[PATCH 11/12] iommu/vt-d: Add page response ops support

From: Lu Baolu <baolu.lu@linux.intel.com>
To: Joerg Roedel <joro@8bytes.org>
Cc: iommu@lists.linux-foundation.org
Subject: [PATCH 11/12] iommu/vt-d: Add page response ops support
Date: Fri, 24 Jul 2020 09:49:24 +0800	[thread overview]
Message-ID: <20200724014925.15523-12-baolu.lu@linux.intel.com> (raw)
In-Reply-To: <20200724014925.15523-1-baolu.lu@linux.intel.com>

After page requests are handled, software must respond to the device
which raised the page request with the result. This is done through
the iommu ops.page_response if the request was reported to outside of
vendor iommu driver through iommu_report_device_fault(). This adds the
VT-d implementation of page_response ops.

Co-developed-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Co-developed-by: Liu Yi L <yi.l.liu@intel.com>
Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
---
 drivers/iommu/intel/iommu.c |  1 +
 drivers/iommu/intel/svm.c   | 99 +++++++++++++++++++++++++++++++++++++
 include/linux/intel-iommu.h |  3 ++
 3 files changed, 103 insertions(+)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 097a71b3b75d..a939d17d40a1 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -6073,6 +6073,7 @@ const struct iommu_ops intel_iommu_ops = {
 	.sva_bind		= intel_svm_bind,
 	.sva_unbind		= intel_svm_unbind,
 	.sva_get_pasid		= intel_svm_get_pasid,
+	.page_response		= intel_svm_page_response,
 #endif
 };
 
diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
index 140114ab1375..85ce8daa3177 100644
--- a/drivers/iommu/intel/svm.c
+++ b/drivers/iommu/intel/svm.c
@@ -1078,3 +1078,102 @@ int intel_svm_get_pasid(struct iommu_sva *sva)
 
 	return pasid;
 }
+
+int intel_svm_page_response(struct device *dev,
+			    struct iommu_fault_event *evt,
+			    struct iommu_page_response *msg)
+{
+	struct iommu_fault_page_request *prm;
+	struct intel_svm_dev *sdev = NULL;
+	struct intel_svm *svm = NULL;
+	struct intel_iommu *iommu;
+	bool private_present;
+	bool pasid_present;
+	bool last_page;
+	u8 bus, devfn;
+	int ret = 0;
+	u16 sid;
+
+	if (!dev || !dev_is_pci(dev))
+		return -ENODEV;
+
+	iommu = device_to_iommu(dev, &bus, &devfn);
+	if (!iommu)
+		return -ENODEV;
+
+	if (!msg || !evt)
+		return -EINVAL;
+
+	mutex_lock(&pasid_mutex);
+
+	prm = &evt->fault.prm;
+	sid = PCI_DEVID(bus, devfn);
+	pasid_present = prm->flags & IOMMU_FAULT_PAGE_REQUEST_PASID_VALID;
+	private_present = prm->flags & IOMMU_FAULT_PAGE_REQUEST_PRIV_DATA;
+	last_page = prm->flags & IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE;
+
+	if (!pasid_present) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (prm->pasid == 0 || prm->pasid >= PASID_MAX) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	ret = pasid_to_svm_sdev(dev, prm->pasid, &svm, &sdev);
+	if (ret || !sdev) {
+		ret = -ENODEV;
+		goto out;
+	}
+
+	/*
+	 * For responses from userspace, need to make sure that the
+	 * pasid has been bound to its mm.
+	 */
+	if (svm->flags & SVM_FLAG_GUEST_MODE) {
+		struct mm_struct *mm;
+
+		mm = get_task_mm(current);
+		if (!mm) {
+			ret = -EINVAL;
+			goto out;
+		}
+
+		if (mm != svm->mm) {
+			ret = -ENODEV;
+			mmput(mm);
+			goto out;
+		}
+
+		mmput(mm);
+	}
+
+	/*
+	 * Per VT-d spec. v3.0 ch7.7, system software must respond
+	 * with page group response if private data is present (PDP)
+	 * or last page in group (LPIG) bit is set. This is an
+	 * additional VT-d requirement beyond PCI ATS spec.
+	 */
+	if (last_page || private_present) {
+		struct qi_desc desc;
+
+		desc.qw0 = QI_PGRP_PASID(prm->pasid) | QI_PGRP_DID(sid) |
+				QI_PGRP_PASID_P(pasid_present) |
+				QI_PGRP_PDP(private_present) |
+				QI_PGRP_RESP_CODE(msg->code) |
+				QI_PGRP_RESP_TYPE;
+		desc.qw1 = QI_PGRP_IDX(prm->grpid) | QI_PGRP_LPIG(last_page);
+		desc.qw2 = 0;
+		desc.qw3 = 0;
+		if (private_present)
+			memcpy(&desc.qw2, prm->private_data,
+			       sizeof(prm->private_data));
+
+		qi_submit_sync(iommu, &desc, 1, 0);
+	}
+out:
+	mutex_unlock(&pasid_mutex);
+	return ret;
+}
diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
index 7e69aec60592..b1ed2f25f7c0 100644
--- a/include/linux/intel-iommu.h
+++ b/include/linux/intel-iommu.h
@@ -742,6 +742,9 @@ struct iommu_sva *intel_svm_bind(struct device *dev, struct mm_struct *mm,
 				 void *drvdata);
 void intel_svm_unbind(struct iommu_sva *handle);
 int intel_svm_get_pasid(struct iommu_sva *handle);
+int intel_svm_page_response(struct device *dev, struct iommu_fault_event *evt,
+			    struct iommu_page_response *msg);
+
 struct svm_dev_ops;
 
 struct intel_svm_dev {
-- 
2.17.1

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