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| author | Vineeth Pillai (Google) <vineeth@bitbyteword.org> | 2025-09-18 13:01:59 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-10-15 12:00:13 +0200 |
| commit | d8cf7b59c49f9118fa875462e18686cb6b131bb5 (patch) | |
| tree | 0c36653e981e0306aeee0ed0a196dfef3758627c /drivers/iommu | |
| parent | 6e7d9fa61d7df463d8a8462e72d51e0b86b2ff3a (diff) | |
| download | linux-d8cf7b59c49f9118fa875462e18686cb6b131bb5.tar.gz linux-d8cf7b59c49f9118fa875462e18686cb6b131bb5.tar.bz2 linux-d8cf7b59c49f9118fa875462e18686cb6b131bb5.zip | |
iommu/vt-d: debugfs: Fix legacy mode page table dump logic
[ Upstream commit fbe6070c73badca726e4ff7877320e6c62339917 ]
In legacy mode, SSPTPTR is ignored if TT is not 00b or 01b. SSPTPTR
maybe uninitialized or zero in that case and may cause oops like:
Oops: general protection fault, probably for non-canonical address
0xf00087d3f000f000: 0000 [#1] SMP NOPTI
CPU: 2 UID: 0 PID: 786 Comm: cat Not tainted 6.16.0 #191 PREEMPT(voluntary)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.17.0-5.fc42 04/01/2014
RIP: 0010:pgtable_walk_level+0x98/0x150
RSP: 0018:ffffc90000f279c0 EFLAGS: 00010206
RAX: 0000000040000000 RBX: ffffc90000f27ab0 RCX: 000000000000001e
RDX: 0000000000000003 RSI: f00087d3f000f000 RDI: f00087d3f0010000
RBP: ffffc90000f27a00 R08: ffffc90000f27a98 R09: 0000000000000002
R10: 0000000000000000 R11: 0000000000000000 R12: f00087d3f000f000
R13: 0000000000000000 R14: 0000000040000000 R15: ffffc90000f27a98
FS: 0000764566dcb740(0000) GS:ffff8881f812c000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000764566d44000 CR3: 0000000109d81003 CR4: 0000000000772ef0
PKRU: 55555554
Call Trace:
<TASK>
pgtable_walk_level+0x88/0x150
domain_translation_struct_show.isra.0+0x2d9/0x300
dev_domain_translation_struct_show+0x20/0x40
seq_read_iter+0x12d/0x490
...
Avoid walking the page table if TT is not 00b or 01b.
Fixes: 2b437e804566 ("iommu/vt-d: debugfs: Support dumping a specified page table")
Signed-off-by: Vineeth Pillai (Google) <vineeth@bitbyteword.org>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20250814163153.634680-1-vineeth@bitbyteword.org
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/iommu')
| -rw-r--r-- | drivers/iommu/intel/debugfs.c | 17 |
1 files changed, 15 insertions, 2 deletions
diff --git a/drivers/iommu/intel/debugfs.c b/drivers/iommu/intel/debugfs.c index affbf4a1558d..5aa7f46a420b 100644 --- a/drivers/iommu/intel/debugfs.c +++ b/drivers/iommu/intel/debugfs.c @@ -435,8 +435,21 @@ static int domain_translation_struct_show(struct seq_file *m, } pgd &= VTD_PAGE_MASK; } else { /* legacy mode */ - pgd = context->lo & VTD_PAGE_MASK; - agaw = context->hi & 7; + u8 tt = (u8)(context->lo & GENMASK_ULL(3, 2)) >> 2; + + /* + * According to Translation Type(TT), + * get the page table pointer(SSPTPTR). + */ + switch (tt) { + case CONTEXT_TT_MULTI_LEVEL: + case CONTEXT_TT_DEV_IOTLB: + pgd = context->lo & VTD_PAGE_MASK; + agaw = context->hi & 7; + break; + default: + goto iommu_unlock; + } } seq_printf(m, "Device %04x:%02x:%02x.%x ", |