linux-kernel - [PATCH v4] powerpc/pseries/eeh: Fix get PE state translation

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <20250115143529.136704-1-nnmlinux@linux.ibm.com>
Date: Wed, 15 Jan 2025 08:35:29 -0600
From: Narayana Murty N <nnmlinux@...ux.ibm.com>
To: linuxppc-dev@...ts.ozlabs.org, mpe@...erman.id.au,
        linux-kernel@...r.kernel.org
Cc: stable@...r.kernel.org, mahesh@...ux.ibm.com, oohall@...il.com,
        npiggin@...il.com, christophe.leroy@...roup.eu, maddy@...ux.ibm.com,
        naveen@...nel.org, vaibhav@...ux.ibm.com, ganeshgr@...ux.ibm.com,
        sbhat@...ux.ibm.com, ritesh.list@...il.com
Subject: [PATCH v4] 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@...r.kernel.org>
Signed-off-by: Narayana Murty N <nnmlinux@...ux.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.com
--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 |
-- 
2.47.1