[Qemu-devel] [PATCH v9 2/4] vfio: Add vfio_container_ioctl()

[Alexey Kardashevskiy <aik@ozlabs.ru>]

While most operations with VFIO IOMMU driver are generic and used inside
vfio.c, there are still some operations which only specific VFIO IOMMU
drivers implement. The first example of it will be reading a DMA window
start from the host.

This adds a helper which passes an ioctl request to the container's fd.

The helper will check if @req is known. For this, stub is added. This return
-1 on any requests for now.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
Changes:
v9:
* added a stub for @req checking
* vfio_container_ioctl -> vfio_container_ioctl + static vfio_container_do_ioctl

v8:
* s/vfio_container_spapr_get_info/vfio_container_ioctl/ - now it is
generalized

v7:
* do not return a group fd from the helper

v6:
* added dup() to protect group_fd from accidental disposal

v5:
* reworked to reflect change in vfio_get_group() from one
of previous patches change

v4:
* fixed possible leaks on error paths
---
 hw/misc/vfio.c         | 42 ++++++++++++++++++++++++++++++++++++++++++
 include/hw/misc/vfio.h |  9 +++++++++
 2 files changed, 51 insertions(+)
 create mode 100644 include/hw/misc/vfio.h

diff --git a/hw/misc/vfio.c b/hw/misc/vfio.c
index 7437c2e..bdd6e33 100644
--- a/hw/misc/vfio.c
+++ b/hw/misc/vfio.c
@@ -39,6 +39,7 @@
 #include "qemu/range.h"
 #include "sysemu/kvm.h"
 #include "sysemu/sysemu.h"
+#include "hw/misc/vfio.h"
 
 /* #define DEBUG_VFIO */
 #ifdef DEBUG_VFIO
@@ -4318,3 +4319,44 @@ static void register_vfio_pci_dev_type(void)
 }
 
 type_init(register_vfio_pci_dev_type)
+
+static int vfio_container_do_ioctl(AddressSpace *as, int32_t groupid,
+                                   int req, void *param)
+{
+    VFIOGroup *group;
+    VFIOContainer *container;
+    int ret = -1;
+
+    group = vfio_get_group(groupid, as);
+    if (!group) {
+        error_report("vfio: group %d not registered", groupid);
+        return ret;
+    }
+
+    container = group->container;
+    if (group->container) {
+        ret = ioctl(container->fd, req, param);
+        if (ret < 0) {
+            error_report("vfio: failed to ioctl container: ret=%d, %s",
+                         ret, strerror(errno));
+        }
+    }
+
+    vfio_put_group(group);
+
+    return ret;
+}
+
+int vfio_container_ioctl(AddressSpace *as, int32_t groupid,
+                         int req, void *param)
+{
+    /* We allow only certain ioctls to the container */
+    switch (req) {
+    default:
+        /* Return an error on unknown requests */
+        error_report("vfio: unsupported ioctl %X", req);
+        return -1;
+    }
+
+    return vfio_container_do_ioctl(as, groupid, req, param);
+}
diff --git a/include/hw/misc/vfio.h b/include/hw/misc/vfio.h
new file mode 100644
index 0000000..0b26cd8
--- /dev/null
+++ b/include/hw/misc/vfio.h
@@ -0,0 +1,9 @@
+#ifndef VFIO_API_H
+#define VFIO_API_H
+
+#include "qemu/typedefs.h"
+
+extern int vfio_container_ioctl(AddressSpace *as, int32_t groupid,
+                                int req, void *param);
+
+#endif
-- 
2.0.0