RE: [PATCH v4 0/2] PCI/P2PDMA: Allow P2PDMA on Intel Xeon server CPUs

[Popov, Pavel E]

Hi Bjorn,

Gentle ping on this series. Is this OK for v7.5?

Thanks,
Pavel

> -----Original Message-----
> From: Popov, Pavel E <pavel.e.popov@xxxxxxxxx>
> Sent: Tuesday, October 20, 2026 10:38 AM
> To: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>; Logan Gunthorpe
> <logang@xxxxxxxxxxxx>
> Cc: Popov, Pavel E <pavel.e.popov@xxxxxxxxx>; Leon Romanovsky
> <leon@xxxxxxxxxx>; Lukas Wunner <lukas@xxxxxxxxx>; Jim Chow
> <jim.chow@xxxxxxxxxxxx>; Radu Rugina <radu.rugina@xxxxxxxxxxxx>;
> Alexey Makhalov <alexey.makhalov@xxxxxxxxxxxx>; Wei Liu
> <wei.liu@xxxxxxxxxx>; Michael Kelley <mhklinux@xxxxxxxxxxx>; Nathan
> Ciobanu <nathan.d.ciobanu@xxxxxxxxxxxxxxx>; bcm-kernel-feedback-
> list@xxxxxxxxxxxx; virtualization@xxxxxxxxxxxxxxx; linux-
> hyperv@xxxxxxxxxxxxxxx; linux-pci@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx
> Subject: [PATCH v4 0/2] PCI/P2PDMA: Allow P2PDMA on Intel Xeon server
> CPUs
> 
> 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)
> 
> Changes in v3:
> - Drop the hypervisor check and move the Xeon list into
>   cpu_supports_p2pdma(), next to the AMD check, as suggested by Logan
>   Gunthorpe and Leon Romanovsky [1]
> - Fold the VMware and Hyper-V patches into one, as the check no longer
>   depends on the hypervisor
> 
> Changes in v2:
> - Replace the Skylake-and-newer threshold with an explicit list of Intel
>   Xeon server generations, from Skylake-SP to Diamond Rapids (Logan
>   Gunthorpe)
> - Move the CONFIG_X86 #ifdef out of hypervisor_supports_p2pdma()
>   (Logan Gunthorpe)
> - Rebased on current mainline
> 
> [1] https://lore.kernel.org/r/20261016153147.GC219304@unreal
> 
> v3: https://lore.kernel.org/r/20261020151305.65218-1-
> pavel.e.popov@xxxxxxxxx
> v2: https://lore.kernel.org/r/20261016223402.19991-1-
> pavel.e.popov@xxxxxxxxx
> v1: https://lore.kernel.org/r/20261009154034.82321-1-
> pavel.e.popov@xxxxxxxxx
> 
> Pavel Popov (2):
>   PCI/P2PDMA: Move CONFIG_X86 #ifdef out of cpu_supports_p2pdma()
>   PCI/P2PDMA: Allow P2PDMA on Intel Xeon server CPUs
> 
>  drivers/pci/p2pdma.c | 33 +++++++++++++++++++++++++++++++--
>  1 file changed, 31 insertions(+), 2 deletions(-)
> 
> 
> base-commit: c03c1a14507dfaf8b856c2608f9ac216021fc222
> --
> 2.53.0