The following commit has been merged into the x86/urgent branch of tip:
Commit-ID: 9f8614f5567eb4e38579422d38a1bdfeeb648ffc
Gitweb:
https://git.kernel.org/tip/9f8614f5567eb4e38579422d38a1bdfeeb648ffc
Author: Jean-Philippe Brucker <jean-phili...@linaro.org>
AuthorDate: Wed, 14 Apr 2021 10:26:34 +02:00
Committer: Borislav Petkov <b...@suse.de>
CommitterDate: Thu, 15 Apr 2021 10:27:29 +02:00
x86/dma: Tear down DMA ops on driver unbind
Since
08a27c1c3ecf ("iommu: Add support to change default domain of an iommu group")
a user can switch a device between IOMMU and direct DMA through sysfs.
This doesn't work for AMD IOMMU at the moment because dev->dma_ops is
not cleared when switching from a DMA to an identity IOMMU domain. The
DMA layer thus attempts to use the dma-iommu ops on an identity domain,
causing an oops:
# echo 0000:00:05.0 > /sys/sys/bus/pci/drivers/e1000e/unbind
# echo identity > /sys/bus/pci/devices/0000:00:05.0/iommu_group/type
# echo 0000:00:05.0 > /sys/sys/bus/pci/drivers/e1000e/bind
...
BUG: kernel NULL pointer dereference, address: 0000000000000028
...
Call Trace:
iommu_dma_alloc
e1000e_setup_tx_resources
e1000e_open
Implement arch_teardown_dma_ops() on x86 to clear the device's dma_ops
pointer during driver unbind.
[ bp: Massage commit message. ]
Fixes: 08a27c1c3ecf ("iommu: Add support to change default domain of an iommu
group")
Signed-off-by: Jean-Philippe Brucker <jean-phili...@linaro.org>
Signed-off-by: Borislav Petkov <b...@suse.de>
Link: https://lkml.kernel.org/r/20210414082633.877461-1-jean-phili...@linaro.org
---
arch/x86/Kconfig | 1 +
arch/x86/kernel/pci-dma.c | 7 +++++++
2 files changed, 8 insertions(+)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 2792879..2c90f8d 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -85,6 +85,7 @@ config X86
select ARCH_HAS_STRICT_MODULE_RWX
select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
select ARCH_HAS_SYSCALL_WRAPPER
+ select ARCH_HAS_TEARDOWN_DMA_OPS if IOMMU_DMA
select ARCH_HAS_UBSAN_SANITIZE_ALL
select ARCH_HAS_DEBUG_WX
select ARCH_HAVE_NMI_SAFE_CMPXCHG
diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index de234e7..60a4ec2 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -154,3 +154,10 @@ static void via_no_dac(struct pci_dev *dev)
DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_VIA, PCI_ANY_ID,
PCI_CLASS_BRIDGE_PCI, 8, via_no_dac);
#endif
+
+#ifdef CONFIG_ARCH_HAS_TEARDOWN_DMA_OPS
+void arch_teardown_dma_ops(struct device *dev)
+{
+ set_dma_ops(dev, NULL);
+}
+#endif
