4 files changed, 81 insertions, 7 deletions

diff --git a/include/hw/ide/internal.h b/include/hw/ide/internal.h
index 880413ddc7..8efd03132b 100644
--- a/include/hw/ide/internal.h
+++ b/include/hw/ide/internal.h
@@ -346,7 +346,6 @@ extern const char *IDE_DMA_CMD_lookup[IDE_DMA__COUNT];
 
 typedef struct IDEBufferedRequest {
     QLIST_ENTRY(IDEBufferedRequest) list;
-    struct iovec iov;
     QEMUIOVector qiov;
     QEMUIOVector *original_qiov;
     BlockCompletionFunc *original_cb;
@@ -405,7 +404,6 @@ struct IDEState {
     int atapi_dma; /* true if dma is requested for the packet cmd */
     BlockAcctCookie acct;
     BlockAIOCB *pio_aiocb;
-    struct iovec iov;
     QEMUIOVector qiov;
     QLIST_HEAD(, IDEBufferedRequest) buffered_requests;
     /* ATA DMA state */
@@ -457,7 +455,6 @@ struct IDEDMAOps {
 
 struct IDEDMA {
     const struct IDEDMAOps *ops;
-    struct iovec iov;
     QEMUIOVector qiov;
     BlockAIOCB *aiocb;
 };
diff --git a/include/hw/virtio/virtio-blk.h b/include/hw/virtio/virtio-blk.h
index 5117431d96..cddcfbebe9 100644
--- a/include/hw/virtio/virtio-blk.h
+++ b/include/hw/virtio/virtio-blk.h
@@ -35,11 +35,11 @@ struct VirtIOBlkConf
     BlockConf conf;
     IOThread *iothread;
     char *serial;
-    uint32_t scsi;
-    uint32_t config_wce;
     uint32_t request_merging;
     uint16_t num_queues;
     uint16_t queue_size;
+    uint32_t max_discard_sectors;
+    uint32_t max_write_zeroes_sectors;
 };
 
 struct VirtIOBlockDataPlane;
@@ -57,6 +57,8 @@ typedef struct VirtIOBlock {
     bool dataplane_disabled;
     bool dataplane_started;
     struct VirtIOBlockDataPlane *dataplane;
+    uint64_t host_features;
+    size_t config_size;
 } VirtIOBlock;
 
 typedef struct VirtIOBlockReq {
diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
index 9c1fa07d6d..ce9516236a 100644
--- a/include/hw/virtio/virtio.h
+++ b/include/hw/virtio/virtio.h
@@ -37,6 +37,21 @@ static inline hwaddr vring_align(hwaddr addr,
     return QEMU_ALIGN_UP(addr, align);
 }
 
+/*
+ * Calculate the number of bytes up to and including the given 'field' of
+ * 'container'.
+ */
+#define virtio_endof(container, field) \
+    (offsetof(container, field) + sizeof_field(container, field))
+
+typedef struct VirtIOFeature {
+    uint64_t flags;
+    size_t end;
+} VirtIOFeature;
+
+size_t virtio_feature_get_config_size(VirtIOFeature *features,
+                                      uint64_t host_features);
+
 typedef struct VirtQueue VirtQueue;
 
 #define VIRTQUEUE_MAX_SIZE 1024
diff --git a/include/qemu/iov.h b/include/qemu/iov.h
index 5f433c7768..48b45987b7 100644
--- a/include/qemu/iov.h
+++ b/include/qemu/iov.h
@@ -133,10 +133,70 @@ size_t iov_discard_back(struct iovec *iov, unsigned int *iov_cnt,
 typedef struct QEMUIOVector {
     struct iovec *iov;
     int niov;
-    int nalloc;
-    size_t size;
+
+    /*
+     * For external @iov (qemu_iovec_init_external()) or allocated @iov
+     * (qemu_iovec_init()), @size is the cumulative size of iovecs and
+     * @local_iov is invalid and unused.
+     *
+     * For embedded @iov (QEMU_IOVEC_INIT_BUF() or qemu_iovec_init_buf()),
+     * @iov is equal to &@local_iov, and @size is valid, as it has same
+     * offset and type as @local_iov.iov_len, which is guaranteed by
+     * static assertion below.
+     *
+     * @nalloc is always valid and is -1 both for embedded and external
+     * cases. It is included in the union only to ensure the padding prior
+     * to the @size field will not result in a 0-length array.
+     */
+    union {
+        struct {
+            int nalloc;
+            struct iovec local_iov;
+        };
+        struct {
+            char __pad[sizeof(int) + offsetof(struct iovec, iov_len)];
+            size_t size;
+        };
+    };
 } QEMUIOVector;
 
+QEMU_BUILD_BUG_ON(offsetof(QEMUIOVector, size) !=
+                  offsetof(QEMUIOVector, local_iov.iov_len));
+
+#define QEMU_IOVEC_INIT_BUF(self, buf, len)              \
+{                                                        \
+    .iov = &(self).local_iov,                            \
+    .niov = 1,                                           \
+    .nalloc = -1,                                        \
+    .local_iov = {                                       \
+        .iov_base = (void *)(buf), /* cast away const */ \
+        .iov_len = (len),                                \
+    },                                                   \
+}
+
+/*
+ * qemu_iovec_init_buf
+ *
+ * Initialize embedded QEMUIOVector.
+ *
+ * Note: "const" is used over @buf pointer to make it simple to pass
+ * const pointers, appearing in read functions. Then this "const" is
+ * cast away by QEMU_IOVEC_INIT_BUF().
+ */
+static inline void qemu_iovec_init_buf(QEMUIOVector *qiov,
+                                       const void *buf, size_t len)
+{
+    *qiov = (QEMUIOVector) QEMU_IOVEC_INIT_BUF(*qiov, buf, len);
+}
+
+static inline void *qemu_iovec_buf(QEMUIOVector *qiov)
+{
+    /* Only supports embedded iov */
+    assert(qiov->nalloc == -1 && qiov->iov == &qiov->local_iov);
+
+    return qiov->local_iov.iov_base;
+}
+
 void qemu_iovec_init(QEMUIOVector *qiov, int alloc_hint);
 void qemu_iovec_init_external(QEMUIOVector *qiov, struct iovec *iov, int niov);
 void qemu_iovec_add(QEMUIOVector *qiov, void *base, size_t len);