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 Signed-off-by: Narayana Murty N nnmlinux@linux.ibm.com
--- Changelog: V1:https://lore.kernel.org/all/20241107042027.338065-1-nnmlinux@linux.ibm.com/ --added Fixes tag for "powerpc/pseries: Cleanup on pseries_eeh_get_state()". V2:https://lore.kernel.org/stable/20241212075044.10563-1-nnmlinux%40linux.ibm.c... --Updated the patch description to include it in the stable kernel tree. V3:https://lore.kernel.org/all/87v7vm8pwz.fsf@gmail.com/ --Updated commit description. --- arch/powerpc/platforms/pseries/eeh_pseries.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/platforms/pseries/eeh_pseries.c b/arch/powerpc/platforms/pseries/eeh_pseries.c index 1893f66371fa..b12ef382fec7 100644 --- a/arch/powerpc/platforms/pseries/eeh_pseries.c +++ b/arch/powerpc/platforms/pseries/eeh_pseries.c @@ -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 |