Re: [PATCH v8 07/15] iommu/amd: Setup GCR3 table in advance if domain is SVA capable

[Klara Modin <klarasmodin@gmail.com>]

On 2024-05-06 09:31, Vasant Hegde wrote:
> Hi Klara,
> 

> Thanks for the report.
> 
> Looking into the attached dmesg :
> 
> 2024-04-29T10:35:05+02:00 soda.int.kasm.eu kernel: AMD-Vi: Using global IVHD
> EFR:0x0, EFR2:0x0
> 
> --> This means BIOS didn't setup the EFR flags in ACPI IVRS table (its BIOS issue).
> 
> Commit 8e0179733172 (iommu/amd: Enable Guest Translation before registering
> devices) changed GT feature enablement in control register.
> 
> Now it tries to enable CONTROL[GT] flag before reading IOMMU feature register
> (late_iommu_features_init()).
> 
> In attach device path, it assumed GT is supported (based on IOMMU EFR register
> value) and enabled DTE[GV]. Hence we hit ILLEGAL_DEV_TABLE_ENTRY error.
> 
> 
> Can you please try below fix?
> 
> 
> -Vasant
> 
> ---
> 
> 
> diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c
> index fd3e76e43699..b292181995b7 100644
> --- a/drivers/iommu/amd/init.c
> +++ b/drivers/iommu/amd/init.c
> @@ -2046,6 +2046,8 @@ static int __init iommu_init_pci(struct amd_iommu *iommu)
>   			amd_iommu_max_glx_val = glxval;
>   		else
>   			amd_iommu_max_glx_val = min(amd_iommu_max_glx_val, glxval);
> +
> +		iommu_enable_gt(iommu);
>   	}
> 
>   	if (check_feature(FEATURE_PPR) && amd_iommu_alloc_ppr_log(iommu))
> @@ -2732,7 +2734,6 @@ static void early_enable_iommu(struct amd_iommu *iommu)
>   	iommu_enable_command_buffer(iommu);
>   	iommu_enable_event_buffer(iommu);
>   	iommu_set_exclusion_range(iommu);
> -	iommu_enable_gt(iommu);
>   	iommu_enable_ga(iommu);
>   	iommu_enable_xt(iommu);
>   	iommu_enable_irtcachedis(iommu);
> @@ -2789,7 +2790,6 @@ static void early_enable_iommus(void)
>   			iommu_disable_irtcachedis(iommu);
>   			iommu_enable_command_buffer(iommu);
>   			iommu_enable_event_buffer(iommu);
> -			iommu_enable_gt(iommu);
>   			iommu_enable_ga(iommu);
>   			iommu_enable_xt(iommu);
>   			iommu_enable_irtcachedis(iommu);

This fixes the issue for me.

Thanks,
Tested-by: Klara Modin <klarasmodin@gmail.com>