[PATCH v5 7/7] vhost-user-devive: Add shmem BAR

[Albert Esteve <aesteve@redhat.com>]

Add a shmem BAR block in the vhost-user-device,
which files can be directly mapped into.

The number, shmid, and size of the VIRTIO Shared
Memory subregions is retrieved through a
get_shmem_config message sent by the
vhost-user-base module on the realize step,
after virtio_init().

By default, if VHOST_USER_PROTOCOL_F_SHMEM
feature is not supported by the backend,
there is no cache.

Signed-off-by: Albert Esteve <aesteve@redhat.com>
---
 hw/virtio/vhost-user-base.c       | 47 +++++++++++++++++++++++++++++--
 hw/virtio/vhost-user-device-pci.c | 34 ++++++++++++++++++++--
 2 files changed, 76 insertions(+), 5 deletions(-)

diff --git a/hw/virtio/vhost-user-base.c b/hw/virtio/vhost-user-base.c
index ff67a020b4..e86e391fa5 100644
--- a/hw/virtio/vhost-user-base.c
+++ b/hw/virtio/vhost-user-base.c
@@ -16,6 +16,7 @@
 #include "hw/virtio/virtio-bus.h"
 #include "hw/virtio/vhost-user-base.h"
 #include "qemu/error-report.h"
+#include "migration/blocker.h"
 
 static void vub_start(VirtIODevice *vdev)
 {
@@ -276,7 +277,8 @@ static void vub_device_realize(DeviceState *dev, Error **errp)
 {
     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
     VHostUserBase *vub = VHOST_USER_BASE(dev);
-    int ret;
+    uint64_t memory_sizes[VIRTIO_MAX_SHMEM_REGIONS];
+    int i, ret, nregions;
 
     if (!vub->chardev.chr) {
         error_setg(errp, "vhost-user-base: missing chardev");
@@ -319,7 +321,7 @@ static void vub_device_realize(DeviceState *dev, Error **errp)
 
     /* Allocate queues */
     vub->vqs = g_ptr_array_sized_new(vub->num_vqs);
-    for (int i = 0; i < vub->num_vqs; i++) {
+    for (i = 0; i < vub->num_vqs; i++) {
         g_ptr_array_add(vub->vqs,
                         virtio_add_queue(vdev, vub->vq_size,
                                          vub_handle_output));
@@ -333,11 +335,50 @@ static void vub_device_realize(DeviceState *dev, Error **errp)
                          VHOST_BACKEND_TYPE_USER, 0, errp);
 
     if (ret < 0) {
-        do_vhost_user_cleanup(vdev, vub);
+        goto err;
+    }
+
+    ret = vub->vhost_dev.vhost_ops->vhost_get_shmem_config(&vub->vhost_dev,
+                                                           &nregions,
+                                                           memory_sizes,
+                                                           errp);
+
+    if (ret < 0) {
+        goto err;
+    }
+
+    for (i = 0; i < nregions; i++) {
+        if (memory_sizes[i]) {
+            if (vub->vhost_dev.migration_blocker == NULL) {
+                error_setg(&vub->vhost_dev.migration_blocker,
+                       "Migration disabled: devices with VIRTIO Shared Memory "
+                       "Regions do not support migration yet.");
+                ret = migrate_add_blocker_normal(
+                    &vub->vhost_dev.migration_blocker,
+                    errp);
+
+                if (ret < 0) {
+                    goto err;
+                }
+            }
+
+            if (memory_sizes[i] % qemu_real_host_page_size() != 0) {
+                error_setg(errp, "Shared memory %d size must be a power of 2 "
+                                 "no smaller than the page size", i);
+                goto err;
+            }
+
+            memory_region_init(virtio_new_shmem_region(vdev, i)->mr,
+                               OBJECT(vdev), "vub-shm-" + i,
+                               memory_sizes[i]);
+        }
     }
 
     qemu_chr_fe_set_handlers(&vub->chardev, NULL, NULL, vub_event, NULL,
                              dev, NULL, true);
+    return;
+err:
+    do_vhost_user_cleanup(vdev, vub);
 }
 
 static void vub_device_unrealize(DeviceState *dev)
diff --git a/hw/virtio/vhost-user-device-pci.c b/hw/virtio/vhost-user-device-pci.c
index f10bac874e..eeb52671a0 100644
--- a/hw/virtio/vhost-user-device-pci.c
+++ b/hw/virtio/vhost-user-device-pci.c
@@ -8,14 +8,18 @@
  */
 
 #include "qemu/osdep.h"
+#include "qapi/error.h"
 #include "hw/qdev-properties.h"
 #include "hw/virtio/vhost-user-base.h"
 #include "hw/virtio/virtio-pci.h"
 
+#define VIRTIO_DEVICE_PCI_SHMEM_BAR 2
+
 struct VHostUserDevicePCI {
     VirtIOPCIProxy parent_obj;
 
     VHostUserBase vub;
+    MemoryRegion shmembar;
 };
 
 #define TYPE_VHOST_USER_DEVICE_PCI "vhost-user-device-pci-base"
@@ -25,10 +29,36 @@ OBJECT_DECLARE_SIMPLE_TYPE(VHostUserDevicePCI, VHOST_USER_DEVICE_PCI)
 static void vhost_user_device_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
 {
     VHostUserDevicePCI *dev = VHOST_USER_DEVICE_PCI(vpci_dev);
-    DeviceState *vdev = DEVICE(&dev->vub);
+    DeviceState *dev_state = DEVICE(&dev->vub);
+    VirtIODevice *vdev = VIRTIO_DEVICE(dev_state);
+    VirtSharedMemory *shmem, *next;
+    uint64_t offset = 0, shmem_size = 0;
 
     vpci_dev->nvectors = 1;
-    qdev_realize(vdev, BUS(&vpci_dev->bus), errp);
+    qdev_realize(dev_state, BUS(&vpci_dev->bus), errp);
+
+    QSIMPLEQ_FOREACH_SAFE(shmem, &vdev->shmem_list, entry, next) {
+        if (shmem->mr->size > UINT64_MAX - shmem_size) {
+            error_setg(errp, "Total shared memory required overflow");
+            return;
+        }
+        shmem_size = shmem_size + shmem->mr->size;
+    }
+    if (shmem_size) {
+        memory_region_init(&dev->shmembar, OBJECT(vpci_dev),
+                           "vhost-device-pci-shmembar", shmem_size);
+        QSIMPLEQ_FOREACH_SAFE(shmem, &vdev->shmem_list, entry, next) {
+            memory_region_add_subregion(&dev->shmembar, offset, shmem->mr);
+            virtio_pci_add_shm_cap(vpci_dev, VIRTIO_DEVICE_PCI_SHMEM_BAR,
+                                   offset, shmem->mr->size, 0);
+            offset = offset + shmem->mr->size;
+        }
+        pci_register_bar(&vpci_dev->pci_dev, VIRTIO_DEVICE_PCI_SHMEM_BAR,
+                        PCI_BASE_ADDRESS_SPACE_MEMORY |
+                        PCI_BASE_ADDRESS_MEM_PREFETCH |
+                        PCI_BASE_ADDRESS_MEM_TYPE_64,
+                        &dev->shmembar);
+    }
 }
 
 static void vhost_user_device_pci_class_init(ObjectClass *klass,
-- 
2.49.0