[PATCH RFC v2 6/8] hw/block/nvme: refactor nvme_dma

[Klaus Jensen]

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

The nvme_dma function doesn't just do DMA (QEMUSGList-based) memory transfers;
it also handles QEMUIOVector copies.

Introduce the NvmeTxDirection enum and rename to nvme_tx. Remove mapping
of PRPs/SGLs from nvme_tx and instead assert that they have been mapped
previously. This allows more fine-grained use in subsequent patches.

Add new (better named) helpers, nvme_{c2h,h2c}, that does both PRP/SGL
mapping and transfer.

Signed-off-by: Klaus Jensen <k.jensen@samsung.com>
---
 hw/block/nvme.c | 143 ++++++++++++++++++++++++++----------------------
 1 file changed, 77 insertions(+), 66 deletions(-)

diff --git a/hw/block/nvme.c b/hw/block/nvme.c
index 24156699b035..2752e5d8572a 100644
--- a/hw/block/nvme.c
+++ b/hw/block/nvme.c
@@ -843,48 +843,72 @@ static uint16_t nvme_map_dptr(NvmeCtrl *n, NvmeSg *sg, 
size_t len,
     }
 }
 
-static uint16_t nvme_dma(NvmeCtrl *n, uint8_t *ptr, uint32_t len,
-                         DMADirection dir, NvmeRequest *req)
+typedef enum NvmeTxDirection {
+    NVME_TX_DIRECTION_TO_DEVICE   = 0,
+    NVME_TX_DIRECTION_FROM_DEVICE = 1,
+} NvmeTxDirection;
+
+static uint16_t nvme_tx(NvmeCtrl *n, NvmeSg *sg, uint8_t *ptr, uint32_t len,
+                        NvmeTxDirection dir)
 {
-    uint16_t status = NVME_SUCCESS;
+    /* assert that exactly one of qsg and iov carries data */
+    assert((sg->qsg.nsg > 0) != (sg->iov.niov > 0));
+
+    if (sg->qsg.nsg > 0) {
+        uint64_t residual;
+
+        if (dir == NVME_TX_DIRECTION_TO_DEVICE) {
+            residual = dma_buf_write(ptr, len, &sg->qsg);
+        } else {
+            residual = dma_buf_read(ptr, len, &sg->qsg);
+        }
+
+        if (unlikely(residual)) {
+            trace_pci_nvme_err_invalid_dma();
+            return NVME_INVALID_FIELD | NVME_DNR;
+        }
+    } else {
+        size_t bytes;
+
+        if (dir == NVME_TX_DIRECTION_TO_DEVICE) {
+            bytes = qemu_iovec_to_buf(&sg->iov, 0, ptr, len);
+        } else {
+            bytes = qemu_iovec_from_buf(&sg->iov, 0, ptr, len);
+        }
+
+        if (unlikely(bytes != len)) {
+            trace_pci_nvme_err_invalid_dma();
+            return NVME_INVALID_FIELD | NVME_DNR;
+        }
+    }
+
+    return NVME_SUCCESS;
+}
+
+static inline uint16_t nvme_c2h(NvmeCtrl *n, uint8_t *ptr, uint32_t len,
+                                NvmeRequest *req)
+{
+    uint16_t status;
 
     status = nvme_map_dptr(n, &req->sg, len, &req->cmd);
     if (status) {
         return status;
     }
 
-    /* assert that only one of qsg and iov carries data */
-    assert((req->sg.qsg.nsg > 0) != (req->sg.iov.niov > 0));
+    return nvme_tx(n, &req->sg, ptr, len, NVME_TX_DIRECTION_FROM_DEVICE);
+}
 
-    if (req->sg.qsg.nsg > 0) {
-        uint64_t residual;
+static inline uint16_t nvme_h2c(NvmeCtrl *n, uint8_t *ptr, uint32_t len,
+                                NvmeRequest *req)
+{
+    uint16_t status;
 
-        if (dir == DMA_DIRECTION_TO_DEVICE) {
-            residual = dma_buf_write(ptr, len, &req->sg.qsg);
-        } else {
-            residual = dma_buf_read(ptr, len, &req->sg.qsg);
-        }
-
-        if (unlikely(residual)) {
-            trace_pci_nvme_err_invalid_dma();
-            status = NVME_INVALID_FIELD | NVME_DNR;
-        }
-    } else {
-        size_t bytes;
-
-        if (dir == DMA_DIRECTION_TO_DEVICE) {
-            bytes = qemu_iovec_to_buf(&req->sg.iov, 0, ptr, len);
-        } else {
-            bytes = qemu_iovec_from_buf(&req->sg.iov, 0, ptr, len);
-        }
-
-        if (unlikely(bytes != len)) {
-            trace_pci_nvme_err_invalid_dma();
-            status = NVME_INVALID_FIELD | NVME_DNR;
-        }
+    status = nvme_map_dptr(n, &req->sg, len, &req->cmd);
+    if (status) {
+        return status;
     }
 
-    return status;
+    return nvme_tx(n, &req->sg, ptr, len, NVME_TX_DIRECTION_TO_DEVICE);
 }
 
 static inline void nvme_blk_read(BlockBackend *blk, int64_t offset,
@@ -1683,8 +1707,7 @@ static void nvme_compare_cb(void *opaque, int ret)
 
     buf = g_malloc(ctx->iov.size);
 
-    status = nvme_dma(nvme_ctrl(req), buf, ctx->iov.size,
-                      DMA_DIRECTION_TO_DEVICE, req);
+    status = nvme_h2c(nvme_ctrl(req), buf, ctx->iov.size, req);
     if (status) {
         req->status = status;
         goto out;
@@ -1720,8 +1743,7 @@ static uint16_t nvme_dsm(NvmeCtrl *n, NvmeRequest *req)
         NvmeDsmRange range[nr];
         uintptr_t *discards = (uintptr_t *)&req->opaque;
 
-        status = nvme_dma(n, (uint8_t *)range, sizeof(range),
-                          DMA_DIRECTION_TO_DEVICE, req);
+        status = nvme_h2c(n, (uint8_t *)range, sizeof(range), req);
         if (status) {
             return status;
         }
@@ -1803,8 +1825,8 @@ static uint16_t nvme_copy(NvmeCtrl *n, NvmeRequest *req)
 
     range = g_new(NvmeCopySourceRange, nr);
 
-    status = nvme_dma(n, (uint8_t *)range, nr * sizeof(NvmeCopySourceRange),
-                      DMA_DIRECTION_TO_DEVICE, req);
+    status = nvme_h2c(n, (uint8_t *)range, nr * sizeof(NvmeCopySourceRange),
+                      req);
     if (status) {
         return status;
     }
@@ -2413,8 +2435,7 @@ static uint16_t nvme_zone_mgmt_send(NvmeCtrl *n, 
NvmeRequest *req)
             return NVME_INVALID_FIELD | NVME_DNR;
         }
         zd_ext = nvme_get_zd_extension(ns, zone_idx);
-        status = nvme_dma(n, zd_ext, ns->params.zd_extension_size,
-                          DMA_DIRECTION_TO_DEVICE, req);
+        status = nvme_h2c(n, zd_ext, ns->params.zd_extension_size, req);
         if (status) {
             trace_pci_nvme_err_zd_extension_map_error(zone_idx);
             return status;
@@ -2569,8 +2590,7 @@ static uint16_t nvme_zone_mgmt_recv(NvmeCtrl *n, 
NvmeRequest *req)
         }
     }
 
-    status = nvme_dma(n, (uint8_t *)buf, data_size,
-                      DMA_DIRECTION_FROM_DEVICE, req);
+    status = nvme_c2h(n, (uint8_t *)buf, data_size, req);
 
     g_free(buf);
 
@@ -2814,8 +2834,7 @@ static uint16_t nvme_smart_info(NvmeCtrl *n, uint8_t rae, 
uint32_t buf_len,
         nvme_clear_events(n, NVME_AER_TYPE_SMART);
     }
 
-    return nvme_dma(n, (uint8_t *) &smart + off, trans_len,
-                    DMA_DIRECTION_FROM_DEVICE, req);
+    return nvme_c2h(n, (uint8_t *) &smart + off, trans_len, req);
 }
 
 static uint16_t nvme_fw_log_info(NvmeCtrl *n, uint32_t buf_len, uint64_t off,
@@ -2833,8 +2852,7 @@ static uint16_t nvme_fw_log_info(NvmeCtrl *n, uint32_t 
buf_len, uint64_t off,
     strpadcpy((char *)&fw_log.frs1, sizeof(fw_log.frs1), "1.0", ' ');
     trans_len = MIN(sizeof(fw_log) - off, buf_len);
 
-    return nvme_dma(n, (uint8_t *) &fw_log + off, trans_len,
-                    DMA_DIRECTION_FROM_DEVICE, req);
+    return nvme_c2h(n, (uint8_t *) &fw_log + off, trans_len, req);
 }
 
 static uint16_t nvme_error_info(NvmeCtrl *n, uint8_t rae, uint32_t buf_len,
@@ -2854,8 +2872,7 @@ static uint16_t nvme_error_info(NvmeCtrl *n, uint8_t rae, 
uint32_t buf_len,
     memset(&errlog, 0x0, sizeof(errlog));
     trans_len = MIN(sizeof(errlog) - off, buf_len);
 
-    return nvme_dma(n, (uint8_t *)&errlog, trans_len,
-                    DMA_DIRECTION_FROM_DEVICE, req);
+    return nvme_c2h(n, (uint8_t *)&errlog, trans_len, req);
 }
 
 static uint16_t nvme_cmd_effects(NvmeCtrl *n, uint8_t csi, uint32_t buf_len,
@@ -2895,8 +2912,7 @@ static uint16_t nvme_cmd_effects(NvmeCtrl *n, uint8_t 
csi, uint32_t buf_len,
 
     trans_len = MIN(sizeof(log) - off, buf_len);
 
-    return nvme_dma(n, ((uint8_t *)&log) + off, trans_len,
-                    DMA_DIRECTION_FROM_DEVICE, req);
+    return nvme_c2h(n, ((uint8_t *)&log) + off, trans_len, req);
 }
 
 static uint16_t nvme_get_log(NvmeCtrl *n, NvmeRequest *req)
@@ -3066,7 +3082,7 @@ static uint16_t nvme_rpt_empty_id_struct(NvmeCtrl *n, 
NvmeRequest *req)
 {
     uint8_t id[NVME_IDENTIFY_DATA_SIZE] = {};
 
-    return nvme_dma(n, id, sizeof(id), DMA_DIRECTION_FROM_DEVICE, req);
+    return nvme_c2h(n, id, sizeof(id), req);
 }
 
 static inline bool nvme_csi_has_nvm_support(NvmeNamespace *ns)
@@ -3083,8 +3099,7 @@ static uint16_t nvme_identify_ctrl(NvmeCtrl *n, 
NvmeRequest *req)
 {
     trace_pci_nvme_identify_ctrl();
 
-    return nvme_dma(n, (uint8_t *)&n->id_ctrl, sizeof(n->id_ctrl),
-                    DMA_DIRECTION_FROM_DEVICE, req);
+    return nvme_c2h(n, (uint8_t *)&n->id_ctrl, sizeof(n->id_ctrl), req);
 }
 
 static uint16_t nvme_identify_ctrl_csi(NvmeCtrl *n, NvmeRequest *req)
@@ -3100,8 +3115,7 @@ static uint16_t nvme_identify_ctrl_csi(NvmeCtrl *n, 
NvmeRequest *req)
         if (n->params.zasl_bs) {
             id.zasl = n->zasl;
         }
-        return nvme_dma(n, (uint8_t *)&id, sizeof(id),
-                        DMA_DIRECTION_FROM_DEVICE, req);
+        return nvme_c2h(n, (uint8_t *)&id, sizeof(id), req);
     }
 
     return NVME_INVALID_FIELD | NVME_DNR;
@@ -3125,8 +3139,7 @@ static uint16_t nvme_identify_ns(NvmeCtrl *n, NvmeRequest 
*req)
     }
 
     if (c->csi == NVME_CSI_NVM && nvme_csi_has_nvm_support(ns)) {
-        return nvme_dma(n, (uint8_t *)&ns->id_ns, sizeof(NvmeIdNs),
-                        DMA_DIRECTION_FROM_DEVICE, req);
+        return nvme_c2h(n, (uint8_t *)&ns->id_ns, sizeof(NvmeIdNs), req);
     }
 
     return NVME_INVALID_CMD_SET | NVME_DNR;
@@ -3152,8 +3165,8 @@ static uint16_t nvme_identify_ns_csi(NvmeCtrl *n, 
NvmeRequest *req)
     if (c->csi == NVME_CSI_NVM && nvme_csi_has_nvm_support(ns)) {
         return nvme_rpt_empty_id_struct(n, req);
     } else if (c->csi == NVME_CSI_ZONED && ns->csi == NVME_CSI_ZONED) {
-        return nvme_dma(n, (uint8_t *)ns->id_ns_zoned, sizeof(NvmeIdNsZoned),
-                        DMA_DIRECTION_FROM_DEVICE, req);
+        return nvme_c2h(n, (uint8_t *)ns->id_ns_zoned, sizeof(NvmeIdNsZoned),
+                        req);
     }
 
     return NVME_INVALID_FIELD | NVME_DNR;
@@ -3195,7 +3208,7 @@ static uint16_t nvme_identify_nslist(NvmeCtrl *n, 
NvmeRequest *req)
         }
     }
 
-    return nvme_dma(n, list, data_len, DMA_DIRECTION_FROM_DEVICE, req);
+    return nvme_c2h(n, list, data_len, req);
 }
 
 static uint16_t nvme_identify_nslist_csi(NvmeCtrl *n, NvmeRequest *req)
@@ -3235,7 +3248,7 @@ static uint16_t nvme_identify_nslist_csi(NvmeCtrl *n, 
NvmeRequest *req)
         }
     }
 
-    return nvme_dma(n, list, data_len, DMA_DIRECTION_FROM_DEVICE, req);
+    return nvme_c2h(n, list, data_len, req);
 }
 
 static uint16_t nvme_identify_ns_descr_list(NvmeCtrl *n, NvmeRequest *req)
@@ -3282,7 +3295,7 @@ static uint16_t nvme_identify_ns_descr_list(NvmeCtrl *n, 
NvmeRequest *req)
     ns_descrs->csi.hdr.nidl = NVME_NIDL_CSI;
     ns_descrs->csi.v = ns->csi;
 
-    return nvme_dma(n, list, sizeof(list), DMA_DIRECTION_FROM_DEVICE, req);
+    return nvme_c2h(n, list, sizeof(list), req);
 }
 
 static uint16_t nvme_identify_cmd_set(NvmeCtrl *n, NvmeRequest *req)
@@ -3295,7 +3308,7 @@ static uint16_t nvme_identify_cmd_set(NvmeCtrl *n, 
NvmeRequest *req)
     NVME_SET_CSI(*list, NVME_CSI_NVM);
     NVME_SET_CSI(*list, NVME_CSI_ZONED);
 
-    return nvme_dma(n, list, data_len, DMA_DIRECTION_FROM_DEVICE, req);
+    return nvme_c2h(n, list, data_len, req);
 }
 
 static uint16_t nvme_identify(NvmeCtrl *n, NvmeRequest *req)
@@ -3384,8 +3397,7 @@ static uint16_t nvme_get_feature_timestamp(NvmeCtrl *n, 
NvmeRequest *req)
 {
     uint64_t timestamp = nvme_get_timestamp(n);
 
-    return nvme_dma(n, (uint8_t *)&timestamp, sizeof(timestamp),
-                    DMA_DIRECTION_FROM_DEVICE, req);
+    return nvme_c2h(n, (uint8_t *)&timestamp, sizeof(timestamp), req);
 }
 
 static uint16_t nvme_get_feature(NvmeCtrl *n, NvmeRequest *req)
@@ -3545,8 +3557,7 @@ static uint16_t nvme_set_feature_timestamp(NvmeCtrl *n, 
NvmeRequest *req)
     uint16_t ret;
     uint64_t timestamp;
 
-    ret = nvme_dma(n, (uint8_t *)&timestamp, sizeof(timestamp),
-                   DMA_DIRECTION_TO_DEVICE, req);
+    ret = nvme_h2c(n, (uint8_t *)&timestamp, sizeof(timestamp), req);
     if (ret) {
         return ret;
     }
-- 
2.30.0