From b6bc2d692f4f3c41b61c0917d4709e91827c8432 Mon Sep 17 00:00:00 2001

From: Peter Xu <peterx@redhat.com>

Date: Mon, 3 Sep 2018 04:52:36 +0200

Subject: [PATCH 21/29] intel-iommu: only do page walk for MAP notifiers

RH-Author: Peter Xu <peterx@redhat.com>

Message-id: <20180903045241.6456-5-peterx@redhat.com>

Patchwork-id: 82024

O-Subject: [RHEL-7.6 qemu-kvm-rhev PATCH 4/9] intel-iommu: only do page walk for MAP notifiers

Bugzilla: 1623859

RH-Acked-by: Xiao Wang <jasowang@redhat.com>

RH-Acked-by: Auger Eric <eric.auger@redhat.com>

RH-Acked-by: Michael S. Tsirkin <mst@redhat.com>

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: Peter Xu <peterx@redhat.com>

Reviewed-by: Michael S. Tsirkin <mst@redhat.com>

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

(cherry picked from commit 4f8a62a933a79094e44bc1b16b63bb23e62d67b4)

Signed-off-by: Peter Xu <peterx@redhat.com>

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>

---

 hw/i386/intel_iommu.c         | 44 ++++++++++++++++++++++++++++++++++++++-----

 include/hw/i386/intel_iommu.h |  2 ++

 2 files changed, 41 insertions(+), 5 deletions(-)

diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c

index 8d4069d..38ccc74 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_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,

-                          vtd_page_invalidate_notify_hook,

-                          (void *)&vtd_as->iommu, true, s->aw_bits);

+            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);

-        vtd_page_walk(&ce, 0, ~0ULL, vtd_replay_hook, (void *)n, false,

-                      s->aw_bits);

+        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));

diff --git a/include/hw/i386/intel_iommu.h b/include/hw/i386/intel_iommu.h

index 016e74b..156f35e 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 {

-- 

1.8.3.1