PCI: hv: Use nested hypercall for retargeting interrupts

[PATCH] PCI: hv: Use nested hypercall for retargeting interrupts

Posted by Jinank Jain 2 years, 10 months ago

In case of nested MSHV, retargeting interrupt hypercall should be sent
to L0 hypervisor instead of L1 hypervisor.

Signed-off-by: Jinank Jain <jinankjain@linux.microsoft.com>
---
 drivers/pci/controller/pci-hyperv.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
index f33370b75628..2123f632ecf7 100644
--- a/drivers/pci/controller/pci-hyperv.c
+++ b/drivers/pci/controller/pci-hyperv.c
@@ -704,8 +704,14 @@ static void hv_arch_irq_unmask(struct irq_data *data)
 		}
 	}
 
-	res = hv_do_hypercall(HVCALL_RETARGET_INTERRUPT | (var_size << 17),
-			      params, NULL);
+	if (hv_nested)
+		res = hv_do_nested_hypercall(HVCALL_RETARGET_INTERRUPT |
+					     (var_size << 17),
+					     params, NULL);
+	else
+		res = hv_do_hypercall(HVCALL_RETARGET_INTERRUPT |
+				      (var_size << 17),
+				      params, NULL);
 
 exit_unlock:
 	spin_unlock_irqrestore(&hbus->retarget_msi_interrupt_lock, flags);
-- 
2.34.1

Re: [PATCH] PCI: hv: Use nested hypercall for retargeting interrupts

Posted by Wei Liu 2 years, 10 months ago

On Tue, Apr 04, 2023 at 11:35:46AM +0000, Jinank Jain wrote:
> In case of nested MSHV, retargeting interrupt hypercall should be sent
> to L0 hypervisor instead of L1 hypervisor.
> 
> Signed-off-by: Jinank Jain <jinankjain@linux.microsoft.com>

While I think this is a sensible change -- how did you discover this?
Can you provide a bit more information?

> ---
>  drivers/pci/controller/pci-hyperv.c | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
> index f33370b75628..2123f632ecf7 100644
> --- a/drivers/pci/controller/pci-hyperv.c
> +++ b/drivers/pci/controller/pci-hyperv.c
> @@ -704,8 +704,14 @@ static void hv_arch_irq_unmask(struct irq_data *data)
>  		}
>  	}
>  
> -	res = hv_do_hypercall(HVCALL_RETARGET_INTERRUPT | (var_size << 17),
> -			      params, NULL);
> +	if (hv_nested)
> +		res = hv_do_nested_hypercall(HVCALL_RETARGET_INTERRUPT |
> +					     (var_size << 17),
> +					     params, NULL);
> +	else
> +		res = hv_do_hypercall(HVCALL_RETARGET_INTERRUPT |
> +				      (var_size << 17),
> +				      params, NULL);
>  
>  exit_unlock:
>  	spin_unlock_irqrestore(&hbus->retarget_msi_interrupt_lock, flags);
> -- 
> 2.34.1
>

Re: [PATCH] PCI: hv: Use nested hypercall for retargeting interrupts

Posted by Jinank Jain 2 years, 10 months ago

This was observed while testing pass-through PCI devices on the nested 
MSHV setup.

Regards,

Jinank

On 4/6/2023 4:47 AM, Wei Liu wrote:
> On Tue, Apr 04, 2023 at 11:35:46AM +0000, Jinank Jain wrote:
>> In case of nested MSHV, retargeting interrupt hypercall should be sent
>> to L0 hypervisor instead of L1 hypervisor.
>>
>> Signed-off-by: Jinank Jain <jinankjain@linux.microsoft.com>
> While I think this is a sensible change -- how did you discover this?
> Can you provide a bit more information?
>
>> ---
>>   drivers/pci/controller/pci-hyperv.c | 10 ++++++++--
>>   1 file changed, 8 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
>> index f33370b75628..2123f632ecf7 100644
>> --- a/drivers/pci/controller/pci-hyperv.c
>> +++ b/drivers/pci/controller/pci-hyperv.c
>> @@ -704,8 +704,14 @@ static void hv_arch_irq_unmask(struct irq_data *data)
>>   		}
>>   	}
>>   
>> -	res = hv_do_hypercall(HVCALL_RETARGET_INTERRUPT | (var_size << 17),
>> -			      params, NULL);
>> +	if (hv_nested)
>> +		res = hv_do_nested_hypercall(HVCALL_RETARGET_INTERRUPT |
>> +					     (var_size << 17),
>> +					     params, NULL);
>> +	else
>> +		res = hv_do_hypercall(HVCALL_RETARGET_INTERRUPT |
>> +				      (var_size << 17),
>> +				      params, NULL);
>>   
>>   exit_unlock:
>>   	spin_unlock_irqrestore(&hbus->retarget_msi_interrupt_lock, flags);
>> -- 
>> 2.34.1
>>

Re: [PATCH] PCI: hv: Use nested hypercall for retargeting interrupts

Posted by Nuno Das Neves 2 years, 10 months ago

Reviewed-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>

On 4/4/2023 4:35 AM, Jinank Jain wrote:
> In case of nested MSHV, retargeting interrupt hypercall should be sent
> to L0 hypervisor instead of L1 hypervisor.
> 
> Signed-off-by: Jinank Jain <jinankjain@linux.microsoft.com>
> ---
>  drivers/pci/controller/pci-hyperv.c | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
> index f33370b75628..2123f632ecf7 100644
> --- a/drivers/pci/controller/pci-hyperv.c
> +++ b/drivers/pci/controller/pci-hyperv.c
> @@ -704,8 +704,14 @@ static void hv_arch_irq_unmask(struct irq_data *data)
>  		}
>  	}
>  
> -	res = hv_do_hypercall(HVCALL_RETARGET_INTERRUPT | (var_size << 17),
> -			      params, NULL);
> +	if (hv_nested)
> +		res = hv_do_nested_hypercall(HVCALL_RETARGET_INTERRUPT |
> +					     (var_size << 17),
> +					     params, NULL);
> +	else
> +		res = hv_do_hypercall(HVCALL_RETARGET_INTERRUPT |
> +				      (var_size << 17),
> +				      params, NULL);
>  
>  exit_unlock:
>  	spin_unlock_irqrestore(&hbus->retarget_msi_interrupt_lock, flags);