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

Tian, Kevin
2021-03-04T05:59:54Z

> From: Jacob Pan <jacob.jun.pan@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@arm.com>
> wrote:
>
> > From: Jean-Philippe Brucker <jean-philippe.brucker@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@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@arm.com>
> > Cc: Joerg Roedel <joro@8bytes.org>
> > Cc: Will Deacon <will.deacon@arm.com>
> > Cc: Michael S. Tsirkin <mst@redhat.com>
> > Cc: Robin Murphy <robin.murphy@arm.com>
> > Cc: Jean-Philippe Brucker <jean-philippe@linaro.org>
> > Cc: Eric Auger <eric.auger@redhat.com>
> > Cc: Alex Williamson <alex.williamson@redhat.com>
> > Cc: Kevin Tian <kevin.tian@intel.com>
> > Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
> > Cc: Liu Yi L <yi.l.liu@intel.com>
> > Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> > Cc: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@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