[PULL 4/6] hw/nvme: error handling for too many mappings

[Klaus Jensen <its@irrelevant.dk>]

From: Padmakar Kalghatgi <p.kalghatgi@samsung.com>

If the number of PRP/SGL mappings exceed 1024, reads and writes will
fail because of an internal QEMU limitation of max 1024 vectors.

Signed-off-by: Padmakar Kalghatgi <p.kalghatgi@samsung.com>
Reviewed-by: Klaus Jensen <k.jensen@samsung.com>
[k.jensen: changed the error message to be more generic]
Signed-off-by: Klaus Jensen <k.jensen@samsung.com>
---
 hw/nvme/ctrl.c       | 13 +++++++++++++
 hw/nvme/trace-events |  1 +
 2 files changed, 14 insertions(+)

diff --git a/hw/nvme/ctrl.c b/hw/nvme/ctrl.c
index 90e3ee2b70ee..ead7531bde5e 100644
--- a/hw/nvme/ctrl.c
+++ b/hw/nvme/ctrl.c
@@ -623,6 +623,10 @@ static uint16_t nvme_map_addr(NvmeCtrl *n, NvmeSg *sg, hwaddr addr, size_t len)
             return NVME_INVALID_USE_OF_CMB | NVME_DNR;
         }
 
+        if (sg->iov.niov + 1 > IOV_MAX) {
+            goto max_mappings_exceeded;
+        }
+
         if (cmb) {
             return nvme_map_addr_cmb(n, &sg->iov, addr, len);
         } else {
@@ -634,9 +638,18 @@ static uint16_t nvme_map_addr(NvmeCtrl *n, NvmeSg *sg, hwaddr addr, size_t len)
         return NVME_INVALID_USE_OF_CMB | NVME_DNR;
     }
 
+    if (sg->qsg.nsg + 1 > IOV_MAX) {
+        goto max_mappings_exceeded;
+    }
+
     qemu_sglist_add(&sg->qsg, addr, len);
 
     return NVME_SUCCESS;
+
+max_mappings_exceeded:
+    NVME_GUEST_ERR(pci_nvme_ub_too_many_mappings,
+                   "number of mappings exceed 1024");
+    return NVME_INTERNAL_DEV_ERROR | NVME_DNR;
 }
 
 static inline bool nvme_addr_is_dma(NvmeCtrl *n, hwaddr addr)
diff --git a/hw/nvme/trace-events b/hw/nvme/trace-events
index f9a1f14e2638..430eeb395b24 100644
--- a/hw/nvme/trace-events
+++ b/hw/nvme/trace-events
@@ -199,3 +199,4 @@ pci_nvme_ub_db_wr_invalid_cqhead(uint32_t qid, uint16_t new_head) "completion qu
 pci_nvme_ub_db_wr_invalid_sq(uint32_t qid) "submission queue doorbell write for nonexistent queue, sqid=%"PRIu32", ignoring"
 pci_nvme_ub_db_wr_invalid_sqtail(uint32_t qid, uint16_t new_tail) "submission queue doorbell write value beyond queue size, sqid=%"PRIu32", new_head=%"PRIu16", ignoring"
 pci_nvme_ub_unknown_css_value(void) "unknown value in cc.css field"
+pci_nvme_ub_too_many_mappings(void) "too many prp/sgl mappings"
-- 
2.32.0