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 EF23A1EB1AA; Fri, 16 Oct 2026 22:38:16 +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=1792190297; cv=none; b=oEvO0Eh29zQY41XBDXx6y2gvTxiB44Mu/0qf0HP8ojPenEKhLRzlbmQhtfPCvZjQXTak1wzkG1eBXaMZ21ssCqtX8J8+9adaPc+hL6U7wisWmb80yKhUHDNyG0H8E7VPi/zdgJBj4xhQEocWjqAa6JUtJ/rhdPx/XDzXUsoPwlI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792190297; c=relaxed/simple; bh=n5lHVCc5c4ufCyPkWGEBoNS/TH5ZYTjzchZc1CNvmJ8=; h=Message-ID:From:Subject:To:Cc:In-Reply-To:References:Content-Type: Date; b=VfU7l3AujqBMUaEETKatxTyTswEwWQ6+Ji1Oq1rIIVrgHAW5R/k3+DlKm+oweIfJNKtRvqVHGy7FM92lZ1BMzuWB3PrIV6ALCTQPjaGKuXyC+9vIfJ6/BlbLQJNoBNJM3kaN7ZodGcOgnPcVzSCUiMt7fJ47OV6Nl5+hrq9pZ4M= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=CqaIw04F; 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="CqaIw04F" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5252A1F000C4; Fri, 16 Oct 2026 22:38:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792190296; bh=n5lHVCc5c4ufCyPkWGEBoNS/TH5ZYTjzchZc1CNvmJ8=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=CqaIw04FYV6W9/GmGaHLBwYKJsC7tHK59Gvh7pm3KIMU/IvuwfkPDU+7SrVcvIGBm ZPRs6a1KdxIYx9Ug3v3JKzDIrfbsRIv3hUMkYi/QeoSQiBYT1+OYFXn6TGjW2arF7F bWRH94OCUAewUmgpFd3ay+sh0NrRWXrAVi6wn7+HriTCgyzH7Yl6rr81ies7VAiZVG sLhyPcVPzK8QOj5/f9PHfde+DLjvYEFVYOiC5XhYu08eeaxFv/FPKpBfYRZgktai3R oMqNE0qrcIi/0g4VZMm60Q/PpKer1jfyjdtD+DzzcQWRdq9vB0CpyW17SoTuGXE9J5 i0zW64ckrQohg== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH v2 2/2] PCI/P2PDMA: Allow P2PDMA in Hyper-V 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: <20261016223402.19991-3-pavel.e.popov@intel.com> References: <20261016223402.19991-1-pavel.e.popov@intel.com> <20261016223402.19991-3-pavel.e.popov@intel.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Fri, 16 Oct 2026 22:38:15 +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 > 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 > The P2PDMA host bridge check does not work in a Hyper-V guest. Apply > the same bypass as for VMware, on the same Intel Xeon generations. >=20 > Tested with the Intel Level Zero P2P benchmark (ze_peer) on Arc Pro B60 > cards in a Linux guest on Windows Server 2025 (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=3D2