hw/nvme: Implement the Function Level Reset

This patch implements the Function Level Reset, a feature currently not
implemented for the Nvme device, while listed as a mandatory ("shall")
in the 1.4 spec.

The implementation reuses FLR-related building blocks defined for the
pci-bridge module, and follows the same logic:
    - FLR capability is advertised in the PCIE config,
    - custom pci_write_config callback detects a write to the trigger
      register and performs the PCI reset,
    - which, eventually, calls the custom dc->reset handler.

Depending on reset type, parts of the state should (or should not) be
cleared. To distinguish the type of reset, an additional parameter is
passed to the reset function.

This patch also enables advertisement of the Power Management PCI
capability. The main reason behind it is to announce the no_soft_reset=1
bit, to signal SR-IOV support where each VF can be reset individually.

The implementation purposedly ignores writes to the PMCS.PS register,
as even such naïve behavior is enough to correctly handle the D3->D0
transition.

It’s worth to note, that the power state transition back to to D3, with
all the corresponding side effects, wasn't and stil isn't handled
properly.

Signed-off-by: Łukasz Gieryk <lukasz.gieryk@linux.intel.com>
Reviewed-by: Klaus Jensen <k.jensen@samsung.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Klaus Jensen <k.jensen@samsung.com>

hw/nvme/ctrl.c

@@ -5903,7 +5903,7 @@ static void nvme_process_sq(void *opaque)
     }
 }
 
-static void nvme_ctrl_reset(NvmeCtrl *n)
+static void nvme_ctrl_reset(NvmeCtrl *n, NvmeResetType rst)
 {
     NvmeNamespace *ns;
     int i;
@@ -5935,7 +5935,9 @@ static void nvme_ctrl_reset(NvmeCtrl *n)
     }
 
     if (!pci_is_vf(&n->parent_obj) && n->params.sriov_max_vfs) {
-        pcie_sriov_pf_disable_vfs(&n->parent_obj);
+        if (rst != NVME_RESET_CONTROLLER) {
+            pcie_sriov_pf_disable_vfs(&n->parent_obj);
+        }
     }
 
     n->aer_queued = 0;
@@ -6169,7 +6171,7 @@ static void nvme_write_bar(NvmeCtrl *n, hwaddr offset, uint64_t data,
             }
         } else if (!NVME_CC_EN(data) && NVME_CC_EN(cc)) {
             trace_pci_nvme_mmio_stopped();
-            nvme_ctrl_reset(n);
+            nvme_ctrl_reset(n, NVME_RESET_CONTROLLER);
             cc = 0;
             csts &= ~NVME_CSTS_READY;
         }
@@ -6727,6 +6729,28 @@ static void nvme_init_sriov(NvmeCtrl *n, PCIDevice *pci_dev, uint16_t offset,
                               PCI_BASE_ADDRESS_MEM_TYPE_64, bar_size);
 }
 
+static int nvme_add_pm_capability(PCIDevice *pci_dev, uint8_t offset)
+{
+    Error *err = NULL;
+    int ret;
+
+    ret = pci_add_capability(pci_dev, PCI_CAP_ID_PM, offset,
+                             PCI_PM_SIZEOF, &err);
+    if (err) {
+        error_report_err(err);
+        return ret;
+    }
+
+    pci_set_word(pci_dev->config + offset + PCI_PM_PMC,
+                 PCI_PM_CAP_VER_1_2);
+    pci_set_word(pci_dev->config + offset + PCI_PM_CTRL,
+                 PCI_PM_CTRL_NO_SOFT_RESET);
+    pci_set_word(pci_dev->wmask + offset + PCI_PM_CTRL,
+                 PCI_PM_CTRL_STATE_MASK);
+
+    return 0;
+}
+
 static int nvme_init_pci(NvmeCtrl *n, PCIDevice *pci_dev, Error **errp)
 {
     uint8_t *pci_conf = pci_dev->config;
@@ -6748,7 +6772,9 @@ static int nvme_init_pci(NvmeCtrl *n, PCIDevice *pci_dev, Error **errp)
     }
 
     pci_config_set_class(pci_conf, PCI_CLASS_STORAGE_EXPRESS);
+    nvme_add_pm_capability(pci_dev, 0x60);
     pcie_endpoint_cap_init(pci_dev, 0x80);
+    pcie_cap_flr_init(pci_dev);
     if (n->params.sriov_max_vfs) {
         pcie_ari_init(pci_dev, 0x100, 1);
     }
@@ -6999,7 +7025,7 @@ static void nvme_exit(PCIDevice *pci_dev)
     NvmeNamespace *ns;
     int i;
 
-    nvme_ctrl_reset(n);
+    nvme_ctrl_reset(n, NVME_RESET_FUNCTION);
 
     if (n->subsys) {
         for (i = 1; i <= NVME_MAX_NAMESPACES; i++) {
@@ -7098,6 +7124,22 @@ static void nvme_set_smart_warning(Object *obj, Visitor *v, const char *name,
     }
 }
 
+static void nvme_pci_reset(DeviceState *qdev)
+{
+    PCIDevice *pci_dev = PCI_DEVICE(qdev);
+    NvmeCtrl *n = NVME(pci_dev);
+
+    trace_pci_nvme_pci_reset();
+    nvme_ctrl_reset(n, NVME_RESET_FUNCTION);
+}
+
+static void nvme_pci_write_config(PCIDevice *dev, uint32_t address,
+                                  uint32_t val, int len)
+{
+    pci_default_write_config(dev, address, val, len);
+    pcie_cap_flr_write_config(dev, address, val, len);
+}
+
 static const VMStateDescription nvme_vmstate = {
     .name = "nvme",
     .unmigratable = 1,
@@ -7109,6 +7151,7 @@ static void nvme_class_init(ObjectClass *oc, void *data)
     PCIDeviceClass *pc = PCI_DEVICE_CLASS(oc);
 
     pc->realize = nvme_realize;
+    pc->config_write = nvme_pci_write_config;
     pc->exit = nvme_exit;
     pc->class_id = PCI_CLASS_STORAGE_EXPRESS;
     pc->revision = 2;
@@ -7117,6 +7160,7 @@ static void nvme_class_init(ObjectClass *oc, void *data)
     dc->desc = "Non-Volatile Memory Express";
     device_class_set_props(dc, nvme_props);
     dc->vmsd = &nvme_vmstate;
+    dc->reset = nvme_pci_reset;
 }
 
 static void nvme_instance_init(Object *obj)

hw/nvme/nvme.h

@@ -488,6 +488,11 @@ typedef struct NvmeCtrl {
     NvmeSecCtrlList sec_ctrl_list;
 } NvmeCtrl;
 
+typedef enum NvmeResetType {
+    NVME_RESET_FUNCTION   = 0,
+    NVME_RESET_CONTROLLER = 1,
+} NvmeResetType;
+
 static inline NvmeNamespace *nvme_ns(NvmeCtrl *n, uint32_t nsid)
 {
     if (!nsid || nsid > NVME_MAX_NAMESPACES) {

hw/nvme/trace-events

@@ -110,6 +110,7 @@ pci_nvme_zd_extension_set(uint32_t zone_idx) "set descriptor extension for zone_
 pci_nvme_clear_ns_close(uint32_t state, uint64_t slba) "zone state=%"PRIu32", slba=%"PRIu64" transitioned to Closed state"
 pci_nvme_clear_ns_reset(uint32_t state, uint64_t slba) "zone state=%"PRIu32", slba=%"PRIu64" transitioned to Empty state"
 pci_nvme_zoned_zrwa_implicit_flush(uint64_t zslba, uint32_t nlb) "zslba 0x%"PRIx64" nlb %"PRIu32""
+pci_nvme_pci_reset(void) "PCI Function Level Reset"
 
 # error conditions
 pci_nvme_err_mdts(size_t len) "len %zu"