Re: [PATCH 05/67] iommu/amd: Return an error if vCPU affinity is set for non-vCPU IRTE

[Sairaj Kodilkar]

On 4/5/2025 1:08 AM, Sean Christopherson wrote:
> Return -EINVAL instead of success if amd_ir_set_vcpu_affinity() is
> invoked without use_vapic; lying to KVM about whether or not the IRTE was
> configured to post IRQs is all kinds of bad.
>
> Fixes: d98de49a53e4 ("iommu/amd: Enable vAPIC interrupt remapping mode by default")
> Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
> ---
>   drivers/iommu/amd/iommu.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
> index cd5116d8c3b2..b3a01b7757ee 100644
> --- a/drivers/iommu/amd/iommu.c
> +++ b/drivers/iommu/amd/iommu.c
> @@ -3850,7 +3850,7 @@ static int amd_ir_set_vcpu_affinity(struct irq_data *data, void *vcpu_info)
>   	 * we should not modify the IRTE
>   	 */
>   	if (!dev_data || !dev_data->use_vapic)
> -		return 0;
> +		return -EINVAL;
>   

Hi Sean,
you can update following functions as well to return error when
IOMMU is using legacy interrupt mode.
1. amd_iommu_update_ga
2. amd_iommu_activate_guest_mode
3. amd_iommu_deactivate_guest_mode

Currently these functions return 0 to the kvm layer when they fail to
set the IRTE.

Regards
Sairaj Kodilkar