[PATCH v2] x86/iommu: adjust type in arch_iommu_hwdom_init()

Roger Pau Monne posted 1 patch 1 year ago
Patches applied successfully (tree, apply log)
git fetch https://gitlab.com/xen-project/patchew/xen tags/patchew/20230524143050.17573-1-roger.pau@citrix.com
xen/drivers/passthrough/x86/iommu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
[PATCH v2] x86/iommu: adjust type in arch_iommu_hwdom_init()
Posted by Roger Pau Monne 1 year ago
The 'i' iterator index stores a PDX, not a PFN, and hence the initial
assignation of start (which stores a PFN) needs a conversion from PFN
to PDX.

This is harmless currently, as the PDX compression skips the bottom
MAX_ORDER bits which cover the low 1MB, but still do the conversion
from PDX to PFN for type correctness.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
---
Changes since v1:
 - Soften the description as it's not an error.
---
 xen/drivers/passthrough/x86/iommu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/xen/drivers/passthrough/x86/iommu.c b/xen/drivers/passthrough/x86/iommu.c
index cb0788960a08..6bc79e7ec843 100644
--- a/xen/drivers/passthrough/x86/iommu.c
+++ b/xen/drivers/passthrough/x86/iommu.c
@@ -406,7 +406,7 @@ void __hwdom_init arch_iommu_hwdom_init(struct domain *d)
      */
     start = paging_mode_translate(d) ? PFN_DOWN(MB(1)) : 0;
 
-    for ( i = start, count = 0; i < top; )
+    for ( i = pfn_to_pdx(start), count = 0; i < top; )
     {
         unsigned long pfn = pdx_to_pfn(i);
         unsigned int perms = hwdom_iommu_map(d, pfn, max_pfn);
-- 
2.40.0


Re: [PATCH v2] x86/iommu: adjust type in arch_iommu_hwdom_init()
Posted by Jan Beulich 1 year ago
On 24.05.2023 16:30, Roger Pau Monne wrote:
> The 'i' iterator index stores a PDX, not a PFN, and hence the initial
> assignation of start (which stores a PFN) needs a conversion from PFN
> to PDX.
> 
> This is harmless currently, as the PDX compression skips the bottom
> MAX_ORDER bits which cover the low 1MB, but still do the conversion
> from PDX to PFN for type correctness.
> 
> Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>

Acked-by: Jan Beulich <jbeulich@suse.com>