<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/drivers/iommu, branch v6.2.2</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>iommu/mediatek-v1: Fix an error handling path in mtk_iommu_v1_probe()</title>
<updated>2023-01-13T12:46:32+00:00</updated>
<author>
<name>Christophe JAILLET</name>
<email>christophe.jaillet@wanadoo.fr</email>
</author>
<published>2022-12-19T18:06:22+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=142e821f68cf5da79ce722cb9c1323afae30e185'/>
<id>142e821f68cf5da79ce722cb9c1323afae30e185</id>
<content type='text'>
A clk, prepared and enabled in mtk_iommu_v1_hw_init(), is not released in
the error handling path of mtk_iommu_v1_probe().

Add the corresponding clk_disable_unprepare(), as already done in the
remove function.

Fixes: b17336c55d89 ("iommu/mediatek: add support for mtk iommu generation one HW")
Signed-off-by: Christophe JAILLET &lt;christophe.jaillet@wanadoo.fr&gt;
Reviewed-by: Yong Wu &lt;yong.wu@mediatek.com&gt;
Reviewed-by: AngeloGioacchino Del Regno &lt;angelogioacchino.delregno@collabora.com&gt;
Reviewed-by: Matthias Brugger &lt;matthias.bgg@gmail.com&gt;
Link: https://lore.kernel.org/r/593e7b7d97c6e064b29716b091a9d4fd122241fb.1671473163.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Joerg Roedel &lt;jroedel@suse.de&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
A clk, prepared and enabled in mtk_iommu_v1_hw_init(), is not released in
the error handling path of mtk_iommu_v1_probe().

Add the corresponding clk_disable_unprepare(), as already done in the
remove function.

Fixes: b17336c55d89 ("iommu/mediatek: add support for mtk iommu generation one HW")
Signed-off-by: Christophe JAILLET &lt;christophe.jaillet@wanadoo.fr&gt;
Reviewed-by: Yong Wu &lt;yong.wu@mediatek.com&gt;
Reviewed-by: AngeloGioacchino Del Regno &lt;angelogioacchino.delregno@collabora.com&gt;
Reviewed-by: Matthias Brugger &lt;matthias.bgg@gmail.com&gt;
Link: https://lore.kernel.org/r/593e7b7d97c6e064b29716b091a9d4fd122241fb.1671473163.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Joerg Roedel &lt;jroedel@suse.de&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>iommu/iova: Fix alloc iova overflows issue</title>
<updated>2023-01-13T12:46:31+00:00</updated>
<author>
<name>Yunfei Wang</name>
<email>yf.wang@mediatek.com</email>
</author>
<published>2023-01-11T06:38:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=dcdb3ba7e2a8caae7bfefd603bc22fd0ce9a389c'/>
<id>dcdb3ba7e2a8caae7bfefd603bc22fd0ce9a389c</id>
<content type='text'>
In __alloc_and_insert_iova_range, there is an issue that retry_pfn
overflows. The value of iovad-&gt;anchor.pfn_hi is ~0UL, then when
iovad-&gt;cached_node is iovad-&gt;anchor, curr_iova-&gt;pfn_hi + 1 will
overflow. As a result, if the retry logic is executed, low_pfn is
updated to 0, and then new_pfn &lt; low_pfn returns false to make the
allocation successful.

This issue occurs in the following two situations:
1. The first iova size exceeds the domain size. When initializing
iova domain, iovad-&gt;cached_node is assigned as iovad-&gt;anchor. For
example, the iova domain size is 10M, start_pfn is 0x1_F000_0000,
and the iova size allocated for the first time is 11M. The
following is the log information, new-&gt;pfn_lo is smaller than
iovad-&gt;cached_node.

Example log as follows:
[  223.798112][T1705487] sh: [name:iova&amp;]__alloc_and_insert_iova_range
start_pfn:0x1f0000,retry_pfn:0x0,size:0xb00,limit_pfn:0x1f0a00
[  223.799590][T1705487] sh: [name:iova&amp;]__alloc_and_insert_iova_range
success start_pfn:0x1f0000,new-&gt;pfn_lo:0x1efe00,new-&gt;pfn_hi:0x1f08ff

2. The node with the largest iova-&gt;pfn_lo value in the iova domain
is deleted, iovad-&gt;cached_node will be updated to iovad-&gt;anchor,
and then the alloc iova size exceeds the maximum iova size that can
be allocated in the domain.

After judging that retry_pfn is less than limit_pfn, call retry_pfn+1
to fix the overflow issue.

Signed-off-by: jianjiao zeng &lt;jianjiao.zeng@mediatek.com&gt;
Signed-off-by: Yunfei Wang &lt;yf.wang@mediatek.com&gt;
Cc: &lt;stable@vger.kernel.org&gt; # 5.15.*
Fixes: 4e89dce72521 ("iommu/iova: Retry from last rb tree node if iova search fails")
Acked-by: Robin Murphy &lt;robin.murphy@arm.com&gt;
Link: https://lore.kernel.org/r/20230111063801.25107-1-yf.wang@mediatek.com
Signed-off-by: Joerg Roedel &lt;jroedel@suse.de&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
In __alloc_and_insert_iova_range, there is an issue that retry_pfn
overflows. The value of iovad-&gt;anchor.pfn_hi is ~0UL, then when
iovad-&gt;cached_node is iovad-&gt;anchor, curr_iova-&gt;pfn_hi + 1 will
overflow. As a result, if the retry logic is executed, low_pfn is
updated to 0, and then new_pfn &lt; low_pfn returns false to make the
allocation successful.

This issue occurs in the following two situations:
1. The first iova size exceeds the domain size. When initializing
iova domain, iovad-&gt;cached_node is assigned as iovad-&gt;anchor. For
example, the iova domain size is 10M, start_pfn is 0x1_F000_0000,
and the iova size allocated for the first time is 11M. The
following is the log information, new-&gt;pfn_lo is smaller than
iovad-&gt;cached_node.

Example log as follows:
[  223.798112][T1705487] sh: [name:iova&amp;]__alloc_and_insert_iova_range
start_pfn:0x1f0000,retry_pfn:0x0,size:0xb00,limit_pfn:0x1f0a00
[  223.799590][T1705487] sh: [name:iova&amp;]__alloc_and_insert_iova_range
success start_pfn:0x1f0000,new-&gt;pfn_lo:0x1efe00,new-&gt;pfn_hi:0x1f08ff

2. The node with the largest iova-&gt;pfn_lo value in the iova domain
is deleted, iovad-&gt;cached_node will be updated to iovad-&gt;anchor,
and then the alloc iova size exceeds the maximum iova size that can
be allocated in the domain.

After judging that retry_pfn is less than limit_pfn, call retry_pfn+1
to fix the overflow issue.

Signed-off-by: jianjiao zeng &lt;jianjiao.zeng@mediatek.com&gt;
Signed-off-by: Yunfei Wang &lt;yf.wang@mediatek.com&gt;
Cc: &lt;stable@vger.kernel.org&gt; # 5.15.*
Fixes: 4e89dce72521 ("iommu/iova: Retry from last rb tree node if iova search fails")
Acked-by: Robin Murphy &lt;robin.murphy@arm.com&gt;
Link: https://lore.kernel.org/r/20230111063801.25107-1-yf.wang@mediatek.com
Signed-off-by: Joerg Roedel &lt;jroedel@suse.de&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>iommu: Fix refcount leak in iommu_device_claim_dma_owner</title>
<updated>2023-01-13T12:46:22+00:00</updated>
<author>
<name>Miaoqian Lin</name>
<email>linmq006@gmail.com</email>
</author>
<published>2022-12-30T08:31:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=a6a9a5da68084d5eac6ef85ad09df7fc9c971de4'/>
<id>a6a9a5da68084d5eac6ef85ad09df7fc9c971de4</id>
<content type='text'>
iommu_group_get() returns the group with the reference incremented.
Move iommu_group_get() after owner check to fix the refcount leak.

Fixes: 89395ccedbc1 ("iommu: Add device-centric DMA ownership interfaces")
Signed-off-by: Miaoqian Lin &lt;linmq006@gmail.com&gt;
Reviewed-by: Lu Baolu &lt;baolu.lu@linux.intel.com&gt;
Reviewed-by: Jason Gunthorpe &lt;jgg@nvidia.com&gt;
Link: https://lore.kernel.org/r/20221230083100.1489569-1-linmq006@gmail.com
[ joro: Remove *group = NULL initialization ]
Signed-off-by: Joerg Roedel &lt;jroedel@suse.de&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
iommu_group_get() returns the group with the reference incremented.
Move iommu_group_get() after owner check to fix the refcount leak.

Fixes: 89395ccedbc1 ("iommu: Add device-centric DMA ownership interfaces")
Signed-off-by: Miaoqian Lin &lt;linmq006@gmail.com&gt;
Reviewed-by: Lu Baolu &lt;baolu.lu@linux.intel.com&gt;
Reviewed-by: Jason Gunthorpe &lt;jgg@nvidia.com&gt;
Link: https://lore.kernel.org/r/20221230083100.1489569-1-linmq006@gmail.com
[ joro: Remove *group = NULL initialization ]
Signed-off-by: Joerg Roedel &lt;jroedel@suse.de&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>iommu/arm-smmu-v3: Don't unregister on shutdown</title>
<updated>2023-01-13T12:46:21+00:00</updated>
<author>
<name>Vladimir Oltean</name>
<email>vladimir.oltean@nxp.com</email>
</author>
<published>2022-12-15T14:12:51+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=32ea2c57dc216b6ad8125fa680d31daa5d421c95'/>
<id>32ea2c57dc216b6ad8125fa680d31daa5d421c95</id>
<content type='text'>
Similar to SMMUv2, this driver calls iommu_device_unregister() from the
shutdown path, which removes the IOMMU groups with no coordination
whatsoever with their users - shutdown methods are optional in device
drivers. This can lead to NULL pointer dereferences in those drivers'
DMA API calls, or worse.

Instead of calling the full arm_smmu_device_remove() from
arm_smmu_device_shutdown(), let's pick only the relevant function call -
arm_smmu_device_disable() - more or less the reverse of
arm_smmu_device_reset() - and call just that from the shutdown path.

Fixes: 57365a04c921 ("iommu: Move bus setup to IOMMU device registration")
Suggested-by: Robin Murphy &lt;robin.murphy@arm.com&gt;
Signed-off-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Link: https://lore.kernel.org/r/20221215141251.3688780-2-vladimir.oltean@nxp.com
Signed-off-by: Will Deacon &lt;will@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Similar to SMMUv2, this driver calls iommu_device_unregister() from the
shutdown path, which removes the IOMMU groups with no coordination
whatsoever with their users - shutdown methods are optional in device
drivers. This can lead to NULL pointer dereferences in those drivers'
DMA API calls, or worse.

Instead of calling the full arm_smmu_device_remove() from
arm_smmu_device_shutdown(), let's pick only the relevant function call -
arm_smmu_device_disable() - more or less the reverse of
arm_smmu_device_reset() - and call just that from the shutdown path.

Fixes: 57365a04c921 ("iommu: Move bus setup to IOMMU device registration")
Suggested-by: Robin Murphy &lt;robin.murphy@arm.com&gt;
Signed-off-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Link: https://lore.kernel.org/r/20221215141251.3688780-2-vladimir.oltean@nxp.com
Signed-off-by: Will Deacon &lt;will@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>iommu/arm-smmu: Don't unregister on shutdown</title>
<updated>2023-01-13T12:46:20+00:00</updated>
<author>
<name>Vladimir Oltean</name>
<email>vladimir.oltean@nxp.com</email>
</author>
<published>2022-12-15T14:12:50+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ce31e6ca68bd7639bd3e5ef97be215031842bbab'/>
<id>ce31e6ca68bd7639bd3e5ef97be215031842bbab</id>
<content type='text'>
Michael Walle says he noticed the following stack trace while performing
a shutdown with "reboot -f". He suggests he got "lucky" and just hit the
correct spot for the reboot while there was a packet transmission in
flight.

Unable to handle kernel NULL pointer dereference at virtual address 0000000000000098
CPU: 0 PID: 23 Comm: kworker/0:1 Not tainted 6.1.0-rc5-00088-gf3600ff8e322 #1930
Hardware name: Kontron KBox A-230-LS (DT)
pc : iommu_get_dma_domain+0x14/0x20
lr : iommu_dma_map_page+0x9c/0x254
Call trace:
 iommu_get_dma_domain+0x14/0x20
 dma_map_page_attrs+0x1ec/0x250
 enetc_start_xmit+0x14c/0x10b0
 enetc_xmit+0x60/0xdc
 dev_hard_start_xmit+0xb8/0x210
 sch_direct_xmit+0x11c/0x420
 __dev_queue_xmit+0x354/0xb20
 ip6_finish_output2+0x280/0x5b0
 __ip6_finish_output+0x15c/0x270
 ip6_output+0x78/0x15c
 NF_HOOK.constprop.0+0x50/0xd0
 mld_sendpack+0x1bc/0x320
 mld_ifc_work+0x1d8/0x4dc
 process_one_work+0x1e8/0x460
 worker_thread+0x178/0x534
 kthread+0xe0/0xe4
 ret_from_fork+0x10/0x20
Code: d503201f f9416800 d503233f d50323bf (f9404c00)
---[ end trace 0000000000000000 ]---
Kernel panic - not syncing: Oops: Fatal exception in interrupt

This appears to be reproducible when the board has a fixed IP address,
is ping flooded from another host, and "reboot -f" is used.

The following is one more manifestation of the issue:

$ reboot -f
kvm: exiting hardware virtualization
cfg80211: failed to load regulatory.db
arm-smmu 5000000.iommu: disabling translation
sdhci-esdhc 2140000.mmc: Removing from iommu group 11
sdhci-esdhc 2150000.mmc: Removing from iommu group 12
fsl-edma 22c0000.dma-controller: Removing from iommu group 17
dwc3 3100000.usb: Removing from iommu group 9
dwc3 3110000.usb: Removing from iommu group 10
ahci-qoriq 3200000.sata: Removing from iommu group 2
fsl-qdma 8380000.dma-controller: Removing from iommu group 20
platform f080000.display: Removing from iommu group 0
etnaviv-gpu f0c0000.gpu: Removing from iommu group 1
etnaviv etnaviv: Removing from iommu group 1
caam_jr 8010000.jr: Removing from iommu group 13
caam_jr 8020000.jr: Removing from iommu group 14
caam_jr 8030000.jr: Removing from iommu group 15
caam_jr 8040000.jr: Removing from iommu group 16
fsl_enetc 0000:00:00.0: Removing from iommu group 4
arm-smmu 5000000.iommu: Blocked unknown Stream ID 0x429; boot with "arm-smmu.disable_bypass=0" to allow, but this may have security implications
arm-smmu 5000000.iommu:         GFSR 0x80000002, GFSYNR0 0x00000002, GFSYNR1 0x00000429, GFSYNR2 0x00000000
fsl_enetc 0000:00:00.1: Removing from iommu group 5
arm-smmu 5000000.iommu: Blocked unknown Stream ID 0x429; boot with "arm-smmu.disable_bypass=0" to allow, but this may have security implications
arm-smmu 5000000.iommu:         GFSR 0x80000002, GFSYNR0 0x00000002, GFSYNR1 0x00000429, GFSYNR2 0x00000000
arm-smmu 5000000.iommu: Blocked unknown Stream ID 0x429; boot with "arm-smmu.disable_bypass=0" to allow, but this may have security implications
arm-smmu 5000000.iommu:         GFSR 0x80000002, GFSYNR0 0x00000000, GFSYNR1 0x00000429, GFSYNR2 0x00000000
fsl_enetc 0000:00:00.2: Removing from iommu group 6
fsl_enetc_mdio 0000:00:00.3: Removing from iommu group 8
mscc_felix 0000:00:00.5: Removing from iommu group 3
fsl_enetc 0000:00:00.6: Removing from iommu group 7
pcieport 0001:00:00.0: Removing from iommu group 18
arm-smmu 5000000.iommu: Blocked unknown Stream ID 0x429; boot with "arm-smmu.disable_bypass=0" to allow, but this may have security implications
arm-smmu 5000000.iommu:         GFSR 0x00000002, GFSYNR0 0x00000000, GFSYNR1 0x00000429, GFSYNR2 0x00000000
pcieport 0002:00:00.0: Removing from iommu group 19
Unable to handle kernel NULL pointer dereference at virtual address 00000000000000a8
pc : iommu_get_dma_domain+0x14/0x20
lr : iommu_dma_unmap_page+0x38/0xe0
Call trace:
 iommu_get_dma_domain+0x14/0x20
 dma_unmap_page_attrs+0x38/0x1d0
 enetc_unmap_tx_buff.isra.0+0x6c/0x80
 enetc_poll+0x170/0x910
 __napi_poll+0x40/0x1e0
 net_rx_action+0x164/0x37c
 __do_softirq+0x128/0x368
 run_ksoftirqd+0x68/0x90
 smpboot_thread_fn+0x14c/0x190
Code: d503201f f9416800 d503233f d50323bf (f9405400)
---[ end trace 0000000000000000 ]---
Kernel panic - not syncing: Oops: Fatal exception in interrupt
---[ end Kernel panic - not syncing: Oops: Fatal exception in interrupt ]---

The problem seems to be that iommu_group_remove_device() is allowed to
run with no coordination whatsoever with the shutdown procedure of the
enetc PCI device. In fact, it almost seems as if it implies that the
pci_driver :: shutdown() method is mandatory if DMA is used with an
IOMMU, otherwise this is inevitable. That was never the case; shutdown
methods are optional in device drivers.

This is the call stack that leads to iommu_group_remove_device() during
reboot:

kernel_restart
-&gt; device_shutdown
   -&gt; platform_shutdown
      -&gt; arm_smmu_device_shutdown
         -&gt; arm_smmu_device_remove
            -&gt; iommu_device_unregister
               -&gt; bus_for_each_dev
                  -&gt; remove_iommu_group
                     -&gt; iommu_release_device
                        -&gt; iommu_group_remove_device

I don't know much about the arm_smmu driver, but
arm_smmu_device_shutdown() invoking arm_smmu_device_remove() looks
suspicious, since it causes the IOMMU device to unregister and that's
where everything starts to unravel. It forces all other devices which
depend on IOMMU groups to also point their -&gt;shutdown() to -&gt;remove(),
which will make reboot slower overall.

There are 2 moments relevant to this behavior. First was commit
b06c076ea962 ("Revert "iommu/arm-smmu: Make arm-smmu explicitly
non-modular"") when arm_smmu_device_shutdown() was made to run the exact
same thing as arm_smmu_device_remove(). Prior to that, there was no
iommu_device_unregister() call in arm_smmu_device_shutdown(). However,
that was benign until commit 57365a04c921 ("iommu: Move bus setup to
IOMMU device registration"), which made iommu_device_unregister() call
remove_iommu_group().

Restore the old shutdown behavior by making remove() call shutdown(),
but shutdown() does not call the remove() specific bits.

Fixes: 57365a04c921 ("iommu: Move bus setup to IOMMU device registration")
Reported-by: Michael Walle &lt;michael@walle.cc&gt;
Tested-by: Michael Walle &lt;michael@walle.cc&gt; # on kontron-sl28
Signed-off-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Link: https://lore.kernel.org/r/20221215141251.3688780-1-vladimir.oltean@nxp.com
Signed-off-by: Will Deacon &lt;will@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Michael Walle says he noticed the following stack trace while performing
a shutdown with "reboot -f". He suggests he got "lucky" and just hit the
correct spot for the reboot while there was a packet transmission in
flight.

Unable to handle kernel NULL pointer dereference at virtual address 0000000000000098
CPU: 0 PID: 23 Comm: kworker/0:1 Not tainted 6.1.0-rc5-00088-gf3600ff8e322 #1930
Hardware name: Kontron KBox A-230-LS (DT)
pc : iommu_get_dma_domain+0x14/0x20
lr : iommu_dma_map_page+0x9c/0x254
Call trace:
 iommu_get_dma_domain+0x14/0x20
 dma_map_page_attrs+0x1ec/0x250
 enetc_start_xmit+0x14c/0x10b0
 enetc_xmit+0x60/0xdc
 dev_hard_start_xmit+0xb8/0x210
 sch_direct_xmit+0x11c/0x420
 __dev_queue_xmit+0x354/0xb20
 ip6_finish_output2+0x280/0x5b0
 __ip6_finish_output+0x15c/0x270
 ip6_output+0x78/0x15c
 NF_HOOK.constprop.0+0x50/0xd0
 mld_sendpack+0x1bc/0x320
 mld_ifc_work+0x1d8/0x4dc
 process_one_work+0x1e8/0x460
 worker_thread+0x178/0x534
 kthread+0xe0/0xe4
 ret_from_fork+0x10/0x20
Code: d503201f f9416800 d503233f d50323bf (f9404c00)
---[ end trace 0000000000000000 ]---
Kernel panic - not syncing: Oops: Fatal exception in interrupt

This appears to be reproducible when the board has a fixed IP address,
is ping flooded from another host, and "reboot -f" is used.

The following is one more manifestation of the issue:

$ reboot -f
kvm: exiting hardware virtualization
cfg80211: failed to load regulatory.db
arm-smmu 5000000.iommu: disabling translation
sdhci-esdhc 2140000.mmc: Removing from iommu group 11
sdhci-esdhc 2150000.mmc: Removing from iommu group 12
fsl-edma 22c0000.dma-controller: Removing from iommu group 17
dwc3 3100000.usb: Removing from iommu group 9
dwc3 3110000.usb: Removing from iommu group 10
ahci-qoriq 3200000.sata: Removing from iommu group 2
fsl-qdma 8380000.dma-controller: Removing from iommu group 20
platform f080000.display: Removing from iommu group 0
etnaviv-gpu f0c0000.gpu: Removing from iommu group 1
etnaviv etnaviv: Removing from iommu group 1
caam_jr 8010000.jr: Removing from iommu group 13
caam_jr 8020000.jr: Removing from iommu group 14
caam_jr 8030000.jr: Removing from iommu group 15
caam_jr 8040000.jr: Removing from iommu group 16
fsl_enetc 0000:00:00.0: Removing from iommu group 4
arm-smmu 5000000.iommu: Blocked unknown Stream ID 0x429; boot with "arm-smmu.disable_bypass=0" to allow, but this may have security implications
arm-smmu 5000000.iommu:         GFSR 0x80000002, GFSYNR0 0x00000002, GFSYNR1 0x00000429, GFSYNR2 0x00000000
fsl_enetc 0000:00:00.1: Removing from iommu group 5
arm-smmu 5000000.iommu: Blocked unknown Stream ID 0x429; boot with "arm-smmu.disable_bypass=0" to allow, but this may have security implications
arm-smmu 5000000.iommu:         GFSR 0x80000002, GFSYNR0 0x00000002, GFSYNR1 0x00000429, GFSYNR2 0x00000000
arm-smmu 5000000.iommu: Blocked unknown Stream ID 0x429; boot with "arm-smmu.disable_bypass=0" to allow, but this may have security implications
arm-smmu 5000000.iommu:         GFSR 0x80000002, GFSYNR0 0x00000000, GFSYNR1 0x00000429, GFSYNR2 0x00000000
fsl_enetc 0000:00:00.2: Removing from iommu group 6
fsl_enetc_mdio 0000:00:00.3: Removing from iommu group 8
mscc_felix 0000:00:00.5: Removing from iommu group 3
fsl_enetc 0000:00:00.6: Removing from iommu group 7
pcieport 0001:00:00.0: Removing from iommu group 18
arm-smmu 5000000.iommu: Blocked unknown Stream ID 0x429; boot with "arm-smmu.disable_bypass=0" to allow, but this may have security implications
arm-smmu 5000000.iommu:         GFSR 0x00000002, GFSYNR0 0x00000000, GFSYNR1 0x00000429, GFSYNR2 0x00000000
pcieport 0002:00:00.0: Removing from iommu group 19
Unable to handle kernel NULL pointer dereference at virtual address 00000000000000a8
pc : iommu_get_dma_domain+0x14/0x20
lr : iommu_dma_unmap_page+0x38/0xe0
Call trace:
 iommu_get_dma_domain+0x14/0x20
 dma_unmap_page_attrs+0x38/0x1d0
 enetc_unmap_tx_buff.isra.0+0x6c/0x80
 enetc_poll+0x170/0x910
 __napi_poll+0x40/0x1e0
 net_rx_action+0x164/0x37c
 __do_softirq+0x128/0x368
 run_ksoftirqd+0x68/0x90
 smpboot_thread_fn+0x14c/0x190
Code: d503201f f9416800 d503233f d50323bf (f9405400)
---[ end trace 0000000000000000 ]---
Kernel panic - not syncing: Oops: Fatal exception in interrupt
---[ end Kernel panic - not syncing: Oops: Fatal exception in interrupt ]---

The problem seems to be that iommu_group_remove_device() is allowed to
run with no coordination whatsoever with the shutdown procedure of the
enetc PCI device. In fact, it almost seems as if it implies that the
pci_driver :: shutdown() method is mandatory if DMA is used with an
IOMMU, otherwise this is inevitable. That was never the case; shutdown
methods are optional in device drivers.

This is the call stack that leads to iommu_group_remove_device() during
reboot:

kernel_restart
-&gt; device_shutdown
   -&gt; platform_shutdown
      -&gt; arm_smmu_device_shutdown
         -&gt; arm_smmu_device_remove
            -&gt; iommu_device_unregister
               -&gt; bus_for_each_dev
                  -&gt; remove_iommu_group
                     -&gt; iommu_release_device
                        -&gt; iommu_group_remove_device

I don't know much about the arm_smmu driver, but
arm_smmu_device_shutdown() invoking arm_smmu_device_remove() looks
suspicious, since it causes the IOMMU device to unregister and that's
where everything starts to unravel. It forces all other devices which
depend on IOMMU groups to also point their -&gt;shutdown() to -&gt;remove(),
which will make reboot slower overall.

There are 2 moments relevant to this behavior. First was commit
b06c076ea962 ("Revert "iommu/arm-smmu: Make arm-smmu explicitly
non-modular"") when arm_smmu_device_shutdown() was made to run the exact
same thing as arm_smmu_device_remove(). Prior to that, there was no
iommu_device_unregister() call in arm_smmu_device_shutdown(). However,
that was benign until commit 57365a04c921 ("iommu: Move bus setup to
IOMMU device registration"), which made iommu_device_unregister() call
remove_iommu_group().

Restore the old shutdown behavior by making remove() call shutdown(),
but shutdown() does not call the remove() specific bits.

Fixes: 57365a04c921 ("iommu: Move bus setup to IOMMU device registration")
Reported-by: Michael Walle &lt;michael@walle.cc&gt;
Tested-by: Michael Walle &lt;michael@walle.cc&gt; # on kontron-sl28
Signed-off-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Link: https://lore.kernel.org/r/20221215141251.3688780-1-vladimir.oltean@nxp.com
Signed-off-by: Will Deacon &lt;will@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>iommu/arm-smmu: Report IOMMU_CAP_CACHE_COHERENCY even betterer</title>
<updated>2023-01-13T12:46:20+00:00</updated>
<author>
<name>Robin Murphy</name>
<email>robin.murphy@arm.com</email>
</author>
<published>2022-12-15T16:51:55+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ac9c5e92dd15b9927e7355ccf79df76a58b44344'/>
<id>ac9c5e92dd15b9927e7355ccf79df76a58b44344</id>
<content type='text'>
Although it's vanishingly unlikely that anyone would integrate an SMMU
within a coherent interconnect without also making the pagetable walk
interface coherent, the same effect happens if a coherent SMMU fails to
advertise CTTW correctly. This turns out to be the case on some popular
NXP SoCs, where VFIO started failing the IOMMU_CAP_CACHE_COHERENCY test,
even though IOMMU_CACHE *was* previously achieving the desired effect
anyway thanks to the underlying integration.

While those SoCs stand to gain some more general benefits from a
firmware update to override CTTW correctly in DT/ACPI, it's also easy
to work around this in Linux as well, to avoid imposing too much on
affected users - since the upstream client devices *are* correctly
marked as coherent, we can trivially infer their coherent paths through
the SMMU as well.

Reported-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Fixes: df198b37e72c ("iommu/arm-smmu: Report IOMMU_CAP_CACHE_COHERENCY better")
Signed-off-by: Robin Murphy &lt;robin.murphy@arm.com&gt;
Tested-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Link: https://lore.kernel.org/r/d6dc41952961e5c7b21acac08a8bf1eb0f69e124.1671123115.git.robin.murphy@arm.com
Signed-off-by: Will Deacon &lt;will@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Although it's vanishingly unlikely that anyone would integrate an SMMU
within a coherent interconnect without also making the pagetable walk
interface coherent, the same effect happens if a coherent SMMU fails to
advertise CTTW correctly. This turns out to be the case on some popular
NXP SoCs, where VFIO started failing the IOMMU_CAP_CACHE_COHERENCY test,
even though IOMMU_CACHE *was* previously achieving the desired effect
anyway thanks to the underlying integration.

While those SoCs stand to gain some more general benefits from a
firmware update to override CTTW correctly in DT/ACPI, it's also easy
to work around this in Linux as well, to avoid imposing too much on
affected users - since the upstream client devices *are* correctly
marked as coherent, we can trivially infer their coherent paths through
the SMMU as well.

Reported-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Fixes: df198b37e72c ("iommu/arm-smmu: Report IOMMU_CAP_CACHE_COHERENCY better")
Signed-off-by: Robin Murphy &lt;robin.murphy@arm.com&gt;
Tested-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Link: https://lore.kernel.org/r/d6dc41952961e5c7b21acac08a8bf1eb0f69e124.1671123115.git.robin.murphy@arm.com
Signed-off-by: Will Deacon &lt;will@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'iommu-updates-v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu</title>
<updated>2022-12-19T14:34:39+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2022-12-19T14:34:39+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=b8fd76f41820951d8a6e2521c25f54afadf338bd'/>
<id>b8fd76f41820951d8a6e2521c25f54afadf338bd</id>
<content type='text'>
Pull iommu updates from Joerg Roedel:
 "Core code:
   - map/unmap_pages() cleanup
   - SVA and IOPF refactoring
   - Clean up and document return codes from device/domain attachment

  AMD driver:
   - Rework and extend parsing code for ivrs_ioapic, ivrs_hpet and
     ivrs_acpihid command line options
   - Some smaller cleanups

  Intel driver:
   - Blocking domain support
   - Cleanups

  S390 driver:
   - Fixes and improvements for attach and aperture handling

  PAMU driver:
   - Resource leak fix and cleanup

  Rockchip driver:
   - Page table permission bit fix

  Mediatek driver:
   - Improve safety from invalid dts input
   - Smaller fixes and improvements

  Exynos driver:
   - Fix driver initialization sequence

  Sun50i driver:
   - Remove IOMMU_DOMAIN_IDENTITY as it has not been working forever
   - Various other fixes"

* tag 'iommu-updates-v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu: (74 commits)
  iommu/mediatek: Fix forever loop in error handling
  iommu/mediatek: Fix crash on isr after kexec()
  iommu/sun50i: Remove IOMMU_DOMAIN_IDENTITY
  iommu/amd: Fix typo in macro parameter name
  iommu/mediatek: Remove unused "mapping" member from mtk_iommu_data
  iommu/mediatek: Improve safety for mediatek,smi property in larb nodes
  iommu/mediatek: Validate number of phandles associated with "mediatek,larbs"
  iommu/mediatek: Add error path for loop of mm_dts_parse
  iommu/mediatek: Use component_match_add
  iommu/mediatek: Add platform_device_put for recovering the device refcnt
  iommu/fsl_pamu: Fix resource leak in fsl_pamu_probe()
  iommu/vt-d: Use real field for indication of first level
  iommu/vt-d: Remove unnecessary domain_context_mapped()
  iommu/vt-d: Rename domain_add_dev_info()
  iommu/vt-d: Rename iommu_disable_dev_iotlb()
  iommu/vt-d: Add blocking domain support
  iommu/vt-d: Add device_block_translation() helper
  iommu/vt-d: Allocate pasid table in device probe path
  iommu/amd: Check return value of mmu_notifier_register()
  iommu/amd: Fix pci device refcount leak in ppr_notifier()
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull iommu updates from Joerg Roedel:
 "Core code:
   - map/unmap_pages() cleanup
   - SVA and IOPF refactoring
   - Clean up and document return codes from device/domain attachment

  AMD driver:
   - Rework and extend parsing code for ivrs_ioapic, ivrs_hpet and
     ivrs_acpihid command line options
   - Some smaller cleanups

  Intel driver:
   - Blocking domain support
   - Cleanups

  S390 driver:
   - Fixes and improvements for attach and aperture handling

  PAMU driver:
   - Resource leak fix and cleanup

  Rockchip driver:
   - Page table permission bit fix

  Mediatek driver:
   - Improve safety from invalid dts input
   - Smaller fixes and improvements

  Exynos driver:
   - Fix driver initialization sequence

  Sun50i driver:
   - Remove IOMMU_DOMAIN_IDENTITY as it has not been working forever
   - Various other fixes"

* tag 'iommu-updates-v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu: (74 commits)
  iommu/mediatek: Fix forever loop in error handling
  iommu/mediatek: Fix crash on isr after kexec()
  iommu/sun50i: Remove IOMMU_DOMAIN_IDENTITY
  iommu/amd: Fix typo in macro parameter name
  iommu/mediatek: Remove unused "mapping" member from mtk_iommu_data
  iommu/mediatek: Improve safety for mediatek,smi property in larb nodes
  iommu/mediatek: Validate number of phandles associated with "mediatek,larbs"
  iommu/mediatek: Add error path for loop of mm_dts_parse
  iommu/mediatek: Use component_match_add
  iommu/mediatek: Add platform_device_put for recovering the device refcnt
  iommu/fsl_pamu: Fix resource leak in fsl_pamu_probe()
  iommu/vt-d: Use real field for indication of first level
  iommu/vt-d: Remove unnecessary domain_context_mapped()
  iommu/vt-d: Rename domain_add_dev_info()
  iommu/vt-d: Rename iommu_disable_dev_iotlb()
  iommu/vt-d: Add blocking domain support
  iommu/vt-d: Add device_block_translation() helper
  iommu/vt-d: Allocate pasid table in device probe path
  iommu/amd: Check return value of mmu_notifier_register()
  iommu/amd: Fix pci device refcount leak in ppr_notifier()
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'x86_mm_for_6.2_v2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip</title>
<updated>2022-12-17T20:06:53+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2022-12-17T20:06:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=4f292c4de4f6fb83776c0ff22674121eb6ddfa2f'/>
<id>4f292c4de4f6fb83776c0ff22674121eb6ddfa2f</id>
<content type='text'>
Pull x86 mm updates from Dave Hansen:
 "New Feature:

   - Randomize the per-cpu entry areas

  Cleanups:

   - Have CR3_ADDR_MASK use PHYSICAL_PAGE_MASK instead of open coding it

   - Move to "native" set_memory_rox() helper

   - Clean up pmd_get_atomic() and i386-PAE

   - Remove some unused page table size macros"

* tag 'x86_mm_for_6.2_v2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (35 commits)
  x86/mm: Ensure forced page table splitting
  x86/kasan: Populate shadow for shared chunk of the CPU entry area
  x86/kasan: Add helpers to align shadow addresses up and down
  x86/kasan: Rename local CPU_ENTRY_AREA variables to shorten names
  x86/mm: Populate KASAN shadow for entire per-CPU range of CPU entry area
  x86/mm: Recompute physical address for every page of per-CPU CEA mapping
  x86/mm: Rename __change_page_attr_set_clr(.checkalias)
  x86/mm: Inhibit _PAGE_NX changes from cpa_process_alias()
  x86/mm: Untangle __change_page_attr_set_clr(.checkalias)
  x86/mm: Add a few comments
  x86/mm: Fix CR3_ADDR_MASK
  x86/mm: Remove P*D_PAGE_MASK and P*D_PAGE_SIZE macros
  mm: Convert __HAVE_ARCH_P..P_GET to the new style
  mm: Remove pointless barrier() after pmdp_get_lockless()
  x86/mm/pae: Get rid of set_64bit()
  x86_64: Remove pointless set_64bit() usage
  x86/mm/pae: Be consistent with pXXp_get_and_clear()
  x86/mm/pae: Use WRITE_ONCE()
  x86/mm/pae: Don't (ab)use atomic64
  mm/gup: Fix the lockless PMD access
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull x86 mm updates from Dave Hansen:
 "New Feature:

   - Randomize the per-cpu entry areas

  Cleanups:

   - Have CR3_ADDR_MASK use PHYSICAL_PAGE_MASK instead of open coding it

   - Move to "native" set_memory_rox() helper

   - Clean up pmd_get_atomic() and i386-PAE

   - Remove some unused page table size macros"

* tag 'x86_mm_for_6.2_v2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (35 commits)
  x86/mm: Ensure forced page table splitting
  x86/kasan: Populate shadow for shared chunk of the CPU entry area
  x86/kasan: Add helpers to align shadow addresses up and down
  x86/kasan: Rename local CPU_ENTRY_AREA variables to shorten names
  x86/mm: Populate KASAN shadow for entire per-CPU range of CPU entry area
  x86/mm: Recompute physical address for every page of per-CPU CEA mapping
  x86/mm: Rename __change_page_attr_set_clr(.checkalias)
  x86/mm: Inhibit _PAGE_NX changes from cpa_process_alias()
  x86/mm: Untangle __change_page_attr_set_clr(.checkalias)
  x86/mm: Add a few comments
  x86/mm: Fix CR3_ADDR_MASK
  x86/mm: Remove P*D_PAGE_MASK and P*D_PAGE_SIZE macros
  mm: Convert __HAVE_ARCH_P..P_GET to the new style
  mm: Remove pointless barrier() after pmdp_get_lockless()
  x86/mm/pae: Get rid of set_64bit()
  x86_64: Remove pointless set_64bit() usage
  x86/mm/pae: Be consistent with pXXp_get_and_clear()
  x86/mm/pae: Use WRITE_ONCE()
  x86/mm/pae: Don't (ab)use atomic64
  mm/gup: Fix the lockless PMD access
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>x86_64: Remove pointless set_64bit() usage</title>
<updated>2022-12-15T18:37:27+00:00</updated>
<author>
<name>Peter Zijlstra</name>
<email>peterz@infradead.org</email>
</author>
<published>2022-10-21T12:11:38+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=9ee850acd25dc290d3cad2707e99380e372ad490'/>
<id>9ee850acd25dc290d3cad2707e99380e372ad490</id>
<content type='text'>
The use of set_64bit() in X86_64 only code is pretty pointless, seeing
how it's a direct assignment. Remove all this nonsense.

[nathanchance: unbreak irte]
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Link: https://lkml.kernel.org/r/20221022114425.168036718%40infradead.org
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The use of set_64bit() in X86_64 only code is pretty pointless, seeing
how it's a direct assignment. Remove all this nonsense.

[nathanchance: unbreak irte]
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Link: https://lkml.kernel.org/r/20221022114425.168036718%40infradead.org
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'for-linus-iommufd' of git://git.kernel.org/pub/scm/linux/kernel/git/jgg/iommufd</title>
<updated>2022-12-14T17:15:43+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2022-12-14T17:15:43+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=08cdc2157966c07d3f986a097ddaa74cee312751'/>
<id>08cdc2157966c07d3f986a097ddaa74cee312751</id>
<content type='text'>
Pull iommufd implementation from Jason Gunthorpe:
 "iommufd is the user API to control the IOMMU subsystem as it relates
  to managing IO page tables that point at user space memory.

  It takes over from drivers/vfio/vfio_iommu_type1.c (aka the VFIO
  container) which is the VFIO specific interface for a similar idea.

  We see a broad need for extended features, some being highly IOMMU
  device specific:
   - Binding iommu_domain's to PASID/SSID
   - Userspace IO page tables, for ARM, x86 and S390
   - Kernel bypassed invalidation of user page tables
   - Re-use of the KVM page table in the IOMMU
   - Dirty page tracking in the IOMMU
   - Runtime Increase/Decrease of IOPTE size
   - PRI support with faults resolved in userspace

  Many of these HW features exist to support VM use cases - for instance
  the combination of PASID, PRI and Userspace IO Page Tables allows an
  implementation of DMA Shared Virtual Addressing (vSVA) within a guest.
  Dirty tracking enables VM live migration with SRIOV devices and PASID
  support allow creating "scalable IOV" devices, among other things.

  As these features are fundamental to a VM platform they need to be
  uniformly exposed to all the driver families that do DMA into VMs,
  which is currently VFIO and VDPA"

For more background, see the extended explanations in Jason's pull request:

  https://lore.kernel.org/lkml/Y5dzTU8dlmXTbzoJ@nvidia.com/

* tag 'for-linus-iommufd' of git://git.kernel.org/pub/scm/linux/kernel/git/jgg/iommufd: (62 commits)
  iommufd: Change the order of MSI setup
  iommufd: Improve a few unclear bits of code
  iommufd: Fix comment typos
  vfio: Move vfio group specific code into group.c
  vfio: Refactor dma APIs for emulated devices
  vfio: Wrap vfio group module init/clean code into helpers
  vfio: Refactor vfio_device open and close
  vfio: Make vfio_device_open() truly device specific
  vfio: Swap order of vfio_device_container_register() and open_device()
  vfio: Set device-&gt;group in helper function
  vfio: Create wrappers for group register/unregister
  vfio: Move the sanity check of the group to vfio_create_group()
  vfio: Simplify vfio_create_group()
  iommufd: Allow iommufd to supply /dev/vfio/vfio
  vfio: Make vfio_container optionally compiled
  vfio: Move container related MODULE_ALIAS statements into container.c
  vfio-iommufd: Support iommufd for emulated VFIO devices
  vfio-iommufd: Support iommufd for physical VFIO devices
  vfio-iommufd: Allow iommufd to be used in place of a container fd
  vfio: Use IOMMU_CAP_ENFORCE_CACHE_COHERENCY for vfio_file_enforced_coherent()
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull iommufd implementation from Jason Gunthorpe:
 "iommufd is the user API to control the IOMMU subsystem as it relates
  to managing IO page tables that point at user space memory.

  It takes over from drivers/vfio/vfio_iommu_type1.c (aka the VFIO
  container) which is the VFIO specific interface for a similar idea.

  We see a broad need for extended features, some being highly IOMMU
  device specific:
   - Binding iommu_domain's to PASID/SSID
   - Userspace IO page tables, for ARM, x86 and S390
   - Kernel bypassed invalidation of user page tables
   - Re-use of the KVM page table in the IOMMU
   - Dirty page tracking in the IOMMU
   - Runtime Increase/Decrease of IOPTE size
   - PRI support with faults resolved in userspace

  Many of these HW features exist to support VM use cases - for instance
  the combination of PASID, PRI and Userspace IO Page Tables allows an
  implementation of DMA Shared Virtual Addressing (vSVA) within a guest.
  Dirty tracking enables VM live migration with SRIOV devices and PASID
  support allow creating "scalable IOV" devices, among other things.

  As these features are fundamental to a VM platform they need to be
  uniformly exposed to all the driver families that do DMA into VMs,
  which is currently VFIO and VDPA"

For more background, see the extended explanations in Jason's pull request:

  https://lore.kernel.org/lkml/Y5dzTU8dlmXTbzoJ@nvidia.com/

* tag 'for-linus-iommufd' of git://git.kernel.org/pub/scm/linux/kernel/git/jgg/iommufd: (62 commits)
  iommufd: Change the order of MSI setup
  iommufd: Improve a few unclear bits of code
  iommufd: Fix comment typos
  vfio: Move vfio group specific code into group.c
  vfio: Refactor dma APIs for emulated devices
  vfio: Wrap vfio group module init/clean code into helpers
  vfio: Refactor vfio_device open and close
  vfio: Make vfio_device_open() truly device specific
  vfio: Swap order of vfio_device_container_register() and open_device()
  vfio: Set device-&gt;group in helper function
  vfio: Create wrappers for group register/unregister
  vfio: Move the sanity check of the group to vfio_create_group()
  vfio: Simplify vfio_create_group()
  iommufd: Allow iommufd to supply /dev/vfio/vfio
  vfio: Make vfio_container optionally compiled
  vfio: Move container related MODULE_ALIAS statements into container.c
  vfio-iommufd: Support iommufd for emulated VFIO devices
  vfio-iommufd: Support iommufd for physical VFIO devices
  vfio-iommufd: Allow iommufd to be used in place of a container fd
  vfio: Use IOMMU_CAP_ENFORCE_CACHE_COHERENCY for vfio_file_enforced_coherent()
  ...
</pre>
</div>
</content>
</entry>
</feed>
