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Date: Tue, 29 Dec 2020 16:38:20 +0800
From: Lu Baolu <baolu.lu@...ux.intel.com>
To: Liu Yi L <yi.l.liu@...el.com>, joro@...tes.org, will@...nel.org
Cc: baolu.lu@...ux.intel.com, kevin.tian@...el.com,
jacob.jun.pan@...ux.intel.com, ashok.raj@...el.com,
jun.j.tian@...el.com, yi.y.sun@...el.com,
iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
Xin Zeng <xin.zeng@...el.com>
Subject: Re: [PATCH v3 2/3] iommu/vt-d: Track device aux-attach with
subdevice_domain_info
Hi Yi,
On 2020/12/29 11:25, Liu Yi L wrote:
> In the existing code, loop all devices attached to a domain does not
> include sub-devices attached via iommu_aux_attach_device().
>
> This was found by when I'm working on the belwo patch, There is no
^^^^^
below
> device in the domain->devices list, thus unable to get the cap and
> ecap of iommu unit. But this domain actually has subdevice which is
> attached via aux-manner. But it is tracked by domain. This patch is
> going to fix it.
>
> https://lore.kernel.org/kvm/1599734733-6431-17-git-send-email-yi.l.liu@intel.com/
>
> And this fix goes beyond the patch above, such sub-device tracking is
> necessary for other cases. For example, flushing device_iotlb for a
> domain which has sub-devices attached by auxiliary manner.
>
> Co-developed-by: Xin Zeng <xin.zeng@...el.com>
> Signed-off-by: Xin Zeng <xin.zeng@...el.com>
> Signed-off-by: Liu Yi L <yi.l.liu@...el.com>
Others look good to me.
Fixes: 67b8e02b5e761 ("iommu/vt-d: Aux-domain specific domain
attach/detach")
Acked-by: Lu Baolu <baolu.lu@...ux.intel.com>
Best regards,
baolu
> ---
> drivers/iommu/intel/iommu.c | 95 +++++++++++++++++++++++++++----------
> include/linux/intel-iommu.h | 16 +++++--
> 2 files changed, 82 insertions(+), 29 deletions(-)
>
> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> index 788119c5b021..d7720a836268 100644
> --- a/drivers/iommu/intel/iommu.c
> +++ b/drivers/iommu/intel/iommu.c
> @@ -1877,6 +1877,7 @@ static struct dmar_domain *alloc_domain(int flags)
> domain->flags |= DOMAIN_FLAG_USE_FIRST_LEVEL;
> domain->has_iotlb_device = false;
> INIT_LIST_HEAD(&domain->devices);
> + INIT_LIST_HEAD(&domain->subdevices);
>
> return domain;
> }
> @@ -2547,7 +2548,7 @@ static struct dmar_domain *dmar_insert_one_dev_info(struct intel_iommu *iommu,
> info->iommu = iommu;
> info->pasid_table = NULL;
> info->auxd_enabled = 0;
> - INIT_LIST_HEAD(&info->auxiliary_domains);
> + INIT_LIST_HEAD(&info->subdevices);
>
> if (dev && dev_is_pci(dev)) {
> struct pci_dev *pdev = to_pci_dev(info->dev);
> @@ -4475,33 +4476,61 @@ is_aux_domain(struct device *dev, struct iommu_domain *domain)
> domain->type == IOMMU_DOMAIN_UNMANAGED;
> }
>
> -static void auxiliary_link_device(struct dmar_domain *domain,
> - struct device *dev)
> +static inline struct subdev_domain_info *
> +lookup_subdev_info(struct dmar_domain *domain, struct device *dev)
> +{
> + struct subdev_domain_info *sinfo;
> +
> + if (!list_empty(&domain->subdevices)) {
> + list_for_each_entry(sinfo, &domain->subdevices, link_domain) {
> + if (sinfo->pdev == dev)
> + return sinfo;
> + }
> + }
> +
> + return NULL;
> +}
> +
> +static int auxiliary_link_device(struct dmar_domain *domain,
> + struct device *dev)
> {
> struct device_domain_info *info = get_domain_info(dev);
> + struct subdev_domain_info *sinfo = lookup_subdev_info(domain, dev);
>
> assert_spin_locked(&device_domain_lock);
> if (WARN_ON(!info))
> - return;
> + return -EINVAL;
> +
> + if (!sinfo) {
> + sinfo = kzalloc(sizeof(*sinfo), GFP_ATOMIC);
> + sinfo->domain = domain;
> + sinfo->pdev = dev;
> + list_add(&sinfo->link_phys, &info->subdevices);
> + list_add(&sinfo->link_domain, &domain->subdevices);
> + }
>
> - domain->auxd_refcnt++;
> - list_add(&domain->auxd, &info->auxiliary_domains);
> + return ++sinfo->users;
> }
>
> -static void auxiliary_unlink_device(struct dmar_domain *domain,
> - struct device *dev)
> +static int auxiliary_unlink_device(struct dmar_domain *domain,
> + struct device *dev)
> {
> struct device_domain_info *info = get_domain_info(dev);
> + struct subdev_domain_info *sinfo = lookup_subdev_info(domain, dev);
> + int ret;
>
> assert_spin_locked(&device_domain_lock);
> - if (WARN_ON(!info))
> - return;
> + if (WARN_ON(!info || !sinfo || sinfo->users <= 0))
> + return -EINVAL;
>
> - list_del(&domain->auxd);
> - domain->auxd_refcnt--;
> + ret = --sinfo->users;
> + if (!ret) {
> + list_del(&sinfo->link_phys);
> + list_del(&sinfo->link_domain);
> + kfree(sinfo);
> + }
>
> - if (!domain->auxd_refcnt && domain->default_pasid > 0)
> - ioasid_put(domain->default_pasid);
> + return ret;
> }
>
> static int aux_domain_add_dev(struct dmar_domain *domain,
> @@ -4530,6 +4559,19 @@ static int aux_domain_add_dev(struct dmar_domain *domain,
> }
>
> spin_lock_irqsave(&device_domain_lock, flags);
> + ret = auxiliary_link_device(domain, dev);
> + if (ret <= 0)
> + goto link_failed;
> +
> + /*
> + * Subdevices from the same physical device can be attached to the
> + * same domain. For such cases, only the first subdevice attachment
> + * needs to go through the full steps in this function. So if ret >
> + * 1, just goto out.
> + */
> + if (ret > 1)
> + goto out;
> +
> /*
> * iommu->lock must be held to attach domain to iommu and setup the
> * pasid entry for second level translation.
> @@ -4548,10 +4590,9 @@ static int aux_domain_add_dev(struct dmar_domain *domain,
> domain->default_pasid);
> if (ret)
> goto table_failed;
> - spin_unlock(&iommu->lock);
> -
> - auxiliary_link_device(domain, dev);
>
> + spin_unlock(&iommu->lock);
> +out:
> spin_unlock_irqrestore(&device_domain_lock, flags);
>
> return 0;
> @@ -4560,8 +4601,10 @@ static int aux_domain_add_dev(struct dmar_domain *domain,
> domain_detach_iommu(domain, iommu);
> attach_failed:
> spin_unlock(&iommu->lock);
> + auxiliary_unlink_device(domain, dev);
> +link_failed:
> spin_unlock_irqrestore(&device_domain_lock, flags);
> - if (!domain->auxd_refcnt && domain->default_pasid > 0)
> + if (list_empty(&domain->subdevices) && domain->default_pasid > 0)
> ioasid_put(domain->default_pasid);
>
> return ret;
> @@ -4581,14 +4624,18 @@ static void aux_domain_remove_dev(struct dmar_domain *domain,
> info = get_domain_info(dev);
> iommu = info->iommu;
>
> - auxiliary_unlink_device(domain, dev);
> -
> - spin_lock(&iommu->lock);
> - intel_pasid_tear_down_entry(iommu, dev, domain->default_pasid, false);
> - domain_detach_iommu(domain, iommu);
> - spin_unlock(&iommu->lock);
> + if (!auxiliary_unlink_device(domain, dev)) {
> + spin_lock(&iommu->lock);
> + intel_pasid_tear_down_entry(iommu, dev,
> + domain->default_pasid, false);
> + domain_detach_iommu(domain, iommu);
> + spin_unlock(&iommu->lock);
> + }
>
> spin_unlock_irqrestore(&device_domain_lock, flags);
> +
> + if (list_empty(&domain->subdevices) && domain->default_pasid > 0)
> + ioasid_put(domain->default_pasid);
> }
>
> static int prepare_domain_attach_device(struct iommu_domain *domain,
> diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
> index 94522685a0d9..09c6a0bf3892 100644
> --- a/include/linux/intel-iommu.h
> +++ b/include/linux/intel-iommu.h
> @@ -533,11 +533,10 @@ struct dmar_domain {
> /* Domain ids per IOMMU. Use u16 since
> * domain ids are 16 bit wide according
> * to VT-d spec, section 9.3 */
> - unsigned int auxd_refcnt; /* Refcount of auxiliary attaching */
>
> bool has_iotlb_device;
> struct list_head devices; /* all devices' list */
> - struct list_head auxd; /* link to device's auxiliary list */
> + struct list_head subdevices; /* all subdevices' list */
> struct iova_domain iovad; /* iova's that belong to this domain */
>
> struct dma_pte *pgd; /* virtual address */
> @@ -610,14 +609,21 @@ struct intel_iommu {
> struct dmar_drhd_unit *drhd;
> };
>
> +/* Per subdevice private data */
> +struct subdev_domain_info {
> + struct list_head link_phys; /* link to phys device siblings */
> + struct list_head link_domain; /* link to domain siblings */
> + struct device *pdev; /* physical device derived from */
> + struct dmar_domain *domain; /* aux-domain */
> + int users; /* user count */
> +};
> +
> /* PCI domain-device relationship */
> struct device_domain_info {
> struct list_head link; /* link to domain siblings */
> struct list_head global; /* link to global list */
> struct list_head table; /* link to pasid table */
> - struct list_head auxiliary_domains; /* auxiliary domains
> - * attached to this device
> - */
> + struct list_head subdevices; /* subdevices sibling */
> u32 segment; /* PCI segment number */
> u8 bus; /* PCI bus number */
> u8 devfn; /* PCI devfn number */
>
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