Commit 4f8a62a9 authored by Peter Xu's avatar Peter Xu Committed by Michael S. Tsirkin
Browse files

intel-iommu: only do page walk for MAP notifiers 



For UNMAP-only IOMMU notifiers, we don't 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.

CC: QEMU Stable <qemu-stable@nongnu.org>
Signed-off-by: default avatarPeter Xu <peterx@redhat.com>
Reviewed-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent 1d9efa73

hw/i386/intel_iommu.c

+39 −5
Original line number Diff line number Diff line
@@ -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_has_map_notifier(VTDAddressSpace *as)

{

    return as->notifier_flags & IOMMU_NOTIFIER_MAP;

}



/* GHashTable functions */

static gboolean vtd_uint64_equal(gconstpointer v1, gconstpointer v2)

{
@@ -1436,14 +1442,36 @@ 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->vtd_as_with_notifiers), 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,

            if (vtd_as_has_map_notifier(vtd_as)) {

                /*

                 * As long as we have MAP notifications registered in

                 * any of our IOMMU notifiers, we need 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);

            }

        }

    }

}
@@ -2383,6 +2411,9 @@ 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) {

        QLIST_INSERT_HEAD(&s->vtd_as_with_notifiers, vtd_as, next);

    } else if (new == IOMMU_NOTIFIER_NONE) {
@@ -2891,8 +2922,11 @@ 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);

        if (vtd_as_has_map_notifier(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));

include/hw/i386/intel_iommu.h

+2 −0
Original line number Diff line number Diff line
@@ -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 {