Messages in this thread Patch in this message | | | From | Lu Baolu <> | Subject | [PATCH 1/2] iommu/vt-d: Check capability before disabling protected memory | Date | Wed, 20 Mar 2019 09:58:33 +0800 |
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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
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