[v8] Error recovery for vfio-pci devices on s390x

[PATCH v8 9/9] vfio: Remove the pcie check for VFIO_PCI_ERR_IRQ_INDEX

Posted by Farhan Ali 2 weeks, 3 days ago

We are configuring the error signaling on the vast majority of devices and
it's extremely rare that it fires anyway. This allows userspace to be
notified on errors for legacy PCI devices. The Internal Shared Memory (ISM)
device on s390x is one such device. For PCI devices on IBM s390x error
recovery involves platform firmware and notification to operating system
is done by architecture specific way. So the ISM device can still be
recovered when notified of an error.

Signed-off-by: Farhan Ali <alifm@linux.ibm.com>
---
 drivers/vfio/pci/vfio_pci_core.c  | 8 ++------
 drivers/vfio/pci/vfio_pci_intrs.c | 3 +--
 2 files changed, 3 insertions(+), 8 deletions(-)

diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
index c92c6c512b24..9d44df9e21db 100644
--- a/drivers/vfio/pci/vfio_pci_core.c
+++ b/drivers/vfio/pci/vfio_pci_core.c
@@ -778,8 +778,7 @@ static int vfio_pci_get_irq_count(struct vfio_pci_core_device *vdev, int irq_typ
 			return (flags & PCI_MSIX_FLAGS_QSIZE) + 1;
 		}
 	} else if (irq_type == VFIO_PCI_ERR_IRQ_INDEX) {
-		if (pci_is_pcie(vdev->pdev))
-			return 1;
+		return 1;
 	} else if (irq_type == VFIO_PCI_REQ_IRQ_INDEX) {
 		return 1;
 	}
@@ -1155,11 +1154,8 @@ static int vfio_pci_ioctl_get_irq_info(struct vfio_pci_core_device *vdev,
 	switch (info.index) {
 	case VFIO_PCI_INTX_IRQ_INDEX ... VFIO_PCI_MSIX_IRQ_INDEX:
 	case VFIO_PCI_REQ_IRQ_INDEX:
-		break;
 	case VFIO_PCI_ERR_IRQ_INDEX:
-		if (pci_is_pcie(vdev->pdev))
-			break;
-		fallthrough;
+		break;
 	default:
 		return -EINVAL;
 	}
diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c
index c76e753b3cec..b6cedaf0bcca 100644
--- a/drivers/vfio/pci/vfio_pci_intrs.c
+++ b/drivers/vfio/pci/vfio_pci_intrs.c
@@ -859,8 +859,7 @@ int vfio_pci_set_irqs_ioctl(struct vfio_pci_core_device *vdev, uint32_t flags,
 	case VFIO_PCI_ERR_IRQ_INDEX:
 		switch (flags & VFIO_IRQ_SET_ACTION_TYPE_MASK) {
 		case VFIO_IRQ_SET_ACTION_TRIGGER:
-			if (pci_is_pcie(vdev->pdev))
-				func = vfio_pci_set_err_trigger;
+			func = vfio_pci_set_err_trigger;
 			break;
 		}
 		break;
-- 
2.43.0

Re: [PATCH v8 9/9] vfio: Remove the pcie check for VFIO_PCI_ERR_IRQ_INDEX

Posted by Niklas Schnelle 1 week, 5 days ago

On Thu, 2026-01-22 at 11:44 -0800, Farhan Ali wrote:
> We are configuring the error signaling on the vast majority of devices and
> it's extremely rare that it fires anyway. This allows userspace to be
> notified on errors for legacy PCI devices. The Internal Shared Memory (ISM)
> device on s390x is one such device. For PCI devices on IBM s390x error
> recovery involves platform firmware and notification to operating system
> is done by architecture specific way. So the ISM device can still be
> recovered when notified of an error.

Nit: In the kernel context the guidance is to stick to the "s390" name
instead of s390x as in QEMU and even though technically it's all s390x
now ;)

> 
> Signed-off-by: Farhan Ali <alifm@linux.ibm.com>
> ---
>  drivers/vfio/pci/vfio_pci_core.c  | 8 ++------
>  drivers/vfio/pci/vfio_pci_intrs.c | 3 +--
>  2 files changed, 3 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
> index c92c6c512b24..9d44df9e21db 100644
> --- a/drivers/vfio/pci/vfio_pci_core.c
> +++ b/drivers/vfio/pci/vfio_pci_core.c
> @@ -778,8 +778,7 @@ static int vfio_pci_get_irq_count(struct vfio_pci_core_device *vdev, int irq_typ
>  			return (flags & PCI_MSIX_FLAGS_QSIZE) + 1;
>  		}
>  	} else if (irq_type == VFIO_PCI_ERR_IRQ_INDEX) {
> -		if (pci_is_pcie(vdev->pdev))
> -			return 1;
> +		return 1;
>  	} else if (irq_type == VFIO_PCI_REQ_IRQ_INDEX) {
>  		return 1;
>  	}
> @@ -1155,11 +1154,8 @@ static int vfio_pci_ioctl_get_irq_info(struct vfio_pci_core_device *vdev,
>  	switch (info.index) {
>  	case VFIO_PCI_INTX_IRQ_INDEX ... VFIO_PCI_MSIX_IRQ_INDEX:
>  	case VFIO_PCI_REQ_IRQ_INDEX:
> -		break;
>  	case VFIO_PCI_ERR_IRQ_INDEX:
> -		if (pci_is_pcie(vdev->pdev))
> -			break;
> -		fallthrough;
> +		break;
>  	default:
>  		return -EINVAL;
>  	}
> diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c
> index c76e753b3cec..b6cedaf0bcca 100644
> --- a/drivers/vfio/pci/vfio_pci_intrs.c
> +++ b/drivers/vfio/pci/vfio_pci_intrs.c
> @@ -859,8 +859,7 @@ int vfio_pci_set_irqs_ioctl(struct vfio_pci_core_device *vdev, uint32_t flags,
>  	case VFIO_PCI_ERR_IRQ_INDEX:
>  		switch (flags & VFIO_IRQ_SET_ACTION_TYPE_MASK) {
>  		case VFIO_IRQ_SET_ACTION_TRIGGER:
> -			if (pci_is_pcie(vdev->pdev))
> -				func = vfio_pci_set_err_trigger;
> +			func = vfio_pci_set_err_trigger;
>  			break;
>  		}
>  		break;

Apart from the nit on the commit message this looks good to me. Thanks!
Feel free to add my:

Reviewed-by: Niklas Schnelle <schnelle@linux.ibm.com>

Re: [PATCH v8 9/9] vfio: Remove the pcie check for VFIO_PCI_ERR_IRQ_INDEX

Posted by Julian Ruess 1 week, 5 days ago

On Thu Jan 22, 2026 at 8:44 PM CET, Farhan Ali wrote:
> We are configuring the error signaling on the vast majority of devices and
> it's extremely rare that it fires anyway. This allows userspace to be
> notified on errors for legacy PCI devices. The Internal Shared Memory (ISM)
> device on s390x is one such device. For PCI devices on IBM s390x error
> recovery involves platform firmware and notification to operating system
> is done by architecture specific way. So the ISM device can still be
> recovered when notified of an error.
>
> Signed-off-by: Farhan Ali <alifm@linux.ibm.com>
> ---
>  drivers/vfio/pci/vfio_pci_core.c  | 8 ++------
>  drivers/vfio/pci/vfio_pci_intrs.c | 3 +--
>  2 files changed, 3 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
> index c92c6c512b24..9d44df9e21db 100644
> --- a/drivers/vfio/pci/vfio_pci_core.c
> +++ b/drivers/vfio/pci/vfio_pci_core.c
> @@ -778,8 +778,7 @@ static int vfio_pci_get_irq_count(struct vfio_pci_core_device *vdev, int irq_typ
>  			return (flags & PCI_MSIX_FLAGS_QSIZE) + 1;
>  		}
>  	} else if (irq_type == VFIO_PCI_ERR_IRQ_INDEX) {
> -		if (pci_is_pcie(vdev->pdev))
> -			return 1;
> +		return 1;
>  	} else if (irq_type == VFIO_PCI_REQ_IRQ_INDEX) {
>  		return 1;
>  	}
> @@ -1155,11 +1154,8 @@ static int vfio_pci_ioctl_get_irq_info(struct vfio_pci_core_device *vdev,
>  	switch (info.index) {
>  	case VFIO_PCI_INTX_IRQ_INDEX ... VFIO_PCI_MSIX_IRQ_INDEX:
>  	case VFIO_PCI_REQ_IRQ_INDEX:
> -		break;
>  	case VFIO_PCI_ERR_IRQ_INDEX:
> -		if (pci_is_pcie(vdev->pdev))
> -			break;
> -		fallthrough;
> +		break;
>  	default:
>  		return -EINVAL;
>  	}
> diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c
> index c76e753b3cec..b6cedaf0bcca 100644
> --- a/drivers/vfio/pci/vfio_pci_intrs.c
> +++ b/drivers/vfio/pci/vfio_pci_intrs.c
> @@ -859,8 +859,7 @@ int vfio_pci_set_irqs_ioctl(struct vfio_pci_core_device *vdev, uint32_t flags,
>  	case VFIO_PCI_ERR_IRQ_INDEX:
>  		switch (flags & VFIO_IRQ_SET_ACTION_TYPE_MASK) {
>  		case VFIO_IRQ_SET_ACTION_TRIGGER:
> -			if (pci_is_pcie(vdev->pdev))
> -				func = vfio_pci_set_err_trigger;
> +			func = vfio_pci_set_err_trigger;
>  			break;
>  		}
>  		break;

Feel free to add my
Reviewed-by: Julian Ruess <julianr@linux.ibm.com>

Thanks,
Julian

Re: [PATCH v8 9/9] vfio: Remove the pcie check for VFIO_PCI_ERR_IRQ_INDEX

Posted by Julian Ruess 1 week, 6 days ago

On Thu Jan 22, 2026 at 8:44 PM CET, Farhan Ali wrote:
> We are configuring the error signaling on the vast majority of devices and
> it's extremely rare that it fires anyway. This allows userspace to be
> notified on errors for legacy PCI devices. The Internal Shared Memory (ISM)
> device on s390x is one such device. For PCI devices on IBM s390x error
> recovery involves platform firmware and notification to operating system
> is done by architecture specific way. So the ISM device can still be
> recovered when notified of an error.
>
> Signed-off-by: Farhan Ali <alifm@linux.ibm.com>
> ---
>  drivers/vfio/pci/vfio_pci_core.c  | 8 ++------
>  drivers/vfio/pci/vfio_pci_intrs.c | 3 +--
>  2 files changed, 3 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
> index c92c6c512b24..9d44df9e21db 100644
> --- a/drivers/vfio/pci/vfio_pci_core.c
> +++ b/drivers/vfio/pci/vfio_pci_core.c
> @@ -778,8 +778,7 @@ static int vfio_pci_get_irq_count(struct vfio_pci_core_device *vdev, int irq_typ
>  			return (flags & PCI_MSIX_FLAGS_QSIZE) + 1;
>  		}
>  	} else if (irq_type == VFIO_PCI_ERR_IRQ_INDEX) {
> -		if (pci_is_pcie(vdev->pdev))

I'm wondering why this pci_is_pcie was introduced here in the first place.
Do you have any ideas?

-- snip --

Re: [PATCH v8 9/9] vfio: Remove the pcie check for VFIO_PCI_ERR_IRQ_INDEX

Posted by Farhan Ali 1 week, 6 days ago

On 1/26/2026 7:31 AM, Julian Ruess wrote:
> On Thu Jan 22, 2026 at 8:44 PM CET, Farhan Ali wrote:
>> We are configuring the error signaling on the vast majority of devices and
>> it's extremely rare that it fires anyway. This allows userspace to be
>> notified on errors for legacy PCI devices. The Internal Shared Memory (ISM)
>> device on s390x is one such device. For PCI devices on IBM s390x error
>> recovery involves platform firmware and notification to operating system
>> is done by architecture specific way. So the ISM device can still be
>> recovered when notified of an error.
>>
>> Signed-off-by: Farhan Ali <alifm@linux.ibm.com>
>> ---
>>   drivers/vfio/pci/vfio_pci_core.c  | 8 ++------
>>   drivers/vfio/pci/vfio_pci_intrs.c | 3 +--
>>   2 files changed, 3 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
>> index c92c6c512b24..9d44df9e21db 100644
>> --- a/drivers/vfio/pci/vfio_pci_core.c
>> +++ b/drivers/vfio/pci/vfio_pci_core.c
>> @@ -778,8 +778,7 @@ static int vfio_pci_get_irq_count(struct vfio_pci_core_device *vdev, int irq_typ
>>   			return (flags & PCI_MSIX_FLAGS_QSIZE) + 1;
>>   		}
>>   	} else if (irq_type == VFIO_PCI_ERR_IRQ_INDEX) {
>> -		if (pci_is_pcie(vdev->pdev))
> I'm wondering why this pci_is_pcie was introduced here in the first place.
>
> Do you have any ideas?
>
We actually don't know why it was originally added. The change was added 
with the commit dad9f89 "VFIO-AER:Vfio-pci driver changes for supporting 
AER".

But after discussion on it with Alex, we decided to remove the check 
(https://lore.kernel.org/all/ffc2fc08-2e95-4b35-840c-be8f5511340f@linux.ibm.com/) 


Thanks

Farhan

> -- snip --