[PATCH RFC server 07/11] vfio-user: handle DMA mappings

[Jagannathan Raman]

Define and register callbacks to manage the RAM regions used for
device DMA

Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
Signed-off-by: John G Johnson <john.g.johnson@oracle.com>
Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
---
 hw/remote/vfio-user-obj.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++
 hw/remote/trace-events    |  2 ++
 2 files changed, 60 insertions(+)

diff --git a/hw/remote/vfio-user-obj.c b/hw/remote/vfio-user-obj.c
index 60d9fa8..d158a7f 100644
--- a/hw/remote/vfio-user-obj.c
+++ b/hw/remote/vfio-user-obj.c
@@ -161,6 +161,57 @@ static ssize_t vfu_object_cfg_access(vfu_ctx_t *vfu_ctx, 
char * const buf,
     return count;
 }
 
+static void dma_register(vfu_ctx_t *vfu_ctx, vfu_dma_info_t *info)
+{
+    MemoryRegion *subregion = NULL;
+    g_autofree char *name = NULL;
+    static unsigned int suffix;
+    struct iovec *iov = &info->iova;
+
+    if (!info->vaddr) {
+        return;
+    }
+
+    name = g_strdup_printf("remote-mem-%u", suffix++);
+
+    subregion = g_new0(MemoryRegion, 1);
+
+    qemu_mutex_lock_iothread();
+
+    memory_region_init_ram_ptr(subregion, NULL, name,
+                               iov->iov_len, info->vaddr);
+
+    memory_region_add_subregion(get_system_memory(), (hwaddr)iov->iov_base,
+                                subregion);
+
+    qemu_mutex_unlock_iothread();
+
+    trace_vfu_dma_register((uint64_t)iov->iov_base, iov->iov_len);
+}
+
+static int dma_unregister(vfu_ctx_t *vfu_ctx, vfu_dma_info_t *info)
+{
+    MemoryRegion *mr = NULL;
+    ram_addr_t offset;
+
+    mr = memory_region_from_host(info->vaddr, &offset);
+    if (!mr) {
+        return 0;
+    }
+
+    qemu_mutex_lock_iothread();
+
+    memory_region_del_subregion(get_system_memory(), mr);
+
+    object_unparent((OBJECT(mr)));
+
+    qemu_mutex_unlock_iothread();
+
+    trace_vfu_dma_unregister((uint64_t)info->iova.iov_base);
+
+    return 0;
+}
+
 static void vfu_object_machine_done(Notifier *notifier, void *data)
 {
     VfuObject *o = container_of(notifier, VfuObject, machine_done);
@@ -208,6 +259,13 @@ static void vfu_object_machine_done(Notifier *notifier, 
void *data)
         return;
     }
 
+    ret = vfu_setup_device_dma(o->vfu_ctx, &dma_register, &dma_unregister);
+    if (ret < 0) {
+        error_setg(&error_abort, "vfu: Failed to setup DMA handlers for %s",
+                   o->devid);
+        return;
+    }
+
     qemu_thread_create(&o->vfu_ctx_thread, "VFU ctx runner", 
vfu_object_ctx_run,
                        o, QEMU_THREAD_JOINABLE);
 }
diff --git a/hw/remote/trace-events b/hw/remote/trace-events
index 2ef7884..f945c7e 100644
--- a/hw/remote/trace-events
+++ b/hw/remote/trace-events
@@ -7,3 +7,5 @@ mpqemu_recv_io_error(int cmd, int size, int nfds) "failed to 
receive %d size %d,
 vfu_prop(const char *prop, const char *val) "vfu: setting %s as %s"
 vfu_cfg_read(uint32_t offset, uint32_t val) "vfu: cfg: 0x%u -> 0x%x"
 vfu_cfg_write(uint32_t offset, uint32_t val) "vfu: cfg: 0x%u <- 0x%x"
+vfu_dma_register(uint64_t gpa, size_t len) "vfu: registering GPA 0x%"PRIx64", 
%zu bytes"
+vfu_dma_unregister(uint64_t gpa) "vfu: unregistering GPA 0x%"PRIx64""
-- 
1.8.3.1