Re: [Xen-devel] [PATCH V2 2/6] iommu/arm: Add ability to handle deferred probing request

[Oleksandr <olekstysh@xxxxxxxxx>]

On 15.08.19 15:54, Julien Grall wrote:
> Hi,
Hi Julien


> I noticed there was already a panic() in iommu_setup() just in case the user
> force the use of IOMMU but they were not initialized. I was half-tempted to set
> iommu_force to true for Arm, but I think this is a different issue.
>
> So here my take (not tested nor compiled).
Thank you. I will check it and come back with results.


> diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
> index 2c5d1372c0..8f94f618b0 100644
> --- a/xen/arch/arm/setup.c
> +++ b/xen/arch/arm/setup.c
> @@ -755,6 +755,7 @@ void __init start_xen(unsigned long boot_phys_offset,
>           .max_grant_frames = gnttab_dom0_frames(),
>           .max_maptrack_frames = opt_max_maptrack_frames,
>       };
> +    int rc;
>   
>       dcache_line_bytes = read_dcache_line_bytes();
>   
> @@ -890,7 +891,9 @@ void __init start_xen(unsigned long boot_phys_offset,
>   
>       setup_virt_paging();
>   
> -    iommu_setup();
> +    rc = iommu_setup();
> +    if ( !iommu_enabled && rc != -ENODEV )
> +        panic("Couldn't configure correctly all the IOMMUs.");
>   
>       do_initcalls();
>   
> diff --git a/xen/drivers/passthrough/arm/iommu.c b/xen/drivers/passthrough/arm/iommu.c
> index 2135233736..f219de9ac3 100644
> --- a/xen/drivers/passthrough/arm/iommu.c
> +++ b/xen/drivers/passthrough/arm/iommu.c
> @@ -51,6 +51,14 @@ int __init iommu_hardware_setup(void)
>           rc = device_init(np, DEVICE_IOMMU, NULL);
>           if ( !rc )
>               num_iommus++;
> +        /*
> +         * Ignore the following error codes:
> +         *   - EBADF: Indicate the current not is not an IOMMU
> +         *   - ENODEV: The IOMMU is not present or cannot be used by
> +         *     Xen.
> +         */
> +        else if ( rc != -EBADF && rc != -ENODEV )
> +            return rc;
>       }
>   
>       return ( num_iommus > 0 ) ? 0 : -ENODEV;
>
>
>
> > Cheers,
--
Regards,

Oleksandr Tyshchenko


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