From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F110E45EF5D; Fri, 16 Oct 2026 22:35:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792190156; cv=none; b=cR63eGJ6sRULj7zLtoL8aFv7/Tq/BfilUg3dXys9hLei/+g/1VGRI4DzNF6zFM/AS/E4LTeKW5k+EVnJMuTiyC9YZYRlXrEavVg6X+KfzJ5T9DSkSRVsNRnVr5xbmd3cxjBbKPZwxjbsh2O5K0lD7Ecdbgon087KWaxHdmm+jxA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792190156; c=relaxed/simple; bh=nMz8CfTznkAaUKWgj9faS4i5NX2Ao7g5/UlPRhx25B4=; h=Message-ID:From:Subject:To:Cc:In-Reply-To:References:Content-Type: Date; b=AtElr07c6ubUO4L2DYSiB7NRbcnLEoXOOfMWsPcrCbxRdgC+oTFv1zlz60AmPU0FCiDxVWO8x/sL3PFZV7ADiGpAtxsL3SAdVgog1VNPyqz7MYF7jvdeL0XUvE56Tm62/2tB1qNpCqj2gOwM6oQPU1yINhHof1JGfYzTcKJt+OE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=jdCRqBGi; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="jdCRqBGi" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A72001F000C4; Fri, 16 Oct 2026 22:35:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792190154; bh=nMz8CfTznkAaUKWgj9faS4i5NX2Ao7g5/UlPRhx25B4=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=jdCRqBGiBDqwLziw9VBDI1ifk6InJHUx+G6U+PcZZwi7v8peA5IsJrsQD43W8heLc qWH6f1cPlj7Rk4eX5zRVgi8LH26Lj0HS9qfvztYvTyklyIZHzVnL+T34xukz+nTKdU AnWjAlwRc1ctzGM5wQIE2n1QBynrgnacLdGydgmmYdWJ/un/Ec6Kzn/3MOTUp606kb A6I1Jt571LihJaRAmFwuOMn3r1YZqag2qhB+yUwU6inz2StHYNtf6Cwgb7Rbv+xgEz lV5l5AM+nGt5ZjFBLrn0CXG7kQlOBhNxgvrhZ1Wi4culXsfy4TzSJqc71bPuwEjRPU NlAo8b1eiuYMg== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH v2 1/2] PCI/P2PDMA: Allow P2PDMA in VMware guests on Intel hosts 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: <20261016223402.19991-2-pavel.e.popov@intel.com> References: <20261016223402.19991-1-pavel.e.popov@intel.com> <20261016223402.19991-2-pavel.e.popov@intel.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Fri, 16 Oct 2026 22:35:54 +0000 Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: > 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. 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 > The P2PDMA host bridge check does not work in a VMware guest. Bypass it > for host CPUs whose host bridges are in pci_p2pdma_whitelist[] without > restrictions. The list covers the Intel Xeon server generations from > Skylake-SP to Diamond Rapids. 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/20261016223402.1999= 1-1-pavel.e.popov@intel.com?part=3D1