hw/nvme: fix missing endian conversions for doorbell buffers

The eventidx and doorbell value are not handling endianness correctly.
Fix this.

Fixes: 3f7fe8de ("hw/nvme: Implement shadow doorbell buffer support")
Cc: qemu-stable@nongnu.org
Reported-by: NGuenter Roeck <linux@roeck-us.net>
Reviewed-by: NKeith Busch <kbusch@kernel.org>
Signed-off-by: NKlaus Jensen <k.jensen@samsung.com>

hw/nvme/ctrl.c

@@ -1336,8 +1336,11 @@ static inline void nvme_blk_write(BlockBackend *blk, int64_t offset,
 
 static void nvme_update_cq_head(NvmeCQueue *cq)
 {
-    pci_dma_read(PCI_DEVICE(cq->ctrl), cq->db_addr, &cq->head,
-                 sizeof(cq->head));
+    uint32_t v;
+
+    pci_dma_read(PCI_DEVICE(cq->ctrl), cq->db_addr, &v, sizeof(v));
+
+    cq->head = le32_to_cpu(v);
 
     trace_pci_nvme_update_cq_head(cq->cqid, cq->head);
 }
@@ -6148,16 +6151,20 @@ static uint16_t nvme_admin_cmd(NvmeCtrl *n, NvmeRequest *req)
 
 static void nvme_update_sq_eventidx(const NvmeSQueue *sq)
 {
+    uint32_t v = cpu_to_le32(sq->tail);
+
     trace_pci_nvme_update_sq_eventidx(sq->sqid, sq->tail);
 
-    pci_dma_write(PCI_DEVICE(sq->ctrl), sq->ei_addr, &sq->tail,
-                  sizeof(sq->tail));
+    pci_dma_write(PCI_DEVICE(sq->ctrl), sq->ei_addr, &v, sizeof(v));
 }
 
 static void nvme_update_sq_tail(NvmeSQueue *sq)
 {
-    pci_dma_read(PCI_DEVICE(sq->ctrl), sq->db_addr, &sq->tail,
-                 sizeof(sq->tail));
+    uint32_t v;
+
+    pci_dma_read(PCI_DEVICE(sq->ctrl), sq->db_addr, &v, sizeof(v));
+
+    sq->tail = le32_to_cpu(v);
 
     trace_pci_nvme_update_sq_tail(sq->sqid, sq->tail);
 }