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Merge branch 'remotes/lorenzo/pci/hv' 

- Fix Hyper-V use-after-free in pci_dev removal (Dexuan Cui)

  - Fix Hyper-V build error in non-sysfs config (Randy Dunlap)

  - Reallocate to avoid Hyper-V domain number collisions (Haiyang Zhang)

  - Use Hyper-V instance ID bytes 4-5 to reduce domain collisions (Haiyang
    Zhang)

* remotes/lorenzo/pci/hv:
  PCI: hv: Use bytes 4 and 5 from instance ID as the PCI domain numbers
  PCI: hv: Detect and fix Hyper-V PCI domain number collision
  PCI: pci-hyperv: Fix build errors on non-SYSFS config
  PCI: hv: Avoid use of hv_pci_dev->pci_slot after freeing it
This commit is contained in:
Bjorn Helgaas 2019-09-23 16:10:19 -05:00
parent b83e445d46 f73f8a504e
commit a40c4b379f
2 changed files with 81 additions and 15 deletions
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2
drivers/pci/Kconfig
View File

@ -181,7 +181,7 @@ config PCI_LABEL
config PCI_HYPERV
tristate "Hyper-V PCI Frontend"
depends on X86 && HYPERV && PCI_MSI && PCI_MSI_IRQ_DOMAIN && X86_64
depends on X86_64 && HYPERV && PCI_MSI && PCI_MSI_IRQ_DOMAIN && SYSFS
help
The PCI device frontend driver allows the kernel to import arbitrary
PCI devices from a PCI backend to support PCI driver domains.

94
drivers/pci/controller/pci-hyperv.c
View File

@ -2510,6 +2510,48 @@ static void put_hvpcibus(struct hv_pcibus_device *hbus)
complete(&hbus->remove_event);
}
#define HVPCI_DOM_MAP_SIZE (64 * 1024)
static DECLARE_BITMAP(hvpci_dom_map, HVPCI_DOM_MAP_SIZE);
/*
* PCI domain number 0 is used by emulated devices on Gen1 VMs, so define 0
* as invalid for passthrough PCI devices of this driver.
*/
#define HVPCI_DOM_INVALID 0
/**
* hv_get_dom_num() - Get a valid PCI domain number
* Check if the PCI domain number is in use, and return another number if
* it is in use.
*
* @dom: Requested domain number
*
* return: domain number on success, HVPCI_DOM_INVALID on failure
*/
static u16 hv_get_dom_num(u16 dom)
{
unsigned int i;
if (test_and_set_bit(dom, hvpci_dom_map) == 0)
return dom;
for_each_clear_bit(i, hvpci_dom_map, HVPCI_DOM_MAP_SIZE) {
if (test_and_set_bit(i, hvpci_dom_map) == 0)
return i;
}
return HVPCI_DOM_INVALID;
}
/**
* hv_put_dom_num() - Mark the PCI domain number as free
* @dom: Domain number to be freed
*/
static void hv_put_dom_num(u16 dom)
{
clear_bit(dom, hvpci_dom_map);
}
/**
* hv_pci_probe() - New VMBus channel probe, for a root PCI bus
* @hdev: VMBus's tracking struct for this root PCI bus
@ -2521,6 +2563,7 @@ static int hv_pci_probe(struct hv_device *hdev,
const struct hv_vmbus_device_id *dev_id)
{
struct hv_pcibus_device *hbus;
u16 dom_req, dom;
int ret;
/*
@ -2535,19 +2578,34 @@ static int hv_pci_probe(struct hv_device *hdev,
hbus->state = hv_pcibus_init;
/*
* The PCI bus "domain" is what is called "segment" in ACPI and
* other specs. Pull it from the instance ID, to get something
* unique. Bytes 8 and 9 are what is used in Windows guests, so
* do the same thing for consistency. Note that, since this code
* only runs in a Hyper-V VM, Hyper-V can (and does) guarantee
* that (1) the only domain in use for something that looks like
* a physical PCI bus (which is actually emulated by the
* hypervisor) is domain 0 and (2) there will be no overlap
* between domains derived from these instance IDs in the same
* VM.
* The PCI bus "domain" is what is called "segment" in ACPI and other
* specs. Pull it from the instance ID, to get something usually
* unique. In rare cases of collision, we will find out another number
* not in use.
*
* Note that, since this code only runs in a Hyper-V VM, Hyper-V
* together with this guest driver can guarantee that (1) The only
* domain used by Gen1 VMs for something that looks like a physical
* PCI bus (which is actually emulated by the hypervisor) is domain 0.
* (2) There will be no overlap between domains (after fixing possible
* collisions) in the same VM.
*/
hbus->sysdata.domain = hdev->dev_instance.b[9] |
hdev->dev_instance.b[8] << 8;
dom_req = hdev->dev_instance.b[5] << 8 | hdev->dev_instance.b[4];
dom = hv_get_dom_num(dom_req);
if (dom == HVPCI_DOM_INVALID) {
dev_err(&hdev->device,
"Unable to use dom# 0x%hx or other numbers", dom_req);
ret = -EINVAL;
goto free_bus;
}
if (dom != dom_req)
dev_info(&hdev->device,
"PCI dom# 0x%hx has collision, using 0x%hx",
dom_req, dom);
hbus->sysdata.domain = dom;
hbus->hdev = hdev;
refcount_set(&hbus->remove_lock, 1);
@ -2562,7 +2620,7 @@ static int hv_pci_probe(struct hv_device *hdev,
hbus->sysdata.domain);
if (!hbus->wq) {
ret = -ENOMEM;
goto free_bus;
goto free_dom;
}
ret = vmbus_open(hdev->channel, pci_ring_size, pci_ring_size, NULL, 0,
@ -2639,6 +2697,8 @@ close:
vmbus_close(hdev->channel);
destroy_wq:
destroy_workqueue(hbus->wq);
free_dom:
hv_put_dom_num(hbus->sysdata.domain);
free_bus:
free_page((unsigned long)hbus);
return ret;
@ -2701,8 +2761,8 @@ static int hv_pci_remove(struct hv_device *hdev)
/* Remove the bus from PCI's point of view. */
pci_lock_rescan_remove();
pci_stop_root_bus(hbus->pci_bus);
pci_remove_root_bus(hbus->pci_bus);
hv_pci_remove_slots(hbus);
pci_remove_root_bus(hbus->pci_bus);
pci_unlock_rescan_remove();
hbus->state = hv_pcibus_removed;
}
@ -2720,6 +2780,9 @@ static int hv_pci_remove(struct hv_device *hdev)
put_hvpcibus(hbus);
wait_for_completion(&hbus->remove_event);
destroy_workqueue(hbus->wq);
hv_put_dom_num(hbus->sysdata.domain);
free_page((unsigned long)hbus);
return 0;
}
@ -2747,6 +2810,9 @@ static void __exit exit_hv_pci_drv(void)
static int __init init_hv_pci_drv(void)
{
/* Set the invalid domain number's bit, so it will not be used */
set_bit(HVPCI_DOM_INVALID, hvpci_dom_map);
return vmbus_driver_register(&hv_pci_drv);
}