RE: [PATCH v6 3/8] iommu/vt-d: Add helper for nested domain allocation

[Liu, Yi L]

> From: Baolu Lu <baolu.lu@xxxxxxxxxxxxxxx>
> Sent: Friday, October 20, 2023 7:49 PM
> 
> On 2023/10/20 17:32, Yi Liu wrote:
> > From: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> >
> > This adds helper for accepting user parameters and allocate a nested
> > domain.
> >
> > Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>
> > Signed-off-by: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
> > Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> > Signed-off-by: Yi Liu <yi.l.liu@xxxxxxxxx>
> > ---
> >   drivers/iommu/intel/Makefile |  2 +-
> >   drivers/iommu/intel/iommu.h  |  2 ++
> >   drivers/iommu/intel/nested.c | 55 ++++++++++++++++++++++++++++++++++++
> >   3 files changed, 58 insertions(+), 1 deletion(-)
> >   create mode 100644 drivers/iommu/intel/nested.c
> >
> > diff --git a/drivers/iommu/intel/Makefile b/drivers/iommu/intel/Makefile
> > index 7af3b8a4f2a0..5dabf081a779 100644
> > --- a/drivers/iommu/intel/Makefile
> > +++ b/drivers/iommu/intel/Makefile
> > @@ -1,6 +1,6 @@
> >   # SPDX-License-Identifier: GPL-2.0
> >   obj-$(CONFIG_DMAR_TABLE) += dmar.o
> > -obj-$(CONFIG_INTEL_IOMMU) += iommu.o pasid.o
> > +obj-$(CONFIG_INTEL_IOMMU) += iommu.o pasid.o nested.o
> >   obj-$(CONFIG_DMAR_TABLE) += trace.o cap_audit.o
> >   obj-$(CONFIG_DMAR_PERF) += perf.o
> >   obj-$(CONFIG_INTEL_IOMMU_DEBUGFS) += debugfs.o
> > diff --git a/drivers/iommu/intel/iommu.h b/drivers/iommu/intel/iommu.h
> > index a91077a063ee..ff55184456dd 100644
> > --- a/drivers/iommu/intel/iommu.h
> > +++ b/drivers/iommu/intel/iommu.h
> > @@ -866,6 +866,8 @@ void *alloc_pgtable_page(int node, gfp_t gfp);
> >   void free_pgtable_page(void *vaddr);
> >   void iommu_flush_write_buffer(struct intel_iommu *iommu);
> >   struct intel_iommu *device_to_iommu(struct device *dev, u8 *bus, u8 *devfn);
> > +struct iommu_domain *intel_nested_domain_alloc(struct iommu_domain
> *s2_domain,
> > +					       const struct iommu_user_data *user_data);
> >
> >   #ifdef CONFIG_INTEL_IOMMU_SVM
> >   void intel_svm_check(struct intel_iommu *iommu);
> > diff --git a/drivers/iommu/intel/nested.c b/drivers/iommu/intel/nested.c
> > new file mode 100644
> > index 000000000000..5a2920a98e47
> > --- /dev/null
> > +++ b/drivers/iommu/intel/nested.c
> > @@ -0,0 +1,55 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * nested.c - nested mode translation support
> > + *
> > + * Copyright (C) 2023 Intel Corporation
> > + *
> > + * Author: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> > + *         Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
> > + *         Yi Liu <yi.l.liu@xxxxxxxxx>
> > + */
> > +
> > +#define pr_fmt(fmt)	"DMAR: " fmt
> > +
> > +#include <linux/iommu.h>
> > +
> > +#include "iommu.h"
> > +
> > +static void intel_nested_domain_free(struct iommu_domain *domain)
> > +{
> > +	kfree(to_dmar_domain(domain));
> > +}
> > +
> > +static const struct iommu_domain_ops intel_nested_domain_ops = {
> > +	.free			= intel_nested_domain_free,
> > +};
> > +
> > +struct iommu_domain *intel_nested_domain_alloc(struct iommu_domain
> *s2_domain,
> > +					       const struct iommu_user_data *user_data)
> > +{
> > +	struct iommu_hwpt_vtd_s1 vtd;
> > +	struct dmar_domain *domain;
> > +	int ret;
> > +
> > +	ret = iommu_copy_struct_from_user(&vtd, user_data,
> > +					  IOMMU_HWPT_DATA_VTD_S1, __reserved);
> > +	if (ret)
> > +		return ERR_PTR(ret);
> > +
> > +	domain = kzalloc(sizeof(*domain), GFP_KERNEL_ACCOUNT);
> > +	if (!domain)
> > +		return NULL;
> 
> 	return ERR_PTR(-ENOMEM);
> ?

Yes, good catch!

> > +
> > +	domain->use_first_level = true;
> > +	domain->s2_domain = to_dmar_domain(s2_domain);
> > +	domain->s1_pgtbl = vtd.pgtbl_addr;
> > +	domain->s1_cfg = vtd;
> > +	domain->domain.ops = &intel_nested_domain_ops;
> > +	domain->domain.type = IOMMU_DOMAIN_NESTED;
> > +	INIT_LIST_HEAD(&domain->devices);
> > +	INIT_LIST_HEAD(&domain->dev_pasids);
> > +	spin_lock_init(&domain->lock);
> > +	xa_init(&domain->iommu_array);
> > +
> > +	return &domain->domain;
> > +}
> 
> Best regards,
> baolu