[PATCH RFC v1 12/15] iommu/virtio: Add support for INVALIDATE request

[Tian, Kevin]

> From: Jacob Pan <jacob.jun.pan at linux.intel.com>
> Sent: Thursday, March 4, 2021 2:29 AM
> 
> Hi Vivek,
> 
> On Fri, 15 Jan 2021 17:43:39 +0530, Vivek Gautam <vivek.gautam at arm.com>
> wrote:
> 
> > From: Jean-Philippe Brucker <jean-philippe.brucker at arm.com>
> >
> > Add support for tlb invalidation ops that can send invalidation
> > requests to back-end virtio-iommu when stage-1 page tables are
> > supported.
> >
> Just curious if it possible to reuse the iommu uapi for invalidation and others.
> When we started out designing the iommu uapi, the intention was to support
> both emulated and virtio iommu.

IIUC this patch is about the protocol between virtio-iommu frontend and backend.
After the virtio-iommu backend receives invalidation ops, it then needs to
forward the request to the host IOMMU driver through the existing iommu
uapi that you referred to, as a emulated VT-d or SMMU would do.

Thanks
Kevin

> 
> > Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker at arm.com>
> > [Vivek: Refactoring the iommu_flush_ops, and adding only one pasid sync
> >         op that's needed with current iommu-pasid-table infrastructure.
> > 	Also updating uapi defines as required by latest changes]
> > Signed-off-by: Vivek Gautam <vivek.gautam at arm.com>
> > Cc: Joerg Roedel <joro at 8bytes.org>
> > Cc: Will Deacon <will.deacon at arm.com>
> > Cc: Michael S. Tsirkin <mst at redhat.com>
> > Cc: Robin Murphy <robin.murphy at arm.com>
> > Cc: Jean-Philippe Brucker <jean-philippe at linaro.org>
> > Cc: Eric Auger <eric.auger at redhat.com>
> > Cc: Alex Williamson <alex.williamson at redhat.com>
> > Cc: Kevin Tian <kevin.tian at intel.com>
> > Cc: Jacob Pan <jacob.jun.pan at linux.intel.com>
> > Cc: Liu Yi L <yi.l.liu at intel.com>
> > Cc: Lorenzo Pieralisi <lorenzo.pieralisi at arm.com>
> > Cc: Shameerali Kolothum Thodi <shameerali.kolothum.thodi at huawei.com>
> > ---
> >  drivers/iommu/virtio-iommu.c | 95
> ++++++++++++++++++++++++++++++++++++
> >  1 file changed, 95 insertions(+)
> >
> > diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c
> > index ae5dfd3f8269..004ea94e3731 100644
> > --- a/drivers/iommu/virtio-iommu.c
> > +++ b/drivers/iommu/virtio-iommu.c
> > @@ -13,6 +13,7 @@
> >  #include <linux/freezer.h>
> >  #include <linux/interval_tree.h>
> >  #include <linux/iommu.h>
> > +#include <linux/io-pgtable.h>
> >  #include <linux/module.h>
> >  #include <linux/of_iommu.h>
> >  #include <linux/of_platform.h>
> > @@ -63,6 +64,8 @@ struct viommu_mapping {
> >  };
> >
> >  struct viommu_mm {
> > +	int				pasid;
> > +	u64				archid;
> >  	struct io_pgtable_ops		*ops;
> >  	struct viommu_domain		*domain;
> >  };
> > @@ -692,6 +695,98 @@ static void viommu_event_handler(struct
> virtqueue
> > *vq) virtqueue_kick(vq);
> >  }
> >
> > +/* PASID and pgtable APIs */
> > +
> > +static void __viommu_flush_pasid_tlb_all(struct viommu_domain
> *vdomain,
> > +					 int pasid, u64 arch_id, int
> > type) +{
> > +	struct virtio_iommu_req_invalidate req = {
> > +		.head.type	= VIRTIO_IOMMU_T_INVALIDATE,
> > +		.inv_gran	=
> > cpu_to_le32(VIRTIO_IOMMU_INVAL_G_PASID),
> > +		.flags		=
> > cpu_to_le32(VIRTIO_IOMMU_INVAL_F_PASID),
> > +		.inv_type	= cpu_to_le32(type),
> > +
> > +		.domain		= cpu_to_le32(vdomain->id),
> > +		.pasid		= cpu_to_le32(pasid),
> > +		.archid		= cpu_to_le64(arch_id),
> > +	};
> > +
> > +	if (viommu_send_req_sync(vdomain->viommu, &req, sizeof(req)))
> > +		pr_debug("could not send invalidate request\n");
> > +}
> > +
> > +static void viommu_flush_tlb_add(struct iommu_iotlb_gather *gather,
> > +				 unsigned long iova, size_t granule,
> > +				 void *cookie)
> > +{
> > +	struct viommu_mm *viommu_mm = cookie;
> > +	struct viommu_domain *vdomain = viommu_mm->domain;
> > +	struct iommu_domain *domain = &vdomain->domain;
> > +
> > +	iommu_iotlb_gather_add_page(domain, gather, iova, granule);
> > +}
> > +
> > +static void viommu_flush_tlb_walk(unsigned long iova, size_t size,
> > +				  size_t granule, void *cookie)
> > +{
> > +	struct viommu_mm *viommu_mm = cookie;
> > +	struct viommu_domain *vdomain = viommu_mm->domain;
> > +	struct virtio_iommu_req_invalidate req = {
> > +		.head.type	= VIRTIO_IOMMU_T_INVALIDATE,
> > +		.inv_gran	= cpu_to_le32(VIRTIO_IOMMU_INVAL_G_VA),
> > +		.inv_type	=
> cpu_to_le32(VIRTIO_IOMMU_INV_T_IOTLB),
> > +		.flags		=
> > cpu_to_le32(VIRTIO_IOMMU_INVAL_F_ARCHID), +
> > +		.domain		= cpu_to_le32(vdomain->id),
> > +		.pasid		= cpu_to_le32(viommu_mm->pasid),
> > +		.archid		= cpu_to_le64(viommu_mm->archid),
> > +		.virt_start	= cpu_to_le64(iova),
> > +		.nr_pages	= cpu_to_le64(size / granule),
> > +		.granule	= ilog2(granule),
> > +	};
> > +
> > +	if (viommu_add_req(vdomain->viommu, &req, sizeof(req)))
> > +		pr_debug("could not add invalidate request\n");
> > +}
> > +
> > +static void viommu_flush_tlb_all(void *cookie)
> > +{
> > +	struct viommu_mm *viommu_mm = cookie;
> > +
> > +	if (!viommu_mm->archid)
> > +		return;
> > +
> > +	__viommu_flush_pasid_tlb_all(viommu_mm->domain,
> viommu_mm->pasid,
> > +				     viommu_mm->archid,
> > +				     VIRTIO_IOMMU_INV_T_IOTLB);
> > +}
> > +
> > +static struct iommu_flush_ops viommu_flush_ops = {
> > +	.tlb_flush_all		= viommu_flush_tlb_all,
> > +	.tlb_flush_walk		= viommu_flush_tlb_walk,
> > +	.tlb_add_page		= viommu_flush_tlb_add,
> > +};
> > +
> > +static void viommu_flush_pasid(void *cookie, int pasid, bool leaf)
> > +{
> > +	struct viommu_domain *vdomain = cookie;
> > +	struct virtio_iommu_req_invalidate req = {
> > +		.head.type	= VIRTIO_IOMMU_T_INVALIDATE,
> > +		.inv_gran	=
> > cpu_to_le32(VIRTIO_IOMMU_INVAL_G_PASID),
> > +		.inv_type	=
> cpu_to_le32(VIRTIO_IOMMU_INV_T_PASID),
> > +		.flags		=
> > cpu_to_le32(VIRTIO_IOMMU_INVAL_F_PASID), +
> > +		.domain		= cpu_to_le32(vdomain->id),
> > +		.pasid		= cpu_to_le32(pasid),
> > +	};
> > +
> > +	if (leaf)
> > +		req.flags	|=
> > cpu_to_le32(VIRTIO_IOMMU_INVAL_F_LEAF); +
> > +	if (viommu_send_req_sync(vdomain->viommu, &req, sizeof(req)))
> > +		pr_debug("could not send invalidate request\n");
> > +}
> > +
> >  /* IOMMU API */
> >
> >  static struct iommu_domain *viommu_domain_alloc(unsigned type)
> 
> 
> Thanks,
> 
> Jacob