As analyzed in https://bugzilla.kernel.org/show_bug.cgi?id=76331
we can have multiple DRHDs in a system and each may support different
guest address widths. We can add a device behind a less capable DRHD
to a domain so long as the lesser DRHD can map the existing domain
page table. We should never increase the address width as a result
of adding a device to the domain. The current code simply updates
the width to the last added device. Change to keep it at the
minumum DRHD width.
Reported-by: mspe...@users.sourceforge.net
Signed-off-by: Alex Williamson <alex.william...@redhat.com>
Cc: David Woodhouse <dw...@infradead.org>
---
drivers/iommu/intel-iommu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index e68f44b..cd41d8d 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -4276,7 +4276,7 @@ static int intel_iommu_attach_device(struct iommu_domain
*domain,
__func__, addr_width, dmar_domain->max_addr);
return -EFAULT;
}
- dmar_domain->gaw = addr_width;
+ dmar_domain->gaw = min(addr_width, dmar_domain->gaw);
/*
* Knock out extra levels of page tables if necessary
--
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