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

[Cao jin]

Hi Michael

On 10/13/2015 04:51 PM, Michael S. Tsirkin wrote:
On Tue, Oct 13, 2015 at 04:41:35PM +0800, Cao jin wrote:
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.f...@cn.fujitsu.com>

I think this patch should come first, before we enable the
functionality that depends on it.

Do you mean, the function should be removed individually in any 
condition? Because as you know, device_del pci_dev will remove all the 
functions in the slot that are fulled exposed to the guest, Alex also 
mentioned this limitation before.

---
  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
.


--
Yours Sincerely,

Cao Jin