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powerpc/pseries/eeh: Fix get PE state translation
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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: 00ba05a ("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
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Narayana Murty N authored and Madhavan Srinivasan committed Jan 21, 2025
1 parent 2bf66e6 commit 11b9355
Showing 1 changed file with 4 additions and 2 deletions.
6 changes: 4 additions & 2 deletions arch/powerpc/platforms/pseries/eeh_pseries.c
Original file line number Diff line number Diff line change
Expand Up @@ -580,8 +580,10 @@ static int pseries_eeh_get_state(struct eeh_pe *pe, int *delay)

switch(rets[0]) {
case 0:
result = EEH_STATE_MMIO_ACTIVE |
EEH_STATE_DMA_ACTIVE;
result = EEH_STATE_MMIO_ACTIVE |
EEH_STATE_DMA_ACTIVE |
EEH_STATE_MMIO_ENABLED |
EEH_STATE_DMA_ENABLED;
break;
case 1:
result = EEH_STATE_RESET_ACTIVE |
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