drm: Switch to refactored proto headers

https://gitlab.freedesktop.org/mesa/mesa/-/commit/b90244776added6cfce76e68d37e142607e09040
extracted some common vdrm structs, for things that ended up identical
for intel and amd.  This commit makes the same change on the
virglrenderer side.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Part-of: <https://gitlab.freedesktop.org/virgl/virglrenderer/-/merge_requests/1334>

3 files changed, 117 insertions, 100 deletions

diff --git a/src/drm/msm/msm_proto.h b/src/drm/msm/msm_proto.h
index b5138e4..ba66ab9 100644
--- a/src/drm/msm/msm_proto.h
+++ b/src/drm/msm/msm_proto.h
@@ -23,31 +23,7 @@
  * Defines the layout of shmem buffer used for host->guest communication.
  */
 struct msm_shmem {
-   /**
-    * The sequence # of last cmd processed by the host
-    */
-   uint32_t seqno;
-
-   /**
-    * Offset to the start of rsp memory region in the shmem buffer.  This
-    * is set by the host when the shmem buffer is allocated, to allow for
-    * extending the shmem buffer with new fields.  The size of the rsp
-    * memory region is the size of the shmem buffer (controlled by the
-    * guest) minus rsp_mem_offset.
-    *
-    * The guest should use the msm_shmem_has_field() macro to determine
-    * if the host supports a given field, ie. to handle compatibility of
-    * newer guest vs older host.
-    *
-    * Making the guest userspace responsible for backwards compatibility
-    * simplifies the host VMM.
-    */
-   uint32_t rsp_mem_offset;
-
-#define msm_shmem_has_field(shmem, field) ({                         \
-      struct msm_shmem *_shmem = (shmem);                            \
-      (_shmem->rsp_mem_offset > offsetof(struct msm_shmem, field));  \
-   })
+   struct vdrm_shmem base;
 
    /**
     * Counter that is incremented on asynchronous errors, like SUBMIT
@@ -61,12 +37,7 @@ struct msm_shmem {
     */
    uint32_t global_faults;
 };
-
-#define DEFINE_CAST(parent, child)                                             \
-   static inline struct child *to_##child(const struct parent *x)              \
-   {                                                                           \
-      return (struct child *)x;                                                \
-   }
+DEFINE_CAST(vdrm_shmem, msm_shmem)
 
 /*
  * Possible cmd types for "command stream", ie. payload of EXECBUF ioctl:
@@ -86,30 +57,13 @@ enum msm_ccmd {
    MSM_CCMD_LAST,
 };
 
-struct msm_ccmd_req {
-   uint32_t cmd;
-   uint32_t len;
-   uint32_t seqno;
-
-   /* Offset into shmem ctrl buffer to write response.  The host ensures
-    * that it doesn't write outside the bounds of the ctrl buffer, but
-    * otherwise it is up to the guest to manage allocation of where responses
-    * should be written in the ctrl buf.
-    */
-   uint32_t rsp_off;
-};
-
-struct msm_ccmd_rsp {
-   uint32_t len;
-};
-
 #ifdef __cplusplus
 #define MSM_CCMD(_cmd, _len) {                      \
        .cmd = MSM_CCMD_##_cmd,                      \
        .len = (_len),                               \
    }
 #else
-#define MSM_CCMD(_cmd, _len) (struct msm_ccmd_req){ \
+#define MSM_CCMD(_cmd, _len) (struct vdrm_ccmd_req){ \
        .cmd = MSM_CCMD_##_cmd,                      \
        .len = (_len),                               \
    }
@@ -119,7 +73,7 @@ struct msm_ccmd_rsp {
  * MSM_CCMD_NOP
  */
 struct msm_ccmd_nop_req {
-   struct msm_ccmd_req hdr;
+   struct vdrm_ccmd_req hdr;
 };
 
 /*
@@ -128,15 +82,15 @@ struct msm_ccmd_nop_req {
  * Forward simple/flat IOC_RW or IOC_W ioctls.  Limited ioctls are supported.
  */
 struct msm_ccmd_ioctl_simple_req {
-   struct msm_ccmd_req hdr;
+   struct vdrm_ccmd_req hdr;
 
    uint32_t cmd;
    uint8_t payload[];
 };
-DEFINE_CAST(msm_ccmd_req, msm_ccmd_ioctl_simple_req)
+DEFINE_CAST(vdrm_ccmd_req, msm_ccmd_ioctl_simple_req)
 
 struct msm_ccmd_ioctl_simple_rsp {
-   struct msm_ccmd_rsp hdr;
+   struct vdrm_ccmd_rsp hdr;
 
    /* ioctl return value, interrupted syscalls are handled on the host without
     * returning to the guest.
@@ -160,14 +114,14 @@ struct msm_ccmd_ioctl_simple_rsp {
  * No response.
  */
 struct msm_ccmd_gem_new_req {
-   struct msm_ccmd_req hdr;
+   struct vdrm_ccmd_req hdr;
 
    uint64_t iova;
    uint64_t size;
    uint32_t flags;
    uint32_t blob_id;
 };
-DEFINE_CAST(msm_ccmd_req, msm_ccmd_gem_new_req)
+DEFINE_CAST(vdrm_ccmd_req, msm_ccmd_gem_new_req)
 
 /*
  * MSM_CCMD_GEM_SET_IOVA
@@ -176,12 +130,12 @@ DEFINE_CAST(msm_ccmd_req, msm_ccmd_gem_new_req)
  * (by setting it to zero) when a BO is freed.
  */
 struct msm_ccmd_gem_set_iova_req {
-   struct msm_ccmd_req hdr;
+   struct vdrm_ccmd_req hdr;
 
    uint64_t iova;
    uint32_t res_id;
 };
-DEFINE_CAST(msm_ccmd_req, msm_ccmd_gem_set_iova_req)
+DEFINE_CAST(vdrm_ccmd_req, msm_ccmd_gem_set_iova_req)
 
 /*
  * MSM_CCMD_GEM_CPU_PREP
@@ -193,15 +147,15 @@ DEFINE_CAST(msm_ccmd_req, msm_ccmd_gem_set_iova_req)
  * should poll if needed.
  */
 struct msm_ccmd_gem_cpu_prep_req {
-   struct msm_ccmd_req hdr;
+   struct vdrm_ccmd_req hdr;
 
    uint32_t res_id;
    uint32_t op;
 };
-DEFINE_CAST(msm_ccmd_req, msm_ccmd_gem_cpu_prep_req)
+DEFINE_CAST(vdrm_ccmd_req, msm_ccmd_gem_cpu_prep_req)
 
 struct msm_ccmd_gem_cpu_prep_rsp {
-   struct msm_ccmd_rsp hdr;
+   struct vdrm_ccmd_rsp hdr;
 
    int32_t ret;
 };
@@ -214,7 +168,7 @@ struct msm_ccmd_gem_cpu_prep_rsp {
  * No response.
  */
 struct msm_ccmd_gem_set_name_req {
-   struct msm_ccmd_req hdr;
+   struct vdrm_ccmd_req hdr;
 
    uint32_t res_id;
    /* Note: packet size aligned to 4 bytes, so the string name may
@@ -223,7 +177,7 @@ struct msm_ccmd_gem_set_name_req {
    uint32_t len;
    uint8_t  payload[];
 };
-DEFINE_CAST(msm_ccmd_req, msm_ccmd_gem_set_name_req)
+DEFINE_CAST(vdrm_ccmd_req, msm_ccmd_gem_set_name_req)
 
 /*
  * MSM_CCMD_GEM_SUBMIT
@@ -241,7 +195,7 @@ DEFINE_CAST(msm_ccmd_req, msm_ccmd_gem_set_name_req)
  * No response.
  */
 struct msm_ccmd_gem_submit_req {
-   struct msm_ccmd_req hdr;
+   struct vdrm_ccmd_req hdr;
 
    uint32_t flags;
    uint32_t queue_id;
@@ -265,7 +219,7 @@ struct msm_ccmd_gem_submit_req {
     */
    int8_t   payload[];
 };
-DEFINE_CAST(msm_ccmd_req, msm_ccmd_gem_submit_req)
+DEFINE_CAST(vdrm_ccmd_req, msm_ccmd_gem_submit_req)
 
 /*
  * MSM_CCMD_GEM_UPLOAD
@@ -275,7 +229,7 @@ DEFINE_CAST(msm_ccmd_req, msm_ccmd_gem_submit_req)
  * No response.
  */
 struct msm_ccmd_gem_upload_req {
-   struct msm_ccmd_req hdr;
+   struct vdrm_ccmd_req hdr;
 
    uint32_t res_id;
    uint32_t pad;
@@ -287,7 +241,7 @@ struct msm_ccmd_gem_upload_req {
    uint32_t len;
    uint8_t  payload[];
 };
-DEFINE_CAST(msm_ccmd_req, msm_ccmd_gem_upload_req)
+DEFINE_CAST(vdrm_ccmd_req, msm_ccmd_gem_upload_req)
 
 /*
  * MSM_CCMD_SUBMITQUEUE_QUERY
@@ -295,16 +249,16 @@ DEFINE_CAST(msm_ccmd_req, msm_ccmd_gem_upload_req)
  * Maps to DRM_MSM_SUBMITQUEUE_QUERY
  */
 struct msm_ccmd_submitqueue_query_req {
-   struct msm_ccmd_req hdr;
+   struct vdrm_ccmd_req hdr;
 
    uint32_t queue_id;
    uint32_t param;
    uint32_t len;   /* size of payload in rsp */
 };
-DEFINE_CAST(msm_ccmd_req, msm_ccmd_submitqueue_query_req)
+DEFINE_CAST(vdrm_ccmd_req, msm_ccmd_submitqueue_query_req)
 
 struct msm_ccmd_submitqueue_query_rsp {
-   struct msm_ccmd_rsp hdr;
+   struct vdrm_ccmd_rsp hdr;
 
    int32_t  ret;
    uint32_t out_len;
@@ -321,15 +275,15 @@ struct msm_ccmd_submitqueue_query_rsp {
  * should poll if needed.
  */
 struct msm_ccmd_wait_fence_req {
-   struct msm_ccmd_req hdr;
+   struct vdrm_ccmd_req hdr;
 
    uint32_t queue_id;
    uint32_t fence;
 };
-DEFINE_CAST(msm_ccmd_req, msm_ccmd_wait_fence_req)
+DEFINE_CAST(vdrm_ccmd_req, msm_ccmd_wait_fence_req)
 
 struct msm_ccmd_wait_fence_rsp {
-   struct msm_ccmd_rsp hdr;
+   struct vdrm_ccmd_rsp hdr;
 
    int32_t ret;
 };
@@ -346,7 +300,7 @@ struct msm_ccmd_wait_fence_rsp {
  * No response.
  */
 struct msm_ccmd_set_debuginfo_req {
-   struct msm_ccmd_req hdr;
+   struct vdrm_ccmd_req hdr;
 
    uint32_t comm_len;
    uint32_t cmdline_len;
@@ -357,6 +311,6 @@ struct msm_ccmd_set_debuginfo_req {
     */
    int8_t   payload[];
 };
-DEFINE_CAST(msm_ccmd_req, msm_ccmd_set_debuginfo_req)
+DEFINE_CAST(vdrm_ccmd_req, msm_ccmd_set_debuginfo_req)
 
 #endif /* MSM_PROTO_H_ */
diff --git a/src/drm/msm/msm_renderer.c b/src/drm/msm/msm_renderer.c
index 1b230a9..5133672 100644
--- a/src/drm/msm/msm_renderer.c
+++ b/src/drm/msm/msm_renderer.c
@@ -26,6 +26,7 @@
 #include "util/u_thread.h"
 
 #include "drm_fence.h"
+#include "drm_hw.h"
 
 #include "msm_drm.h"
 #include "msm_proto.h"
@@ -62,7 +63,7 @@ struct msm_context {
    uint8_t *rsp_mem;
    uint32_t rsp_mem_sz;
 
-   struct msm_ccmd_rsp *current_rsp;
+   struct vdrm_ccmd_rsp *current_rsp;
 
    int fd;
 
@@ -327,7 +328,7 @@ msm_renderer_unmap_blob(struct msm_context *mctx)
    if (!mctx->shmem)
       return;
 
-   uint32_t blob_size = mctx->rsp_mem_sz + mctx->shmem->rsp_mem_offset;
+   uint32_t blob_size = mctx->rsp_mem_sz + mctx->shmem->base.rsp_mem_offset;
 
    munmap(mctx->shmem, blob_size);
 
@@ -533,11 +534,11 @@ msm_renderer_get_blob(struct virgl_context *vctx, uint32_t res_id, uint64_t blob
          return -ENOMEM;
       }
 
-      mctx->shmem->rsp_mem_offset = sizeof(*mctx->shmem);
+      mctx->shmem->base.rsp_mem_offset = sizeof(*mctx->shmem);
 
       uint8_t *ptr = (uint8_t *)mctx->shmem;
-      mctx->rsp_mem = &ptr[mctx->shmem->rsp_mem_offset];
-      mctx->rsp_mem_sz = blob_size - mctx->shmem->rsp_mem_offset;
+      mctx->rsp_mem = &ptr[mctx->shmem->base.rsp_mem_offset];
+      mctx->rsp_mem_sz = blob_size - mctx->shmem->base.rsp_mem_offset;
 
       blob->type = VIRGL_RESOURCE_FD_SHM;
       blob->u.fd = fd;
@@ -608,13 +609,13 @@ msm_renderer_get_blob(struct virgl_context *vctx, uint32_t res_id, uint64_t blob
 }
 
 static void *
-msm_context_rsp_noshadow(struct msm_context *mctx, const struct msm_ccmd_req *hdr)
+msm_context_rsp_noshadow(struct msm_context *mctx, const struct vdrm_ccmd_req *hdr)
 {
    return &mctx->rsp_mem[hdr->rsp_off];
 }
 
 static void *
-msm_context_rsp(struct msm_context *mctx, const struct msm_ccmd_req *hdr, unsigned len)
+msm_context_rsp(struct msm_context *mctx, const struct vdrm_ccmd_req *hdr, unsigned len)
 {
    unsigned rsp_mem_sz = mctx->rsp_mem_sz;
    unsigned off = hdr->rsp_off;
@@ -624,7 +625,7 @@ msm_context_rsp(struct msm_context *mctx, const struct msm_ccmd_req *hdr, unsign
       return NULL;
    }
 
-   struct msm_ccmd_rsp *rsp = msm_context_rsp_noshadow(mctx, hdr);
+   struct vdrm_ccmd_rsp *rsp = msm_context_rsp_noshadow(mctx, hdr);
 
    assert(len >= sizeof(*rsp));
 
@@ -646,13 +647,13 @@ msm_context_rsp(struct msm_context *mctx, const struct msm_ccmd_req *hdr, unsign
 }
 
 static int
-msm_ccmd_nop(UNUSED struct msm_context *mctx, UNUSED const struct msm_ccmd_req *hdr)
+msm_ccmd_nop(UNUSED struct msm_context *mctx, UNUSED const struct vdrm_ccmd_req *hdr)
 {
    return 0;
 }
 
 static int
-msm_ccmd_ioctl_simple(struct msm_context *mctx, const struct msm_ccmd_req *hdr)
+msm_ccmd_ioctl_simple(struct msm_context *mctx, const struct vdrm_ccmd_req *hdr)
 {
    const struct msm_ccmd_ioctl_simple_req *req = to_msm_ccmd_ioctl_simple_req(hdr);
    unsigned payload_len = _IOC_SIZE(req->cmd);
@@ -716,7 +717,7 @@ msm_ccmd_ioctl_simple(struct msm_context *mctx, const struct msm_ccmd_req *hdr)
 }
 
 static int
-msm_ccmd_gem_new(struct msm_context *mctx, const struct msm_ccmd_req *hdr)
+msm_ccmd_gem_new(struct msm_context *mctx, const struct vdrm_ccmd_req *hdr)
 {
    const struct msm_ccmd_gem_new_req *req = to_msm_ccmd_gem_new_req(hdr);
    int ret = 0;
@@ -778,7 +779,7 @@ out_error:
 }
 
 static int
-msm_ccmd_gem_set_iova(struct msm_context *mctx, const struct msm_ccmd_req *hdr)
+msm_ccmd_gem_set_iova(struct msm_context *mctx, const struct vdrm_ccmd_req *hdr)
 {
    const struct msm_ccmd_gem_set_iova_req *req = to_msm_ccmd_gem_set_iova_req(hdr);
    struct msm_object *obj = msm_get_object_from_res_id(mctx, req->res_id);
@@ -815,7 +816,7 @@ out_error:
 }
 
 static int
-msm_ccmd_gem_cpu_prep(struct msm_context *mctx, const struct msm_ccmd_req *hdr)
+msm_ccmd_gem_cpu_prep(struct msm_context *mctx, const struct vdrm_ccmd_req *hdr)
 {
    const struct msm_ccmd_gem_cpu_prep_req *req = to_msm_ccmd_gem_cpu_prep_req(hdr);
    struct msm_ccmd_gem_cpu_prep_rsp *rsp = msm_context_rsp(mctx, hdr, sizeof(*rsp));
@@ -837,7 +838,7 @@ msm_ccmd_gem_cpu_prep(struct msm_context *mctx, const struct msm_ccmd_req *hdr)
 }
 
 static int
-msm_ccmd_gem_set_name(struct msm_context *mctx, const struct msm_ccmd_req *hdr)
+msm_ccmd_gem_set_name(struct msm_context *mctx, const struct vdrm_ccmd_req *hdr)
 {
    const struct msm_ccmd_gem_set_name_req *req = to_msm_ccmd_gem_set_name_req(hdr);
 
@@ -880,7 +881,7 @@ msm_dump_submit(struct drm_msm_gem_submit *req)
 }
 
 static int
-msm_ccmd_gem_submit(struct msm_context *mctx, const struct msm_ccmd_req *hdr)
+msm_ccmd_gem_submit(struct msm_context *mctx, const struct vdrm_ccmd_req *hdr)
 {
    const struct msm_ccmd_gem_submit_req *req = to_msm_ccmd_gem_submit_req(hdr);
 
@@ -991,7 +992,7 @@ map_object(struct msm_context *mctx, struct msm_object *obj)
 }
 
 static int
-msm_ccmd_gem_upload(struct msm_context *mctx, const struct msm_ccmd_req *hdr)
+msm_ccmd_gem_upload(struct msm_context *mctx, const struct vdrm_ccmd_req *hdr)
 {
    const struct msm_ccmd_gem_upload_req *req = to_msm_ccmd_gem_upload_req(hdr);
    int ret;
@@ -1017,7 +1018,7 @@ msm_ccmd_gem_upload(struct msm_context *mctx, const struct msm_ccmd_req *hdr)
 }
 
 static int
-msm_ccmd_submitqueue_query(struct msm_context *mctx, const struct msm_ccmd_req *hdr)
+msm_ccmd_submitqueue_query(struct msm_context *mctx, const struct vdrm_ccmd_req *hdr)
 {
    const struct msm_ccmd_submitqueue_query_req *req =
       to_msm_ccmd_submitqueue_query_req(hdr);
@@ -1043,7 +1044,7 @@ msm_ccmd_submitqueue_query(struct msm_context *mctx, const struct msm_ccmd_req *
 }
 
 static int
-msm_ccmd_wait_fence(struct msm_context *mctx, const struct msm_ccmd_req *hdr)
+msm_ccmd_wait_fence(struct msm_context *mctx, const struct vdrm_ccmd_req *hdr)
 {
    const struct msm_ccmd_wait_fence_req *req = to_msm_ccmd_wait_fence_req(hdr);
    struct msm_ccmd_wait_fence_rsp *rsp = msm_context_rsp(mctx, hdr, sizeof(*rsp));
@@ -1073,7 +1074,7 @@ msm_ccmd_wait_fence(struct msm_context *mctx, const struct msm_ccmd_req *hdr)
 }
 
 static int
-msm_ccmd_set_debuginfo(struct msm_context *mctx, const struct msm_ccmd_req *hdr)
+msm_ccmd_set_debuginfo(struct msm_context *mctx, const struct vdrm_ccmd_req *hdr)
 {
    const struct msm_ccmd_set_debuginfo_req *req = to_msm_ccmd_set_debuginfo_req(hdr);
 
@@ -1109,7 +1110,7 @@ msm_ccmd_set_debuginfo(struct msm_context *mctx, const struct msm_ccmd_req *hdr)
 
 static const struct ccmd {
    const char *name;
-   int (*handler)(struct msm_context *mctx, const struct msm_ccmd_req *hdr);
+   int (*handler)(struct msm_context *mctx, const struct vdrm_ccmd_req *hdr);
    size_t size;
 } ccmd_dispatch[] = {
 #define HANDLER(N, n)                                                                    \
@@ -1128,7 +1129,7 @@ static const struct ccmd {
 };
 
 static int
-submit_cmd_dispatch(struct msm_context *mctx, const struct msm_ccmd_req *hdr)
+submit_cmd_dispatch(struct msm_context *mctx, const struct vdrm_ccmd_req *hdr)
 {
    int ret;
 
@@ -1159,7 +1160,7 @@ submit_cmd_dispatch(struct msm_context *mctx, const struct msm_ccmd_req *hdr)
       memcpy(&buf[0], hdr, hdr->len);
       memset(&buf[hdr->len], 0, ccmd->size - hdr->len);
 
-      ret = ccmd->handler(mctx, (struct msm_ccmd_req *)buf);
+      ret = ccmd->handler(mctx, (struct vdrm_ccmd_req *)buf);
    } else {
       ret = ccmd->handler(mctx, hdr);
    }
@@ -1176,7 +1177,7 @@ submit_cmd_dispatch(struct msm_context *mctx, const struct msm_ccmd_req *hdr)
     * copy is used, and we need to copy back to the actual rsp
     * buffer.
     */
-   struct msm_ccmd_rsp *rsp = msm_context_rsp_noshadow(mctx, hdr);
+   struct vdrm_ccmd_rsp *rsp = msm_context_rsp_noshadow(mctx, hdr);
    if (mctx->current_rsp && (mctx->current_rsp != rsp)) {
       unsigned len = rsp->len;
       memcpy(rsp, mctx->current_rsp, len);
@@ -1195,7 +1196,7 @@ submit_cmd_dispatch(struct msm_context *mctx, const struct msm_ccmd_req *hdr)
        * could just use p_atomic_set.
        */
       uint32_t seqno = hdr->seqno;
-      p_atomic_xchg(&mctx->shmem->seqno, seqno);
+      p_atomic_xchg(&mctx->shmem->base.seqno, seqno);
    }
 
    return 0;
@@ -1207,8 +1208,8 @@ msm_renderer_submit_cmd(struct virgl_context *vctx, const void *_buffer, size_t
    struct msm_context *mctx = to_msm_context(vctx);
    const uint8_t *buffer = _buffer;
 
-   while (size >= sizeof(struct msm_ccmd_req)) {
-      const struct msm_ccmd_req *hdr = (const struct msm_ccmd_req *)buffer;
+   while (size >= sizeof(struct vdrm_ccmd_req)) {
+      const struct vdrm_ccmd_req *hdr = (const struct vdrm_ccmd_req *)buffer;
 
       /* Sanity check first: */
       if ((hdr->len > size) || (hdr->len < sizeof(*hdr)) || (hdr->len % 4)) {
diff --git a/src/drm_hw.h b/src/drm_hw.h
index eb17d75..45a2f4f 100644
--- a/src/drm_hw.h
+++ b/src/drm_hw.h
@@ -30,4 +30,66 @@ struct virgl_renderer_capset_drm {
    } u;
 };
 
+/**
+ * Defines the layout of shmem buffer used for host->guest communication.
+ */
+struct vdrm_shmem {
+   /**
+    * The sequence # of last cmd processed by the host
+    */
+   uint32_t seqno;
+
+   /**
+    * Offset to the start of rsp memory region in the shmem buffer.  This
+    * is set by the host when the shmem buffer is allocated, to allow for
+    * extending the shmem buffer with new fields.  The size of the rsp
+    * memory region is the size of the shmem buffer (controlled by the
+    * guest) minus rsp_mem_offset.
+    *
+    * The guest should use the vdrm_shmem_has_field() macro to determine
+    * if the host supports a given field, ie. to handle compatibility of
+    * newer guest vs older host.
+    *
+    * Making the guest userspace responsible for backwards compatibility
+    * simplifies the host VMM.
+    */
+   uint32_t rsp_mem_offset;
+
+#define vdrm_shmem_has_field(shmem, field) ({                             \
+      struct vdrm_shmem *_shmem = &(shmem)->base;                         \
+      (_shmem->rsp_mem_offset > offsetof(__typeof__(*(shmem)), field));   \
+   })
+};
+
+/**
+ * A Guest -> Host request header.
+ */
+struct vdrm_ccmd_req {
+   uint32_t cmd;
+   uint32_t len;
+   uint32_t seqno;
+
+   /* Offset into shmem ctrl buffer to write response.  The host ensures
+    * that it doesn't write outside the bounds of the ctrl buffer, but
+    * otherwise it is up to the guest to manage allocation of where responses
+    * should be written in the ctrl buf.
+    *
+    * Only applicable for cmds that have a response message.
+    */
+   uint32_t rsp_off;
+};
+
+/**
+ * A Guest <- Host response header.
+ */
+struct vdrm_ccmd_rsp {
+   uint32_t len;
+};
+
+#define DEFINE_CAST(parent, child)                                             \
+   static inline struct child *to_##child(const struct parent *x)              \
+   {                                                                           \
+      return (struct child *)x;                                                \
+   }
+
 #endif /* DRM_HW_H_ */