| Message ID | d10b5f08212a42c4a710ec649bffe082599dbb46.1564702313.git.sathyanarayanan.kuppuswamy@linux.intel.com (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
| Series | Fix PF/VF dependency issue | expand |
On Thu, Aug 01, 2019 at 05:06:02PM -0700, sathyanarayanan.kuppuswamy@linux.intel.com wrote: > From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> > > When IOMMU tries to enable PASID for VF device in > iommu_enable_dev_iotlb(), it always fails because PASID support for PCIe > VF device is currently broken in PCIE driver. Current implementation > expects the given PCIe device (PF & VF) to implement PASID capability > before enabling the PASID support. But this assumption is incorrect. As > per PCIe spec r4.0, sec 9.3.7.14, all VFs associated with PF can only > use the PASID of the PF and not implement it. > > Also, since PASID is a shared resource between PF/VF, following rules > should apply. > > 1. Use proper locking before accessing/modifying PF resources in VF > PASID enable/disable call. > 2. Use reference count logic to track the usage of PASID resource. > 3. Disable PASID only if the PASID reference count (pasid_ref_cnt) is zero. > > Cc: Ashok Raj <ashok.raj@intel.com> > Cc: Keith Busch <keith.busch@intel.com> > Suggested-by: Ashok Raj <ashok.raj@intel.com> > Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> > --- > drivers/pci/ats.c | 113 ++++++++++++++++++++++++++++++++++---------- > include/linux/pci.h | 2 + > 2 files changed, 90 insertions(+), 25 deletions(-) > > diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c > index 079dc5444444..9384afd7d00e 100644 > --- a/drivers/pci/ats.c > +++ b/drivers/pci/ats.c > @@ -402,6 +402,8 @@ void pci_pasid_init(struct pci_dev *pdev) > if (pdev->is_virtfn) > return; > > + mutex_init(&pdev->pasid_lock); > + > pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PASID); > if (!pos) > return; > @@ -436,32 +438,57 @@ void pci_pasid_init(struct pci_dev *pdev) > int pci_enable_pasid(struct pci_dev *pdev, int features) > { > u16 control, supported; > + int ret = 0; > + struct pci_dev *pf = pci_physfn(pdev); > > - if (WARN_ON(pdev->pasid_enabled)) > - return -EBUSY; > + mutex_lock(&pf->pasid_lock); > > - if (!pdev->eetlp_prefix_path) > - return -EINVAL; > + if (WARN_ON(pdev->pasid_enabled)) { > + ret = -EBUSY; > + goto pasid_unlock; > + } > > - if (!pdev->pasid_cap) > - return -EINVAL; > + if (!pdev->eetlp_prefix_path) { > + ret = -EINVAL; > + goto pasid_unlock; > + } > > - pci_read_config_word(pdev, pdev->pasid_cap + PCI_PASID_CAP, > - &supported); > + if (!pf->pasid_cap) { > + ret = -EINVAL; > + goto pasid_unlock; > + } > + > + if (pdev->is_virtfn && pf->pasid_enabled) > + goto update_status; > + > + pci_read_config_word(pf, pf->pasid_cap + PCI_PASID_CAP, &supported); > supported &= PCI_PASID_CAP_EXEC | PCI_PASID_CAP_PRIV; > > /* User wants to enable anything unsupported? */ > - if ((supported & features) != features) > - return -EINVAL; > + if ((supported & features) != features) { > + ret = -EINVAL; > + goto pasid_unlock; > + } > > control = PCI_PASID_CTRL_ENABLE | features; > - pdev->pasid_features = features; > - > + pf->pasid_features = features; > pci_write_config_word(pdev, pdev->pasid_cap + PCI_PASID_CTRL, control); > > - pdev->pasid_enabled = 1; > + /* > + * If PASID is not already enabled in PF, increment pasid_ref_cnt > + * to count PF PASID usage. > + */ > + if (pdev->is_virtfn && !pf->pasid_enabled) { > + atomic_inc(&pf->pasid_ref_cnt); > + pf->pasid_enabled = 1; > + } > > - return 0; > +update_status: > + atomic_inc(&pf->pasid_ref_cnt); > + pdev->pasid_enabled = 1; > +pasid_unlock: > + mutex_unlock(&pf->pasid_lock); > + return ret; > } > EXPORT_SYMBOL_GPL(pci_enable_pasid); > > @@ -472,16 +499,29 @@ EXPORT_SYMBOL_GPL(pci_enable_pasid); > void pci_disable_pasid(struct pci_dev *pdev) > { > u16 control = 0; > + struct pci_dev *pf = pci_physfn(pdev); > + > + mutex_lock(&pf->pasid_lock); > > if (WARN_ON(!pdev->pasid_enabled)) > - return; > + goto pasid_unlock; > > - if (!pdev->pasid_cap) > - return; > + if (!pf->pasid_cap) > + goto pasid_unlock; > > - pci_write_config_word(pdev, pdev->pasid_cap + PCI_PASID_CTRL, control); > + atomic_dec(&pf->pasid_ref_cnt); > > + if (atomic_read(&pf->pasid_ref_cnt)) > + goto done; > + > + /* Disable PASID only if pasid_ref_cnt is zero */ > + pci_write_config_word(pf, pf->pasid_cap + PCI_PASID_CTRL, control); > + > +done: > pdev->pasid_enabled = 0; > +pasid_unlock: > + mutex_unlock(&pf->pasid_lock); > + > } > EXPORT_SYMBOL_GPL(pci_disable_pasid); > > @@ -492,15 +532,25 @@ EXPORT_SYMBOL_GPL(pci_disable_pasid); > void pci_restore_pasid_state(struct pci_dev *pdev) > { > u16 control; > + struct pci_dev *pf = pci_physfn(pdev); > > if (!pdev->pasid_enabled) > return; > > - if (!pdev->pasid_cap) > + if (!pf->pasid_cap) > return; > > + mutex_lock(&pf->pasid_lock); > + > + pci_read_config_word(pf, pf->pasid_cap + PCI_PASID_CTRL, &control); > + if (control & PCI_PASID_CTRL_ENABLE) > + goto pasid_unlock; > + > control = PCI_PASID_CTRL_ENABLE | pdev->pasid_features; > - pci_write_config_word(pdev, pdev->pasid_cap + PCI_PASID_CTRL, control); > + pci_write_config_word(pf, pf->pasid_cap + PCI_PASID_CTRL, control); > + > +pasid_unlock: > + mutex_unlock(&pf->pasid_lock); > } > EXPORT_SYMBOL_GPL(pci_restore_pasid_state); > > @@ -517,15 +567,22 @@ EXPORT_SYMBOL_GPL(pci_restore_pasid_state); > int pci_pasid_features(struct pci_dev *pdev) > { > u16 supported; > + struct pci_dev *pf = pci_physfn(pdev); > + > + mutex_lock(&pf->pasid_lock); > > - if (!pdev->pasid_cap) > + if (!pf->pasid_cap) { > + mutex_unlock(&pf->pasid_lock); > return -EINVAL; > + } > > - pci_read_config_word(pdev, pdev->pasid_cap + PCI_PASID_CAP, > + pci_read_config_word(pf, pf->pasid_cap + PCI_PASID_CAP, > &supported); > > supported &= PCI_PASID_CAP_EXEC | PCI_PASID_CAP_PRIV; > > + mutex_unlock(&pf->pasid_lock); > + > return supported; > } > EXPORT_SYMBOL_GPL(pci_pasid_features); > @@ -579,15 +636,21 @@ EXPORT_SYMBOL_GPL(pci_prg_resp_pasid_required); > int pci_max_pasids(struct pci_dev *pdev) > { > u16 supported; > + struct pci_dev *pf = pci_physfn(pdev); > + > + mutex_lock(&pf->pasid_lock); > > - if (!pdev->pasid_cap) > + if (!pf->pasid_cap) { > + mutex_unlock(&pf->pasid_lock); > return -EINVAL; > + } > > - pci_read_config_word(pdev, pdev->pasid_cap + PCI_PASID_CAP, > - &supported); > + pci_read_config_word(pf, pf->pasid_cap + PCI_PASID_CAP, &supported); > > supported = (supported & PASID_NUMBER_MASK) >> PASID_NUMBER_SHIFT; > > + mutex_unlock(&pf->pasid_lock); > + > return (1 << supported); > } > EXPORT_SYMBOL_GPL(pci_max_pasids); > diff --git a/include/linux/pci.h b/include/linux/pci.h > index 3c9c4c82be27..4bfcca045afd 100644 > --- a/include/linux/pci.h > +++ b/include/linux/pci.h > @@ -461,8 +461,10 @@ struct pci_dev { > atomic_t pri_ref_cnt; /* Number of PF/VF PRI users */ > #endif > #ifdef CONFIG_PCI_PASID > + struct mutex pasid_lock; /* PASID enable lock */ I think these locks are finer-grained than necessary. I'm not sure it's worth having two mutexes for every device (one for PRI and another for PASID). Is there really a performance benefit for having two? Do it (or do they) need to be in struct pci_dev? You only use the PF mutexes, so maybe it could be in the struct pci_sriov, which I think is only one per PF. > u16 pasid_cap; /* PASID Capability offset */ > u16 pasid_features; > + atomic_t pasid_ref_cnt; /* Number of VFs with PASID enabled */ > #endif > #ifdef CONFIG_PCI_P2PDMA > struct pci_p2pdma *p2pdma; > -- > 2.21.0 >
On Mon, Aug 12, 2019 at 03:05:08PM -0500, Bjorn Helgaas wrote: > On Thu, Aug 01, 2019 at 05:06:02PM -0700, sathyanarayanan.kuppuswamy@linux.intel.com wrote: > > From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> > > > > When IOMMU tries to enable PASID for VF device in > > iommu_enable_dev_iotlb(), it always fails because PASID support for PCIe > > VF device is currently broken in PCIE driver. Current implementation > > expects the given PCIe device (PF & VF) to implement PASID capability > > before enabling the PASID support. But this assumption is incorrect. As > > per PCIe spec r4.0, sec 9.3.7.14, all VFs associated with PF can only > > use the PASID of the PF and not implement it. > > > > Also, since PASID is a shared resource between PF/VF, following rules > > should apply. > > > > 1. Use proper locking before accessing/modifying PF resources in VF > > PASID enable/disable call. > > 2. Use reference count logic to track the usage of PASID resource. > > 3. Disable PASID only if the PASID reference count (pasid_ref_cnt) is zero. > > > > Cc: Ashok Raj <ashok.raj@intel.com> > > Cc: Keith Busch <keith.busch@intel.com> > > Suggested-by: Ashok Raj <ashok.raj@intel.com> > > Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> > > --- > > drivers/pci/ats.c | 113 ++++++++++++++++++++++++++++++++++---------- > > include/linux/pci.h | 2 + > > 2 files changed, 90 insertions(+), 25 deletions(-) > > > > diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c > > index 079dc5444444..9384afd7d00e 100644 > > --- a/drivers/pci/ats.c > > +++ b/drivers/pci/ats.c > > @@ -402,6 +402,8 @@ void pci_pasid_init(struct pci_dev *pdev) > > if (pdev->is_virtfn) > > return; > > > > + mutex_init(&pdev->pasid_lock); > > + > > pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PASID); > > if (!pos) > > return; > > @@ -436,32 +438,57 @@ void pci_pasid_init(struct pci_dev *pdev) > > int pci_enable_pasid(struct pci_dev *pdev, int features) > > { > > u16 control, supported; > > + int ret = 0; > > + struct pci_dev *pf = pci_physfn(pdev); > > > > - if (WARN_ON(pdev->pasid_enabled)) > > - return -EBUSY; > > + mutex_lock(&pf->pasid_lock); > > > > - if (!pdev->eetlp_prefix_path) > > - return -EINVAL; > > + if (WARN_ON(pdev->pasid_enabled)) { > > + ret = -EBUSY; > > + goto pasid_unlock; > > + } > > > > - if (!pdev->pasid_cap) > > - return -EINVAL; > > + if (!pdev->eetlp_prefix_path) { > > + ret = -EINVAL; > > + goto pasid_unlock; > > + } > > > > - pci_read_config_word(pdev, pdev->pasid_cap + PCI_PASID_CAP, > > - &supported); > > + if (!pf->pasid_cap) { > > + ret = -EINVAL; > > + goto pasid_unlock; > > + } > > + > > + if (pdev->is_virtfn && pf->pasid_enabled) > > + goto update_status; > > + > > + pci_read_config_word(pf, pf->pasid_cap + PCI_PASID_CAP, &supported); > > supported &= PCI_PASID_CAP_EXEC | PCI_PASID_CAP_PRIV; > > > > /* User wants to enable anything unsupported? */ > > - if ((supported & features) != features) > > - return -EINVAL; > > + if ((supported & features) != features) { > > + ret = -EINVAL; > > + goto pasid_unlock; > > + } > > > > control = PCI_PASID_CTRL_ENABLE | features; > > - pdev->pasid_features = features; > > - > > + pf->pasid_features = features; > > pci_write_config_word(pdev, pdev->pasid_cap + PCI_PASID_CTRL, control); > > > > - pdev->pasid_enabled = 1; > > + /* > > + * If PASID is not already enabled in PF, increment pasid_ref_cnt > > + * to count PF PASID usage. > > + */ > > + if (pdev->is_virtfn && !pf->pasid_enabled) { > > + atomic_inc(&pf->pasid_ref_cnt); > > + pf->pasid_enabled = 1; > > + } > > > > - return 0; > > +update_status: > > + atomic_inc(&pf->pasid_ref_cnt); > > + pdev->pasid_enabled = 1; > > +pasid_unlock: > > + mutex_unlock(&pf->pasid_lock); > > + return ret; > > } > > EXPORT_SYMBOL_GPL(pci_enable_pasid); > > > > @@ -472,16 +499,29 @@ EXPORT_SYMBOL_GPL(pci_enable_pasid); > > void pci_disable_pasid(struct pci_dev *pdev) > > { > > u16 control = 0; > > + struct pci_dev *pf = pci_physfn(pdev); > > + > > + mutex_lock(&pf->pasid_lock); > > > > if (WARN_ON(!pdev->pasid_enabled)) > > - return; > > + goto pasid_unlock; > > > > - if (!pdev->pasid_cap) > > - return; > > + if (!pf->pasid_cap) > > + goto pasid_unlock; > > > > - pci_write_config_word(pdev, pdev->pasid_cap + PCI_PASID_CTRL, control); > > + atomic_dec(&pf->pasid_ref_cnt); > > > > + if (atomic_read(&pf->pasid_ref_cnt)) > > + goto done; > > + > > + /* Disable PASID only if pasid_ref_cnt is zero */ > > + pci_write_config_word(pf, pf->pasid_cap + PCI_PASID_CTRL, control); > > + > > +done: > > pdev->pasid_enabled = 0; > > +pasid_unlock: > > + mutex_unlock(&pf->pasid_lock); > > + > > } > > EXPORT_SYMBOL_GPL(pci_disable_pasid); > > > > @@ -492,15 +532,25 @@ EXPORT_SYMBOL_GPL(pci_disable_pasid); > > void pci_restore_pasid_state(struct pci_dev *pdev) > > { > > u16 control; > > + struct pci_dev *pf = pci_physfn(pdev); > > > > if (!pdev->pasid_enabled) > > return; > > > > - if (!pdev->pasid_cap) > > + if (!pf->pasid_cap) > > return; > > > > + mutex_lock(&pf->pasid_lock); > > + > > + pci_read_config_word(pf, pf->pasid_cap + PCI_PASID_CTRL, &control); > > + if (control & PCI_PASID_CTRL_ENABLE) > > + goto pasid_unlock; > > + > > control = PCI_PASID_CTRL_ENABLE | pdev->pasid_features; > > - pci_write_config_word(pdev, pdev->pasid_cap + PCI_PASID_CTRL, control); > > + pci_write_config_word(pf, pf->pasid_cap + PCI_PASID_CTRL, control); > > + > > +pasid_unlock: > > + mutex_unlock(&pf->pasid_lock); > > } > > EXPORT_SYMBOL_GPL(pci_restore_pasid_state); > > > > @@ -517,15 +567,22 @@ EXPORT_SYMBOL_GPL(pci_restore_pasid_state); > > int pci_pasid_features(struct pci_dev *pdev) > > { > > u16 supported; > > + struct pci_dev *pf = pci_physfn(pdev); > > + > > + mutex_lock(&pf->pasid_lock); > > > > - if (!pdev->pasid_cap) > > + if (!pf->pasid_cap) { > > + mutex_unlock(&pf->pasid_lock); > > return -EINVAL; > > + } > > > > - pci_read_config_word(pdev, pdev->pasid_cap + PCI_PASID_CAP, > > + pci_read_config_word(pf, pf->pasid_cap + PCI_PASID_CAP, > > &supported); > > > > supported &= PCI_PASID_CAP_EXEC | PCI_PASID_CAP_PRIV; > > > > + mutex_unlock(&pf->pasid_lock); > > + > > return supported; > > } > > EXPORT_SYMBOL_GPL(pci_pasid_features); > > @@ -579,15 +636,21 @@ EXPORT_SYMBOL_GPL(pci_prg_resp_pasid_required); > > int pci_max_pasids(struct pci_dev *pdev) > > { > > u16 supported; > > + struct pci_dev *pf = pci_physfn(pdev); > > + > > + mutex_lock(&pf->pasid_lock); > > > > - if (!pdev->pasid_cap) > > + if (!pf->pasid_cap) { > > + mutex_unlock(&pf->pasid_lock); > > return -EINVAL; > > + } > > > > - pci_read_config_word(pdev, pdev->pasid_cap + PCI_PASID_CAP, > > - &supported); > > + pci_read_config_word(pf, pf->pasid_cap + PCI_PASID_CAP, &supported); > > > > supported = (supported & PASID_NUMBER_MASK) >> PASID_NUMBER_SHIFT; > > > > + mutex_unlock(&pf->pasid_lock); > > + > > return (1 << supported); > > } > > EXPORT_SYMBOL_GPL(pci_max_pasids); > > diff --git a/include/linux/pci.h b/include/linux/pci.h > > index 3c9c4c82be27..4bfcca045afd 100644 > > --- a/include/linux/pci.h > > +++ b/include/linux/pci.h > > @@ -461,8 +461,10 @@ struct pci_dev { > > atomic_t pri_ref_cnt; /* Number of PF/VF PRI users */ > > #endif > > #ifdef CONFIG_PCI_PASID > > + struct mutex pasid_lock; /* PASID enable lock */ > > I think these locks are finer-grained than necessary. I'm not sure > it's worth having two mutexes for every device (one for PRI and > another for PASID). Is there really a performance benefit for having > two? Performance benefit should be minimal. But, PRI and PASID are functionally independent. So I don't think its correct to protect its resources with a common lock. Let me know your comments. > > Do it (or do they) need to be in struct pci_dev? You only use the PF > mutexes, so maybe it could be in the struct pci_sriov, which I think > is only one per PF. Its possible to move it to pci_sriov structure. But is that the right place for it? This lock is only used for protecting PRI and PASID feature updates and PRI/PASID are not dependent on IOV feature. Let me know your comments. If you want to move this lock to pci_sriov structure and use one lock for both PRI/PASID, then the implementation would look like following. We could create physfn lock/unlock functions in include/linux/pci.h similar to pci_physfn() function. #ifdef CONFIG_PCI_IOV static inline void pci_physfn_reslock(struct pci_dev *dev) { struct pci_dev *pf = pci_physfn(dev); if (!pf->is_physfn) return; mutex_lock(&pf->sriov->reslock); } #else static inline void pci_physfn_reslock(struct pci_dev *dev) {}; #endif > > > u16 pasid_cap; /* PASID Capability offset */ > > u16 pasid_features; > > + atomic_t pasid_ref_cnt; /* Number of VFs with PASID enabled */ > > #endif > > #ifdef CONFIG_PCI_P2PDMA > > struct pci_p2pdma *p2pdma; > > -- > > 2.21.0 > >
On Tue, Aug 13, 2019 at 03:19:58PM -0700, Kuppuswamy Sathyanarayanan wrote: > On Mon, Aug 12, 2019 at 03:05:08PM -0500, Bjorn Helgaas wrote: > > On Thu, Aug 01, 2019 at 05:06:02PM -0700, sathyanarayanan.kuppuswamy@linux.intel.com wrote: > > > From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> > > > > > > When IOMMU tries to enable PASID for VF device in > > > iommu_enable_dev_iotlb(), it always fails because PASID support for PCIe > > > VF device is currently broken in PCIE driver. Current implementation > > > expects the given PCIe device (PF & VF) to implement PASID capability > > > before enabling the PASID support. But this assumption is incorrect. As > > > per PCIe spec r4.0, sec 9.3.7.14, all VFs associated with PF can only > > > use the PASID of the PF and not implement it. > > > > > > Also, since PASID is a shared resource between PF/VF, following rules > > > should apply. > > > > > > 1. Use proper locking before accessing/modifying PF resources in VF > > > PASID enable/disable call. > > > 2. Use reference count logic to track the usage of PASID resource. > > > 3. Disable PASID only if the PASID reference count (pasid_ref_cnt) is zero. > > > > > > Cc: Ashok Raj <ashok.raj@intel.com> > > > Cc: Keith Busch <keith.busch@intel.com> > > > Suggested-by: Ashok Raj <ashok.raj@intel.com> > > > Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> > > > --- > > > drivers/pci/ats.c | 113 ++++++++++++++++++++++++++++++++++---------- > > > include/linux/pci.h | 2 + > > > 2 files changed, 90 insertions(+), 25 deletions(-) > > > > > > diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c > > > index 079dc5444444..9384afd7d00e 100644 > > > --- a/drivers/pci/ats.c > > > +++ b/drivers/pci/ats.c > > > @@ -402,6 +402,8 @@ void pci_pasid_init(struct pci_dev *pdev) > > > if (pdev->is_virtfn) > > > return; > > > > > > + mutex_init(&pdev->pasid_lock); > > > + > > > pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PASID); > > > if (!pos) > > > return; > > > @@ -436,32 +438,57 @@ void pci_pasid_init(struct pci_dev *pdev) > > > int pci_enable_pasid(struct pci_dev *pdev, int features) > > > { > > > u16 control, supported; > > > + int ret = 0; > > > + struct pci_dev *pf = pci_physfn(pdev); > > > > > > - if (WARN_ON(pdev->pasid_enabled)) > > > - return -EBUSY; > > > + mutex_lock(&pf->pasid_lock); > > > > > > - if (!pdev->eetlp_prefix_path) > > > - return -EINVAL; > > > + if (WARN_ON(pdev->pasid_enabled)) { > > > + ret = -EBUSY; > > > + goto pasid_unlock; > > > + } > > > > > > - if (!pdev->pasid_cap) > > > - return -EINVAL; > > > + if (!pdev->eetlp_prefix_path) { > > > + ret = -EINVAL; > > > + goto pasid_unlock; > > > + } > > > > > > - pci_read_config_word(pdev, pdev->pasid_cap + PCI_PASID_CAP, > > > - &supported); > > > + if (!pf->pasid_cap) { > > > + ret = -EINVAL; > > > + goto pasid_unlock; > > > + } > > > + > > > + if (pdev->is_virtfn && pf->pasid_enabled) > > > + goto update_status; > > > + > > > + pci_read_config_word(pf, pf->pasid_cap + PCI_PASID_CAP, &supported); > > > supported &= PCI_PASID_CAP_EXEC | PCI_PASID_CAP_PRIV; > > > > > > /* User wants to enable anything unsupported? */ > > > - if ((supported & features) != features) > > > - return -EINVAL; > > > + if ((supported & features) != features) { > > > + ret = -EINVAL; > > > + goto pasid_unlock; > > > + } > > > > > > control = PCI_PASID_CTRL_ENABLE | features; > > > - pdev->pasid_features = features; > > > - > > > + pf->pasid_features = features; > > > pci_write_config_word(pdev, pdev->pasid_cap + PCI_PASID_CTRL, control); > > > > > > - pdev->pasid_enabled = 1; > > > + /* > > > + * If PASID is not already enabled in PF, increment pasid_ref_cnt > > > + * to count PF PASID usage. > > > + */ > > > + if (pdev->is_virtfn && !pf->pasid_enabled) { > > > + atomic_inc(&pf->pasid_ref_cnt); > > > + pf->pasid_enabled = 1; > > > + } > > > > > > - return 0; > > > +update_status: > > > + atomic_inc(&pf->pasid_ref_cnt); > > > + pdev->pasid_enabled = 1; > > > +pasid_unlock: > > > + mutex_unlock(&pf->pasid_lock); > > > + return ret; > > > } > > > EXPORT_SYMBOL_GPL(pci_enable_pasid); > > > > > > @@ -472,16 +499,29 @@ EXPORT_SYMBOL_GPL(pci_enable_pasid); > > > void pci_disable_pasid(struct pci_dev *pdev) > > > { > > > u16 control = 0; > > > + struct pci_dev *pf = pci_physfn(pdev); > > > + > > > + mutex_lock(&pf->pasid_lock); > > > > > > if (WARN_ON(!pdev->pasid_enabled)) > > > - return; > > > + goto pasid_unlock; > > > > > > - if (!pdev->pasid_cap) > > > - return; > > > + if (!pf->pasid_cap) > > > + goto pasid_unlock; > > > > > > - pci_write_config_word(pdev, pdev->pasid_cap + PCI_PASID_CTRL, control); > > > + atomic_dec(&pf->pasid_ref_cnt); > > > > > > + if (atomic_read(&pf->pasid_ref_cnt)) > > > + goto done; > > > + > > > + /* Disable PASID only if pasid_ref_cnt is zero */ > > > + pci_write_config_word(pf, pf->pasid_cap + PCI_PASID_CTRL, control); > > > + > > > +done: > > > pdev->pasid_enabled = 0; > > > +pasid_unlock: > > > + mutex_unlock(&pf->pasid_lock); > > > + > > > } > > > EXPORT_SYMBOL_GPL(pci_disable_pasid); > > > > > > @@ -492,15 +532,25 @@ EXPORT_SYMBOL_GPL(pci_disable_pasid); > > > void pci_restore_pasid_state(struct pci_dev *pdev) > > > { > > > u16 control; > > > + struct pci_dev *pf = pci_physfn(pdev); > > > > > > if (!pdev->pasid_enabled) > > > return; > > > > > > - if (!pdev->pasid_cap) > > > + if (!pf->pasid_cap) > > > return; > > > > > > + mutex_lock(&pf->pasid_lock); > > > + > > > + pci_read_config_word(pf, pf->pasid_cap + PCI_PASID_CTRL, &control); > > > + if (control & PCI_PASID_CTRL_ENABLE) > > > + goto pasid_unlock; > > > + > > > control = PCI_PASID_CTRL_ENABLE | pdev->pasid_features; > > > - pci_write_config_word(pdev, pdev->pasid_cap + PCI_PASID_CTRL, control); > > > + pci_write_config_word(pf, pf->pasid_cap + PCI_PASID_CTRL, control); > > > + > > > +pasid_unlock: > > > + mutex_unlock(&pf->pasid_lock); > > > } > > > EXPORT_SYMBOL_GPL(pci_restore_pasid_state); > > > > > > @@ -517,15 +567,22 @@ EXPORT_SYMBOL_GPL(pci_restore_pasid_state); > > > int pci_pasid_features(struct pci_dev *pdev) > > > { > > > u16 supported; > > > + struct pci_dev *pf = pci_physfn(pdev); > > > + > > > + mutex_lock(&pf->pasid_lock); > > > > > > - if (!pdev->pasid_cap) > > > + if (!pf->pasid_cap) { > > > + mutex_unlock(&pf->pasid_lock); > > > return -EINVAL; > > > + } > > > > > > - pci_read_config_word(pdev, pdev->pasid_cap + PCI_PASID_CAP, > > > + pci_read_config_word(pf, pf->pasid_cap + PCI_PASID_CAP, > > > &supported); > > > > > > supported &= PCI_PASID_CAP_EXEC | PCI_PASID_CAP_PRIV; > > > > > > + mutex_unlock(&pf->pasid_lock); > > > + > > > return supported; > > > } > > > EXPORT_SYMBOL_GPL(pci_pasid_features); > > > @@ -579,15 +636,21 @@ EXPORT_SYMBOL_GPL(pci_prg_resp_pasid_required); > > > int pci_max_pasids(struct pci_dev *pdev) > > > { > > > u16 supported; > > > + struct pci_dev *pf = pci_physfn(pdev); > > > + > > > + mutex_lock(&pf->pasid_lock); > > > > > > - if (!pdev->pasid_cap) > > > + if (!pf->pasid_cap) { > > > + mutex_unlock(&pf->pasid_lock); > > > return -EINVAL; > > > + } > > > > > > - pci_read_config_word(pdev, pdev->pasid_cap + PCI_PASID_CAP, > > > - &supported); > > > + pci_read_config_word(pf, pf->pasid_cap + PCI_PASID_CAP, &supported); > > > > > > supported = (supported & PASID_NUMBER_MASK) >> PASID_NUMBER_SHIFT; > > > > > > + mutex_unlock(&pf->pasid_lock); > > > + > > > return (1 << supported); > > > } > > > EXPORT_SYMBOL_GPL(pci_max_pasids); > > > diff --git a/include/linux/pci.h b/include/linux/pci.h > > > index 3c9c4c82be27..4bfcca045afd 100644 > > > --- a/include/linux/pci.h > > > +++ b/include/linux/pci.h > > > @@ -461,8 +461,10 @@ struct pci_dev { > > > atomic_t pri_ref_cnt; /* Number of PF/VF PRI users */ > > > #endif > > > #ifdef CONFIG_PCI_PASID > > > + struct mutex pasid_lock; /* PASID enable lock */ > > > > I think these locks are finer-grained than necessary. I'm not sure > > it's worth having two mutexes for every device (one for PRI and > > another for PASID). Is there really a performance benefit for having > > two? > Performance benefit should be minimal. But, PRI and PASID are functionally > independent. So I don't think its correct to protect its resources with > a common lock. Let me know your comments. I'm not an expert on PRI and PASID, but if we can figure out a place to put it and a way to manage it, I think it's OK to have a lock that protects both. I'm thinking about the size of the pci_dev -- I'm not sure the benefit of having two locks is commensurate with the size cost. > > Do it (or do they) need to be in struct pci_dev? You only use the PF > > mutexes, so maybe it could be in the struct pci_sriov, which I think > > is only one per PF. > Its possible to move it to pci_sriov structure. But is that the right > place for it? This lock is only used for protecting PRI and PASID feature > updates and PRI/PASID are not dependent on IOV feature. Let me know your > comments. Hmm. I misunderstood the use of these. I had the impression they were only used for PFs. If that were the case, pci_sriov might make sense because we only allocate that for PFs (when we enable SR-IOV in sriov_init()). But IIUC that's *not* the case: even non-SR-IOV devices can use PRI/PASID; it's just that if a *VF* uses them, the VF is actually using the PRI of the PF. > If you want to move this lock to pci_sriov structure and use one lock > for both PRI/PASID, then the implementation would look like following. We > could create physfn lock/unlock functions in include/linux/pci.h similar > to pci_physfn() function. > #ifdef CONFIG_PCI_IOV > static inline void pci_physfn_reslock(struct pci_dev *dev) > { > struct pci_dev *pf = pci_physfn(dev); > > if (!pf->is_physfn) > return; > > mutex_lock(&pf->sriov->reslock); > > } > #else > static inline void pci_physfn_reslock(struct pci_dev *dev) {}; > #endif Yeah, that's not a pretty solution. IIUC, we don't need to lock at all for non-SR-IOV devices, because we're operating on our own device and nobody else should be touching it. Right? Only the SR-IOV case (operating on a PF with SR-IOV enabled or on one of its VFs) needs locking because these are all sharing one resource. So it's kind of a shame to allocate the lock for *every* pci_dev, when we only need it for PFs with SR-IOV enabled. Bjorn
On Thu, Aug 15, 2019 at 12:04:30AM -0500, Bjorn Helgaas wrote: > On Tue, Aug 13, 2019 at 03:19:58PM -0700, Kuppuswamy Sathyanarayanan wrote: > > On Mon, Aug 12, 2019 at 03:05:08PM -0500, Bjorn Helgaas wrote: > > > On Thu, Aug 01, 2019 at 05:06:02PM -0700, sathyanarayanan.kuppuswamy@linux.intel.com wrote: > > > > From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> > > > > > > > > When IOMMU tries to enable PASID for VF device in > > > > iommu_enable_dev_iotlb(), it always fails because PASID support for PCIe > > > > VF device is currently broken in PCIE driver. Current implementation > > > > expects the given PCIe device (PF & VF) to implement PASID capability > > > > before enabling the PASID support. But this assumption is incorrect. As > > > > per PCIe spec r4.0, sec 9.3.7.14, all VFs associated with PF can only > > > > use the PASID of the PF and not implement it. > > > > > > > > Also, since PASID is a shared resource between PF/VF, following rules > > > > should apply. > > > > > > > > 1. Use proper locking before accessing/modifying PF resources in VF > > > > PASID enable/disable call. > > > > 2. Use reference count logic to track the usage of PASID resource. > > > > 3. Disable PASID only if the PASID reference count (pasid_ref_cnt) is zero. > > > > > > > > Cc: Ashok Raj <ashok.raj@intel.com> > > > > Cc: Keith Busch <keith.busch@intel.com> > > > > Suggested-by: Ashok Raj <ashok.raj@intel.com> > > > > Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> > > > > --- > > > > drivers/pci/ats.c | 113 ++++++++++++++++++++++++++++++++++---------- > > > > include/linux/pci.h | 2 + > > > > 2 files changed, 90 insertions(+), 25 deletions(-) > > > > > > > > diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c > > > > index 079dc5444444..9384afd7d00e 100644 > > > > --- a/drivers/pci/ats.c > > > > +++ b/drivers/pci/ats.c > > > > @@ -402,6 +402,8 @@ void pci_pasid_init(struct pci_dev *pdev) > > > > if (pdev->is_virtfn) > > > > return; > > > > > > > > + mutex_init(&pdev->pasid_lock); > > > > + > > > > pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PASID); > > > > if (!pos) > > > > return; > > > > @@ -436,32 +438,57 @@ void pci_pasid_init(struct pci_dev *pdev) > > > > int pci_enable_pasid(struct pci_dev *pdev, int features) > > > > { > > > > u16 control, supported; > > > > + int ret = 0; > > > > + struct pci_dev *pf = pci_physfn(pdev); > > > > > > > > - if (WARN_ON(pdev->pasid_enabled)) > > > > - return -EBUSY; > > > > + mutex_lock(&pf->pasid_lock); > > > > > > > > - if (!pdev->eetlp_prefix_path) > > > > - return -EINVAL; > > > > + if (WARN_ON(pdev->pasid_enabled)) { > > > > + ret = -EBUSY; > > > > + goto pasid_unlock; > > > > + } > > > > > > > > - if (!pdev->pasid_cap) > > > > - return -EINVAL; > > > > + if (!pdev->eetlp_prefix_path) { > > > > + ret = -EINVAL; > > > > + goto pasid_unlock; > > > > + } > > > > > > > > - pci_read_config_word(pdev, pdev->pasid_cap + PCI_PASID_CAP, > > > > - &supported); > > > > + if (!pf->pasid_cap) { > > > > + ret = -EINVAL; > > > > + goto pasid_unlock; > > > > + } > > > > + > > > > + if (pdev->is_virtfn && pf->pasid_enabled) > > > > + goto update_status; > > > > + > > > > + pci_read_config_word(pf, pf->pasid_cap + PCI_PASID_CAP, &supported); > > > > supported &= PCI_PASID_CAP_EXEC | PCI_PASID_CAP_PRIV; > > > > > > > > /* User wants to enable anything unsupported? */ > > > > - if ((supported & features) != features) > > > > - return -EINVAL; > > > > + if ((supported & features) != features) { > > > > + ret = -EINVAL; > > > > + goto pasid_unlock; > > > > + } > > > > > > > > control = PCI_PASID_CTRL_ENABLE | features; > > > > - pdev->pasid_features = features; > > > > - > > > > + pf->pasid_features = features; > > > > pci_write_config_word(pdev, pdev->pasid_cap + PCI_PASID_CTRL, control); > > > > > > > > - pdev->pasid_enabled = 1; > > > > + /* > > > > + * If PASID is not already enabled in PF, increment pasid_ref_cnt > > > > + * to count PF PASID usage. > > > > + */ > > > > + if (pdev->is_virtfn && !pf->pasid_enabled) { > > > > + atomic_inc(&pf->pasid_ref_cnt); > > > > + pf->pasid_enabled = 1; > > > > + } > > > > > > > > - return 0; > > > > +update_status: > > > > + atomic_inc(&pf->pasid_ref_cnt); > > > > + pdev->pasid_enabled = 1; > > > > +pasid_unlock: > > > > + mutex_unlock(&pf->pasid_lock); > > > > + return ret; > > > > } > > > > EXPORT_SYMBOL_GPL(pci_enable_pasid); > > > > > > > > @@ -472,16 +499,29 @@ EXPORT_SYMBOL_GPL(pci_enable_pasid); > > > > void pci_disable_pasid(struct pci_dev *pdev) > > > > { > > > > u16 control = 0; > > > > + struct pci_dev *pf = pci_physfn(pdev); > > > > + > > > > + mutex_lock(&pf->pasid_lock); > > > > > > > > if (WARN_ON(!pdev->pasid_enabled)) > > > > - return; > > > > + goto pasid_unlock; > > > > > > > > - if (!pdev->pasid_cap) > > > > - return; > > > > + if (!pf->pasid_cap) > > > > + goto pasid_unlock; > > > > > > > > - pci_write_config_word(pdev, pdev->pasid_cap + PCI_PASID_CTRL, control); > > > > + atomic_dec(&pf->pasid_ref_cnt); > > > > > > > > + if (atomic_read(&pf->pasid_ref_cnt)) > > > > + goto done; > > > > + > > > > + /* Disable PASID only if pasid_ref_cnt is zero */ > > > > + pci_write_config_word(pf, pf->pasid_cap + PCI_PASID_CTRL, control); > > > > + > > > > +done: > > > > pdev->pasid_enabled = 0; > > > > +pasid_unlock: > > > > + mutex_unlock(&pf->pasid_lock); > > > > + > > > > } > > > > EXPORT_SYMBOL_GPL(pci_disable_pasid); > > > > > > > > @@ -492,15 +532,25 @@ EXPORT_SYMBOL_GPL(pci_disable_pasid); > > > > void pci_restore_pasid_state(struct pci_dev *pdev) > > > > { > > > > u16 control; > > > > + struct pci_dev *pf = pci_physfn(pdev); > > > > > > > > if (!pdev->pasid_enabled) > > > > return; > > > > > > > > - if (!pdev->pasid_cap) > > > > + if (!pf->pasid_cap) > > > > return; > > > > > > > > + mutex_lock(&pf->pasid_lock); > > > > + > > > > + pci_read_config_word(pf, pf->pasid_cap + PCI_PASID_CTRL, &control); > > > > + if (control & PCI_PASID_CTRL_ENABLE) > > > > + goto pasid_unlock; > > > > + > > > > control = PCI_PASID_CTRL_ENABLE | pdev->pasid_features; > > > > - pci_write_config_word(pdev, pdev->pasid_cap + PCI_PASID_CTRL, control); > > > > + pci_write_config_word(pf, pf->pasid_cap + PCI_PASID_CTRL, control); > > > > + > > > > +pasid_unlock: > > > > + mutex_unlock(&pf->pasid_lock); > > > > } > > > > EXPORT_SYMBOL_GPL(pci_restore_pasid_state); > > > > > > > > @@ -517,15 +567,22 @@ EXPORT_SYMBOL_GPL(pci_restore_pasid_state); > > > > int pci_pasid_features(struct pci_dev *pdev) > > > > { > > > > u16 supported; > > > > + struct pci_dev *pf = pci_physfn(pdev); > > > > + > > > > + mutex_lock(&pf->pasid_lock); > > > > > > > > - if (!pdev->pasid_cap) > > > > + if (!pf->pasid_cap) { > > > > + mutex_unlock(&pf->pasid_lock); > > > > return -EINVAL; > > > > + } > > > > > > > > - pci_read_config_word(pdev, pdev->pasid_cap + PCI_PASID_CAP, > > > > + pci_read_config_word(pf, pf->pasid_cap + PCI_PASID_CAP, > > > > &supported); > > > > > > > > supported &= PCI_PASID_CAP_EXEC | PCI_PASID_CAP_PRIV; > > > > > > > > + mutex_unlock(&pf->pasid_lock); > > > > + > > > > return supported; > > > > } > > > > EXPORT_SYMBOL_GPL(pci_pasid_features); > > > > @@ -579,15 +636,21 @@ EXPORT_SYMBOL_GPL(pci_prg_resp_pasid_required); > > > > int pci_max_pasids(struct pci_dev *pdev) > > > > { > > > > u16 supported; > > > > + struct pci_dev *pf = pci_physfn(pdev); > > > > + > > > > + mutex_lock(&pf->pasid_lock); > > > > > > > > - if (!pdev->pasid_cap) > > > > + if (!pf->pasid_cap) { > > > > + mutex_unlock(&pf->pasid_lock); > > > > return -EINVAL; > > > > + } > > > > > > > > - pci_read_config_word(pdev, pdev->pasid_cap + PCI_PASID_CAP, > > > > - &supported); > > > > + pci_read_config_word(pf, pf->pasid_cap + PCI_PASID_CAP, &supported); > > > > > > > > supported = (supported & PASID_NUMBER_MASK) >> PASID_NUMBER_SHIFT; > > > > > > > > + mutex_unlock(&pf->pasid_lock); > > > > + > > > > return (1 << supported); > > > > } > > > > EXPORT_SYMBOL_GPL(pci_max_pasids); > > > > diff --git a/include/linux/pci.h b/include/linux/pci.h > > > > index 3c9c4c82be27..4bfcca045afd 100644 > > > > --- a/include/linux/pci.h > > > > +++ b/include/linux/pci.h > > > > @@ -461,8 +461,10 @@ struct pci_dev { > > > > atomic_t pri_ref_cnt; /* Number of PF/VF PRI users */ > > > > #endif > > > > #ifdef CONFIG_PCI_PASID > > > > + struct mutex pasid_lock; /* PASID enable lock */ > > > > > > I think these locks are finer-grained than necessary. I'm not sure > > > it's worth having two mutexes for every device (one for PRI and > > > another for PASID). Is there really a performance benefit for having > > > two? > > > Performance benefit should be minimal. But, PRI and PASID are functionally > > independent. So I don't think its correct to protect its resources with > > a common lock. Let me know your comments. > > I'm not an expert on PRI and PASID, but if we can figure out a place > to put it and a way to manage it, I think it's OK to have a lock that > protects both. I'm thinking about the size of the pci_dev -- I'm not > sure the benefit of having two locks is commensurate with the size > cost. > > > > Do it (or do they) need to be in struct pci_dev? You only use the PF > > > mutexes, so maybe it could be in the struct pci_sriov, which I think > > > is only one per PF. > > > Its possible to move it to pci_sriov structure. But is that the right > > place for it? This lock is only used for protecting PRI and PASID feature > > updates and PRI/PASID are not dependent on IOV feature. Let me know your > > comments. > > Hmm. I misunderstood the use of these. I had the impression they > were only used for PFs. If that were the case, pci_sriov might make > sense because we only allocate that for PFs (when we enable SR-IOV in > sriov_init()). But IIUC that's *not* the case: even non-SR-IOV > devices can use PRI/PASID; it's just that if a *VF* uses them, the VF > is actually using the PRI of the PF. Yes, your current interpretation is correct. Even non SR-IOV devices can use PRI/PASID. But the race condition issue only exists in SR-IOV (PF/VF) devices. > > > If you want to move this lock to pci_sriov structure and use one lock > > for both PRI/PASID, then the implementation would look like following. We > > could create physfn lock/unlock functions in include/linux/pci.h similar > > to pci_physfn() function. > > > #ifdef CONFIG_PCI_IOV > > static inline void pci_physfn_reslock(struct pci_dev *dev) > > { > > struct pci_dev *pf = pci_physfn(dev); > > > > if (!pf->is_physfn) > > return; > > > > mutex_lock(&pf->sriov->reslock); > > > > } > > #else > > static inline void pci_physfn_reslock(struct pci_dev *dev) {}; > > #endif > > Yeah, that's not a pretty solution. IIUC, we don't need to lock at > all for non-SR-IOV devices, because we're operating on our own device > and nobody else should be touching it. Right? Yes, we don't need to lock for non-SR-IOV devices. > > Only the SR-IOV case (operating on a PF with SR-IOV enabled or on one > of its VFs) needs locking because these are all sharing one resource. > > So it's kind of a shame to allocate the lock for *every* pci_dev, when > we only need it for PFs with SR-IOV enabled. if not pci_dev structure, then next appropriate place to add this lock is struct pci_sriov. Since the issue is specific to SR-IOV devices, even if PASID/PRI has no dependency on SR-IOV, I think the we can add the reslock to pci_sriov structure. Please check the attached patch for sample implementation. > > Bjorn
diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c index 079dc5444444..9384afd7d00e 100644 --- a/drivers/pci/ats.c +++ b/drivers/pci/ats.c @@ -402,6 +402,8 @@ void pci_pasid_init(struct pci_dev *pdev) if (pdev->is_virtfn) return; + mutex_init(&pdev->pasid_lock); + pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PASID); if (!pos) return; @@ -436,32 +438,57 @@ void pci_pasid_init(struct pci_dev *pdev) int pci_enable_pasid(struct pci_dev *pdev, int features) { u16 control, supported; + int ret = 0; + struct pci_dev *pf = pci_physfn(pdev); - if (WARN_ON(pdev->pasid_enabled)) - return -EBUSY; + mutex_lock(&pf->pasid_lock); - if (!pdev->eetlp_prefix_path) - return -EINVAL; + if (WARN_ON(pdev->pasid_enabled)) { + ret = -EBUSY; + goto pasid_unlock; + } - if (!pdev->pasid_cap) - return -EINVAL; + if (!pdev->eetlp_prefix_path) { + ret = -EINVAL; + goto pasid_unlock; + } - pci_read_config_word(pdev, pdev->pasid_cap + PCI_PASID_CAP, - &supported); + if (!pf->pasid_cap) { + ret = -EINVAL; + goto pasid_unlock; + } + + if (pdev->is_virtfn && pf->pasid_enabled) + goto update_status; + + pci_read_config_word(pf, pf->pasid_cap + PCI_PASID_CAP, &supported); supported &= PCI_PASID_CAP_EXEC | PCI_PASID_CAP_PRIV; /* User wants to enable anything unsupported? */ - if ((supported & features) != features) - return -EINVAL; + if ((supported & features) != features) { + ret = -EINVAL; + goto pasid_unlock; + } control = PCI_PASID_CTRL_ENABLE | features; - pdev->pasid_features = features; - + pf->pasid_features = features; pci_write_config_word(pdev, pdev->pasid_cap + PCI_PASID_CTRL, control); - pdev->pasid_enabled = 1; + /* + * If PASID is not already enabled in PF, increment pasid_ref_cnt + * to count PF PASID usage. + */ + if (pdev->is_virtfn && !pf->pasid_enabled) { + atomic_inc(&pf->pasid_ref_cnt); + pf->pasid_enabled = 1; + } - return 0; +update_status: + atomic_inc(&pf->pasid_ref_cnt); + pdev->pasid_enabled = 1; +pasid_unlock: + mutex_unlock(&pf->pasid_lock); + return ret; } EXPORT_SYMBOL_GPL(pci_enable_pasid); @@ -472,16 +499,29 @@ EXPORT_SYMBOL_GPL(pci_enable_pasid); void pci_disable_pasid(struct pci_dev *pdev) { u16 control = 0; + struct pci_dev *pf = pci_physfn(pdev); + + mutex_lock(&pf->pasid_lock); if (WARN_ON(!pdev->pasid_enabled)) - return; + goto pasid_unlock; - if (!pdev->pasid_cap) - return; + if (!pf->pasid_cap) + goto pasid_unlock; - pci_write_config_word(pdev, pdev->pasid_cap + PCI_PASID_CTRL, control); + atomic_dec(&pf->pasid_ref_cnt); + if (atomic_read(&pf->pasid_ref_cnt)) + goto done; + + /* Disable PASID only if pasid_ref_cnt is zero */ + pci_write_config_word(pf, pf->pasid_cap + PCI_PASID_CTRL, control); + +done: pdev->pasid_enabled = 0; +pasid_unlock: + mutex_unlock(&pf->pasid_lock); + } EXPORT_SYMBOL_GPL(pci_disable_pasid); @@ -492,15 +532,25 @@ EXPORT_SYMBOL_GPL(pci_disable_pasid); void pci_restore_pasid_state(struct pci_dev *pdev) { u16 control; + struct pci_dev *pf = pci_physfn(pdev); if (!pdev->pasid_enabled) return; - if (!pdev->pasid_cap) + if (!pf->pasid_cap) return; + mutex_lock(&pf->pasid_lock); + + pci_read_config_word(pf, pf->pasid_cap + PCI_PASID_CTRL, &control); + if (control & PCI_PASID_CTRL_ENABLE) + goto pasid_unlock; + control = PCI_PASID_CTRL_ENABLE | pdev->pasid_features; - pci_write_config_word(pdev, pdev->pasid_cap + PCI_PASID_CTRL, control); + pci_write_config_word(pf, pf->pasid_cap + PCI_PASID_CTRL, control); + +pasid_unlock: + mutex_unlock(&pf->pasid_lock); } EXPORT_SYMBOL_GPL(pci_restore_pasid_state); @@ -517,15 +567,22 @@ EXPORT_SYMBOL_GPL(pci_restore_pasid_state); int pci_pasid_features(struct pci_dev *pdev) { u16 supported; + struct pci_dev *pf = pci_physfn(pdev); + + mutex_lock(&pf->pasid_lock); - if (!pdev->pasid_cap) + if (!pf->pasid_cap) { + mutex_unlock(&pf->pasid_lock); return -EINVAL; + } - pci_read_config_word(pdev, pdev->pasid_cap + PCI_PASID_CAP, + pci_read_config_word(pf, pf->pasid_cap + PCI_PASID_CAP, &supported); supported &= PCI_PASID_CAP_EXEC | PCI_PASID_CAP_PRIV; + mutex_unlock(&pf->pasid_lock); + return supported; } EXPORT_SYMBOL_GPL(pci_pasid_features); @@ -579,15 +636,21 @@ EXPORT_SYMBOL_GPL(pci_prg_resp_pasid_required); int pci_max_pasids(struct pci_dev *pdev) { u16 supported; + struct pci_dev *pf = pci_physfn(pdev); + + mutex_lock(&pf->pasid_lock); - if (!pdev->pasid_cap) + if (!pf->pasid_cap) { + mutex_unlock(&pf->pasid_lock); return -EINVAL; + } - pci_read_config_word(pdev, pdev->pasid_cap + PCI_PASID_CAP, - &supported); + pci_read_config_word(pf, pf->pasid_cap + PCI_PASID_CAP, &supported); supported = (supported & PASID_NUMBER_MASK) >> PASID_NUMBER_SHIFT; + mutex_unlock(&pf->pasid_lock); + return (1 << supported); } EXPORT_SYMBOL_GPL(pci_max_pasids); diff --git a/include/linux/pci.h b/include/linux/pci.h index 3c9c4c82be27..4bfcca045afd 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -461,8 +461,10 @@ struct pci_dev { atomic_t pri_ref_cnt; /* Number of PF/VF PRI users */ #endif #ifdef CONFIG_PCI_PASID + struct mutex pasid_lock; /* PASID enable lock */ u16 pasid_cap; /* PASID Capability offset */ u16 pasid_features; + atomic_t pasid_ref_cnt; /* Number of VFs with PASID enabled */ #endif #ifdef CONFIG_PCI_P2PDMA struct pci_p2pdma *p2pdma;