diff mbox series

[02/39] iommu/vt-d: Remove bogus check for multi MSI-X

Message ID 20221111122013.713848846@linutronix.de
State New
Headers
Series genirq, PCI/MSI: Support for per device MSI and PCI/IMS - Part 1 cleanups |

Commit Message

Thomas Gleixner Nov. 11, 2022, 1:54 p.m. UTC 
  PCI/Multi-MSI is MSI specific and not supported for MSI-X.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 drivers/iommu/intel/irq_remapping.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

Comments

Ashok Raj Nov. 16, 2022, 3:52 p.m. UTC | #1 
On Fri, Nov 11, 2022 at 02:54:17PM +0100, Thomas Gleixner wrote:
> PCI/Multi-MSI is MSI specific and not supported for MSI-X.
> 
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> ---
>  drivers/iommu/intel/irq_remapping.c |    3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> --- a/drivers/iommu/intel/irq_remapping.c
> +++ b/drivers/iommu/intel/irq_remapping.c
> @@ -1334,8 +1334,7 @@ static int intel_irq_remapping_alloc(str
>  
>  	if (!info || !iommu)
>  		return -EINVAL;
> -	if (nr_irqs > 1 && info->type != X86_IRQ_ALLOC_TYPE_PCI_MSI &&
> -	    info->type != X86_IRQ_ALLOC_TYPE_PCI_MSIX)
> +	if (nr_irqs > 1 && info->type != X86_IRQ_ALLOC_TYPE_PCI_MSI)
>  		return -EINVAL;
>  
>  	/*
> 

This check is only making sure that when multi-msi is requested that the
type has to be either MSI/MSIX. 

Wouldn't this change return -EINVAL when type = MSIX?
Thomas Gleixner Nov. 16, 2022, 5:02 p.m. UTC | #2 
On Wed, Nov 16 2022 at 07:52, Ashok Raj wrote:
> On Fri, Nov 11, 2022 at 02:54:17PM +0100, Thomas Gleixner wrote:
>> PCI/Multi-MSI is MSI specific and not supported for MSI-X.
>> 
>> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
>> ---
>>  drivers/iommu/intel/irq_remapping.c |    3 +--
>>  1 file changed, 1 insertion(+), 2 deletions(-)
>> 
>> --- a/drivers/iommu/intel/irq_remapping.c
>> +++ b/drivers/iommu/intel/irq_remapping.c
>> @@ -1334,8 +1334,7 @@ static int intel_irq_remapping_alloc(str
>>  
>>  	if (!info || !iommu)
>>  		return -EINVAL;
>> -	if (nr_irqs > 1 && info->type != X86_IRQ_ALLOC_TYPE_PCI_MSI &&
>> -	    info->type != X86_IRQ_ALLOC_TYPE_PCI_MSIX)
>> +	if (nr_irqs > 1 && info->type != X86_IRQ_ALLOC_TYPE_PCI_MSI)
>>  		return -EINVAL;
>>  
>>  	/*
>> 
>
> This check is only making sure that when multi-msi is requested that the
> type has to be either MSI/MSIX.

MSI-X does not support multi vector allocations on a single entry.

> Wouldn't this change return -EINVAL when type = MSIX?

Rightfully so. MSIX vectors are allocated one by one. Has been that way
forever.

Thanks,

        tglx
Ashok Raj Nov. 16, 2022, 5:39 p.m. UTC | #3 
On Wed, Nov 16, 2022 at 06:02:30PM +0100, Thomas Gleixner wrote:
> On Wed, Nov 16 2022 at 07:52, Ashok Raj wrote:
> > On Fri, Nov 11, 2022 at 02:54:17PM +0100, Thomas Gleixner wrote:
> >> PCI/Multi-MSI is MSI specific and not supported for MSI-X.
> >> 
> >> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> >> ---
> >>  drivers/iommu/intel/irq_remapping.c |    3 +--
> >>  1 file changed, 1 insertion(+), 2 deletions(-)
> >> 
> >> --- a/drivers/iommu/intel/irq_remapping.c
> >> +++ b/drivers/iommu/intel/irq_remapping.c
> >> @@ -1334,8 +1334,7 @@ static int intel_irq_remapping_alloc(str
> >>  
> >>  	if (!info || !iommu)
> >>  		return -EINVAL;
> >> -	if (nr_irqs > 1 && info->type != X86_IRQ_ALLOC_TYPE_PCI_MSI &&
> >> -	    info->type != X86_IRQ_ALLOC_TYPE_PCI_MSIX)
> >> +	if (nr_irqs > 1 && info->type != X86_IRQ_ALLOC_TYPE_PCI_MSI)
> >>  		return -EINVAL;
> >>  
> >>  	/*
> >> 
> >
> > This check is only making sure that when multi-msi is requested that the
> > type has to be either MSI/MSIX.
> 
> MSI-X does not support multi vector allocations on a single entry.
> 
> > Wouldn't this change return -EINVAL when type = MSIX?
> 
> Rightfully so. MSIX vectors are allocated one by one. Has been that way
> forever.
> 

I thought why block multi-vector allocation on MSIX, but if there is no
use case makes perfect sense.

Thanks for the clarification.

Reviewed-by: Ashok Raj <ashok.raj@intel.com>
diff mbox series

Patch

--- a/drivers/iommu/intel/irq_remapping.c
+++ b/drivers/iommu/intel/irq_remapping.c
@@ -1334,8 +1334,7 @@  static int intel_irq_remapping_alloc(str
 
 	if (!info || !iommu)
 		return -EINVAL;
-	if (nr_irqs > 1 && info->type != X86_IRQ_ALLOC_TYPE_PCI_MSI &&
-	    info->type != X86_IRQ_ALLOC_TYPE_PCI_MSIX)
+	if (nr_irqs > 1 && info->type != X86_IRQ_ALLOC_TYPE_PCI_MSI)
 		return -EINVAL;
 
 	/*