From: sashiko-bot@kernel.org
To: "Pavel Popov" <pavel.e.popov@intel.com>
Cc: virtualization@lists.linux.dev, linux-pci@vger.kernel.org,
"Michael S. Tsirkin" <mst@redhat.com>,
"Eugenio Perez" <eperezma@redhat.com>
Subject: Re: [PATCH v2 2/2] PCI/P2PDMA: Allow P2PDMA in Hyper-V guests on Intel hosts
Date: Fri, 16 Oct 2026 22:38:15 +0000 [thread overview]
Message-ID: <sashiko-outbox-175023@kernel.org> (raw)
In-Reply-To: <20261016223402.19991-3-pavel.e.popov@intel.com>
> 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.
>
> This affects discrete devices such as GPUs, NICs and NVMe drives.
>
> 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.
>
> 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).
>
> Signed-off-by: Pavel Popov <pavel.e.popov@intel.com>
Sashiko has reviewed this patch and found no issues.
--
Sashiko AI review · https://sashiko.dev/#/patchset/20261016223402.19991-1-pavel.e.popov@intel.com?part=2
prev parent reply other threads:[~2026-10-16 22:38 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-16 22:34 [PATCH v2 0/2] PCI/P2PDMA: Allow P2PDMA in VMware and Hyper-V guests on Intel hosts Pavel Popov
2026-10-16 22:34 ` [PATCH v2 1/2] PCI/P2PDMA: Allow P2PDMA in VMware " Pavel Popov
2026-10-16 22:35 ` sashiko-bot
2026-10-16 22:55 ` Logan Gunthorpe
2026-10-17 0:31 ` Popov, Pavel E
2026-10-16 22:34 ` [PATCH v2 2/2] PCI/P2PDMA: Allow P2PDMA in Hyper-V " Pavel Popov
2026-10-16 22:38 ` sashiko-bot [this message]
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