powerpc/pseries/eeh: Fix get PE state translation
authorNarayana Murty N <nnmlinux@linux.ibm.com>
Thu, 16 Jan 2025 10:39:54 +0000 (04:39 -0600)
committerMadhavan Srinivasan <maddy@linux.ibm.com>
Tue, 21 Jan 2025 05:13:08 +0000 (10:43 +0530)
commit11b93559000c686ad7e5ab0547e76f21cc143844
tree07cafe12acce352c08be02311fdae54a222aa5e4
parent2bf66e66d2e6feece6175ec09ec590a0a8563bdd
powerpc/pseries/eeh: Fix get PE state translation

The PE Reset State "0" returned by RTAS calls
"ibm_read_slot_reset_[state|state2]" indicates that the reset is
deactivated and the PE is in a state where MMIO and DMA are allowed.
However, the current implementation of "pseries_eeh_get_state()" does
not reflect this, causing drivers to incorrectly assume that MMIO and
DMA operations cannot be resumed.

The userspace drivers as a part of EEH recovery using VFIO ioctls fail
to detect when the recovery process is complete. The VFIO_EEH_PE_GET_STATE
ioctl does not report the expected EEH_PE_STATE_NORMAL state, preventing
userspace drivers from functioning properly on pseries systems.

The patch addresses this issue by updating 'pseries_eeh_get_state()'
to include "EEH_STATE_MMIO_ENABLED" and "EEH_STATE_DMA_ENABLED" in
the result mask for PE Reset State "0". This ensures correct state
reporting to the callers, aligning the behavior with the PAPR specification
and fixing the bug in EEH recovery for VFIO user workflows.

Fixes: 00ba05a12b3c ("powerpc/pseries: Cleanup on pseries_eeh_get_state()")
Cc: stable@vger.kernel.org
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Signed-off-by: Narayana Murty N <nnmlinux@linux.ibm.com>
Link: https://lore.kernel.org/stable/20241212075044.10563-1-nnmlinux%40linux.ibm.com
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/20250116103954.17324-1-nnmlinux@linux.ibm.com
arch/powerpc/platforms/pseries/eeh_pseries.c