hw/block/nvme: refactor nvme_dma

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>
Reviewed-by: Keith Busch <kbusch@kernel.org>

1 files changed, 66 insertions, 52 deletions

diff --git a/hw/block/nvme.c b/hw/block/nvme.c
index 59942f8811..bfab80c457 100644
--- a/hw/block/nvme.c
+++ b/hw/block/nvme.c
@@ -871,45 +871,71 @@ 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)
-{
-    uint16_t status = NVME_SUCCESS;
+typedef enum NvmeTxDirection {
+    NVME_TX_DIRECTION_TO_DEVICE   = 0,
+    NVME_TX_DIRECTION_FROM_DEVICE = 1,
+} NvmeTxDirection;
 
-    status = nvme_map_dptr(n, &req->sg, len, &req->cmd);
-    if (status) {
-        return status;
-    }
+static uint16_t nvme_tx(NvmeCtrl *n, NvmeSg *sg, uint8_t *ptr, uint32_t len,
+                        NvmeTxDirection dir)
+{
+    assert(sg->flags & NVME_SG_ALLOC);
 
-    if (req->sg.flags & NVME_SG_DMA) {
+    if (sg->flags & NVME_SG_DMA) {
         uint64_t residual;
 
-        if (dir == DMA_DIRECTION_TO_DEVICE) {
-            residual = dma_buf_write(ptr, len, &req->sg.qsg);
+        if (dir == NVME_TX_DIRECTION_TO_DEVICE) {
+            residual = dma_buf_write(ptr, len, &sg->qsg);
         } else {
-            residual = dma_buf_read(ptr, len, &req->sg.qsg);
+            residual = dma_buf_read(ptr, len, &sg->qsg);
         }
 
         if (unlikely(residual)) {
             trace_pci_nvme_err_invalid_dma();
-            status = NVME_INVALID_FIELD | NVME_DNR;
+            return 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);
+        if (dir == NVME_TX_DIRECTION_TO_DEVICE) {
+            bytes = qemu_iovec_to_buf(&sg->iov, 0, ptr, len);
         } else {
-            bytes = qemu_iovec_from_buf(&req->sg.iov, 0, ptr, len);
+            bytes = qemu_iovec_from_buf(&sg->iov, 0, ptr, len);
         }
 
         if (unlikely(bytes != len)) {
             trace_pci_nvme_err_invalid_dma();
-            status = NVME_INVALID_FIELD | NVME_DNR;
+            return NVME_INVALID_FIELD | NVME_DNR;
         }
     }
 
-    return status;
+    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;
+    }
+
+    return nvme_tx(n, &req->sg, ptr, len, NVME_TX_DIRECTION_FROM_DEVICE);
+}
+
+static inline uint16_t nvme_h2c(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;
+    }
+
+    return nvme_tx(n, &req->sg, ptr, len, NVME_TX_DIRECTION_TO_DEVICE);
 }
 
 static inline void nvme_blk_read(BlockBackend *blk, int64_t offset,
@@ -1746,8 +1772,7 @@ 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;
@@ -1783,8 +1808,7 @@ 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;
         }
@@ -1870,8 +1894,8 @@ 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;
     }
@@ -2522,8 +2546,7 @@ 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;
@@ -2677,8 +2700,7 @@ 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);
 
@@ -2944,8 +2966,7 @@ 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,
@@ -2963,8 +2984,7 @@ 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,
@@ -2984,8 +3004,7 @@ 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,
@@ -3025,8 +3044,7 @@ 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)
@@ -3194,7 +3212,7 @@ 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)
@@ -3211,8 +3229,7 @@ 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)
@@ -3235,7 +3252,7 @@ static uint16_t nvme_identify_ctrl_csi(NvmeCtrl *n, NvmeRequest *req)
         return NVME_INVALID_FIELD | NVME_DNR;
     }
 
-    return nvme_dma(n, id, sizeof(id), DMA_DIRECTION_FROM_DEVICE, req);
+    return nvme_c2h(n, id, sizeof(id), req);
 }
 
 static uint16_t nvme_identify_ns(NvmeCtrl *n, NvmeRequest *req)
@@ -3256,8 +3273,7 @@ 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;
@@ -3283,8 +3299,8 @@ 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;
@@ -3326,7 +3342,7 @@ 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)
@@ -3366,7 +3382,7 @@ 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)
@@ -3413,7 +3429,7 @@ 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)
@@ -3426,7 +3442,7 @@ 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)
@@ -3518,8 +3534,7 @@ 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)
@@ -3680,8 +3695,7 @@ 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;
     }