[PULL 03/30] hw/block/nvme: handle dma errors

From: Klaus Jensen <its@irrelevant.dk>
To: peter.maydell@linaro.org, qemu-devel@nongnu.org
Cc: Klaus Jensen <its@irrelevant.dk>, Keith Busch <kbusch@kernel.org>,
	qemu-block@nongnu.org, Klaus Jensen <k.jensen@samsung.com>
Subject: [PULL 03/30] hw/block/nvme: handle dma errors
Date: Tue, 27 Oct 2020 11:49:05 +0100	[thread overview]
Message-ID: <20201027104932.558087-4-its@irrelevant.dk> (raw)
In-Reply-To: <20201027104932.558087-1-its@irrelevant.dk>

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

Handling DMA errors gracefully is required for the device to pass the
block/011 test ("disable PCI device while doing I/O") in the blktests
suite.

With this patch the device sets the Controller Fatal Status bit in the
CSTS register when failing to read from a submission queue or writing to
a completion queue; expecting the host to reset the controller.

If DMA errors occur at any other point in the execution of the command
(say, while mapping the PRPs), the command is aborted with a Data
Transfer Error status code.

Signed-off-by: Klaus Jensen <k.jensen@samsung.com>
Reviewed-by: Keith Busch <kbusch@kernel.org>
---
 hw/block/nvme.c       | 41 +++++++++++++++++++++++++++++++----------
 hw/block/trace-events |  3 +++
 2 files changed, 34 insertions(+), 10 deletions(-)

diff --git a/hw/block/nvme.c b/hw/block/nvme.c
index 44fa5b90769b..7d328c08b894 100644
--- a/hw/block/nvme.c
+++ b/hw/block/nvme.c
@@ -140,14 +140,14 @@ static inline void *nvme_addr_to_cmb(NvmeCtrl *n, hwaddr addr)
     return &n->cmbuf[addr - n->ctrl_mem.addr];
 }
 
-static void nvme_addr_read(NvmeCtrl *n, hwaddr addr, void *buf, int size)
+static int nvme_addr_read(NvmeCtrl *n, hwaddr addr, void *buf, int size)
 {
     if (n->bar.cmbsz && nvme_addr_is_cmb(n, addr)) {
         memcpy(buf, nvme_addr_to_cmb(n, addr), size);
-        return;
+        return 0;
     }
 
-    pci_dma_read(&n->parent_obj, addr, buf, size);
+    return pci_dma_read(&n->parent_obj, addr, buf, size);
 }
 
 static int nvme_check_sqid(NvmeCtrl *n, uint16_t sqid)
@@ -307,6 +307,7 @@ static uint16_t nvme_map_prp(NvmeCtrl *n, uint64_t prp1, uint64_t prp2,
     int num_prps = (len >> n->page_bits) + 1;
     uint16_t status;
     bool prp_list_in_cmb = false;
+    int ret;
 
     QEMUSGList *qsg = &req->qsg;
     QEMUIOVector *iov = &req->iov;
@@ -347,7 +348,11 @@ static uint16_t nvme_map_prp(NvmeCtrl *n, uint64_t prp1, uint64_t prp2,
 
             nents = (len + n->page_size - 1) >> n->page_bits;
             prp_trans = MIN(n->max_prp_ents, nents) * sizeof(uint64_t);
-            nvme_addr_read(n, prp2, (void *)prp_list, prp_trans);
+            ret = nvme_addr_read(n, prp2, (void *)prp_list, prp_trans);
+            if (ret) {
+                trace_pci_nvme_err_addr_read(prp2);
+                return NVME_DATA_TRAS_ERROR;
+            }
             while (len != 0) {
                 uint64_t prp_ent = le64_to_cpu(prp_list[i]);
 
@@ -364,8 +369,12 @@ static uint16_t nvme_map_prp(NvmeCtrl *n, uint64_t prp1, uint64_t prp2,
                     i = 0;
                     nents = (len + n->page_size - 1) >> n->page_bits;
                     prp_trans = MIN(n->max_prp_ents, nents) * sizeof(uint64_t);
-                    nvme_addr_read(n, prp_ent, (void *)prp_list,
-                        prp_trans);
+                    ret = nvme_addr_read(n, prp_ent, (void *)prp_list,
+                                         prp_trans);
+                    if (ret) {
+                        trace_pci_nvme_err_addr_read(prp_ent);
+                        return NVME_DATA_TRAS_ERROR;
+                    }
                     prp_ent = le64_to_cpu(prp_list[i]);
                 }
 
@@ -457,6 +466,7 @@ static void nvme_post_cqes(void *opaque)
     NvmeCQueue *cq = opaque;
     NvmeCtrl *n = cq->ctrl;
     NvmeRequest *req, *next;
+    int ret;
 
     QTAILQ_FOREACH_SAFE(req, &cq->req_list, entry, next) {
         NvmeSQueue *sq;
@@ -466,15 +476,21 @@ static void nvme_post_cqes(void *opaque)
             break;
         }
 
-        QTAILQ_REMOVE(&cq->req_list, req, entry);
         sq = req->sq;
         req->cqe.status = cpu_to_le16((req->status << 1) | cq->phase);
         req->cqe.sq_id = cpu_to_le16(sq->sqid);
         req->cqe.sq_head = cpu_to_le16(sq->head);
         addr = cq->dma_addr + cq->tail * n->cqe_size;
+        ret = pci_dma_write(&n->parent_obj, addr, (void *)&req->cqe,
+                            sizeof(req->cqe));
+        if (ret) {
+            trace_pci_nvme_err_addr_write(addr);
+            trace_pci_nvme_err_cfs();
+            n->bar.csts = NVME_CSTS_FAILED;
+            break;
+        }
+        QTAILQ_REMOVE(&cq->req_list, req, entry);
         nvme_inc_cq_tail(cq);
-        pci_dma_write(&n->parent_obj, addr, (void *)&req->cqe,
-            sizeof(req->cqe));
         nvme_req_exit(req);
         QTAILQ_INSERT_TAIL(&sq->req_list, req, entry);
     }
@@ -1606,7 +1622,12 @@ static void nvme_process_sq(void *opaque)
 
     while (!(nvme_sq_empty(sq) || QTAILQ_EMPTY(&sq->req_list))) {
         addr = sq->dma_addr + sq->head * n->sqe_size;
-        nvme_addr_read(n, addr, (void *)&cmd, sizeof(cmd));
+        if (nvme_addr_read(n, addr, (void *)&cmd, sizeof(cmd))) {
+            trace_pci_nvme_err_addr_read(addr);
+            trace_pci_nvme_err_cfs();
+            n->bar.csts = NVME_CSTS_FAILED;
+            break;
+        }
         nvme_inc_sq_head(sq);
 
         req = QTAILQ_FIRST(&sq->req_list);
diff --git a/hw/block/trace-events b/hw/block/trace-events
index 8ff4cbc4932c..5589db4a014f 100644
--- a/hw/block/trace-events
+++ b/hw/block/trace-events
@@ -86,6 +86,9 @@ pci_nvme_mmio_shutdown_cleared(void) "shutdown bit cleared"
 
 # nvme traces for error conditions
 pci_nvme_err_mdts(uint16_t cid, size_t len) "cid %"PRIu16" len %zu"
+pci_nvme_err_addr_read(uint64_t addr) "addr 0x%"PRIx64""
+pci_nvme_err_addr_write(uint64_t addr) "addr 0x%"PRIx64""
+pci_nvme_err_cfs(void) "controller fatal status"
 pci_nvme_err_invalid_dma(void) "PRP/SGL is too small for transfer size"
 pci_nvme_err_invalid_prplist_ent(uint64_t prplist) "PRP list entry is null or not page aligned: 0x%"PRIx64""
 pci_nvme_err_invalid_prp2_align(uint64_t prp2) "PRP2 is not page aligned: 0x%"PRIx64""
-- 
2.29.1


