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[PATCH] xen/amd/iommu: Don't swap the IVMD read and write permissions
- To: <xen-devel@xxxxxxxxxxxxxxxxxxxx>
- From: Stefano Stabellini <stefano.stabellini@xxxxxxx>
- Date: Tue, 20 Oct 2026 15:08:21 -0700
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- Cc: <jbeulich@xxxxxxxx>, <andrew.cooper3@xxxxxxxxxx>, <roger@xxxxxxxxxxxxxx>, <jason.andryuk@xxxxxxx>, <teddy.astie@xxxxxxxxxx>, <stefano.stabellini@xxxxxxx>
- Delivery-date: Tue, 20 Oct 2026 22:08:38 +0000
- List-id: Xen developer discussion <xen-devel.lists.xenproject.org>
Per the IVMD Flags definition, bit 1 is IR and bit 2 is IW, matching
ACPI_IVMD_READ and ACPI_IVMD_WRITE. parse_ivmd_block() takes iw from
the former and ir from the latter, so a unity range firmware declares
read-only is mapped write-only, and vice versa.
Ranges with both permissions, including Xen's own, are unaffected.
Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxx>
---
xen/drivers/passthrough/amd/iommu_acpi.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/xen/drivers/passthrough/amd/iommu_acpi.c
b/xen/drivers/passthrough/amd/iommu_acpi.c
index 4688908824..fe3dee872c 100644
--- a/xen/drivers/passthrough/amd/iommu_acpi.c
+++ b/xen/drivers/passthrough/amd/iommu_acpi.c
@@ -414,8 +414,8 @@ static int __init parse_ivmd_block(const struct
acpi_ivrs_memory *ivmd_block)
exclusion = true;
else if ( ivmd_block->header.flags & ACPI_IVMD_UNITY )
{
- iw = ivmd_block->header.flags & ACPI_IVMD_READ;
- ir = ivmd_block->header.flags & ACPI_IVMD_WRITE;
+ iw = ivmd_block->header.flags & ACPI_IVMD_WRITE;
+ ir = ivmd_block->header.flags & ACPI_IVMD_READ;
}
else
{
--
2.43.0
|
