hw/block/nvme: disable PMR at boot up

The PMR should not be enabled at boot up. Disable the PMR MemoryRegion
initially and implement MMIO for PMRCTL, allowing the host to enable the
PMR explicitly.

Reviewed-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Klaus Jensen <k.jensen@samsung.com>

hw/block/nvme.c

@@ -3848,8 +3848,16 @@ static void nvme_write_bar(NvmeCtrl *n, hwaddr offset, uint64_t data,
         NVME_GUEST_ERR(pci_nvme_ub_mmiowr_pmrcap_readonly,
                        "invalid write to PMRCAP register, ignored");
         return;
-    case 0xE04: /* TODO PMRCTL */
-        break;
+    case 0xE04: /* PMRCTL */
+        n->bar.pmrctl = data;
+        if (NVME_PMRCTL_EN(data)) {
+            memory_region_set_enabled(&n->pmrdev->mr, true);
+            n->bar.pmrsts = 0;
+        } else {
+            memory_region_set_enabled(&n->pmrdev->mr, false);
+            NVME_PMRSTS_SET_NRDY(n->bar.pmrsts, 1);
+        }
+        return;
     case 0xE08: /* PMRSTS */
         NVME_GUEST_ERR(pci_nvme_ub_mmiowr_pmrsts_readonly,
                        "invalid write to PMRSTS register, ignored");
@@ -4225,6 +4233,8 @@ static void nvme_init_pmr(NvmeCtrl *n, PCIDevice *pci_dev)
                      PCI_BASE_ADDRESS_SPACE_MEMORY |
                      PCI_BASE_ADDRESS_MEM_TYPE_64 |
                      PCI_BASE_ADDRESS_MEM_PREFETCH, &n->pmrdev->mr);
+
+    memory_region_set_enabled(&n->pmrdev->mr, false);
 }
 
 static int nvme_init_pci(NvmeCtrl *n, PCIDevice *pci_dev, Error **errp)