On 05/11/2012 02:55 AM, Michael S. Tsirkin wrote:
On Fri, May 11, 2012 at 01:09:13AM +0800, Jiang Liu wrote:
On 05/10/2012 11:44 PM, Amos Kong wrote:
diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c index 806c44f..a7442d9 100644 --- a/drivers/pci/hotplug/acpiphp_glue.c +++ b/drivers/pci/hotplug/acpiphp_glue.c @@ -885,7 +885,7 @@ static void disable_bridges(struct pci_bus *bus) static int disable_device(struct acpiphp_slot *slot) { struct acpiphp_func *func;
- struct pci_dev *pdev;
struct pci_dev *pdev, *tmp; struct pci_bus *bus = slot->bridge->pci_bus;
/* The slot will be enabled when func 0 is added, so check
@@ -902,9 +902,10 @@ static int disable_device(struct acpiphp_slot *slot) func->bridge = NULL; }
pdev = pci_get_slot(slot->bridge->pci_bus,PCI_DEVFN(slot->device, func->function));if (pdev) {
list_for_each_entry_safe(pdev, tmp, &bus->devices, bus_list) {if (PCI_SLOT(pdev->devfn) != slot->device)continue;The pci_bus_sem lock should be acquired when walking the bus->devices list. Otherwise it may cause invalid memory access if another thread is modifying the bus->devices list concurrently.
BTW, what's the relationship with "[PATCH v3] hotplug: add device per func in ACPI DSDT tables"? Seems they are both solving the same issue.
Two work need to be done when we disable a slot, cleaning configuration(in OS) and power off slot.
Currently the second part(power off) works fine, all funcs disappear from "(qemu)#info block" after hot-remove slot. The only problem is func 1~7 are not unconfigured, so I NAKed seabios patch, and try to fix this problem in pci driver.
(btw, winxp & win7 hotplug works currently)
/** * acpiphp_disable_slot - power off slot * @slot: ACPI PHP slot */ int acpiphp_disable_slot(struct acpiphp_slot *slot) { mutex_lock(&slot->crit_sect);
/* unconfigure all functions */ retval = disable_device(slot);
/* power off all functions */ retval = power_off_slot(slot); .... }
That's a bios patch. It's needed if you want broken linux to work. This makes linux behave properly on the original bios.
pci_stop_bus_device(pdev); if (pdev->subordinate) { disable_bridges(pdev->subordinate);