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Message-Id: <20200116173641.22137-122-sashal@kernel.org>
Date: Thu, 16 Jan 2020 12:35:11 -0500
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc: Kevin Mitchell <kevmitch@...sta.com>,
Joerg Roedel <jroedel@...e.de>,
Sasha Levin <sashal@...nel.org>,
iommu@...ts.linux-foundation.org
Subject: [PATCH AUTOSEL 4.9 162/251] iommu/amd: Make iommu_disable safer
From: Kevin Mitchell <kevmitch@...sta.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@...sta.com>
Signed-off-by: Joerg Roedel <jroedel@...e.de>
Signed-off-by: Sasha Levin <sashal@...nel.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 9bb8d64b6f94..c113e46fdc3a 100644
--- a/drivers/iommu/amd_iommu_init.c
+++ b/drivers/iommu/amd_iommu_init.c
@@ -383,6 +383,9 @@ 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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