pcie_sriov: Do not reset NumVFs after disabling VFs

The spec does not NumVFs is reset after disabling VFs except when
resetting the PF. Clearing it is guest visible and out of spec, even
though Linux doesn't rely on this value being preserved, so we never
noticed.

Fixes: 7c0fa8dff811 ("pcie: Add support for Single Root I/O Virtualization (SR/IOV)")
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-Id: <20240228-reuse-v8-4-282660281e60@daynix.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/hw/pci/pcie_sriov.c b/hw/pci/pcie_sriov.c
index 51b66d1bb342e11f1e6dc06b45153ddb44f5c24a..e9b23221d713c0802c2fd91f83eb925a68031c2c 100644 (file)
--- a/hw/pci/pcie_sriov.c
+++ b/hw/pci/pcie_sriov.c
@@ -215,7 +215,6 @@ static void unregister_vfs(PCIDevice *dev)
     g_free(dev->exp.sriov_pf.vf);
     dev->exp.sriov_pf.vf = NULL;
     dev->exp.sriov_pf.num_vfs = 0;
-    pci_set_word(dev->config + dev->exp.sriov_cap + PCI_SRIOV_NUM_VF, 0);
 }
 
 void pcie_sriov_config_write(PCIDevice *dev, uint32_t address,
@@ -260,6 +259,8 @@ void pcie_sriov_pf_reset(PCIDevice *dev)
     pci_set_word(dev->config + sriov_cap + PCI_SRIOV_CTRL, 0);
     unregister_vfs(dev);
 
+    pci_set_word(dev->config + sriov_cap + PCI_SRIOV_NUM_VF, 0);
+
     /*
      * Default is to use 4K pages, software can modify it
      * to any of the supported bits