[PATCH 5.12 454/677] iommu/vt-d: Reject unsupported page request modes

From: Greg Kroah-Hartman
Date: Wed May 12 2021 - 14:58:15 EST


From: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>

[ Upstream commit 78a523fe73b81b4447beb2d6c78c9fafae24eebb ]

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@xxxxxxxxxxxxxxx>
Signed-off-by: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/1614680040-1989-4-git-send-email-jacob.jun.pan@xxxxxxxxxxxxxxx
Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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 574a7e657a9a..4627437ae1c0 100644
--- a/drivers/iommu/intel/svm.c
+++ b/drivers/iommu/intel/svm.c
@@ -920,7 +920,17 @@ 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);
--
2.30.2