crypto: qat - allow disabling SR-IOV VFs

The QAT driver allows enabling SR-IOV VFs but does not allow them to be
disabled through a write to sysfs.
Disabling SR-IOV VFs can be only achieved by bringing down and up a
device using the attribute /sys/bus/pci/devices/<BDF>/qat/state.

The documentation for the sysfs attribute `sriov_numvfs` specifies
that "a userspace application wanting to disable the VFs would write a
zero to this file".

Add support for disabling SR-IOV VFs by writing '0' to the
'sriov_numvfs' attribute in sysfs.

Enabling or disabling SR-IOV always requires adf_dev_down() to be
called. This action subsequently leads to the deletion of the
ADF_KERNEL_SEC configuration section. The keys ADF_NUM_CY and ADF_NUM_DC
within that section must be set to '0', otherwise, the driver will
register into the Linux Crypto Framework. Because of this, the
configuration in the ADF_KERNEL_SEC section must be added before every
sriov_enable.
Signed-off-by: Michal Witwicki <michal.witwicki@intel.com>
Reviewed-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/intel/qat/qat_common/adf_sriov.c

@@ -86,11 +86,133 @@ static int adf_enable_sriov(struct adf_accel_dev *accel_dev)
 	return pci_enable_sriov(pdev, totalvfs);
 }
 
+static int adf_add_sriov_configuration(struct adf_accel_dev *accel_dev)
+{
+	unsigned long val = 0;
+	int ret;
+
+	ret = adf_cfg_section_add(accel_dev, ADF_KERNEL_SEC);
+	if (ret)
+		return ret;
+
+	ret = adf_cfg_add_key_value_param(accel_dev, ADF_KERNEL_SEC, ADF_NUM_CY,
+					  &val, ADF_DEC);
+	if (ret)
+		return ret;
+
+	ret = adf_cfg_add_key_value_param(accel_dev, ADF_KERNEL_SEC, ADF_NUM_DC,
+					  &val, ADF_DEC);
+	if (ret)
+		return ret;
+
+	set_bit(ADF_STATUS_CONFIGURED, &accel_dev->status);
+
+	return ret;
+}
+
+static int adf_do_disable_sriov(struct adf_accel_dev *accel_dev)
+{
+	int ret;
+
+	if (adf_dev_in_use(accel_dev)) {
+		dev_err(&GET_DEV(accel_dev),
+			"Cannot disable SR-IOV, device in use\n");
+		return -EBUSY;
+	}
+
+	if (adf_dev_started(accel_dev)) {
+		if (adf_devmgr_in_reset(accel_dev)) {
+			dev_err(&GET_DEV(accel_dev),
+				"Cannot disable SR-IOV, device in reset\n");
+			return -EBUSY;
+		}
+
+		ret = adf_dev_down(accel_dev);
+		if (ret)
+			goto err_del_cfg;
+	}
+
+	adf_disable_sriov(accel_dev);
+
+	ret = adf_dev_up(accel_dev, true);
+	if (ret)
+		goto err_del_cfg;
+
+	return 0;
+
+err_del_cfg:
+	adf_cfg_del_all_except(accel_dev, ADF_GENERAL_SEC);
+	return ret;
+}
+
+static int adf_do_enable_sriov(struct adf_accel_dev *accel_dev)
+{
+	struct pci_dev *pdev = accel_to_pci_dev(accel_dev);
+	int totalvfs = pci_sriov_get_totalvfs(pdev);
+	unsigned long val;
+	int ret;
+
+	if (!device_iommu_mapped(&GET_DEV(accel_dev))) {
+		dev_warn(&GET_DEV(accel_dev),
+			 "IOMMU should be enabled for SR-IOV to work correctly\n");
+		return -EINVAL;
+	}
+
+	if (adf_dev_started(accel_dev)) {
+		if (adf_devmgr_in_reset(accel_dev) || adf_dev_in_use(accel_dev)) {
+			dev_err(&GET_DEV(accel_dev), "Device busy\n");
+			return -EBUSY;
+		}
+
+		ret = adf_dev_down(accel_dev);
+		if (ret)
+			return ret;
+	}
+
+	ret = adf_add_sriov_configuration(accel_dev);
+	if (ret)
+		goto err_del_cfg;
+
+	/* Allocate memory for VF info structs */
+	accel_dev->pf.vf_info = kcalloc(totalvfs, sizeof(struct adf_accel_vf_info),
+					GFP_KERNEL);
+	ret = -ENOMEM;
+	if (!accel_dev->pf.vf_info)
+		goto err_del_cfg;
+
+	ret = adf_dev_up(accel_dev, false);
+	if (ret) {
+		dev_err(&GET_DEV(accel_dev), "Failed to start qat_dev%d\n",
+			accel_dev->accel_id);
+		goto err_free_vf_info;
+	}
+
+	ret = adf_enable_sriov(accel_dev);
+	if (ret)
+		goto err_free_vf_info;
+
+	val = 1;
+	ret = adf_cfg_add_key_value_param(accel_dev, ADF_GENERAL_SEC, ADF_SRIOV_ENABLED,
+					  &val, ADF_DEC);
+	if (ret)
+		goto err_free_vf_info;
+
+	return totalvfs;
+
+err_free_vf_info:
+	adf_dev_down(accel_dev);
+	kfree(accel_dev->pf.vf_info);
+	accel_dev->pf.vf_info = NULL;
+	return ret;
+err_del_cfg:
+	adf_cfg_del_all_except(accel_dev, ADF_GENERAL_SEC);
+	return ret;
+}
+
 void adf_reenable_sriov(struct adf_accel_dev *accel_dev)
 {
 	struct pci_dev *pdev = accel_to_pci_dev(accel_dev);
 	char cfg[ADF_CFG_MAX_VAL_LEN_IN_BYTES] = {0};
-	unsigned long val = 0;
 
 	if (adf_cfg_get_param_value(accel_dev, ADF_GENERAL_SEC,
 				    ADF_SRIOV_ENABLED, cfg))
@@ -99,15 +221,9 @@ void adf_reenable_sriov(struct adf_accel_dev *accel_dev)
 	if (!accel_dev->pf.vf_info)
 		return;
 
-	if (adf_cfg_add_key_value_param(accel_dev, ADF_KERNEL_SEC, ADF_NUM_CY,
-					&val, ADF_DEC))
-		return;
-
-	if (adf_cfg_add_key_value_param(accel_dev, ADF_KERNEL_SEC, ADF_NUM_DC,
-					&val, ADF_DEC))
+	if (adf_add_sriov_configuration(accel_dev))
 		return;
 
-	set_bit(ADF_STATUS_CONFIGURED, &accel_dev->status);
 	dev_dbg(&pdev->dev, "Re-enabling SRIOV\n");
 	adf_enable_sriov(accel_dev);
 }
@@ -168,70 +284,16 @@ EXPORT_SYMBOL_GPL(adf_disable_sriov);
 int adf_sriov_configure(struct pci_dev *pdev, int numvfs)
 {
 	struct adf_accel_dev *accel_dev = adf_devmgr_pci_to_accel_dev(pdev);
-	int totalvfs = pci_sriov_get_totalvfs(pdev);
-	unsigned long val;
-	int ret;
 
 	if (!accel_dev) {
 		dev_err(&pdev->dev, "Failed to find accel_dev\n");
 		return -EFAULT;
 	}
 
-	if (!device_iommu_mapped(&pdev->dev))
-		dev_warn(&pdev->dev, "IOMMU should be enabled for SR-IOV to work correctly\n");
-
-	if (accel_dev->pf.vf_info) {
-		dev_info(&pdev->dev, "Already enabled for this device\n");
-		return -EINVAL;
-	}
-
-	if (adf_dev_started(accel_dev)) {
-		if (adf_devmgr_in_reset(accel_dev) ||
-		    adf_dev_in_use(accel_dev)) {
-			dev_err(&GET_DEV(accel_dev), "Device busy\n");
-			return -EBUSY;
-		}
-
-		ret = adf_dev_down(accel_dev);
-		if (ret)
-			return ret;
-	}
-
-	if (adf_cfg_section_add(accel_dev, ADF_KERNEL_SEC))
-		return -EFAULT;
-	val = 0;
-	if (adf_cfg_add_key_value_param(accel_dev, ADF_KERNEL_SEC,
-					ADF_NUM_CY, (void *)&val, ADF_DEC))
-		return -EFAULT;
-	ret = adf_cfg_add_key_value_param(accel_dev, ADF_KERNEL_SEC, ADF_NUM_DC,
-					  &val, ADF_DEC);
-	if (ret)
-		return ret;
-
-	set_bit(ADF_STATUS_CONFIGURED, &accel_dev->status);
-
-	/* Allocate memory for VF info structs */
-	accel_dev->pf.vf_info = kcalloc(totalvfs,
-					sizeof(struct adf_accel_vf_info),
-					GFP_KERNEL);
-	if (!accel_dev->pf.vf_info)
-		return -ENOMEM;
-
-	if (adf_dev_up(accel_dev, false)) {
-		dev_err(&GET_DEV(accel_dev), "Failed to start qat_dev%d\n",
-			accel_dev->accel_id);
-		return -EFAULT;
-	}
-
-	ret = adf_enable_sriov(accel_dev);
-	if (ret)
-		return ret;
-
-	val = 1;
-	adf_cfg_add_key_value_param(accel_dev, ADF_GENERAL_SEC, ADF_SRIOV_ENABLED,
-				    &val, ADF_DEC);
-
-	return numvfs;
+	if (numvfs)
+		return adf_do_enable_sriov(accel_dev);
+	else
+		return adf_do_disable_sriov(accel_dev);
 }
 EXPORT_SYMBOL_GPL(adf_sriov_configure);