RE: [PATCH v3 3/3] iommu/vt-d: Fix ineffective devTLB invalidation for subdevices

From: Liu, Yi L
Date: Tue Jan 05 2021 - 00:51:31 EST


Hi Baolu,

> From: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> Sent: Tuesday, December 29, 2020 4:42 PM
>
> Hi Yi,
>
> On 2020/12/29 11:25, Liu Yi L wrote:
> > iommu_flush_dev_iotlb() is called to invalidate caches on device. It only
> > loops the devices which are full-attached to the domain. For sub-devices,
> > this is ineffective. This results in invalid caching entries left on the
> > device. Fix it by adding loop for subdevices as well. Also, the domain->
> > has_iotlb_device needs to be updated when attaching to subdevices.
> >
> > Fixes: 67b8e02b5e761 ("iommu/vt-d: Aux-domain specific domain
> attach/detach")
> > Signed-off-by: Liu Yi L <yi.l.liu@xxxxxxxxx>
> > ---
> > drivers/iommu/intel/iommu.c | 53 ++++++++++++++++++++++++++---------
> --
> > 1 file changed, 37 insertions(+), 16 deletions(-)
> >
> > diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> > index d7720a836268..d48a60b61ba6 100644
> > --- a/drivers/iommu/intel/iommu.c
> > +++ b/drivers/iommu/intel/iommu.c
> > @@ -719,6 +719,8 @@ static int domain_update_device_node(struct
> dmar_domain *domain)
> > return nid;
> > }
> >
> > +static void domain_update_iotlb(struct dmar_domain *domain);
> > +
> > /* Some capabilities may be different across iommus */
> > static void domain_update_iommu_cap(struct dmar_domain *domain)
> > {
> > @@ -744,6 +746,8 @@ static void domain_update_iommu_cap(struct
> dmar_domain *domain)
> > domain->domain.geometry.aperture_end =
> __DOMAIN_MAX_ADDR(domain->gaw - 1);
> > else
> > domain->domain.geometry.aperture_end =
> __DOMAIN_MAX_ADDR(domain->gaw);
> > +
> > + domain_update_iotlb(domain);
> > }
> >
> > struct context_entry *iommu_context_addr(struct intel_iommu *iommu,
> u8 bus,
> > @@ -1464,17 +1468,22 @@ static void domain_update_iotlb(struct
> dmar_domain *domain)
> >
> > assert_spin_locked(&device_domain_lock);
> >
> > - list_for_each_entry(info, &domain->devices, link) {
> > - struct pci_dev *pdev;
> > -
> > - if (!info->dev || !dev_is_pci(info->dev))
> > - continue;
> > -
> > - pdev = to_pci_dev(info->dev);
> > - if (pdev->ats_enabled) {
> > + list_for_each_entry(info, &domain->devices, link)
> > + if (info && info->ats_enabled) {
> > has_iotlb_device = true;
> > break;
> > }
> > +
> > + if (!has_iotlb_device) {
> > + struct subdev_domain_info *sinfo;
> > +
> > + list_for_each_entry(sinfo, &domain->subdevices,
> link_domain) {
> > + info = get_domain_info(sinfo->pdev);
> > + if (info && info->ats_enabled) {
> > + has_iotlb_device = true;
> > + break;
> > + }
> > + }
> > }
> >
> > domain->has_iotlb_device = has_iotlb_device;
> > @@ -1555,25 +1564,37 @@ static void iommu_disable_dev_iotlb(struct
> device_domain_info *info)
> > #endif
> > }
> >
> > +static void __iommu_flush_dev_iotlb(struct device_domain_info *info,
> > + u64 addr, unsigned int mask)
> > +{
> > + u16 sid, qdep;
> > +
> > + if (!info || !info->ats_enabled)
> > + return;
> > +
> > + sid = info->bus << 8 | info->devfn;
> > + qdep = info->ats_qdep;
> > + qi_flush_dev_iotlb(info->iommu, sid, info->pfsid,
> > + qdep, addr, mask);
> > +}
> > +
> > static void iommu_flush_dev_iotlb(struct dmar_domain *domain,
> > u64 addr, unsigned mask)
> > {
> > - u16 sid, qdep;
> > unsigned long flags;
> > struct device_domain_info *info;
> > + struct subdev_domain_info *sinfo;
> >
> > if (!domain->has_iotlb_device)
> > return;
> >
> > spin_lock_irqsave(&device_domain_lock, flags);
> > - list_for_each_entry(info, &domain->devices, link) {
> > - if (!info->ats_enabled)
> > - continue;
> > + list_for_each_entry(info, &domain->devices, link)
> > + __iommu_flush_dev_iotlb(info, addr, mask);
> >
> > - sid = info->bus << 8 | info->devfn;
> > - qdep = info->ats_qdep;
> > - qi_flush_dev_iotlb(info->iommu, sid, info->pfsid,
> > - qdep, addr, mask);
> > + list_for_each_entry(sinfo, &domain->subdevices, link_domain) {
> > + __iommu_flush_dev_iotlb(get_domain_info(sinfo->pdev),
> > + addr, mask);
> > }
>
> Nit:
> list_for_each_entry(sinfo, &domain->subdevices, link_domain) {
> info = get_domain_info(sinfo->pdev);
> __iommu_flush_dev_iotlb(info, addr, mask);
> }

you are right. this should be better.

> Others look good to me.
>
> Acked-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
>
> Best regards,
> baolu

Regards,
Yi Liu

> > spin_unlock_irqrestore(&device_domain_lock, flags);
> > }
> >