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authorDavid Woodhouse <[email protected]>2021-01-05 01:36:13 +0000
committerWill Deacon <[email protected]>2021-01-05 19:24:12 +0000
commitb34f10c2dc5961021850c3c15f46a84b56a0c0e8 (patch)
treec4e48bfe7876269071983825fd99f56f0589b29d
parent12bc4570c14e24e6244d66466aeda994f805634b (diff)
iommu/amd: Stop irq_remapping_select() matching when remapping is disabled
The AMD IOMMU initialisation registers the IRQ remapping domain for each IOMMU before doing the final sanity check that every I/OAPIC is covered. This means that the AMD irq_remapping_select() function gets invoked even when IRQ remapping has been disabled, eventually leading to a NULL pointer dereference in alloc_irq_table(). Unfortunately, the IVRS isn't fully parsed early enough that the sanity check can be done in time to registering the IRQ domain altogether. Doing that would be nice, but is a larger and more error-prone task. The simple fix is just for irq_remapping_select() to refuse to report a match when IRQ remapping has disabled. Link: https://lore.kernel.org/lkml/[email protected] Fixes: a1a785b57242 ("iommu/amd: Implement select() method on remapping irqdomain") Reported-by: Johnathan Smithinovic <[email protected]> Signed-off-by: David Woodhouse <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Will Deacon <[email protected]>
-rw-r--r--drivers/iommu/amd/iommu.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index 7e2c445a1fae..f0adbc48fd17 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -3854,6 +3854,9 @@ static int irq_remapping_select(struct irq_domain *d, struct irq_fwspec *fwspec,
struct amd_iommu *iommu;
int devid = -1;
+ if (!amd_iommu_irq_remap)
+ return 0;
+
if (x86_fwspec_is_ioapic(fwspec))
devid = get_ioapic_devid(fwspec->param[0]);
else if (x86_fwspec_is_hpet(fwspec))