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Thu, 28 Aug 2025 09:39:23 +0000 (UTC) X-Farcaster-Flow-ID: cf079725-5cad-40a9-99e7-2d92fc48a8df 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; Thu, 28 Aug 2025 09:39:23 +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 15.2.2562.17; Thu, 28 Aug 2025 09:39:23 +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 15.02.2562.017; Thu, 28 Aug 2025 09:39:23 +0000 From: "Roy, Patrick" To: "david@redhat.com" , "seanjc@google.com" CC: "Roy, Patrick" , "tabba@google.com" , "ackerleytng@google.com" , "pbonzini@redhat.com" , "kvm@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "kvmarm@lists.linux.dev" , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , "rppt@kernel.org" , "will@kernel.org" , "vbabka@suse.cz" , "Cali, Marco" , "Kalyazin, Nikita" , "Thomson, Jack" , "Manwaring, Derek" Subject: [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: AQHcF/+iTh4+SyN+qUqFXrn8N9N71g== Date: Thu, 28 Aug 2025 09:39:22 +0000 Message-ID: <20250828093902.2719-6-roypat@amazon.co.uk> References: <20250828093902.2719-1-roypat@amazon.co.uk> In-Reply-To: <20250828093902.2719-1-roypat@amazon.co.uk> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [172.19.88.180] Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-Rspamd-Server: rspam03 X-Rspam-User: X-Rspamd-Queue-Id: 12C962000B X-Stat-Signature: 3y3bsdnpqxdzrpqenwpnd6fgaiku9x1p X-HE-Tag: 1756373973-727249 X-HE-Meta: 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 zcqbZXeq 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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.rs= t=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 supp= orted, the 'flags' field=0A= supports GUEST_MEMFD_FLAG_MMAP. Setting this flag on guest_memfd creation= =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' f= ield=0A= +supports GUEST_MEMFG_FLAG_NO_DIRECT_MAP. Setting this flag makes the guest= _memfd=0A= +instance behave similarly to memfd_secret, and unmaps the memory backing i= t 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 the ba= cking=0A= guest_memfd has the GUEST_MEMFD_FLAG_MMAP set, then the fault will always = be=0A= consumed from guest_memfd, regardless of whether it is a shared or a priva= te=0A= -- =0A= 2.50.1=0A= =0A=