From: Kevin Mitchell <kevmitch@arista.com>
Date: Wed, 12 Jun 2019 14:52:03 -0700
Subject: iommu/amd: Make iommu_disable safer
Git-commit: 3ddbe913e55516d3e2165d43d4d5570761769878
Patch-mainline: v5.3-rc1
References: bsc#1140955
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 <kevmitch@arista.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
drivers/iommu/amd_iommu_init.c | 3 +++
1 file changed, 3 insertions(+)
--- a/drivers/iommu/amd_iommu_init.c
+++ b/drivers/iommu/amd_iommu_init.c
@@ -421,6 +421,9 @@ static void iommu_enable(struct amd_iomm
static void iommu_disable(struct amd_iommu *iommu)
{
+ if (!iommu->mmio_base)
+ return;
+
/* Disable command buffer */
iommu_feature_disable(iommu, CONTROL_CMDBUF_EN);