On 2023/11/30 11:46, Stefano Stabellini wrote:
> On Fri, 24 Nov 2023, Jiqian Chen wrote:
>> When device on dom0 side has been reset, the vpci on Xen side
>> won't get notification, so that the cached state in vpci is
>> all out of date with the real device state.
>> To solve that problem, this patch add a function to clear all
>> vpci device state when device is reset on dom0 side.
>>
>> And call that function in pcistub_init_device. Because when
>> we use "pci-assignable-add" to assign a passthrough device in
>> Xen, it will reset passthrough device and the vpci state will
>> out of date, and then device will fail to restore bar state.
>>
>> Signed-off-by: Jiqian Chen <Jiqian.Chen@xxxxxxx>
>> Signed-off-by: Huang Rui <ray.huang@xxxxxxx>
>> ---
>> drivers/xen/pci.c | 12 ++++++++++++
>> drivers/xen/xen-pciback/pci_stub.c | 3 +++
>> include/xen/interface/physdev.h | 2 ++
>> include/xen/pci.h | 6 ++++++
>> 4 files changed, 23 insertions(+)
>>
>> diff --git a/drivers/xen/pci.c b/drivers/xen/pci.c
>> index 72d4e3f193af..e9b30bc09139 100644
>> --- a/drivers/xen/pci.c
>> +++ b/drivers/xen/pci.c
>> @@ -177,6 +177,18 @@ static int xen_remove_device(struct device *dev)
>> return r;
>> }
>>
>> +int xen_reset_device_state(const struct pci_dev *dev)
>> +{
>> + struct physdev_pci_device device = {
>> + .seg = pci_domain_nr(dev->bus),
>> + .bus = dev->bus->number,
>> + .devfn = dev->devfn
>> + };
>> +
>> + return HYPERVISOR_physdev_op(PHYSDEVOP_pci_device_state_reset, &device);
>> +}
>> +EXPORT_SYMBOL_GPL(xen_reset_device_state);
>> +
>> static int xen_pci_notifier(struct notifier_block *nb,
>> unsigned long action, void *data)
>> {
>> diff --git a/drivers/xen/xen-pciback/pci_stub.c b/drivers/xen/xen-pciback/pci_stub.c
>> index e34b623e4b41..5a96b6c66c07 100644
>> --- a/drivers/xen/xen-pciback/pci_stub.c
>> +++ b/drivers/xen/xen-pciback/pci_stub.c
>> @@ -421,6 +421,9 @@ static int pcistub_init_device(struct pci_dev *dev)
>> else {
>> dev_dbg(&dev->dev, "resetting (FLR, D3, etc) the device\n");
>> __pci_reset_function_locked(dev);
>> + err = xen_reset_device_state(dev);
>> + if (err)
>> + goto config_release;
>
> Older versions of Xen won't have the hypercall
> PHYSDEVOP_pci_device_state_reset implemented. I think we should do
> something like:
>
> if (err && xen_pvh_domain())
> goto config_release;
>
>
> Or even:
>
> if (xen_pvh_domain()) {
> err = xen_reset_device_state(dev);
> if (err)
> goto config_release;
> }
>
> depending on whether we want to call xen_reset_device_state also for PV
> guests or not. I am assuming we don't want to error out on failure such
> as -ENOENT for PV guests.
Yes, only for PVH dom0, I will add the condition in next version. Thank you!
>
>
>> pci_restore_state(dev);
>> }
>> /* Now disable the device (this also ensures some private device
>> diff --git a/include/xen/interface/physdev.h b/include/xen/interface/physdev.h
>> index a237af867873..231526f80f6c 100644
>> --- a/include/xen/interface/physdev.h
>> +++ b/include/xen/interface/physdev.h
>> @@ -263,6 +263,8 @@ struct physdev_pci_device {
>> uint8_t devfn;
>> };
>>
>> +#define PHYSDEVOP_pci_device_state_reset 32
>> +
>> #define PHYSDEVOP_DBGP_RESET_PREPARE 1
>> #define PHYSDEVOP_DBGP_RESET_DONE 2
>>
>> diff --git a/include/xen/pci.h b/include/xen/pci.h
>> index b8337cf85fd1..b2e2e856efd6 100644
>> --- a/include/xen/pci.h
>> +++ b/include/xen/pci.h
>> @@ -4,10 +4,16 @@
>> #define __XEN_PCI_H__
>>
>> #if defined(CONFIG_XEN_DOM0)
>> +int xen_reset_device_state(const struct pci_dev *dev);
>> int xen_find_device_domain_owner(struct pci_dev *dev);
>> int xen_register_device_domain_owner(struct pci_dev *dev, uint16_t domain);
>> int xen_unregister_device_domain_owner(struct pci_dev *dev);
>> #else
>> +static inline int xen_reset_device_state(const struct pci_dev *dev)
>> +{
>> + return -1;
>> +}
>> +
>> static inline int xen_find_device_domain_owner(struct pci_dev *dev)
>> {
>> return -1;
>> --
>> 2.34.1
>>
--
Best regards,
Jiqian Chen.
