Intel Xe Enabling SR-IOV PF By Default, Marking Driver As "Broken" For Non-4K Kernels
([Intel] 95 Minutes Ago
Intel Xe)
- Reference: 0001567153
- News link: https://www.phoronix.com/news/Intel-Xe-Linux-6.17-PF-4K
- Source link:
On top of [1]all the Linux 6.17 kernel graphics driver feature changes that landed last week like promoting Panther Lake's Xe3 graphics to on-by-default, SR-IOV for Battlemage GPUs, multi-GPU preparations, Wildcat Lake enablement work, and more, some additional Intel Xe kernel graphics driver changes were submitted today for merging to Linux 6.17 in the coming days.
Sent out today were the drm-xe-next-fixes for the week as primarily some "fixes" to the Intel Xe driver but two items in particular worth calling out.
First up, SR-IOV PF mode is now being enabled by default. The [2]commit enabling Physical Function (PF) by default for Single Root I/O Virtualization (SR-IOV) explains:
"We already claim official support for SR-IOV PF/VF modes on PTL and BMG platforms, but by default we start the Xe driver on those platforms in non-virtualized mode (native) since we still have max_vfs modparam set to disable creation of the VFs.
It's time to let the Xe driver support SR-IOV PF mode by default. We were already testing this on our CI, which was relying on the patch that was enabling it for CONFIG_DRM_XE_DEBUG used by our CI."
The "max_vfs" module parameter for the Xe driver does remain for those wanting to limit the number of Virtual Functions (VFs) that can be managed.
The other notable change with the drm-xe-next-fixes pull is marking the Xe driver as "BROKEN" when the kernel page size is not 4KB. This primarily is around ARM Linux systems where [3]16K or 64K page sizes can yield nice gains on ARM64 .
The Intel Xe driver was designed to be more friendly to non-x86 based architectures given that Intel now produces discrete GPUs compared to the days of just having integrated graphics attached to their x86/x86_64 processors. While the Intel Xe driver is working better for other CPU architectures, it still has assumptions in place around being a 4K kernel page size. Thus is failing on AArch64 systems with 16K or 64K pages as well as on LoongArch systems with a 16K page size or also POWER with larger page sizes.
By gating the Xe driver behind "BROKEN" on non-4K page sizes, building this driver for unsupported configurations will no longer happen. That patch is also marked for back-porting to the Linux 6.8 kernels and newer. Hopefully in time though the Xe graphics driver will be adapted to better work with non-4K kernels.
See [4]this pull request for more details on these fixes going into Linux 6.17 Git soon.
[1] https://www.phoronix.com/news/Linux-6.17-GPU-Drivers
[2] https://gitlab.freedesktop.org/drm/xe/kernel/-/commit/df9bdd4381be100a778c63a5dd810dc82b8c2705
[3] https://www.phoronix.com/review/ampereone-64k-linux611
[4] https://lore.kernel.org/dri-devel/aJNXnIAp2Cq-2pZj@intel.com/T/#u
Sent out today were the drm-xe-next-fixes for the week as primarily some "fixes" to the Intel Xe driver but two items in particular worth calling out.
First up, SR-IOV PF mode is now being enabled by default. The [2]commit enabling Physical Function (PF) by default for Single Root I/O Virtualization (SR-IOV) explains:
"We already claim official support for SR-IOV PF/VF modes on PTL and BMG platforms, but by default we start the Xe driver on those platforms in non-virtualized mode (native) since we still have max_vfs modparam set to disable creation of the VFs.
It's time to let the Xe driver support SR-IOV PF mode by default. We were already testing this on our CI, which was relying on the patch that was enabling it for CONFIG_DRM_XE_DEBUG used by our CI."
The "max_vfs" module parameter for the Xe driver does remain for those wanting to limit the number of Virtual Functions (VFs) that can be managed.
The other notable change with the drm-xe-next-fixes pull is marking the Xe driver as "BROKEN" when the kernel page size is not 4KB. This primarily is around ARM Linux systems where [3]16K or 64K page sizes can yield nice gains on ARM64 .
The Intel Xe driver was designed to be more friendly to non-x86 based architectures given that Intel now produces discrete GPUs compared to the days of just having integrated graphics attached to their x86/x86_64 processors. While the Intel Xe driver is working better for other CPU architectures, it still has assumptions in place around being a 4K kernel page size. Thus is failing on AArch64 systems with 16K or 64K pages as well as on LoongArch systems with a 16K page size or also POWER with larger page sizes.
By gating the Xe driver behind "BROKEN" on non-4K page sizes, building this driver for unsupported configurations will no longer happen. That patch is also marked for back-porting to the Linux 6.8 kernels and newer. Hopefully in time though the Xe graphics driver will be adapted to better work with non-4K kernels.
See [4]this pull request for more details on these fixes going into Linux 6.17 Git soon.
[1] https://www.phoronix.com/news/Linux-6.17-GPU-Drivers
[2] https://gitlab.freedesktop.org/drm/xe/kernel/-/commit/df9bdd4381be100a778c63a5dd810dc82b8c2705
[3] https://www.phoronix.com/review/ampereone-64k-linux611
[4] https://lore.kernel.org/dri-devel/aJNXnIAp2Cq-2pZj@intel.com/T/#u
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