pcie_sriov: Remove num_vfs from PCIESriovPF

num_vfs is not migrated so use PCI_SRIOV_CTRL_VFE and PCI_SRIOV_NUM_VF
instead.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-Id: <20250116-reuse-v20-10-7cb370606368@daynix.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

hw/pci/pcie_sriov.c

@@ -51,7 +51,6 @@ bool pcie_sriov_pf_init(PCIDevice *dev, uint16_t offset,
     pcie_add_capability(dev, PCI_EXT_CAP_ID_SRIOV, 1,
                         offset, PCI_EXT_CAP_SRIOV_SIZEOF);
     dev->exp.sriov_cap = offset;
-    dev->exp.sriov_pf.num_vfs = 0;
     dev->exp.sriov_pf.vf = NULL;
 
     pci_set_word(cfg + PCI_SRIOV_VF_OFFSET, vf_offset);
@@ -188,29 +187,28 @@ static void register_vfs(PCIDevice *dev)
 
     assert(sriov_cap > 0);
     num_vfs = pci_get_word(dev->config + sriov_cap + PCI_SRIOV_NUM_VF);
-    if (num_vfs > pci_get_word(dev->config + sriov_cap + PCI_SRIOV_TOTAL_VF)) {
-        return;
-    }
 
     trace_sriov_register_vfs(dev->name, PCI_SLOT(dev->devfn),
                              PCI_FUNC(dev->devfn), num_vfs);
     for (i = 0; i < num_vfs; i++) {
         pci_set_enabled(dev->exp.sriov_pf.vf[i], true);
     }
-    dev->exp.sriov_pf.num_vfs = num_vfs;
+
+    pci_set_word(dev->wmask + sriov_cap + PCI_SRIOV_NUM_VF, 0);
 }
 
 static void unregister_vfs(PCIDevice *dev)
 {
-    uint16_t num_vfs = dev->exp.sriov_pf.num_vfs;
+    uint8_t *cfg = dev->config + dev->exp.sriov_cap;
     uint16_t i;
 
     trace_sriov_unregister_vfs(dev->name, PCI_SLOT(dev->devfn),
-                               PCI_FUNC(dev->devfn), num_vfs);
+                               PCI_FUNC(dev->devfn));
-    for (i = 0; i < num_vfs; i++) {
+    for (i = 0; i < pci_get_word(cfg + PCI_SRIOV_TOTAL_VF); i++) {
         pci_set_enabled(dev->exp.sriov_pf.vf[i], false);
     }
-    dev->exp.sriov_pf.num_vfs = 0;
+
+    pci_set_word(dev->wmask + dev->exp.sriov_cap + PCI_SRIOV_NUM_VF, 0xffff);
 }
 
 void pcie_sriov_config_write(PCIDevice *dev, uint32_t address,
@@ -236,6 +234,17 @@ void pcie_sriov_config_write(PCIDevice *dev, uint32_t address,
         } else {
             unregister_vfs(dev);
         }
+    } else if (range_covers_byte(off, len, PCI_SRIOV_NUM_VF)) {
+        uint8_t *cfg = dev->config + sriov_cap;
+        uint8_t *wmask = dev->wmask + sriov_cap;
+        uint16_t num_vfs = pci_get_word(cfg + PCI_SRIOV_NUM_VF);
+        uint16_t wmask_val = PCI_SRIOV_CTRL_MSE | PCI_SRIOV_CTRL_ARI;
+
+        if (num_vfs <= pci_get_word(cfg + PCI_SRIOV_TOTAL_VF)) {
+            wmask_val |= PCI_SRIOV_CTRL_VFE;
+        }
+
+        pci_set_word(wmask + PCI_SRIOV_CTRL, wmask_val);
     }
 }
 
@@ -252,6 +261,8 @@ void pcie_sriov_pf_reset(PCIDevice *dev)
     unregister_vfs(dev);
 
     pci_set_word(dev->config + sriov_cap + PCI_SRIOV_NUM_VF, 0);
+    pci_set_word(dev->wmask + sriov_cap + PCI_SRIOV_CTRL,
+                 PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE | PCI_SRIOV_CTRL_ARI);
 
     /*
      * Default is to use 4K pages, software can modify it
@@ -298,7 +309,7 @@ PCIDevice *pcie_sriov_get_pf(PCIDevice *dev)
 PCIDevice *pcie_sriov_get_vf_at_index(PCIDevice *dev, int n)
 {
     assert(!pci_is_vf(dev));
-    if (n < dev->exp.sriov_pf.num_vfs) {
+    if (n < pcie_sriov_num_vfs(dev)) {
         return dev->exp.sriov_pf.vf[n];
     }
     return NULL;
@@ -306,5 +317,10 @@ PCIDevice *pcie_sriov_get_vf_at_index(PCIDevice *dev, int n)
 
 uint16_t pcie_sriov_num_vfs(PCIDevice *dev)
 {
-    return dev->exp.sriov_pf.num_vfs;
+    uint16_t sriov_cap = dev->exp.sriov_cap;
+    uint8_t *cfg = dev->config + sriov_cap;
+
+    return sriov_cap &&
+           (pci_get_word(cfg + PCI_SRIOV_CTRL) & PCI_SRIOV_CTRL_VFE) ?
+           pci_get_word(cfg + PCI_SRIOV_NUM_VF) : 0;
 }

hw/pci/trace-events

@@ -14,7 +14,7 @@ msix_write_config(char *name, bool enabled, bool masked) "dev %s enabled %d mask
 
 # hw/pci/pcie_sriov.c
 sriov_register_vfs(const char *name, int slot, int function, int num_vfs) "%s %02x:%x: creating %d vf devs"
-sriov_unregister_vfs(const char *name, int slot, int function, int num_vfs) "%s %02x:%x: Unregistering %d vf devs"
+sriov_unregister_vfs(const char *name, int slot, int function) "%s %02x:%x: Unregistering vf devs"
 sriov_config_write(const char *name, int slot, int fun, uint32_t offset, uint32_t val, uint32_t len) "%s %02x:%x: sriov offset 0x%x val 0x%x len %d"
 
 # pcie.c

include/hw/pci/pcie_sriov.h

@@ -16,7 +16,6 @@
 #include "hw/pci/pci.h"
 
 typedef struct PCIESriovPF {
-    uint16_t num_vfs;   /* Number of virtual functions created */
     uint8_t vf_bar_type[PCI_NUM_REGIONS];   /* Store type for each VF bar */
     PCIDevice **vf;     /* Pointer to an array of num_vfs VF devices */
 } PCIESriovPF;