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authorLu Baolu <baolu.lu@linux.intel.com>2019-03-20 09:58:33 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-04-20 09:17:02 +0200
commitd965161274983e34caf8f38af287f0a1e2adbb27 (patch)
tree10775d6fe0eee7ba1a5074355031390c8e82cb05
parentd9fb98c921a89a178cfa36c8efcb675493644314 (diff)
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iommu/vt-d: Check capability before disabling protected memory
[ Upstream commit 5bb71fc790a88d063507dc5d445ab8b14e845591 ] The spec states in 10.4.16 that the Protected Memory Enable Register should be treated as read-only for implementations not supporting protected memory regions (PLMR and PHMR fields reported as Clear in the Capability register). Cc: Jacob Pan <jacob.jun.pan@linux.intel.com> Cc: mark gross <mgross@intel.com> Suggested-by: Ashok Raj <ashok.raj@intel.com> Fixes: f8bab73515ca5 ("intel-iommu: PMEN support") Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Sasha Levin <sashal@kernel.org>
-rw-r--r--drivers/iommu/intel-iommu.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index dbd6824dfffa..68a21c49c562 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -1534,6 +1534,9 @@ static void iommu_disable_protect_mem_regions(struct intel_iommu *iommu)
u32 pmen;
unsigned long flags;
+ if (!cap_plmr(iommu->cap) && !cap_phmr(iommu->cap))
+ return;
+
raw_spin_lock_irqsave(&iommu->register_lock, flags);
pmen = readl(iommu->reg + DMAR_PMEN_REG);
pmen &= ~DMA_PMEN_EPM;