hw/nvme: generalize the mbar size helper

Generalize the mbar size helper such that it can handle cases where the
MSI-X table and PBA are expected to be in an exclusive bar.

Cc: qemu-stable@nongnu.org
Reviewed-by: Jesper Wendel Devantier <foss@defmacro.it>
Signed-off-by: Klaus Jensen <k.jensen@samsung.com>

hw/nvme/ctrl.c

@@ -8015,13 +8015,18 @@ static void nvme_init_pmr(NvmeCtrl *n, PCIDevice *pci_dev)
     memory_region_set_enabled(&n->pmr.dev->mr, false);
 }
 
-static uint64_t nvme_bar_size(unsigned total_queues, unsigned total_irqs,
-                              unsigned *msix_table_offset,
-                              unsigned *msix_pba_offset)
+static uint64_t nvme_mbar_size(unsigned total_queues, unsigned total_irqs,
+                               unsigned *msix_table_offset,
+                               unsigned *msix_pba_offset)
 {
-    uint64_t bar_size, msix_table_size, msix_pba_size;
+    uint64_t bar_size, msix_table_size;
 
     bar_size = sizeof(NvmeBar) + 2 * total_queues * NVME_DB_SIZE;
+
+    if (total_irqs == 0) {
+        goto out;
+    }
+
     bar_size = QEMU_ALIGN_UP(bar_size, 4 * KiB);
 
     if (msix_table_offset) {
@@ -8036,19 +8041,18 @@ static uint64_t nvme_bar_size(unsigned total_queues, unsigned total_irqs,
         *msix_pba_offset = bar_size;
     }
 
-    msix_pba_size = QEMU_ALIGN_UP(total_irqs, 64) / 8;
-    bar_size += msix_pba_size;
+    bar_size += QEMU_ALIGN_UP(total_irqs, 64) / 8;
 
-    bar_size = pow2ceil(bar_size);
-    return bar_size;
+out:
+    return pow2ceil(bar_size);
 }
 
 static void nvme_init_sriov(NvmeCtrl *n, PCIDevice *pci_dev, uint16_t offset)
 {
     uint16_t vf_dev_id = n->params.use_intel_id ?
                          PCI_DEVICE_ID_INTEL_NVME : PCI_DEVICE_ID_REDHAT_NVME;
     NvmePriCtrlCap *cap = &n->pri_ctrl_cap;
-    uint64_t bar_size = nvme_bar_size(le16_to_cpu(cap->vqfrsm),
+    uint64_t bar_size = nvme_mbar_size(le16_to_cpu(cap->vqfrsm),
                                       le16_to_cpu(cap->vifrsm),
                                       NULL, NULL);
 
@@ -8087,7 +8091,7 @@ static bool nvme_init_pci(NvmeCtrl *n, PCIDevice *pci_dev, Error **errp)
     ERRP_GUARD();
     uint8_t *pci_conf = pci_dev->config;
     uint64_t bar_size;
-    unsigned msix_table_offset, msix_pba_offset;
+    unsigned msix_table_offset = 0, msix_pba_offset = 0;
     int ret;
 
     pci_conf[PCI_INTERRUPT_PIN] = 1;
@@ -8110,8 +8114,8 @@ static bool nvme_init_pci(NvmeCtrl *n, PCIDevice *pci_dev, Error **errp)
     }
 
     /* add one to max_ioqpairs to account for the admin queue pair */
-    bar_size = nvme_bar_size(n->params.max_ioqpairs + 1, n->params.msix_qsize,
-                             &msix_table_offset, &msix_pba_offset);
+    bar_size = nvme_mbar_size(n->params.max_ioqpairs + 1, n->params.msix_qsize,
+                              &msix_table_offset, &msix_pba_offset);
 
     memory_region_init(&n->bar0, OBJECT(n), "nvme-bar0", bar_size);
     memory_region_init_io(&n->iomem, OBJECT(n), &nvme_mmio_ops, n, "nvme",