Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1629650

Re: [PATCH] iommu/arm-smmu: Return IOVA in iova_to_phys when SMMU is bypassed

Show all headers | View raw

On Mon, Apr 17, 2017 at 05:27:26PM +0530, sunil.kovvuri@gmail.com wrote:
> From: Sunil Goutham <sgoutham@cavium.com>
> 
> For software initiated address translation, when domain type is
> IOMMU_DOMAIN_IDENTITY i.e SMMU is bypassed, mimic HW behavior
> i.e return the same IOVA as translated address.
> 
> This patch is an extension to Will Deacon's patchset 
> "Implement SMMU passthrough using the default domain".

Are you actually seeing an issue here? If so, why isn't SMMUv3 affected too?

> Signed-off-by: Sunil Goutham <sgoutham@cavium.com>
> ---
>  drivers/iommu/arm-smmu.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
> index 41afb07..2f4a130 100644
> --- a/drivers/iommu/arm-smmu.c
> +++ b/drivers/iommu/arm-smmu.c
> @@ -1405,6 +1405,9 @@ static phys_addr_t arm_smmu_iova_to_phys(struct iommu_domain *domain,
>  	struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
>  	struct io_pgtable_ops *ops= smmu_domain->pgtbl_ops;
>  
> +	if (domain->type == IOMMU_DOMAIN_IDENTITY)
> +		return iova;
> +
>  	if (!ops)
>  		return 0;

I'd have thought ops would be NULL, since arm_smmu_init_domain_context
doesn't allocate them for an identity domain.

I don't understand this patch. Please can you explain the problem more
clearly?

Will

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH] iommu/arm-smmu: Return IOVA in iova_to_phys when SMMU is bypassed sunil.kovvuri@gmail.com - 2017-04-17 14:00 +0200
  Re: [PATCH] iommu/arm-smmu: Return IOVA in iova_to_phys when SMMU is bypassed Sunil Kovvuri <sunil.kovvuri@gmail.com> - 2017-04-20 06:30 +0200
  Re: [PATCH] iommu/arm-smmu: Return IOVA in iova_to_phys when SMMU is  bypassed Will Deacon <will.deacon@arm.com> - 2017-04-24 16:50 +0200
    Re: [PATCH] iommu/arm-smmu: Return IOVA in iova_to_phys when SMMU is bypassed Sunil Kovvuri <sunil.kovvuri@gmail.com> - 2017-04-24 18:00 +0200
      Re: [PATCH] iommu/arm-smmu: Return IOVA in iova_to_phys when SMMU is  bypassed Will Deacon <will.deacon@arm.com> - 2017-04-24 18:10 +0200
        Re: [PATCH] iommu/arm-smmu: Return IOVA in iova_to_phys when SMMU is bypassed Sunil Kovvuri <sunil.kovvuri@gmail.com> - 2017-04-24 18:30 +0200

csiph-web