error: Use error_setg_errno() to improve error messages

A few error messages show numeric errno codes.  Use error_setg_errno()
to show human-readable text instead.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20251121121438.1249498-13-armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
[Trivial fixup to riscv_kvm_cpu_finalize_features()]

backends/cryptodev-lkcf.c

@@ -218,7 +218,7 @@ static void cryptodev_lkcf_init(CryptoDevBackend *backend, Error **errp)
     }
     lkcf->eventfd = eventfd(0, 0);
     if (lkcf->eventfd < 0) {
-        error_setg(errp, "Failed to create eventfd: %d", errno);
+        error_setg_errno(errp, errno, "Failed to create eventfd");
         return;
     }
 

hw/ppc/spapr.c

@@ -2700,9 +2700,9 @@ static void spapr_set_vsmt_mode(SpaprMachineState *spapr, Error **errp)
         ret = kvmppc_set_smt_threads(spapr->vsmt);
         if (ret) {
             /* Looks like KVM isn't able to change VSMT mode */
-            error_setg(&local_err,
-                       "Failed to set KVM's VSMT mode to %d (errno %d)",
-                       spapr->vsmt, ret);
+            error_setg_errno(&local_err, -ret,
+                             "Failed to set KVM's VSMT mode to %d",
+                             spapr->vsmt);
             /* We can live with that if the default one is big enough
              * for the number of threads, and a submultiple of the one
              * we want.  In this case we'll waste some vcpu ids, but

hw/vfio/migration-multifd.c

@@ -725,8 +725,9 @@ vfio_multifd_save_complete_precopy_thread(SaveCompletePrecopyThreadData *d,
         data_size = read(migration->data_fd, &packet->data,
                          migration->data_buffer_size);
         if (data_size < 0) {
-            error_setg(errp, "%s: reading state buffer %" PRIu32 " failed: %d",
-                       vbasedev->name, idx, errno);
+            error_setg_errno(errp, errno,
+                             "%s: reading state buffer %" PRIu32 " failed",
+                             vbasedev->name, idx);
             goto thread_exit;
         } else if (data_size == 0) {
             break;

migration/rdma.c

@@ -2349,8 +2349,7 @@ static int qemu_get_cm_event_timeout(RDMAContext *rdma,
         error_setg(errp, "RDMA ERROR: poll cm event timeout");
         return -1;
     } else if (ret < 0) {
-        error_setg(errp, "RDMA ERROR: failed to poll cm event, errno=%i",
-                   errno);
+        error_setg_errno(errp, errno, "RDMA ERROR: failed to poll cm event");
         return -1;
     } else if (poll_fd.revents & POLLIN) {
         if (rdma_get_cm_event(rdma->channel, cm_event) < 0) {

net/l2tpv3.c

@@ -639,13 +639,11 @@ int net_init_l2tpv3(const Netdev *netdev,
     }
     fd = socket(result->ai_family, result->ai_socktype, result->ai_protocol);
     if (fd == -1) {
-        fd = -errno;
-        error_setg(errp, "socket creation failed, errno = %d",
-                   -fd);
+        error_setg_errno(errp, errno, "socket creation failed");
         goto outerr;
     }
     if (bind(fd, (struct sockaddr *) result->ai_addr, result->ai_addrlen)) {
-        error_setg(errp, "could not bind socket err=%i", errno);
+        error_setg_errno(errp, errno, "could not bind socket");
         goto outerr;
     }
     if (!qemu_set_blocking(fd, false, errp)) {

target/riscv/kvm/kvm-cpu.c

@@ -1996,8 +1996,8 @@ static bool kvm_cpu_realize(CPUState *cs, Error **errp)
     if (riscv_has_ext(&cpu->env, RVV)) {
         ret = prctl(PR_RISCV_V_SET_CONTROL, PR_RISCV_V_VSTATE_CTRL_ON);
         if (ret) {
-            error_setg(errp, "Error in prctl PR_RISCV_V_SET_CONTROL, code: %s",
-                       strerrorname_np(errno));
+            error_setg_errno(errp, errno,
+                             "Error in prctl PR_RISCV_V_SET_CONTROL");
             return false;
         }
     }
@@ -2032,7 +2032,7 @@ void riscv_kvm_cpu_finalize_features(RISCVCPU *cpu, Error **errp)
         reg.addr = (uint64_t)&val;
         ret = ioctl(kvmcpu.cpufd, KVM_GET_ONE_REG, &reg);
         if (ret != 0) {
-            error_setg(errp, "Unable to read cbom_blocksize, error %d", errno);
+            error_setg_errno(errp, errno, "Unable to read cbom_blocksize");
             return;
         }
 
@@ -2051,7 +2051,7 @@ void riscv_kvm_cpu_finalize_features(RISCVCPU *cpu, Error **errp)
         reg.addr = (uint64_t)&val;
         ret = ioctl(kvmcpu.cpufd, KVM_GET_ONE_REG, &reg);
         if (ret != 0) {
-            error_setg(errp, "Unable to read cboz_blocksize, error %d", errno);
+            error_setg_errno(errp, errno, "Unable to read cboz_blocksize");
             return;
         }
 
@@ -2073,7 +2073,7 @@ void riscv_kvm_cpu_finalize_features(RISCVCPU *cpu, Error **errp)
         reg.addr = (uint64_t)&val;
         ret = ioctl(kvmcpu.cpufd, KVM_GET_ONE_REG, &reg);
         if (ret != 0) {
-            error_setg(errp, "Unable to read vlenb register, error %d", errno);
+            error_setg_errno(errp, errno, "Unable to read vlenb register");
             return;
         }