1 files changed, 90 insertions, 11 deletions

diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index 8760d55..7e6a607 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -31,6 +31,7 @@
 #include "sysemu/kvm_int.h"
 #include "sysemu/runstate.h"
 #include "sysemu/cpus.h"
+#include "sysemu/accel-blocker.h"
 #include "qemu/bswap.h"
 #include "exec/memory.h"
 #include "exec/ram_addr.h"
@@ -46,6 +47,7 @@
 #include "sysemu/hw_accel.h"
 #include "kvm-cpus.h"
 #include "sysemu/dirtylimit.h"
+#include "qemu/range.h"
 
 #include "hw/boards.h"
 #include "monitor/stats.h"
@@ -1292,6 +1294,7 @@ void kvm_set_max_memslot_size(hwaddr max_slot_size)
     kvm_max_slot_size = max_slot_size;
 }
 
+/* Called with KVMMemoryListener.slots_lock held */
 static void kvm_set_phys_mem(KVMMemoryListener *kml,
                              MemoryRegionSection *section, bool add)
 {
@@ -1326,14 +1329,12 @@ static void kvm_set_phys_mem(KVMMemoryListener *kml,
     ram = memory_region_get_ram_ptr(mr) + mr_offset;
     ram_start_offset = memory_region_get_ram_addr(mr) + mr_offset;
 
-    kvm_slots_lock();
-
     if (!add) {
         do {
             slot_size = MIN(kvm_max_slot_size, size);
             mem = kvm_lookup_matching_slot(kml, start_addr, slot_size);
             if (!mem) {
-                goto out;
+                return;
             }
             if (mem->flags & KVM_MEM_LOG_DIRTY_PAGES) {
                 /*
@@ -1371,7 +1372,7 @@ static void kvm_set_phys_mem(KVMMemoryListener *kml,
             start_addr += slot_size;
             size -= slot_size;
         } while (size);
-        goto out;
+        return;
     }
 
     /* register the new slot */
@@ -1396,9 +1397,6 @@ static void kvm_set_phys_mem(KVMMemoryListener *kml,
         ram += slot_size;
         size -= slot_size;
     } while (size);
-
-out:
-    kvm_slots_unlock();
 }
 
 static void *kvm_dirty_ring_reaper_thread(void *data)
@@ -1455,18 +1453,95 @@ static void kvm_region_add(MemoryListener *listener,
                            MemoryRegionSection *section)
 {
     KVMMemoryListener *kml = container_of(listener, KVMMemoryListener, listener);
+    KVMMemoryUpdate *update;
+
+    update = g_new0(KVMMemoryUpdate, 1);
+    update->section = *section;
 
-    memory_region_ref(section->mr);
-    kvm_set_phys_mem(kml, section, true);
+    QSIMPLEQ_INSERT_TAIL(&kml->transaction_add, update, next);
 }
 
 static void kvm_region_del(MemoryListener *listener,
                            MemoryRegionSection *section)
 {
     KVMMemoryListener *kml = container_of(listener, KVMMemoryListener, listener);
+    KVMMemoryUpdate *update;
+
+    update = g_new0(KVMMemoryUpdate, 1);
+    update->section = *section;
+
+    QSIMPLEQ_INSERT_TAIL(&kml->transaction_del, update, next);
+}
+
+static void kvm_region_commit(MemoryListener *listener)
+{
+    KVMMemoryListener *kml = container_of(listener, KVMMemoryListener,
+                                          listener);
+    KVMMemoryUpdate *u1, *u2;
+    bool need_inhibit = false;
+
+    if (QSIMPLEQ_EMPTY(&kml->transaction_add) &&
+        QSIMPLEQ_EMPTY(&kml->transaction_del)) {
+        return;
+    }
+
+    /*
+     * We have to be careful when regions to add overlap with ranges to remove.
+     * We have to simulate atomic KVM memslot updates by making sure no ioctl()
+     * is currently active.
+     *
+     * The lists are order by addresses, so it's easy to find overlaps.
+     */
+    u1 = QSIMPLEQ_FIRST(&kml->transaction_del);
+    u2 = QSIMPLEQ_FIRST(&kml->transaction_add);
+    while (u1 && u2) {
+        Range r1, r2;
+
+        range_init_nofail(&r1, u1->section.offset_within_address_space,
+                          int128_get64(u1->section.size));
+        range_init_nofail(&r2, u2->section.offset_within_address_space,
+                          int128_get64(u2->section.size));
+
+        if (range_overlaps_range(&r1, &r2)) {
+            need_inhibit = true;
+            break;
+        }
+        if (range_lob(&r1) < range_lob(&r2)) {
+            u1 = QSIMPLEQ_NEXT(u1, next);
+        } else {
+            u2 = QSIMPLEQ_NEXT(u2, next);
+        }
+    }
+
+    kvm_slots_lock();
+    if (need_inhibit) {
+        accel_ioctl_inhibit_begin();
+    }
+
+    /* Remove all memslots before adding the new ones. */
+    while (!QSIMPLEQ_EMPTY(&kml->transaction_del)) {
+        u1 = QSIMPLEQ_FIRST(&kml->transaction_del);
+        QSIMPLEQ_REMOVE_HEAD(&kml->transaction_del, next);
 
-    kvm_set_phys_mem(kml, section, false);
-    memory_region_unref(section->mr);
+        kvm_set_phys_mem(kml, &u1->section, false);
+        memory_region_unref(u1->section.mr);
+
+        g_free(u1);
+    }
+    while (!QSIMPLEQ_EMPTY(&kml->transaction_add)) {
+        u1 = QSIMPLEQ_FIRST(&kml->transaction_add);
+        QSIMPLEQ_REMOVE_HEAD(&kml->transaction_add, next);
+
+        memory_region_ref(u1->section.mr);
+        kvm_set_phys_mem(kml, &u1->section, true);
+
+        g_free(u1);
+    }
+
+    if (need_inhibit) {
+        accel_ioctl_inhibit_end();
+    }
+    kvm_slots_unlock();
 }
 
 static void kvm_log_sync(MemoryListener *listener,
@@ -1610,8 +1685,12 @@ void kvm_memory_listener_register(KVMState *s, KVMMemoryListener *kml,
         kml->slots[i].slot = i;
     }
 
+    QSIMPLEQ_INIT(&kml->transaction_add);
+    QSIMPLEQ_INIT(&kml->transaction_del);
+
     kml->listener.region_add = kvm_region_add;
     kml->listener.region_del = kvm_region_del;
+    kml->listener.commit = kvm_region_commit;
     kml->listener.log_start = kvm_log_start;
     kml->listener.log_stop = kvm_log_stop;
     kml->listener.priority = 10;