On 3/6/26 11:44, Zhenzhong Duan wrote:
When guest deletes PASID entries, QEMU will capture the pasid cache
invalidation request, walk through pasid_cache_list in each passthrough
device to find stale VTDACCELPASIDCacheEntry and delete them.
As the comment to the last patch, I think this patch should handle both
update and removal of PASID entry.
This happen before the PASID entry addition, because a new added entry
should never be removed.
This is confusing. TBH. this order is not quite important as the current
implementation, we don't have multiple pasid entires share same cache
entry, so a given pasid entry, we either add new cache entry or
update/delete cache entry. So I would just drop this line.
Signed-off-by: Zhenzhong Duan <[email protected]>
---
hw/i386/intel_iommu_accel.c | 70 +++++++++++++++++++++++++++++++++++++
1 file changed, 70 insertions(+)
diff --git a/hw/i386/intel_iommu_accel.c b/hw/i386/intel_iommu_accel.c
index 0acf3ae77f..5a956af916 100644
--- a/hw/i386/intel_iommu_accel.c
+++ b/hw/i386/intel_iommu_accel.c
@@ -16,6 +16,28 @@
#include "hw/pci/pci_bus.h"
#include "trace.h"
+static inline int vtd_hiod_get_pe_from_pasid(VTDACCELPASIDCacheEntry *vtd_pce,
+ VTDPASIDEntry *pe)
+{
+ VTDHostIOMMUDevice *vtd_hiod = vtd_pce->vtd_hiod;
+ IntelIOMMUState *s = vtd_hiod->iommu_state;
+ uint32_t pasid = vtd_pce->pasid;
+ VTDContextEntry ce;
+ int ret;
+
+ if (!s->dmar_enabled || !s->root_scalable) {
+ return -VTD_FR_RTADDR_INV_TTM;
+ }
+
+ ret = vtd_dev_to_context_entry(s, pci_bus_num(vtd_hiod->bus),
+ vtd_hiod->devfn, &ce);
+ if (ret) {
+ return ret;
+ }
+
+ return vtd_ce_get_pasid_entry(s, &ce, pe, pasid);
+}
+
bool vtd_check_hiod_accel(IntelIOMMUState *s, VTDHostIOMMUDevice *vtd_hiod,
Error **errp)
{
@@ -257,6 +279,52 @@ void vtd_flush_host_piotlb_all_locked(IntelIOMMUState *s,
uint16_t domain_id,
vtd_flush_host_piotlb_locked, &piotlb_info);
}
+static void vtd_pasid_cache_invalidate_one(VTDACCELPASIDCacheEntry *vtd_pce,
+ VTDPASIDCacheInfo *pc_info)
+{
+ VTDPASIDEntry pe;
+ uint16_t did;
+
+ /*
+ * VTD_INV_DESC_PASIDC_G_DSI and VTD_INV_DESC_PASIDC_G_PASID_SI require
+ * DID check. If DID doesn't match the value in cache or memory, then
+ * it's not a pasid entry we want to invalidate.
+ */
+ switch (pc_info->type) {
+ case VTD_INV_DESC_PASIDC_G_PASID_SI:
+ if (pc_info->pasid != vtd_pce->pasid) {
+ return;
+ }
+ /* Fall through */
+ case VTD_INV_DESC_PASIDC_G_DSI:
+ did = VTD_SM_PASID_ENTRY_DID(&vtd_pce->pe);
+ if (pc_info->did != did) {
+ return;
+ }
+ }
+
+ if (vtd_hiod_get_pe_from_pasid(vtd_pce, &pe)) {
+ /*
+ * No valid pasid entry in guest memory. e.g. pasid entry was modified
+ * to be either all-zero or non-present. Either case means existing
+ * pasid cache should be invalidated.
+ */
+ QLIST_REMOVE(vtd_pce, next);
+ g_free(vtd_pce);
call vtd_accel_update_pc() and vtd_accel_delete_pc() accordingly.
+ }
+}
+
+/* Delete invalid pasid cache entry from pasid_cache_list */
+static void vtd_pasid_cache_invalidate(VTDHostIOMMUDevice *vtd_hiod,
+ VTDPASIDCacheInfo *pc_info)
+{
+ VTDACCELPASIDCacheEntry *vtd_pce, *next;
+
+ QLIST_FOREACH_SAFE(vtd_pce, &vtd_hiod->pasid_cache_list, next, next) {
+ vtd_pasid_cache_invalidate_one(vtd_pce, pc_info);
+ }
+}
+
static void vtd_find_add_pc(VTDHostIOMMUDevice *vtd_hiod, uint32_t pasid,
VTDPASIDEntry *pe)
{
@@ -423,6 +491,8 @@ void vtd_pasid_cache_sync_accel(IntelIOMMUState *s,
VTDPASIDCacheInfo *pc_info)
TYPE_HOST_IOMMU_DEVICE_IOMMUFD)) {
continue;
}
+
+ vtd_pasid_cache_invalidate(vtd_hiod, pc_info);
vtd_replay_pasid_bind_for_dev(vtd_hiod, start, end, pc_info);
}
}
