[PATCH 1/2] PCI: Save properties required to handle FLR for replay purposes.

[PATCH 1/2] PCI: Save properties required to handle FLR for replay purposes.

[Ashok Raj]

From: CQ Tang <cq.tang@intel.com>

Requires: https://patchwork.kernel.org/patch/9593891


After a FLR, pci-states need to be restored. This patch saves PASID features
and PRI reqs cached.

Cc: Jean-Phillipe Brucker <jean-philippe.brucker@arm.com>
Cc: David Woodhouse <dwm2@infradead.org>
Cc: iommu@lists.linux-foundation.org

Signed-off-by: CQ Tang <cq.tang@intel.com>
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
---
 drivers/pci/ats.c       | 65 +++++++++++++++++++++++++++++++++++++------------
 drivers/pci/pci.c       |  3 +++
 include/linux/pci-ats.h | 10 ++++++++
 include/linux/pci.h     |  6 +++++
 4 files changed, 69 insertions(+), 15 deletions(-)

diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c
index 2126497..a769955 100644
--- a/drivers/pci/ats.c
+++ b/drivers/pci/ats.c
@@ -160,17 +160,16 @@ int pci_enable_pri(struct pci_dev *pdev, u32 reqs)
 	if (!pos)
 		return -EINVAL;
 
-	pci_read_config_word(pdev, pos + PCI_PRI_CTRL, &control);
 	pci_read_config_word(pdev, pos + PCI_PRI_STATUS, &status);
-	if ((control & PCI_PRI_CTRL_ENABLE) ||
-	    !(status & PCI_PRI_STATUS_STOPPED))
+	if (!(status & PCI_PRI_STATUS_STOPPED))
 		return -EBUSY;
 
 	pci_read_config_dword(pdev, pos + PCI_PRI_MAX_REQ, &max_requests);
 	reqs = min(max_requests, reqs);
+	pdev->pri_reqs_alloc = reqs;
 	pci_write_config_dword(pdev, pos + PCI_PRI_ALLOC_REQ, reqs);
 
-	control |= PCI_PRI_CTRL_ENABLE;
+	control = PCI_PRI_CTRL_ENABLE;
 	pci_write_config_word(pdev, pos + PCI_PRI_CTRL, control);
 
 	pdev->pri_enabled = 1;
@@ -206,6 +205,29 @@ void pci_disable_pri(struct pci_dev *pdev)
 EXPORT_SYMBOL_GPL(pci_disable_pri);
 
 /**
+ * pci_restore_pri_state - Restore PRI
+ * @pdev: PCI device structure
+ *
+ */
+void pci_restore_pri_state(struct pci_dev *pdev)
+{
+   u16 control = PCI_PRI_CTRL_ENABLE;
+   u32 reqs = pdev->pri_reqs_alloc;
+   int pos;
+
+   pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
+   if (!pos)
+       return;
+
+   if (!pdev->pri_enabled)
+       return;
+
+   pci_write_config_dword(pdev, pos + PCI_PRI_ALLOC_REQ, reqs);
+   pci_write_config_word(pdev, pos + PCI_PRI_CTRL, control);
+}
+EXPORT_SYMBOL_GPL(pci_restore_pri_state);
+
+/**
  * pci_reset_pri - Resets device's PRI state
  * @pdev: PCI device structure
  *
@@ -224,12 +246,7 @@ int pci_reset_pri(struct pci_dev *pdev)
 	if (!pos)
 		return -EINVAL;
 
-	pci_read_config_word(pdev, pos + PCI_PRI_CTRL, &control);
-	if (control & PCI_PRI_CTRL_ENABLE)
-		return -EBUSY;
-
-	control |= PCI_PRI_CTRL_RESET;
-
+	control = PCI_PRI_CTRL_RESET;
 	pci_write_config_word(pdev, pos + PCI_PRI_CTRL, control);
 
 	return 0;
@@ -259,12 +276,7 @@ int pci_enable_pasid(struct pci_dev *pdev, int features)
 	if (!pos)
 		return -EINVAL;
 
-	pci_read_config_word(pdev, pos + PCI_PASID_CTRL, &control);
 	pci_read_config_word(pdev, pos + PCI_PASID_CAP, &supported);
-
-	if (control & PCI_PASID_CTRL_ENABLE)
-		return -EINVAL;
-
 	supported &= PCI_PASID_CAP_EXEC | PCI_PASID_CAP_PRIV;
 
 	/* User wants to enable anything unsupported? */
@@ -272,6 +284,7 @@ int pci_enable_pasid(struct pci_dev *pdev, int features)
 		return -EINVAL;
 
 	control = PCI_PASID_CTRL_ENABLE | features;
+	pdev->pasid_features = features;
 
 	pci_write_config_word(pdev, pos + PCI_PASID_CTRL, control);
 
@@ -305,6 +318,28 @@ void pci_disable_pasid(struct pci_dev *pdev)
 EXPORT_SYMBOL_GPL(pci_disable_pasid);
 
 /**
+ * pci_restore_pasid_state - Restore PASID capabilities.
+ * @pdev: PCI device structure
+ *
+ */
+void pci_restore_pasid_state(struct pci_dev *pdev)
+{
+   u16 control;
+   int pos;
+
+   pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PASID);
+   if (!pos)
+       return;
+
+   if (!pdev->pasid_enabled)
+       return;
+
+   control = PCI_PASID_CTRL_ENABLE | pdev->pasid_features;
+   pci_write_config_word(pdev, pos + PCI_PASID_CTRL, control);
+}
+EXPORT_SYMBOL_GPL(pci_restore_pasid_state);
+
+/**
  * pci_pasid_features - Check which PASID features are supported
  * @pdev: PCI device structure
  *
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 7904d02..c9a6510 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -28,6 +28,7 @@
 #include <linux/pm_runtime.h>
 #include <linux/pci_hotplug.h>
 #include <linux/vmalloc.h>
+#include <linux/pci-ats.h>
 #include <asm/setup.h>
 #include <asm/dma.h>
 #include <linux/aer.h>
@@ -1171,6 +1172,8 @@ void pci_restore_state(struct pci_dev *dev)
 
 	/* PCI Express register must be restored first */
 	pci_restore_pcie_state(dev);
+	pci_restore_pasid_state(dev);
+	pci_restore_pri_state(dev);
 	pci_restore_ats_state(dev);
 	pci_restore_vc_state(dev);
 
diff --git a/include/linux/pci-ats.h b/include/linux/pci-ats.h
index 57e0b82..782fb8e 100644
--- a/include/linux/pci-ats.h
+++ b/include/linux/pci-ats.h
@@ -7,6 +7,7 @@
 
 int pci_enable_pri(struct pci_dev *pdev, u32 reqs);
 void pci_disable_pri(struct pci_dev *pdev);
+void pci_restore_pri_state(struct pci_dev *pdev);
 int pci_reset_pri(struct pci_dev *pdev);
 
 #else /* CONFIG_PCI_PRI */
@@ -20,6 +21,10 @@ static inline void pci_disable_pri(struct pci_dev *pdev)
 {
 }
 
+static inline void pci_restore_pri_state(struct pci_dev *pdev)
+{
+}
+
 static inline int pci_reset_pri(struct pci_dev *pdev)
 {
 	return -ENODEV;
@@ -31,6 +36,7 @@ static inline int pci_reset_pri(struct pci_dev *pdev)
 
 int pci_enable_pasid(struct pci_dev *pdev, int features);
 void pci_disable_pasid(struct pci_dev *pdev);
+void pci_restore_pasid_state(struct pci_dev *pdev);
 int pci_pasid_features(struct pci_dev *pdev);
 int pci_max_pasids(struct pci_dev *pdev);
 
@@ -45,6 +51,10 @@ static inline void pci_disable_pasid(struct pci_dev *pdev)
 {
 }
 
+static inline void pci_restore_pasid_state(struct pci_dev *pdev)
+{
+}
+
 static inline int pci_pasid_features(struct pci_dev *pdev)
 {
 	return -EINVAL;
diff --git a/include/linux/pci.h b/include/linux/pci.h
index bee980e..1ddb8e0 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -395,6 +395,12 @@ struct pci_dev {
 	u8		ats_stu;	/* ATS Smallest Translation Unit */
 	atomic_t	ats_ref_cnt;	/* number of VFs with ATS enabled */
 #endif
+#ifdef CONFIG_PCI_PRI
+	u32		pri_reqs_alloc; /* Number of PRI requests allocated */
+#endif
+#ifdef CONFIG_PCI_PASID
+	u16		pasid_features;
+#endif
 	phys_addr_t rom; /* Physical address of ROM if it's not from the BAR */
 	size_t romlen; /* Length of ROM if it's not from the BAR */
 	char *driver_override; /* Driver name to force a match */
-- 
2.7.4

[PATCH 2/2] iommu/vt-d: Helper function to query if a pasid has any active users

[Ashok Raj]

From: CQ Tang <cq.tang@intel.com>

A driver would need to know if there are any active references to a
a PASID before cleaning up its resources. This function helps check
if there are any active users of a PASID before it can perform any
recovery on that device.

To: Joerg Roedel <joro@8bytes.org>
To: linux-kernel@vger.kernel.org
To: David Woodhouse <dwm2@infradead.org>
Cc: Jean-Phillipe Brucker <jean-philippe.brucker@arm.com>
Cc: iommu@lists.linux-foundation.org

Signed-off-by: CQ Tang <cq.tang@intel.com>
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
---
 drivers/iommu/intel-svm.c | 30 ++++++++++++++++++++++++++++++
 include/linux/intel-svm.h | 20 ++++++++++++++++++++
 2 files changed, 50 insertions(+)

diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
index 23c4276..f167c0d 100644
--- a/drivers/iommu/intel-svm.c
+++ b/drivers/iommu/intel-svm.c
@@ -489,6 +489,36 @@ int intel_svm_unbind_mm(struct device *dev, int pasid)
 }
 EXPORT_SYMBOL_GPL(intel_svm_unbind_mm);
 
+int intel_svm_is_pasid_valid(struct device *dev, int pasid)
+{
+	struct intel_iommu *iommu;
+	struct intel_svm *svm;
+	int ret = -EINVAL;
+
+	mutex_lock(&pasid_mutex);
+	iommu = intel_svm_device_to_iommu(dev);
+	if (!iommu || !iommu->pasid_table)
+		goto out;
+
+	svm = idr_find(&iommu->pasid_idr, pasid);
+	if (!svm)
+		goto out;
+
+	/* init_mm is used in this case */
+	if (!svm->mm)
+		ret = 1;
+	else if (atomic_read(&svm->mm->mm_users) > 0)
+		ret = 1;
+	else
+		ret = 0;
+
+ out:
+	mutex_unlock(&pasid_mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(intel_svm_is_pasid_valid);
+
 /* Page request queue descriptor */
 struct page_req_dsc {
 	u64 srr:1;
diff --git a/include/linux/intel-svm.h b/include/linux/intel-svm.h
index 3c25794..99bc5b3 100644
--- a/include/linux/intel-svm.h
+++ b/include/linux/intel-svm.h
@@ -102,6 +102,21 @@ extern int intel_svm_bind_mm(struct device *dev, int *pasid, int flags,
  */
 extern int intel_svm_unbind_mm(struct device *dev, int pasid);
 
+/**
+ * intel_svm_is_pasid_valid() - check if pasid is valid
+ * @dev:	Device for which PASID was allocated
+ * @pasid:	PASID value to be checked
+ *
+ * This function checks if the specified pasid is still valid. A
+ * valid pasid means the backing mm is still having a valid user.
+ * For kernel callers init_mm is always valid. for other mm, if mm->mm_users
+ * is non-zero, it is valid.
+ *
+ * returns -EINVAL if invalid pasid, 0 if pasid ref count is invalid
+ * 1 if pasid is valid.
+ */
+extern int intel_svm_is_pasid_valid(struct device *dev, int pasid);
+
 #else /* CONFIG_INTEL_IOMMU_SVM */
 
 static inline int intel_svm_bind_mm(struct device *dev, int *pasid,
@@ -114,6 +129,11 @@ static inline int intel_svm_unbind_mm(struct device *dev, int pasid)
 {
 	BUG();
 }
+
+static int intel_svm_is_pasid_valid(struct device *dev, int pasid)
+{
+	return -EINVAL;
+}
 #endif /* CONFIG_INTEL_IOMMU_SVM */
 
 #define intel_svm_available(dev) (!intel_svm_bind_mm((dev), NULL, 0, NULL))
-- 
2.7.4

[PATCH 2/2] iommu/vt-d: Helper function to query if a pasid has any active users

[Ashok Raj]

From: CQ Tang <cq.tang@intel.com>

A driver would need to know if there are any active references to a
a PASID before cleaning up its resources. This function helps check
if there are any active users of a PASID before it can perform any
recovery on that device.

To: Joerg Roedel <joro@8bytes.org>
To: linux-kernel@vger.kernel.org
To: David Woodhouse <dwmw2@infradead.org>
Cc: Jean-Phillipe Brucker <jean-philippe.brucker@arm.com>
Cc: iommu@lists.linux-foundation.org

Signed-off-by: CQ Tang <cq.tang@intel.com>
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
---
 drivers/iommu/intel-svm.c | 30 ++++++++++++++++++++++++++++++
 include/linux/intel-svm.h | 20 ++++++++++++++++++++
 2 files changed, 50 insertions(+)

diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
index 23c4276..f167c0d 100644
--- a/drivers/iommu/intel-svm.c
+++ b/drivers/iommu/intel-svm.c
@@ -489,6 +489,36 @@ int intel_svm_unbind_mm(struct device *dev, int pasid)
 }
 EXPORT_SYMBOL_GPL(intel_svm_unbind_mm);
 
+int intel_svm_is_pasid_valid(struct device *dev, int pasid)
+{
+	struct intel_iommu *iommu;
+	struct intel_svm *svm;
+	int ret = -EINVAL;
+
+	mutex_lock(&pasid_mutex);
+	iommu = intel_svm_device_to_iommu(dev);
+	if (!iommu || !iommu->pasid_table)
+		goto out;
+
+	svm = idr_find(&iommu->pasid_idr, pasid);
+	if (!svm)
+		goto out;
+
+	/* init_mm is used in this case */
+	if (!svm->mm)
+		ret = 1;
+	else if (atomic_read(&svm->mm->mm_users) > 0)
+		ret = 1;
+	else
+		ret = 0;
+
+ out:
+	mutex_unlock(&pasid_mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(intel_svm_is_pasid_valid);
+
 /* Page request queue descriptor */
 struct page_req_dsc {
 	u64 srr:1;
diff --git a/include/linux/intel-svm.h b/include/linux/intel-svm.h
index 3c25794..99bc5b3 100644
--- a/include/linux/intel-svm.h
+++ b/include/linux/intel-svm.h
@@ -102,6 +102,21 @@ extern int intel_svm_bind_mm(struct device *dev, int *pasid, int flags,
  */
 extern int intel_svm_unbind_mm(struct device *dev, int pasid);
 
+/**
+ * intel_svm_is_pasid_valid() - check if pasid is valid
+ * @dev:	Device for which PASID was allocated
+ * @pasid:	PASID value to be checked
+ *
+ * This function checks if the specified pasid is still valid. A
+ * valid pasid means the backing mm is still having a valid user.
+ * For kernel callers init_mm is always valid. for other mm, if mm->mm_users
+ * is non-zero, it is valid.
+ *
+ * returns -EINVAL if invalid pasid, 0 if pasid ref count is invalid
+ * 1 if pasid is valid.
+ */
+extern int intel_svm_is_pasid_valid(struct device *dev, int pasid);
+
 #else /* CONFIG_INTEL_IOMMU_SVM */
 
 static inline int intel_svm_bind_mm(struct device *dev, int *pasid,
@@ -114,6 +129,11 @@ static inline int intel_svm_unbind_mm(struct device *dev, int pasid)
 {
 	BUG();
 }
+
+static int intel_svm_is_pasid_valid(struct device *dev, int pasid)
+{
+	return -EINVAL;
+}
 #endif /* CONFIG_INTEL_IOMMU_SVM */
 
 #define intel_svm_available(dev) (!intel_svm_bind_mm((dev), NULL, 0, NULL))
-- 
2.7.4

Re: [PATCH 2/2] iommu/vt-d: Helper function to query if a pasid has any active users

[Joerg Roedel]

On Wed, May 10, 2017 at 11:39:03AM -0700, Ashok Raj wrote:
> From: CQ Tang <cq.tang@intel.com>
> 
> A driver would need to know if there are any active references to a
> a PASID before cleaning up its resources. This function helps check
> if there are any active users of a PASID before it can perform any
> recovery on that device.
> 
> To: Joerg Roedel <joro@8bytes.org>
> To: linux-kernel@vger.kernel.org
> To: David Woodhouse <dwmw2@infradead.org>
> Cc: Jean-Phillipe Brucker <jean-philippe.brucker@arm.com>
> Cc: iommu@lists.linux-foundation.org
> 
> Signed-off-by: CQ Tang <cq.tang@intel.com>
> Signed-off-by: Ashok Raj <ashok.raj@intel.com>
> ---
>  drivers/iommu/intel-svm.c | 30 ++++++++++++++++++++++++++++++
>  include/linux/intel-svm.h | 20 ++++++++++++++++++++
>  2 files changed, 50 insertions(+)

Applied, thanks.