From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792509406; b=V6g+AkerB0NU+4fhfH7bzay5E/tO4RASE0Cfr73Ppww5od2aBO6qH9zGCJ0tY1e3tn9+ 41QJWfQCE3E8lmHWAv5wwe6Xgrcc2JJUaPTIqgJYUIctfpI71ykzWsN0yk8nlJR/VRxbe 6Jq6X8IvaXCZGoG3UBFN0YyDyU+m0jlulQtE+UP3oabfPAp8l7NMv+RLqQI3LgHJke0NO FrC930J6nCpI47L3w8CPfsvyJL0DGcOwjy9R5tdy3gQxXhEn6HYSSmnSVSFYJWmy89w9E 8P9RoqrIq7BX94Jq3/4NSQWuYse7Df9bA01Hfqe3DRyNc/TzrNRBdp77Snp08rQDnZQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792509406; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:To:Cc: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=uh7XaHdHWi03OJCBDDcGtQ8EdbuvqWDDoMUQLrWc6VQ=; b=YAeHrpuYvUCa/ne0Hn7TaDRvFF4CqExSjXtXHX0tv+huGfnaDk3tiR6bg8+dBXd/02Jx yCHBkuoRIQgSfaLuAn5Bf8/lAtP6Nrke/wjBL2jzIt3Zv4Yy6fFMEmTYnGaWmjPsv4WtO oOeEHQghuZ8KJImZYsdQKbMMmUjMRyh9hBadmrXBoQ51cK3GL+z5qevvb18rYynu4YSci 3NDxIcMq5fUf3+jsOG9FI7uJS+MKsBmr+Ho1eu8Rp49aEah9iUV9HjAoyt0qjKiufWbpu dXNcXbqTF8xfJ+JG4d/mNO/jEKpCSgMFkhJ2UP5LXnyawRmeMwWo5xIzH8P/jWdUH4w== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=Yzsm5ljW; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CAE8B606A31C; Tue, 20 Oct 2026 15:16:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=Yzsm5ljW Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1117D1F000C5; Tue, 20 Oct 2026 15:16:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792509405; bh=uh7XaHdHWi03OJCBDDcGtQ8EdbuvqWDDoMUQLrWc6VQ=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=Yzsm5ljWpkrGr+B/08AQ15cSgSn2XJE2Tpb+OimrnPq8sGkjOjBjHLHIGMjwgREHb p5VBrR2oJsJ0qje+dFEGacD1OcXmNdIqZu5oxLrOo3HKurDjeU2lj78GpQ1SWee6G9 1NzMT5aQZtbyVjpuOWPjJA0ugwajZPwlmymJ0OHzXthY9ePYI4Jzmj85ryzppoMp+4 C/xG97zD0DkXxA0xOd7CpYdu8xuz6u+drb2s7ejPVycl/bNo3ADtIDX9VWPMKO/7QI u0/yIq1qJyIGZo0fTGCda6eRTQ2wMsaezhiyp/9kkZh7sFTI6f05ddorGIfbjOThJ2 ATl7vTWmFOylA== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH v3] PCI/P2PDMA: Allow P2PDMA on Intel Xeon server CPUs Reply-To: sashiko-reviews@lists.linux.dev To: "Pavel Popov" Cc: virtualization@lists.linux.dev, linux-pci@vger.kernel.org, "Michael S. Tsirkin" , "Eugenio Perez" In-Reply-To: <20261020151305.65218-1-pavel.e.popov@intel.com> References: <20261020151305.65218-1-pavel.e.popov@intel.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Tue, 20 Oct 2026 15:16:15 +0000 X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list > Peer-to-Peer DMA (P2PDMA) between two devices requires either a shared > upstream bridge or a host bridge matching pci_p2pdma_whitelist[]. In > VMware guests, passthrough devices appear directly on virtual root > buses without host bridge devices. In Hyper-V guests, each passthrough > device appears in a PCI domain of its own without a host bridge > device. Consequently, P2PDMA checks evaluate endpoint Device IDs > against the host bridge whitelist, causing P2PDMA requests to fail > regardless of host support. >=20 > This affects discrete devices such as GPUs, NICs and NVMe drives. >=20 > Add an explicit list of the Intel Xeon server generations from > Skylake-SP to Diamond Rapids to cpu_supports_p2pdma(). These are the > CPUs whose host bridges are in pci_p2pdma_whitelist[] without > restrictions. AMD Zen and newer are already covered by > cpu_supports_p2pdma(), so only Intel entries are needed. >=20 > Tested with the Intel Level Zero P2P benchmark (ze_peer) on Arc Pro B60 > cards in a Linux guest on VMware ESXi 9.0 (Emerald Rapids host). >=20 > Signed-off-by: Pavel Popov Sashiko has reviewed this patch and found no issues. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261020151305.6521= 8-1-pavel.e.popov@intel.com?part=3D1