[ 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 <[email protected]> Cc: mark gross <[email protected]> Suggested-by: Ashok Raj <[email protected]> Fixes: f8bab73515ca5 ("intel-iommu: PMEN support") Signed-off-by: Lu Baolu <[email protected]> Signed-off-by: Joerg Roedel <[email protected]> Signed-off-by: Sasha Levin <[email protected]> --- 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 8b4a4d95669a..3e97c4b2ebed 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -1598,6 +1598,9 @@ 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; -- 2.19.1
