[Qemu-devel] [PATCH v3 2/2] remove function during multi-function hot-add

[Cao jin <caoj.fnst@cn.fujitsu.com>]

In case user regret when hot-adding multi-function, should roll back,
device_del the function added but not exposed to the guest.

Signed-off-by: Cao jin <caoj.fnst@cn.fujitsu.com>
---
 hw/pci/pci_host.c |  6 +++++-
 hw/pci/pcie.c     | 22 +++++++++++++++++-----
 2 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/hw/pci/pci_host.c b/hw/pci/pci_host.c
index 3e26f92..35e5cf3 100644
--- a/hw/pci/pci_host.c
+++ b/hw/pci/pci_host.c
@@ -20,6 +20,7 @@
 
 #include "hw/pci/pci.h"
 #include "hw/pci/pci_host.h"
+#include "hw/pci/pci_bus.h"
 #include "trace.h"
 
 /* debug PCI */
@@ -88,10 +89,13 @@ void pci_data_write(PCIBus *s, uint32_t addr, uint32_t val, int len)
 uint32_t pci_data_read(PCIBus *s, uint32_t addr, int len)
 {
     PCIDevice *pci_dev = pci_dev_find_by_addr(s, addr);
+    PCIDevice *f0 = NULL;
     uint32_t config_addr = addr & (PCI_CONFIG_SPACE_SIZE - 1);
     uint32_t val;
+    uint8_t slot = (addr >> 11) & 0x1F;
 
-    if (!pci_dev) {
+    f0 = s->devices[PCI_DEVFN(slot, 0)];
+    if (!pci_dev || (!f0 && pci_dev)) {
         return ~0x0;
     }
 
diff --git a/hw/pci/pcie.c b/hw/pci/pcie.c
index 89bf61b..58d2153 100644
--- a/hw/pci/pcie.c
+++ b/hw/pci/pcie.c
@@ -261,13 +261,30 @@ void pcie_cap_slot_hotplug_cb(HotplugHandler *hotplug_dev, DeviceState *dev,
     }
 }
 
+static void pcie_unplug_device(PCIBus *bus, PCIDevice *dev, void *opaque)
+{
+    object_unparent(OBJECT(dev));
+}
+
 void pcie_cap_slot_hot_unplug_request_cb(HotplugHandler *hotplug_dev,
                                          DeviceState *dev, Error **errp)
 {
     uint8_t *exp_cap;
+    PCIDevice *pci_dev = PCI_DEVICE(dev);
+    PCIBus *bus = pci_dev->bus;
 
     pcie_cap_slot_hotplug_common(PCI_DEVICE(hotplug_dev), dev, &exp_cap, errp);
 
+    /* In case user regret when hot-adding multi function, remove the function
+     * that is unexposed to guest individually, without interaction with guest.
+     */
+    if (PCI_FUNC(pci_dev->devfn) > 0 &&
+            bus->devices[PCI_DEVFN(PCI_SLOT(pci_dev->devfn), 0)] == NULL) {
+        pcie_unplug_device(bus, pci_dev, NULL);
+
+        return;
+    }
+
     pcie_cap_slot_push_attention_button(PCI_DEVICE(hotplug_dev));
 }
 
@@ -378,11 +395,6 @@ void pcie_cap_slot_reset(PCIDevice *dev)
     hotplug_event_update_event_status(dev);
 }
 
-static void pcie_unplug_device(PCIBus *bus, PCIDevice *dev, void *opaque)
-{
-    object_unparent(OBJECT(dev));
-}
-
 void pcie_cap_slot_write_config(PCIDevice *dev,
                                 uint32_t addr, uint32_t val, int len)
 {
-- 
2.1.0