[PATCH v2 06/16] hw/block/nvme: refactor dma read/write

[Klaus Jensen <its@irrelevant.dk>]

From: Klaus Jensen <k.jensen@samsung.com>

Refactor the nvme_dma_{read,write}_prp functions into a common function
taking a DMADirection parameter.

Signed-off-by: Klaus Jensen <k.jensen@samsung.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Minwoo Im <minwoo.im.dev@gmail.com>
---
 hw/block/nvme.c | 91 +++++++++++++++++++++++++------------------------
 1 file changed, 46 insertions(+), 45 deletions(-)

diff --git a/hw/block/nvme.c b/hw/block/nvme.c
index 8f8257e06eed..571635ebe9f9 100644
--- a/hw/block/nvme.c
+++ b/hw/block/nvme.c
@@ -363,55 +363,53 @@ unmap:
     return status;
 }
 
-static uint16_t nvme_dma_write_prp(NvmeCtrl *n, uint8_t *ptr, uint32_t len,
-                                   uint64_t prp1, uint64_t prp2)
+static uint16_t nvme_dma_prp(NvmeCtrl *n, uint8_t *ptr, uint32_t len,
+                             uint64_t prp1, uint64_t prp2, DMADirection dir)
 {
     QEMUSGList qsg;
     QEMUIOVector iov;
     uint16_t status = NVME_SUCCESS;
 
-    if (nvme_map_prp(&qsg, &iov, prp1, prp2, len, n)) {
-        return NVME_INVALID_FIELD | NVME_DNR;
+    status = nvme_map_prp(&qsg, &iov, prp1, prp2, len, n);
+    if (status) {
+        return status;
     }
+
+    /* assert that only one of qsg and iov carries data */
+    assert((qsg.nsg > 0) != (iov.niov > 0));
+
     if (qsg.nsg > 0) {
-        if (dma_buf_write(ptr, len, &qsg)) {
-            status = NVME_INVALID_FIELD | NVME_DNR;
+        uint64_t residual;
+
+        if (dir == DMA_DIRECTION_TO_DEVICE) {
+            residual = dma_buf_write(ptr, len, &qsg);
+        } else {
+            residual = dma_buf_read(ptr, len, &qsg);
         }
-        qemu_sglist_destroy(&qsg);
-    } else {
-        if (qemu_iovec_to_buf(&iov, 0, ptr, len) != len) {
-            status = NVME_INVALID_FIELD | NVME_DNR;
-        }
-        qemu_iovec_destroy(&iov);
-    }
-    return status;
-}
 
-static uint16_t nvme_dma_read_prp(NvmeCtrl *n, uint8_t *ptr, uint32_t len,
-    uint64_t prp1, uint64_t prp2)
-{
-    QEMUSGList qsg;
-    QEMUIOVector iov;
-    uint16_t status = NVME_SUCCESS;
-
-    trace_pci_nvme_dma_read(prp1, prp2);
-
-    if (nvme_map_prp(&qsg, &iov, prp1, prp2, len, n)) {
-        return NVME_INVALID_FIELD | NVME_DNR;
-    }
-    if (qsg.nsg > 0) {
-        if (unlikely(dma_buf_read(ptr, len, &qsg))) {
+        if (unlikely(residual)) {
             trace_pci_nvme_err_invalid_dma();
             status = NVME_INVALID_FIELD | NVME_DNR;
         }
+
         qemu_sglist_destroy(&qsg);
     } else {
-        if (unlikely(qemu_iovec_from_buf(&iov, 0, ptr, len) != len)) {
+        size_t bytes;
+
+        if (dir == DMA_DIRECTION_TO_DEVICE) {
+            bytes = qemu_iovec_to_buf(&iov, 0, ptr, len);
+        } else {
+            bytes = qemu_iovec_from_buf(&iov, 0, ptr, len);
+        }
+
+        if (unlikely(bytes != len)) {
             trace_pci_nvme_err_invalid_dma();
             status = NVME_INVALID_FIELD | NVME_DNR;
         }
+
         qemu_iovec_destroy(&iov);
     }
+
     return status;
 }
 
@@ -843,8 +841,8 @@ static uint16_t nvme_smart_info(NvmeCtrl *n, NvmeCmd *cmd, uint8_t rae,
         nvme_clear_events(n, NVME_AER_TYPE_SMART);
     }
 
-    return nvme_dma_read_prp(n, (uint8_t *) &smart + off, trans_len, prp1,
-                             prp2);
+    return nvme_dma_prp(n, (uint8_t *) &smart + off, trans_len, prp1, prp2,
+                        DMA_DIRECTION_FROM_DEVICE);
 }
 
 static uint16_t nvme_fw_log_info(NvmeCtrl *n, NvmeCmd *cmd, uint32_t buf_len,
@@ -865,8 +863,8 @@ static uint16_t nvme_fw_log_info(NvmeCtrl *n, NvmeCmd *cmd, uint32_t buf_len,
 
     trans_len = MIN(sizeof(fw_log) - off, buf_len);
 
-    return nvme_dma_read_prp(n, (uint8_t *) &fw_log + off, trans_len, prp1,
-                             prp2);
+    return nvme_dma_prp(n, (uint8_t *) &fw_log + off, trans_len, prp1, prp2,
+                        DMA_DIRECTION_FROM_DEVICE);
 }
 
 static uint16_t nvme_error_info(NvmeCtrl *n, NvmeCmd *cmd, uint8_t rae,
@@ -890,7 +888,8 @@ static uint16_t nvme_error_info(NvmeCtrl *n, NvmeCmd *cmd, uint8_t rae,
 
     trans_len = MIN(sizeof(errlog) - off, buf_len);
 
-    return nvme_dma_read_prp(n, (uint8_t *)&errlog, trans_len, prp1, prp2);
+    return nvme_dma_prp(n, (uint8_t *)&errlog, trans_len, prp1, prp2,
+                        DMA_DIRECTION_FROM_DEVICE);
 }
 
 static uint16_t nvme_get_log(NvmeCtrl *n, NvmeCmd *cmd, NvmeRequest *req)
@@ -1045,8 +1044,8 @@ static uint16_t nvme_identify_ctrl(NvmeCtrl *n, NvmeIdentify *c)
 
     trace_pci_nvme_identify_ctrl();
 
-    return nvme_dma_read_prp(n, (uint8_t *)&n->id_ctrl, sizeof(n->id_ctrl),
-        prp1, prp2);
+    return nvme_dma_prp(n, (uint8_t *)&n->id_ctrl, sizeof(n->id_ctrl), prp1,
+                        prp2, DMA_DIRECTION_FROM_DEVICE);
 }
 
 static uint16_t nvme_identify_ns(NvmeCtrl *n, NvmeIdentify *c)
@@ -1065,8 +1064,8 @@ static uint16_t nvme_identify_ns(NvmeCtrl *n, NvmeIdentify *c)
 
     ns = &n->namespaces[nsid - 1];
 
-    return nvme_dma_read_prp(n, (uint8_t *)&ns->id_ns, sizeof(ns->id_ns),
-        prp1, prp2);
+    return nvme_dma_prp(n, (uint8_t *)&ns->id_ns, sizeof(ns->id_ns), prp1,
+                        prp2, DMA_DIRECTION_FROM_DEVICE);
 }
 
 static uint16_t nvme_identify_nslist(NvmeCtrl *n, NvmeIdentify *c)
@@ -1101,7 +1100,8 @@ static uint16_t nvme_identify_nslist(NvmeCtrl *n, NvmeIdentify *c)
             break;
         }
     }
-    ret = nvme_dma_read_prp(n, (uint8_t *)list, data_len, prp1, prp2);
+    ret = nvme_dma_prp(n, (uint8_t *)list, data_len, prp1, prp2,
+                       DMA_DIRECTION_FROM_DEVICE);
     g_free(list);
     return ret;
 }
@@ -1142,7 +1142,8 @@ static uint16_t nvme_identify_ns_descr_list(NvmeCtrl *n, NvmeIdentify *c)
     ns_descrs->uuid.hdr.nidl = NVME_NIDT_UUID_LEN;
     stl_be_p(&ns_descrs->uuid.v, nsid);
 
-    return nvme_dma_read_prp(n, list, NVME_IDENTIFY_DATA_SIZE, prp1, prp2);
+    return nvme_dma_prp(n, list, NVME_IDENTIFY_DATA_SIZE, prp1, prp2,
+                        DMA_DIRECTION_FROM_DEVICE);
 }
 
 static uint16_t nvme_identify(NvmeCtrl *n, NvmeCmd *cmd)
@@ -1223,8 +1224,8 @@ static uint16_t nvme_get_feature_timestamp(NvmeCtrl *n, NvmeCmd *cmd)
 
     uint64_t timestamp = nvme_get_timestamp(n);
 
-    return nvme_dma_read_prp(n, (uint8_t *)&timestamp,
-                                 sizeof(timestamp), prp1, prp2);
+    return nvme_dma_prp(n, (uint8_t *)&timestamp, sizeof(timestamp), prp1,
+                        prp2, DMA_DIRECTION_FROM_DEVICE);
 }
 
 static uint16_t nvme_get_feature(NvmeCtrl *n, NvmeCmd *cmd, NvmeRequest *req)
@@ -1355,8 +1356,8 @@ static uint16_t nvme_set_feature_timestamp(NvmeCtrl *n, NvmeCmd *cmd)
     uint64_t prp1 = le64_to_cpu(cmd->dptr.prp1);
     uint64_t prp2 = le64_to_cpu(cmd->dptr.prp2);
 
-    ret = nvme_dma_write_prp(n, (uint8_t *)&timestamp,
-                                sizeof(timestamp), prp1, prp2);
+    ret = nvme_dma_prp(n, (uint8_t *)&timestamp, sizeof(timestamp), prp1,
+                       prp2, DMA_DIRECTION_TO_DEVICE);
     if (ret != NVME_SUCCESS) {
         return ret;
     }
-- 
2.27.0