diff mbox series

[18/18] amd_iommu: Do not emit I/O page fault events during replay()

Message ID 20250414020253.443831-19-alejandro.j.jimenez@oracle.com (mailing list archive)
State New
Headers show
Series AMD vIOMMU: DMA remapping support for VFIO devices | expand

Commit Message

Alejandro Jimenez April 14, 2025, 2:02 a.m. UTC 
Do not emit an I/O page fault on amdvi_page_walk() when a valid mapping
is not found. The current role of amdvi_page_walk() is to be a helper
for the translate() method and ultimately the IOMMU replay()
functionality. These operations might be executed while the guest is
running, but do not necessarily correspond 1:1 with guest-initiated page
walks.

One example of such scenario is when VFIO code calls
memory_region_iommu_replay() (which ends up calling amdvi_walk_page())
to sync the dirty bitmap, or after registering a new notifier. The guest
would get IO_PAGE_FAULT events for all the regions where a mapping
doesn't currently exist, which is not correct.

Note that after this change there are no users of amdvi_page_fault(),
but since the IO page fault handling will be addressed in upcoming work,
I am choosing to mark it as unused rather than deleting it.

Signed-off-by: Alejandro Jimenez <alejandro.j.jimenez@oracle.com>
---
 hw/i386/amd_iommu.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)
diff mbox series

Patch

diff --git a/hw/i386/amd_iommu.c b/hw/i386/amd_iommu.c
index dc29a52bd845..ac7000dbafc7 100644
--- a/hw/i386/amd_iommu.c
+++ b/hw/i386/amd_iommu.c
@@ -263,8 +263,8 @@  static void amdvi_encode_event(uint64_t *evt, uint16_t devid, uint64_t addr,
  *
  * @addr: virtual address in translation request
  */
-static void amdvi_page_fault(AMDVIState *s, uint16_t devid,
-                             hwaddr addr, uint16_t info)
+static void __attribute__((unused))
+amdvi_page_fault(AMDVIState *s, uint16_t devid, hwaddr addr, uint16_t info)
 {
     uint64_t evt[2];
 
@@ -1254,9 +1254,6 @@  static void amdvi_page_walk(AMDVIAddressSpace *as, uint64_t *dte,
      */
     if ((pte == (uint64_t)-1) || (pte == (uint64_t)-2) ||
         !IOMMU_PTE_PRESENT(pte) || perms != (perms & amdvi_get_perms(pte))) {
-
-        amdvi_page_fault(as->iommu_state, as->devfn, addr, perms);
-        trace_amdvi_page_fault(addr);
         return;
     }