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[PATCH v1 05/14] iommu/arm-smmu-v3: Remove ARM_SMMU_DOMAIN_NESTED

Nicolin Chen posted 14 patches 2 years, 11 months ago
There is a newer version of this series
[PATCH v1 05/14] iommu/arm-smmu-v3: Remove ARM_SMMU_DOMAIN_NESTED
Posted by Nicolin Chen 2 years, 11 months ago 
IOMMUFD designs two iommu_domain pointers to represent two stages. The S1
iommu_domain (IOMMU_DOMAIN_NESTED type) represents the Context Descriptor
table in the user space. The S2 iommu_domain (IOMMU_DOMAIN_UNMANAGED type)
represents the translation table in the kernel, owned by a hypervisor.

So there comes to no use case of the ARM_SMMU_DOMAIN_NESTED. Drop it, and
use the type IOMMU_DOMAIN_NESTED instead.

Also drop the unused arm_smmu_enable_nesting(). One following patche will
configure the correct smmu_domain->stage.

Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 18 ------------------
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h |  1 -
 2 files changed, 19 deletions(-)

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index c1aac695ae0d..c5616145e2a3 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -1279,7 +1279,6 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_master *master, u32 sid,
 			s1_cfg = &smmu_domain->s1_cfg;
 			break;
 		case ARM_SMMU_DOMAIN_S2:
-		case ARM_SMMU_DOMAIN_NESTED:
 			s2_cfg = &smmu_domain->s2_cfg;
 			break;
 		default:
@@ -2220,7 +2219,6 @@ static int arm_smmu_domain_finalise(struct iommu_domain *domain,
 		fmt = ARM_64_LPAE_S1;
 		finalise_stage_fn = arm_smmu_domain_finalise_s1;
 		break;
-	case ARM_SMMU_DOMAIN_NESTED:
 	case ARM_SMMU_DOMAIN_S2:
 		ias = smmu->ias;
 		oas = smmu->oas;
@@ -2747,21 +2745,6 @@ static struct iommu_group *arm_smmu_device_group(struct device *dev)
 	return group;
 }
 
-static int arm_smmu_enable_nesting(struct iommu_domain *domain)
-{
-	struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
-	int ret = 0;
-
-	mutex_lock(&smmu_domain->init_mutex);
-	if (smmu_domain->smmu)
-		ret = -EPERM;
-	else
-		smmu_domain->stage = ARM_SMMU_DOMAIN_NESTED;
-	mutex_unlock(&smmu_domain->init_mutex);
-
-	return ret;
-}
-
 static int arm_smmu_of_xlate(struct device *dev, struct of_phandle_args *args)
 {
 	return iommu_fwspec_add_ids(dev, args->args, 1);
@@ -2890,7 +2873,6 @@ static struct iommu_ops arm_smmu_ops = {
 		.flush_iotlb_all	= arm_smmu_flush_iotlb_all,
 		.iotlb_sync		= arm_smmu_iotlb_sync,
 		.iova_to_phys		= arm_smmu_iova_to_phys,
-		.enable_nesting		= arm_smmu_enable_nesting,
 		.free			= arm_smmu_domain_free,
 	}
 };
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
index ba2b4562f4b2..233bfc377267 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -704,7 +704,6 @@ struct arm_smmu_master {
 enum arm_smmu_domain_stage {
 	ARM_SMMU_DOMAIN_S1 = 0,
 	ARM_SMMU_DOMAIN_S2,
-	ARM_SMMU_DOMAIN_NESTED,
 	ARM_SMMU_DOMAIN_BYPASS,
 };
 
-- 
2.39.2
Re: [PATCH v1 05/14] iommu/arm-smmu-v3: Remove ARM_SMMU_DOMAIN_NESTED
Posted by Eric Auger 2 years, 11 months ago 
Hi Nicolin,

On 3/9/23 11:53, Nicolin Chen wrote:
> IOMMUFD designs two iommu_domain pointers to represent two stages. The S1
s/designs/uses?
> iommu_domain (IOMMU_DOMAIN_NESTED type) represents the Context Descriptor
> table in the user space. The S2 iommu_domain (IOMMU_DOMAIN_UNMANAGED type)
> represents the translation table in the kernel, owned by a hypervisor.
>
> So there comes to no use case of the ARM_SMMU_DOMAIN_NESTED. Drop it, and
> use the type IOMMU_DOMAIN_NESTED instead.
last sentence may be rephrased as this patch does not use
IOMMU_DOMAIN_NESTED anywhere:
Generic IOMMU_DOMAIN_NESTED type will be used in nested SMMU
implementation instead.
>
> Also drop the unused arm_smmu_enable_nesting(). One following patche will
> configure the correct smmu_domain->stage.
>
> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
> ---
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 18 ------------------
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h |  1 -
If you go this way you may also remove it from arm/arm-smmu/arm-smmu.c.
Then if I am not wrong no other driver does implement enable_nesting cb.
Shouldn't we also remove it and fellow iommu_enable_nesting()?

Thanks

Eric
>  2 files changed, 19 deletions(-)
>
> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> index c1aac695ae0d..c5616145e2a3 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> @@ -1279,7 +1279,6 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_master *master, u32 sid,
>  			s1_cfg = &smmu_domain->s1_cfg;
>  			break;
>  		case ARM_SMMU_DOMAIN_S2:
> -		case ARM_SMMU_DOMAIN_NESTED:
>  			s2_cfg = &smmu_domain->s2_cfg;
>  			break;
>  		default:
> @@ -2220,7 +2219,6 @@ static int arm_smmu_domain_finalise(struct iommu_domain *domain,
>  		fmt = ARM_64_LPAE_S1;
>  		finalise_stage_fn = arm_smmu_domain_finalise_s1;
>  		break;
> -	case ARM_SMMU_DOMAIN_NESTED:
>  	case ARM_SMMU_DOMAIN_S2:
>  		ias = smmu->ias;
>  		oas = smmu->oas;
> @@ -2747,21 +2745,6 @@ static struct iommu_group *arm_smmu_device_group(struct device *dev)
>  	return group;
>  }
>  
> -static int arm_smmu_enable_nesting(struct iommu_domain *domain)
> -{
> -	struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
> -	int ret = 0;
> -
> -	mutex_lock(&smmu_domain->init_mutex);
> -	if (smmu_domain->smmu)
> -		ret = -EPERM;
> -	else
> -		smmu_domain->stage = ARM_SMMU_DOMAIN_NESTED;
> -	mutex_unlock(&smmu_domain->init_mutex);
> -
> -	return ret;
> -}
> -
>  static int arm_smmu_of_xlate(struct device *dev, struct of_phandle_args *args)
>  {
>  	return iommu_fwspec_add_ids(dev, args->args, 1);
> @@ -2890,7 +2873,6 @@ static struct iommu_ops arm_smmu_ops = {
>  		.flush_iotlb_all	= arm_smmu_flush_iotlb_all,
>  		.iotlb_sync		= arm_smmu_iotlb_sync,
>  		.iova_to_phys		= arm_smmu_iova_to_phys,
> -		.enable_nesting		= arm_smmu_enable_nesting,
>  		.free			= arm_smmu_domain_free,
>  	}
>  };
> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
> index ba2b4562f4b2..233bfc377267 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
> @@ -704,7 +704,6 @@ struct arm_smmu_master {
>  enum arm_smmu_domain_stage {
>  	ARM_SMMU_DOMAIN_S1 = 0,
>  	ARM_SMMU_DOMAIN_S2,
> -	ARM_SMMU_DOMAIN_NESTED,
>  	ARM_SMMU_DOMAIN_BYPASS,
>  };
>
Re: [PATCH v1 05/14] iommu/arm-smmu-v3: Remove ARM_SMMU_DOMAIN_NESTED
Posted by Nicolin Chen 2 years, 11 months ago 
On Fri, Mar 10, 2023 at 05:39:22PM +0100, Eric Auger wrote:
> External email: Use caution opening links or attachments
> 
> 
> Hi Nicolin,
> 
> On 3/9/23 11:53, Nicolin Chen wrote:
> > IOMMUFD designs two iommu_domain pointers to represent two stages. The S1
> s/designs/uses?
> > iommu_domain (IOMMU_DOMAIN_NESTED type) represents the Context Descriptor
> > table in the user space. The S2 iommu_domain (IOMMU_DOMAIN_UNMANAGED type)
> > represents the translation table in the kernel, owned by a hypervisor.
> >
> > So there comes to no use case of the ARM_SMMU_DOMAIN_NESTED. Drop it, and
> > use the type IOMMU_DOMAIN_NESTED instead.
> last sentence may be rephrased as this patch does not use
> IOMMU_DOMAIN_NESTED anywhere:
> Generic IOMMU_DOMAIN_NESTED type will be used in nested SMMU
> implementation instead.
> >
> > Also drop the unused arm_smmu_enable_nesting(). One following patche will
> > configure the correct smmu_domain->stage.
> >
> > Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
> > ---
> >  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 18 ------------------
> >  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h |  1 -
> If you go this way you may also remove it from arm/arm-smmu/arm-smmu.c.
> Then if I am not wrong no other driver does implement enable_nesting cb.
> Shouldn't we also remove it and fellow iommu_enable_nesting()?

We had a small discussion before this community version, where
Robin mentioned that we can remove that too after the nesting
series gets merged. Yet, I didn't want to touch the v2 driver
with this series since there's no nesting change adding to it.

And a few month ago, Jason had a patch removing everything of
that API from the top. Perhaps that one can be resent after
all?

Thanks
Nic
Re: [PATCH v1 05/14] iommu/arm-smmu-v3: Remove ARM_SMMU_DOMAIN_NESTED
Posted by Jason Gunthorpe 2 years, 11 months ago 
On Fri, Mar 10, 2023 at 05:39:22PM +0100, Eric Auger wrote:

> > Also drop the unused arm_smmu_enable_nesting(). One following patche will
> > configure the correct smmu_domain->stage.
> >
> > Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
> > ---
> >  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 18 ------------------
> >  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h |  1 -
> If you go this way you may also remove it from arm/arm-smmu/arm-smmu.c.
> Then if I am not wrong no other driver does implement enable_nesting cb.
> Shouldn't we also remove it and fellow iommu_enable_nesting()?

Yes, lets just put this patch in the series please:

https://lore.kernel.org/kvm/0-v1-0093c9b0e345+19-vfio_no_nesting_jgg@nvidia.com/

Jason
Re: [PATCH v1 05/14] iommu/arm-smmu-v3: Remove ARM_SMMU_DOMAIN_NESTED
Posted by Nicolin Chen 2 years, 11 months ago 
On Fri, Mar 10, 2023 at 01:05:36PM -0400, Jason Gunthorpe wrote:
> On Fri, Mar 10, 2023 at 05:39:22PM +0100, Eric Auger wrote:
> 
> > > Also drop the unused arm_smmu_enable_nesting(). One following patche will
> > > configure the correct smmu_domain->stage.
> > >
> > > Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
> > > ---
> > >  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 18 ------------------
> > >  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h |  1 -
> > If you go this way you may also remove it from arm/arm-smmu/arm-smmu.c.
> > Then if I am not wrong no other driver does implement enable_nesting cb.
> > Shouldn't we also remove it and fellow iommu_enable_nesting()?
> 
> Yes, lets just put this patch in the series please:
> 
> https://lore.kernel.org/kvm/0-v1-0093c9b0e345+19-vfio_no_nesting_jgg@nvidia.com/

Oh. Didn't read this before sending my previous reply..

Will do that.

Nic

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