Re: [RFC XEN PATCH v2 1/3] xen/vpci: Clear all vpci status of device

["Chen, Jiqian" <Jiqian.Chen@xxxxxxx>]

On 2023/11/30 19:52, Roger Pau Monné wrote:
> On Thu, Nov 30, 2023 at 06:22:28AM +0000, Chen, Jiqian wrote:
>> Hi Roger and Daniel P. Smith,
>>
>> On 2023/11/28 22:08, Roger Pau Monné wrote:
>>> On Fri, Nov 24, 2023 at 06:41:34PM +0800, Jiqian Chen wrote:
>>>> When a device has been reset on dom0 side, the vpci on Xen
>>>> side won't get notification, so the cached state in vpci is
>>>> all out of date compare with the real device state.
>>>> To solve that problem, this patch add new hypercall to clear
>>>> all vpci device state. And when reset device happens on dom0
>>>> side, dom0 can call this hypercall to notify vpci.
>>>>
>>>> Signed-off-by: Jiqian Chen <Jiqian.Chen@xxxxxxx>
>>>> Signed-off-by: Huang Rui <ray.huang@xxxxxxx>
>>>> ---
>>>>  xen/arch/x86/hvm/hypercall.c  |  1 +
>>>>  xen/drivers/passthrough/pci.c | 21 +++++++++++++++++++++
>>>>  xen/drivers/pci/physdev.c     | 14 ++++++++++++++
>>>>  xen/drivers/vpci/vpci.c       |  9 +++++++++
>>>>  xen/include/public/physdev.h  |  2 ++
>>>>  xen/include/xen/pci.h         |  1 +
>>>>  xen/include/xen/vpci.h        |  6 ++++++
>>>>  7 files changed, 54 insertions(+)
>>>>
>>>> diff --git a/xen/arch/x86/hvm/hypercall.c b/xen/arch/x86/hvm/hypercall.c
>>>> index eeb73e1aa5..6ad5b4d5f1 100644
>>>> --- a/xen/arch/x86/hvm/hypercall.c
>>>> +++ b/xen/arch/x86/hvm/hypercall.c
>>>> @@ -84,6 +84,7 @@ long hvm_physdev_op(int cmd, 
>>>> XEN_GUEST_HANDLE_PARAM(void) arg)
>>>>      case PHYSDEVOP_pci_mmcfg_reserved:
>>>>      case PHYSDEVOP_pci_device_add:
>>>>      case PHYSDEVOP_pci_device_remove:
>>>> +    case PHYSDEVOP_pci_device_state_reset:
>>>>      case PHYSDEVOP_dbgp_op:
>>>>          if ( !is_hardware_domain(currd) )
>>>>              return -ENOSYS;
>>>> diff --git a/xen/drivers/passthrough/pci.c b/xen/drivers/passthrough/pci.c
>>>> index 04d00c7c37..f871715585 100644
>>>> --- a/xen/drivers/passthrough/pci.c
>>>> +++ b/xen/drivers/passthrough/pci.c
>>>> @@ -824,6 +824,27 @@ int pci_remove_device(u16 seg, u8 bus, u8 devfn)
>>>>      return ret;
>>>>  }
>>>>  
>>>> +int pci_reset_device_state(u16 seg, u8 bus, u8 devfn)
>>>
>>> You could use pci_sbdf_t here instead of 3 parameters.
>> Will change in next version, thank you.
>>
>>>
>>> I'm however unsure whether we really need this helper just to fetch
>>> the pdev and call vpci_reset_device_state(), I think you could place
>>> this logic directly in pci_physdev_op().  Unless there are plans to
>>> use such logic outside of pci_physdev_op().
>> If I place the logic of pci_reset_device_state directly in pci_physdev_op. I 
>> think I need to declare vpci_reset_device_state in pci.h? If it is suitable, 
>> I will change in next version.
> 
> Just include xen/vpci.h in drivers/pci/physdev.c AFAICT.
Ok, I will change it in next version. Thanks.

> 
> Thanks, Roger.

-- 
Best regards,
Jiqian Chen.