From 11b93559000c686ad7e5ab0547e76f21cc143844 Mon Sep 17 00:00:00 2001 From: Narayana Murty N Date: Thu, 16 Jan 2025 04:39:54 -0600 Subject: [PATCH 1/2] 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) Signed-off-by: Narayana Murty N Link: https://lore.kernel.org/stable/20241212075044.10563-1-nnmlinux%40linux.ibm.com Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/20250116103954.17324-1-nnmlinux@linux.ibm.com --- 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 1893f66371fa4..b12ef382fec70 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 | From 17391cb2613b82f8c405570fea605af3255ff8d2 Mon Sep 17 00:00:00 2001 From: Shivaprasad G Bhat Date: Mon, 13 Jan 2025 03:48:55 +0000 Subject: [PATCH 2/2] powerpc/pseries/iommu: Don't unset window if it was never set On pSeries, when user attempts to use the same vfio container used by different iommu group, the spapr_tce_set_window() returns -EPERM and the subsequent cleanup leads to the below crash. Kernel attempted to read user page (308) - exploit attempt? BUG: Kernel NULL pointer dereference on read at 0x00000308 Faulting instruction address: 0xc0000000001ce358 Oops: Kernel access of bad area, sig: 11 [#1] NIP: c0000000001ce358 LR: c0000000001ce05c CTR: c00000000005add0 NIP [c0000000001ce358] spapr_tce_unset_window+0x3b8/0x510 LR [c0000000001ce05c] spapr_tce_unset_window+0xbc/0x510 Call Trace: spapr_tce_unset_window+0xbc/0x510 (unreliable) tce_iommu_attach_group+0x24c/0x340 [vfio_iommu_spapr_tce] vfio_container_attach_group+0xec/0x240 [vfio] vfio_group_fops_unl_ioctl+0x548/0xb00 [vfio] sys_ioctl+0x754/0x1580 system_call_exception+0x13c/0x330 system_call_vectored_common+0x15c/0x2ec --- interrupt: 3000 Fix this by having null check for the tbl passed to the spapr_tce_unset_window(). Fixes: f431a8cde7f1 ("powerpc/iommu: Reimplement the iommu_table_group_ops for pSeries") Cc: stable@vger.kernel.org Reported-by: Vaishnavi Bhat Signed-off-by: Shivaprasad G Bhat Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/173674009556.1559.12487885286848752833.stgit@linux.ibm.com --- arch/powerpc/platforms/pseries/iommu.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c index 29f1a0cc59cd5..ae6f7a235d8b2 100644 --- a/arch/powerpc/platforms/pseries/iommu.c +++ b/arch/powerpc/platforms/pseries/iommu.c @@ -2208,6 +2208,9 @@ static long spapr_tce_unset_window(struct iommu_table_group *table_group, int nu const char *win_name; int ret = -ENODEV; + if (!tbl) /* The table was never created OR window was never opened */ + return 0; + mutex_lock(&dma_win_init_mutex); if ((num == 0) && is_default_window_table(table_group, tbl))