diff mbox series

[XEN,v4,5/5] AMD-Vi: Disable intrerrupt remapping if cx16 is not supported

Message ID 26557d23386030166e89dfee240d99d07def6021.1713174878.git.teddy.astie@vates.tech (mailing list archive)
State Superseded
Headers show
Series x86/iommu: Drop IOMMU support when cx16 isn't supported | expand

Commit Message

Teddy Astie April 15, 2024, 12:16 p.m. UTC 
All hardware with AMD-Vi has CMPXCHG16 support.  Check this at initialisation
time, and remove the effectively-dead logic for the non-cx16 case.

Suggested-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Teddy Astie <teddy.astie@vates.tech>
---
 xen/drivers/passthrough/amd/iommu_intr.c | 6 ++++++
 1 file changed, 6 insertions(+)
diff mbox series

Patch

diff --git a/xen/drivers/passthrough/amd/iommu_intr.c b/xen/drivers/passthrough/amd/iommu_intr.c
index 7fc796dec2..9ab7c68749 100644
--- a/xen/drivers/passthrough/amd/iommu_intr.c
+++ b/xen/drivers/passthrough/amd/iommu_intr.c
@@ -649,6 +649,12 @@  bool __init cf_check iov_supports_xt(void)
     if ( !iommu_enable || !iommu_intremap )
         return false;
 
+    if ( unlikely(!cpu_has_cx16) )
+    {
+        AMD_IOMMU_WARN("CPU doesn't support CMPXCHG16B, disable interrupt remapping\n");
+        return false;
+    }
+
     if ( amd_iommu_prepare(true) )
         return false;