= >>=0A= >> diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api= .rst=0A= >> index c17a87a0a5ac..b52c14d58798 100644=0A= >> --- a/Documentation/virt/kvm/api.rst=0A= >> +++ b/Documentation/virt/kvm/api.rst=0A= >> @@ -6418,6 +6418,11 @@ When the capability KVM_CAP_GUEST_MEMFD_MMAP is s= upported, the 'flags' field=0A= >> supports GUEST_MEMFD_FLAG_MMAP. Setting this flag on guest_memfd crea= tion=0A= >> enables mmap() and faulting of guest_memfd memory to host userspace.= =0A= >>=0A= >> +When the capability KVM_CAP_GMEM_NO_DIRECT_MAP is supported, the 'flags= ' field=0A= >> +supports GUEST_MEMFG_FLAG_NO_DIRECT_MAP. Setting this flag makes the gu= est_memfd=0A= >> +instance behave similarly to memfd_secret, and unmaps the memory backin= g it from=0A= >> +the kernel's address space after allocation.=0A= >> +=0A= >> When the KVM MMU performs a PFN lookup to service a guest fault and th= e backing=0A= >> guest_memfd has the GUEST_MEMFD_FLAG_MMAP set, then the fault will alw= ays be=0A= >> consumed from guest_memfd, regardless of whether it is a shared or a p= rivate=0A= > =0A= > WARNING: Missing commit description - Add an appropriate one=0A= =0A= Admittedly wasn't sure what to say that wouldn't just repeat the commit tit= le=0A= or the contents. Maybe that just means this shouldn't be its own patch. Wil= l=0A= squash in the previous one (same for PATCH 11/12).=0A= =0A= > WARNING: From:/Signed-off-by: email name mismatch: 'From: "Roy, Patrick"= =0A= > ' !=3D 'Signed-off-by: Patrick Roy '=0A= =0A= Heh, my git config only ever uses "Patrick Roy ". Not = sure=0A= where "Roy, Patrick" comes from, could it be the mail server mangling thing= s?=0A= =0A= > -- =0A= > Cheers=0A= > =0A= > David / dhildenb=0A= > =0A= Best,=0A= Patrick=0A=