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From: Leon Romanovsky <leon@kernel.org>
To: Pavel Popov <pavel.e.popov@intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>,
	Logan Gunthorpe <logang@deltatee.com>,
	Lukas Wunner <lukas@wunner.de>, Jim Chow <jim.chow@broadcom.com>,
	Radu Rugina <radu.rugina@broadcom.com>,
	Alexey Makhalov <alexey.makhalov@broadcom.com>,
	Wei Liu <wei.liu@kernel.org>,
	Michael Kelley <mhklinux@outlook.com>,
	Nathan Ciobanu <nathan.d.ciobanu@linux.intel.com>,
	bcm-kernel-feedback-list@broadcom.com,
	virtualization@lists.linux.dev, linux-hyperv@vger.kernel.org,
	linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 0/2] PCI/P2PDMA: Allow P2PDMA on Intel Xeon server CPUs
Date: Tue, 20 Oct 2026 21:40:02 +0300	[thread overview]
Message-ID: <20261020184002.GO64621@unreal> (raw)
In-Reply-To: <20261020173736.81755-1-pavel.e.popov@intel.com>

On Tue, Oct 20, 2026 at 10:37:34AM -0700, Pavel Popov wrote:
> VMware and Hyper-V expose passthrough devices to guest VMs without an
> explicit host bridge device. Consequently, host_bridge_whitelist()
> cannot automatically identify the underlying host bridge structure,
> causing Peer-to-Peer DMA (P2PDMA) requests to be rejected unless the
> device IDs are explicitly listed in pci_p2pdma_whitelist[]. To enable
> P2PDMA on Intel hosts, this series extends cpu_supports_p2pdma(), which
> so far covers AMD Zen and newer, with an explicit list of Intel Xeon
> server generations.
> 
> Patch 1 moves the CONFIG_X86 #ifdef out of cpu_supports_p2pdma().
> Patch 2 is the v3 patch rebased on it, with Logan's Reviewed-by carried
> over; the Xeon list and the check are unchanged.
> 
> Changes in v4:
> - Add 1/2, moving the CONFIG_X86 #ifdef out of cpu_supports_p2pdma()
>   (Logan Gunthorpe, Leon Romanovsky)
> - Keep the #ifdef around the asm/ includes, as these headers exist
>   only on x86 (Bjorn Helgaas)

I'm confident that this is wrong usage of asm headers.

Thanks

      parent reply	other threads:[~2026-10-20 18:40 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-10-20 17:37 Pavel Popov
2026-10-20 17:37 ` [PATCH v4 1/2] PCI/P2PDMA: Move CONFIG_X86 #ifdef out of cpu_supports_p2pdma() Pavel Popov
2026-10-20 17:37 ` [PATCH v4 2/2] PCI/P2PDMA: Allow P2PDMA on Intel Xeon server CPUs Pavel Popov
2026-10-20 18:40 ` Leon Romanovsky [this message]

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