From 511d8decd182f6c3b2de08d6ef176db1e675c004 Mon Sep 17 00:00:00 2001 From: Kevin Mitchell Date: Wed, 12 Jun 2019 14:52:03 -0700 Subject: [PATCH] iommu/amd: Make iommu_disable safer [ Upstream commit 3ddbe913e55516d3e2165d43d4d5570761769878 ] Make it safe to call iommu_disable during early init error conditions before mmio_base is set, but after the struct amd_iommu has been added to the amd_iommu_list. For example, this happens if firmware fails to fill in mmio_phys in the ACPI table leading to a NULL pointer dereference in iommu_feature_disable. Fixes: 2c0ae1720c09c ('iommu/amd: Convert iommu initialization to state machine') Signed-off-by: Kevin Mitchell Signed-off-by: Joerg Roedel Signed-off-by: Sasha Levin --- drivers/iommu/amd_iommu_init.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c index 1e9a5da562f0..465f28a7844c 100644 --- a/drivers/iommu/amd_iommu_init.c +++ b/drivers/iommu/amd_iommu_init.c @@ -422,6 +422,9 @@ static void iommu_enable(struct amd_iommu *iommu) static void iommu_disable(struct amd_iommu *iommu) { + if (!iommu->mmio_base) + return; + /* Disable command buffer */ iommu_feature_disable(iommu, CONTROL_CMDBUF_EN); -- 2.11.0