For UNMAP-only IOMMU notifiers, we don't really need to walk the page
tables. Fasten that procedure by skipping the page table walk. That
should boost performance for UNMAP-only notifiers like vhost.
Signed-off-by: Peter Xu <pet...@redhat.com>
---
include/hw/i386/intel_iommu.h | 2 ++
hw/i386/intel_iommu.c | 43 +++++++++++++++++++++++++++++++----
2 files changed, 40 insertions(+), 5 deletions(-)
diff --git a/include/hw/i386/intel_iommu.h b/include/hw/i386/intel_iommu.h
index ee517704e7..9e0a6c1c6a 100644
--- a/include/hw/i386/intel_iommu.h
+++ b/include/hw/i386/intel_iommu.h
@@ -93,6 +93,8 @@ struct VTDAddressSpace {
IntelIOMMUState *iommu_state;
VTDContextCacheEntry context_cache_entry;
QLIST_ENTRY(VTDAddressSpace) next;
+ /* Superset of notifier flags that this address space has */
+ IOMMUNotifierFlag notifier_flags;
};
struct VTDBus {
diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index 112971638d..9a418abfb6 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -138,6 +138,12 @@ static inline void vtd_iommu_unlock(IntelIOMMUState *s)
qemu_mutex_unlock(&s->iommu_lock);
}
+/* Whether the address space needs to notify new mappings */
+static inline gboolean vtd_as_notify_mappings(VTDAddressSpace *as)
+{
+ return as->notifier_flags & IOMMU_NOTIFIER_MAP;
+}
+
/* GHashTable functions */
static gboolean vtd_uint64_equal(gconstpointer v1, gconstpointer v2)
{
@@ -1433,14 +1439,35 @@ static void
vtd_iotlb_page_invalidate_notify(IntelIOMMUState *s,
VTDAddressSpace *vtd_as;
VTDContextEntry ce;
int ret;
+ hwaddr size = (1 << am) * VTD_PAGE_SIZE;
QLIST_FOREACH(vtd_as, &(s->notifiers_list), next) {
ret = vtd_dev_to_context_entry(s, pci_bus_num(vtd_as->bus),
vtd_as->devfn, &ce);
if (!ret && domain_id == VTD_CONTEXT_ENTRY_DID(ce.hi)) {
- vtd_page_walk(&ce, addr, addr + (1 << am) * VTD_PAGE_SIZE,
- vtd_page_invalidate_notify_hook,
- (void *)&vtd_as->iommu, true, s->aw_bits);
+ if (vtd_as_notify_mappings(vtd_as)) {
+ /*
+ * For MAP-inclusive notifiers, we need to walk the
+ * page table to sync the shadow page table.
+ */
+ vtd_page_walk(&ce, addr, addr + size,
+ vtd_page_invalidate_notify_hook,
+ (void *)&vtd_as->iommu, true, s->aw_bits);
+ } else {
+ /*
+ * For UNMAP-only notifiers, we don't need to walk the
+ * page tables. We just deliver the PSI down to
+ * invalidate caches.
+ */
+ IOMMUTLBEntry entry = {
+ .target_as = &address_space_memory,
+ .iova = addr,
+ .translated_addr = 0,
+ .addr_mask = size - 1,
+ .perm = IOMMU_NONE,
+ };
+ memory_region_notify_iommu(&vtd_as->iommu, entry);
+ }
}
}
}
@@ -2380,6 +2407,9 @@ static void
vtd_iommu_notify_flag_changed(IOMMUMemoryRegion *iommu,
exit(1);
}
+ /* Update per-address-space notifier flags */
+ vtd_as->notifier_flags = new;
+
if (old == IOMMU_NOTIFIER_NONE) {
/* Insert new ones */
QLIST_INSERT_HEAD(&s->notifiers_list, vtd_as, next);
@@ -2890,8 +2920,11 @@ static void vtd_iommu_replay(IOMMUMemoryRegion
*iommu_mr, IOMMUNotifier *n)
PCI_FUNC(vtd_as->devfn),
VTD_CONTEXT_ENTRY_DID(ce.hi),
ce.hi, ce.lo);
- vtd_page_walk(&ce, 0, ~0ULL, vtd_replay_hook, (void *)n, false,
- s->aw_bits);
+ if (vtd_as_notify_mappings(vtd_as)) {
+ /* This is required only for MAP typed notifiers */
+ vtd_page_walk(&ce, 0, ~0ULL, vtd_replay_hook, (void *)n, false,
+ s->aw_bits);
+ }
} else {
trace_vtd_replay_ce_invalid(bus_n, PCI_SLOT(vtd_as->devfn),
PCI_FUNC(vtd_as->devfn));
--
2.17.0
