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=1792518072; b=G4AFM4Q7/2qBUqOqUaR7rkgP5TkbuuF9VV1ULiog2DfqkaI4L98s2JUw3u1+M1F9XjZq nqfsWIk5gKMBt4uKYiKqR8UW3pilV0Tk1jkilPvAXVRlDdu7OX8Zoc2iEdQKlZOEp4wEb y6xCI0unys3EJWnd1gffhuh+CX/oHk79x/8bSxGdHRRBrJfsRZ7Gwn7aJaYZtkKbcEuq1 HQvcjAlg3sGkRnfvWwQnVAZ63aLJvbQbw42rViLWlq4bUKywtI2LeeiWc2IRVlJV+zBAe Uzs5pHjlcj3WnZaqfIYPgyo5bBMYBnPCVcgLSe195hpag6tBF/jPnpIdDUlbNZ31wyA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792518072; h=Received:Message-ID:From:Subject:Reply-To:To:Cc:In-Reply-To: References:Content-Type:Content-Transfer-Encoding:Date; bh=4IFx3LZsh0QKtiMdrwYHgGlzGlhP3r07WXzIVRhp8gs=; b=C3g7cspI23E5JWPAObhsXMOxv8qBagNofmNG0HLkgVfrmp/CGgis436IKE3vjdwyyLqD GRdIoycMzmah3bzY0MmyUxQ6Bi+TX0IMP5NHz0sHkTFPBHNWAQBtrnzwNC6FV158ts8jP LrN6cRt6XH9Pz3RIG6KO61khSe6Z0fjtKvar5QW4gZ1kuuJEX/ZiHYP5NvYTUVmgL3gdc 0ihab/42phEBA4nLz+5tKSfhhiKT5SMHPved/WbJtkaIkU1tKBzHWEwEI2k1qRODbIZ8D SK4RmOWnHS7lASjj5JhTVf4LAGxDw78L3MNcu1W3Dxl3jhaIcXo8DXtag/0sysX5ZCw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; 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 D4875606A32F; Tue, 20 Oct 2026 17:41:11 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2D76C1F000CB; Tue, 20 Oct 2026 17:41:11 +0000 (UTC) Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH v4 2/2] 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: <20261020173736.81755-3-pavel.e.popov@intel.com> References: <20261020173736.81755-1-pavel.e.popov@intel.com> <20261020173736.81755-3-pavel.e.popov@intel.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Tue, 20 Oct 2026 17:40:40 +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/20261020173736.8175= 5-1-pavel.e.popov@intel.com?part=3D2