| From | Sasha Levin <> | Subject | [PATCH AUTOSEL 4.14 242/371] iommu/amd: Make iommu_disable safer | Date | Thu, 16 Jan 2020 12:21:54 -0500 |
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From: Kevin Mitchell <kevmitch@arista.com>
[ 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 <kevmitch@arista.com> Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Sasha Levin <sashal@kernel.org> --- 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 6a3cf4d0bd5e..4d2920988d60 100644 --- a/drivers/iommu/amd_iommu_init.c +++ b/drivers/iommu/amd_iommu_init.c @@ -420,6 +420,9 @@ 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); -- 2.20.1
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