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* [PATCH 1/2] iommu/vt-d: Check capability before disabling protected memory
@ 2019-03-20  1:58 Lu Baolu
  2019-03-20  1:58 ` [PATCH 2/2] iommu/vt-d: Save the right domain ID used by hardware Lu Baolu
  2019-03-22  9:38 ` [PATCH 1/2] iommu/vt-d: Check capability before disabling protected memory Joerg Roedel
  0 siblings, 2 replies; 3+ messages in thread
From: Lu Baolu @ 2019-03-20  1:58 UTC (permalink / raw)
  To: Joerg Roedel, David Woodhouse
  Cc: ashok.raj, jacob.jun.pan, kevin.tian, yi.l.liu, iommu,
	linux-kernel, Lu Baolu, Jacob Pan, mark gross

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>
---
 drivers/iommu/intel-iommu.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 87274b54febd..f002d47d2f27 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -1538,6 +1538,9 @@ 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;
-- 
2.17.1


^ permalink raw reply related	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2019-03-22  9:38 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
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2019-03-20  1:58 [PATCH 1/2] iommu/vt-d: Check capability before disabling protected memory Lu Baolu
2019-03-20  1:58 ` [PATCH 2/2] iommu/vt-d: Save the right domain ID used by hardware Lu Baolu
2019-03-22  9:38 ` [PATCH 1/2] iommu/vt-d: Check capability before disabling protected memory Joerg Roedel

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