Re: [PATCH] drm/xe/debugfs: Don't expose dgfx residencies attributes on VF

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

On Fri, Sep 05, 2025 at 08:40:14PM +0200, Michal Wajdeczko wrote:
> 
> 
> On 9/5/2025 8:22 PM, Gustavo Sousa wrote:
> > Quoting Michal Wajdeczko (2025-09-05 14:36:25-03:00)
> >> In addition of checking if we are running on the BATTLEMAGE,
> >> we should also check for not being a VF driver, as VFs can't
> >> access necessary registers, and doing so leads to:
> >>
> >> | .. [drm] GT0: VF is trying to read an inaccessible register 0x35b004+0x0
> >> | RIP: 0010:xe_gt_sriov_vf_read32+0x5e2/0x8a0 [xe]
> >> | Call Trace:
> >> |  xe_mmio_read32+0x110/0x280 [xe]
> >> |  read_residency_counter+0x42/0xd0 [xe]
> >> |  dgfx_pkg_residencies_show+0x115/0x190 [xe]
> >> | .. [drm] Package G2 counter failed to read, ret -19
> >>
> >> or
> >>
> >> | .. [drm] GT0: VF is trying to read an inaccessible register 0x35b004+0x0
> >> | RIP: 0010:xe_gt_sriov_vf_read32+0x5e2/0x8a0 [xe]
> >> | Call Trace:
> >> |  xe_mmio_read32+0x110/0x280 [xe]
> >> |  read_residency_counter+0x42/0xd0 [xe]
> >> |  dgfx_pcie_link_residencies_show+0xe7/0x160 [xe]
> >> | .. [drm] PCIE LINK L0 RESIDENCY counter failed to read, ret -19
> >>
> >> Similarly, there is no point to expose inject_csc_hw_error on VFs,
> >> as HW errors support is already disabled for VFs.
> >>
> >> Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
> >> Cc: Soham Purkait <soham.purkait@intel.com>
> >> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> >> Cc: Riana Tauro <riana.tauro@intel.com>
> > 
> > I posted a very similar patch[1] ~1 month ago.
> 
> oops
> 
> > 
> > There was a spec-related question from Rodrigo, for which I could not
> > find the answer.
> 
> I guess the answer in indirect - there is only small set of registers
> that VFs can read directly, and above one 0x35b004 is not on this list.
> 
> Bspec: 53221

Thank you

Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

> 
> > 
> > [1] https://lore.kernel.org/all/20250729-skip-residency-debugfs-for-vfs-v1-1-3c5edec08c8b@intel.com/
> > 
> > --
> > Gustavo Sousa
> > 
> >> ---
> >> drivers/gpu/drm/xe/xe_debugfs.c | 2 +-
> >> 1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/gpu/drm/xe/xe_debugfs.c b/drivers/gpu/drm/xe/xe_debugfs.c
> >> index 4b71570529a6..8be8304cb05c 100644
> >> --- a/drivers/gpu/drm/xe/xe_debugfs.c
> >> +++ b/drivers/gpu/drm/xe/xe_debugfs.c
> >> @@ -346,7 +346,7 @@ void xe_debugfs_register(struct xe_device *xe)
> >>                                  ARRAY_SIZE(debugfs_list),
> >>                                  root, minor);
> >>
> >> -        if (xe->info.platform == XE_BATTLEMAGE) {
> >> +        if (xe->info.platform == XE_BATTLEMAGE && !IS_SRIOV_VF(xe)) {
> >>                 drm_debugfs_create_files(debugfs_residencies,
> >>                                          ARRAY_SIZE(debugfs_residencies),
> >>                                          root, minor);
> >> -- 
> >> 2.47.1
> >>
>