Re: [Qemu-devel] [PATCH] hw/arm/smmuv3: fix smmu emulation when guest smmu is in passthrough mode

[Peter Maydell <peter.maydell@linaro.org>]

On 7 June 2018 at 14:38, Jia He <hejianet@gmail.com> wrote:
> There is an exception when I passes iommu.passthrough=1 to guest's
> kernel boot parameter(host QDF2400 kernel 4.17, guest kernel 4.14).
> The guest will be hang when booting up.
>
> When guest smmu is in passthrough mode, entry.perm will not be assigned
> to flag in smmuv3_translate. It seems not be correct.
>
> After this patch, I have tested in 4 cases and all passed.
> host smmu on/passthrough + guest smmu on/passthrough
>
> Signed-off-by: jia.he@hxt-semitech.com
> ---
>  hw/arm/smmuv3.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/hw/arm/smmuv3.c b/hw/arm/smmuv3.c
> index 42dc521..5c46102 100644
> --- a/hw/arm/smmuv3.c
> +++ b/hw/arm/smmuv3.c
> @@ -560,6 +560,12 @@ static IOMMUTLBEntry smmuv3_translate(IOMMUMemoryRegion *mr, hwaddr addr,
>      }
>
>      ret = smmuv3_decode_config(mr, &cfg, &event);
> +
> +    if (cfg.bypassed) {
> +        ret = 0;
> +        goto out;
> +    }
> +
>      if (ret) {
>          goto out;
>      }
> --
> 1.8.3.1
>

Ccing Eric as the author of the smmuv3 code.

thanks
-- PMM