[PATCH v2 3/4] iommu/vt-d: Reject unsupported page request modes

From: Jacob Pan <jacob.jun.pan@linux.intel.com>
To: LKML <linux-kernel@vger.kernel.org>,
	iommu@lists.linux-foundation.org, Joerg Roedel <joro@8bytes.org>,
	"Lu Baolu" <baolu.lu@linux.intel.com>,
	David Woodhouse <dwmw2@infradead.org>
Cc: Yi Liu <yi.l.liu@intel.com>, Raj Ashok <ashok.raj@intel.com>,
	"Tian, Kevin" <kevin.tian@intel.com>,
	Eric Auger <eric.auger@redhat.com>,
	Jean-Philippe Brucker <jean-philippe@linaro.com>,
	Jacob Pan <jacob.jun.pan@linux.intel.com>
Subject: [PATCH v2 3/4] iommu/vt-d: Reject unsupported page request modes
Date: Tue,  2 Mar 2021 02:13:59 -0800	[thread overview]
Message-ID: <1614680040-1989-4-git-send-email-jacob.jun.pan@linux.intel.com> (raw)
In-Reply-To: <1614680040-1989-1-git-send-email-jacob.jun.pan@linux.intel.com>

When supervisor/privilige mode SVM is used, we bind init_mm.pgd with
a supervisor PASID. There should not be any page fault for init_mm.
Execution request with DMA read is also not supported.

This patch checks PRQ descriptor for both unsupported configurations,
reject them both with invalid responses.

Fixes: 1c4f88b7f1f92 ("iommu/vt-d: Shared virtual address in scalable
mode")
Acked-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
---
 drivers/iommu/intel/svm.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
index 23a1e4f58c54..ff7ae7cc17d5 100644
--- a/drivers/iommu/intel/svm.c
+++ b/drivers/iommu/intel/svm.c
@@ -1113,7 +1113,17 @@ static irqreturn_t prq_event_thread(int irq, void *d)
 			       ((unsigned long long *)req)[1]);
 			goto no_pasid;
 		}
-
+		/* We shall not receive page request for supervisor SVM */
+		if (req->pm_req && (req->rd_req | req->wr_req)) {
+			pr_err("Unexpected page request in Privilege Mode");
+			/* No need to find the matching sdev as for bad_req */
+			goto no_pasid;
+		}
+		/* DMA read with exec requeset is not supported. */
+		if (req->exe_req && req->rd_req) {
+			pr_err("Execution request not supported\n");
+			goto no_pasid;
+		}
 		if (!svm || svm->pasid != req->pasid) {
 			rcu_read_lock();
 			svm = ioasid_find(NULL, req->pasid, NULL);
-- 
2.25.1

