[RFC,v2,05/21] kvm: Enable KVM_SET_USER_MEMORY_REGION2 for memslot

diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index 185ae16d9620..91cee0878366 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -288,35 +288,68 @@  int kvm_physical_memory_addr_from_host(KVMState *s, void *ram,
 static int kvm_set_user_memory_region(KVMMemoryListener *kml, KVMSlot *slot, bool new)
 {
     KVMState *s = kvm_state;
-    struct kvm_userspace_memory_region mem;
+    struct kvm_userspace_memory_region2 mem;
+    static int cap_user_memory2 = -1;
     int ret;
 
+    if (cap_user_memory2 == -1) {
+        cap_user_memory2 = kvm_check_extension(s, KVM_CAP_USER_MEMORY2);
+    }
+
+    if (!cap_user_memory2 && slot->gmem_fd >= 0) {
+        error_report("%s, KVM doesn't support gmem!", __func__);
+        exit(1);
+    }
+
     mem.slot = slot->slot | (kml->as_id << 16);
     mem.guest_phys_addr = slot->start_addr;
     mem.userspace_addr = (unsigned long)slot->ram;
     mem.flags = slot->flags;
+    mem.gmem_fd = slot->gmem_fd;
+    mem.gmem_offset = slot->ofs;
 
     if (slot->memory_size && !new && (mem.flags ^ slot->old_flags) & KVM_MEM_READONLY) {
         /* Set the slot size to 0 before setting the slot to the desired
          * value. This is needed based on KVM commit 75d61fbc. */
         mem.memory_size = 0;
-        ret = kvm_vm_ioctl(s, KVM_SET_USER_MEMORY_REGION, &mem);
+
+        if (cap_user_memory2) {
+            ret = kvm_vm_ioctl(s, KVM_SET_USER_MEMORY_REGION2, &mem);
+        } else {
+            ret = kvm_vm_ioctl(s, KVM_SET_USER_MEMORY_REGION, &mem);
+	    }
         if (ret < 0) {
             goto err;
         }
     }
     mem.memory_size = slot->memory_size;
-    ret = kvm_vm_ioctl(s, KVM_SET_USER_MEMORY_REGION, &mem);
+    if (cap_user_memory2) {
+        ret = kvm_vm_ioctl(s, KVM_SET_USER_MEMORY_REGION2, &mem);
+    } else {
+        ret = kvm_vm_ioctl(s, KVM_SET_USER_MEMORY_REGION, &mem);
+    }
     slot->old_flags = mem.flags;
 err:
     trace_kvm_set_user_memory(mem.slot >> 16, (uint16_t)mem.slot, mem.flags,
                               mem.guest_phys_addr, mem.memory_size,
-                              mem.userspace_addr, ret);
+                              mem.userspace_addr, mem.gmem_fd,
+			      mem.gmem_offset, ret);
     if (ret < 0) {
-        error_report("%s: KVM_SET_USER_MEMORY_REGION failed, slot=%d,"
-                     " start=0x%" PRIx64 ", size=0x%" PRIx64 ": %s",
-                     __func__, mem.slot, slot->start_addr,
-                     (uint64_t)mem.memory_size, strerror(errno));
+        if (cap_user_memory2) {
+                error_report("%s: KVM_SET_USER_MEMORY_REGION2 failed, slot=%d,"
+                        " start=0x%" PRIx64 ", size=0x%" PRIx64 ","
+                        " flags=0x%" PRIx32 ","
+                        " gmem_fd=%" PRId32 ", gmem_offset=0x%" PRIx64 ": %s",
+                        __func__, mem.slot, slot->start_addr,
+                        (uint64_t)mem.memory_size, mem.flags,
+                        mem.gmem_fd, (uint64_t)mem.gmem_offset,
+                        strerror(errno));
+        } else {
+                error_report("%s: KVM_SET_USER_MEMORY_REGION failed, slot=%d,"
+                            " start=0x%" PRIx64 ", size=0x%" PRIx64 ": %s",
+                            __func__, mem.slot, slot->start_addr,
+                            (uint64_t)mem.memory_size, strerror(errno));
+        }
     }
     return ret;
 }
@@ -472,6 +505,9 @@  static int kvm_mem_flags(MemoryRegion *mr)
     if (readonly && kvm_readonly_mem_allowed) {
         flags |= KVM_MEM_READONLY;
     }
+    if (memory_region_has_gmem_fd(mr)) {
+        flags |= KVM_MEM_PRIVATE;
+    }
     return flags;
 }
 
@@ -1402,6 +1438,9 @@  static void kvm_set_phys_mem(KVMMemoryListener *kml,
         mem->ram_start_offset = ram_start_offset;
         mem->ram = ram;
         mem->flags = kvm_mem_flags(mr);
+        mem->gmem_fd = mr->ram_block->gmem_fd;
+        mem->ofs = (uint8_t*)ram - mr->ram_block->host;
+
         kvm_slot_init_dirty_bitmap(mem);
         err = kvm_set_user_memory_region(kml, mem, true);
         if (err) {
diff --git a/accel/kvm/trace-events b/accel/kvm/trace-events
index 14ebfa1b991c..80694683acea 100644
--- a/accel/kvm/trace-events
+++ b/accel/kvm/trace-events
@@ -15,7 +15,7 @@  kvm_irqchip_update_msi_route(int virq) "Updating MSI route virq=%d"
 kvm_irqchip_release_virq(int virq) "virq %d"
 kvm_set_ioeventfd_mmio(int fd, uint64_t addr, uint32_t val, bool assign, uint32_t size, bool datamatch) "fd: %d @0x%" PRIx64 " val=0x%x assign: %d size: %d match: %d"
 kvm_set_ioeventfd_pio(int fd, uint16_t addr, uint32_t val, bool assign, uint32_t size, bool datamatch) "fd: %d @0x%x val=0x%x assign: %d size: %d match: %d"
-kvm_set_user_memory(uint16_t as, uint16_t slot, uint32_t flags, uint64_t guest_phys_addr, uint64_t memory_size, uint64_t userspace_addr, int ret) "AddrSpace#%d Slot#%d flags=0x%x gpa=0x%"PRIx64 " size=0x%"PRIx64 " ua=0x%"PRIx64 " ret=%d"
+kvm_set_user_memory(uint16_t as, uint16_t slot, uint32_t flags, uint64_t guest_phys_addr, uint64_t memory_size, uint64_t userspace_addr, uint32_t fd, uint64_t fd_offset, int ret) "AddrSpace#%d Slot#%d flags=0x%x gpa=0x%"PRIx64 " size=0x%"PRIx64 " ua=0x%"PRIx64 " gmem_fd=%d" " gmem_fd_offset=0x%" PRIx64 " ret=%d"
 kvm_clear_dirty_log(uint32_t slot, uint64_t start, uint32_t size) "slot#%"PRId32" start 0x%"PRIx64" size 0x%"PRIx32
 kvm_resample_fd_notify(int gsi) "gsi %d"
 kvm_dirty_ring_full(int id) "vcpu %d"
diff --git a/include/sysemu/kvm_int.h b/include/sysemu/kvm_int.h
index 511b42bde5c4..9990889d3494 100644
--- a/include/sysemu/kvm_int.h
+++ b/include/sysemu/kvm_int.h
@@ -30,6 +30,8 @@  typedef struct KVMSlot
     int as_id;
     /* Cache of the offset in ram address space */
     ram_addr_t ram_start_offset;
+    int gmem_fd;
+    hwaddr ofs;
 } KVMSlot;
 
 typedef struct KVMMemoryUpdate {