Re: [PATCH] iommu/amd: Fix legacy interrupt remapping for x2APIC-enabled system

[Suravee Suthikulpanit]

Ping.

Thanks,
Suravee

On 4/22/20 8:30 PM, Suravee Suthikulpanit wrote:
> Currently, system fails to boot because the legacy interrupt remapping
> mode does not enable 128-bit IRTE (GA), which is required for x2APIC
> support.
>
> Fix by using AMD_IOMMU_GUEST_IR_LEGACY_GA mode when booting with
> kernel option amd_iommu_intr=legacy instead. The initialization
> logic will check GASup and automatically fallback to using
> AMD_IOMMU_GUEST_IR_LEGACY if GA mode is not supported.
>
> Fixes: 3928aa3f5775 ("iommu/amd: Detect and enable guest vAPIC support")
> Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>
> ---
>   drivers/iommu/amd_iommu_init.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c
> index 6be3853..2b9a67e 100644
> --- a/drivers/iommu/amd_iommu_init.c
> +++ b/drivers/iommu/amd_iommu_init.c
> @@ -2936,7 +2936,7 @@ static int __init parse_amd_iommu_intr(char *str)
>   {
>   	for (; *str; ++str) {
>   		if (strncmp(str, "legacy", 6) == 0) {
> -			amd_iommu_guest_ir = AMD_IOMMU_GUEST_IR_LEGACY;
> +			amd_iommu_guest_ir = AMD_IOMMU_GUEST_IR_LEGACY_GA;
>   			break;
>   		}
>   		if (strncmp(str, "vapic", 5) == 0) {