[PATCH] iommu: Check for deferred attach in iommu_group_do_dma_attach()

[PATCH] iommu: Check for deferred attach in iommu_group_do_dma_attach()

[Joerg Roedel]

From: Joerg Roedel <jroedel@suse.de>

The iommu_group_do_dma_attach() must not attach devices which have
deferred_attach set. Otherwise devices could cause IOMMU faults when
re-initialized in a kdump kernel.

Fixes: deac0b3bed26 ("iommu: Split off default domain allocation from group assignment")
Reported-by: Jerry Snitselaar <jsnitsel@redhat.com>
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Tested-by: Jerry Snitselaar <jsnitsel@redhat.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
 drivers/iommu/iommu.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index b5ea203f6c68..5a6d509f72b6 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -1680,8 +1680,12 @@ static void probe_alloc_default_domain(struct bus_type *bus,
 static int iommu_group_do_dma_attach(struct device *dev, void *data)
 {
 	struct iommu_domain *domain = data;
+	int ret = 0;
 
-	return __iommu_attach_device(domain, dev);
+	if (!iommu_is_attach_deferred(group->domain, dev))
+		ret = __iommu_attach_device(group->domain, dev);
+
+	return ret;
 }
 
 static int __iommu_group_dma_attach(struct iommu_group *group)
-- 
2.26.2

Re: [PATCH] iommu: Check for deferred attach in iommu_group_do_dma_attach()

[Joerg Roedel]

On Thu, Jun 04, 2020 at 11:19:44AM +0200, Joerg Roedel wrote:
> From: Joerg Roedel <jroedel@suse.de>
> 
> The iommu_group_do_dma_attach() must not attach devices which have
> deferred_attach set. Otherwise devices could cause IOMMU faults when
> re-initialized in a kdump kernel.
> 
> Fixes: deac0b3bed26 ("iommu: Split off default domain allocation from group assignment")
> Reported-by: Jerry Snitselaar <jsnitsel@redhat.com>
> Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
> Tested-by: Jerry Snitselaar <jsnitsel@redhat.com>
> Signed-off-by: Joerg Roedel <jroedel@suse.de>
> ---
>  drivers/iommu/iommu.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> index b5ea203f6c68..5a6d509f72b6 100644
> --- a/drivers/iommu/iommu.c
> +++ b/drivers/iommu/iommu.c
> @@ -1680,8 +1680,12 @@ static void probe_alloc_default_domain(struct bus_type *bus,
>  static int iommu_group_do_dma_attach(struct device *dev, void *data)
>  {
>  	struct iommu_domain *domain = data;
> +	int ret = 0;
>  
> -	return __iommu_attach_device(domain, dev);
> +	if (!iommu_is_attach_deferred(group->domain, dev))
> +		ret = __iommu_attach_device(group->domain, dev);

And of course with the same bug as my original diff. Fixed that up
before applying it. (group->domain -> domain).


	Joerg

Re: [PATCH] iommu: Check for deferred attach in iommu_group_do_dma_attach()

[kernel test robot]

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Hi Joerg,

I love your patch! Yet something to improve:

[auto build test ERROR on iommu/next]
[also build test ERROR on next-20200604]
[cannot apply to v5.7]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/Joerg-Roedel/iommu-Check-for-deferred-attach-in-iommu_group_do_dma_attach/20200604-172315
base:   https://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu.git next
config: arm-randconfig-s032-20200604 (attached as .config)
compiler: arm-linux-gnueabi-gcc (GCC) 9.3.0
reproduce:
        # apt-get install sparse
        # sparse version: v0.6.1-244-g0ee050a8-dirty
        # save the attached .config to linux build tree
        make W=1 C=1 ARCH=arm CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__'

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>, old ones prefixed by <<):

drivers/iommu/iommu.c:386:5: warning: no previous prototype for 'iommu_insert_resv_region' [-Wmissing-prototypes]
386 | int iommu_insert_resv_region(struct iommu_resv_region *new,
|     ^~~~~~~~~~~~~~~~~~~~~~~~
drivers/iommu/iommu.c: In function 'iommu_group_do_dma_attach':
>> drivers/iommu/iommu.c:1685:32: error: 'group' undeclared (first use in this function); did you mean 'cgroup'?
1685 |  if (!iommu_is_attach_deferred(group->domain, dev))
|                                ^~~~~
|                                cgroup
drivers/iommu/iommu.c:1685:32: note: each undeclared identifier is reported only once for each function it appears in
drivers/iommu/iommu.c:1682:23: warning: unused variable 'domain' [-Wunused-variable]
1682 |  struct iommu_domain *domain = data;
|                       ^~~~~~
drivers/iommu/iommu.c: At top level:
drivers/iommu/iommu.c:2171:5: warning: no previous prototype for '__iommu_map' [-Wmissing-prototypes]
2171 | int __iommu_map(struct iommu_domain *domain, unsigned long iova,
|     ^~~~~~~~~~~
drivers/iommu/iommu.c:2322:8: warning: no previous prototype for '__iommu_map_sg' [-Wmissing-prototypes]
2322 | size_t __iommu_map_sg(struct iommu_domain *domain, unsigned long iova,
|        ^~~~~~~~~~~~~~

vim +1685 drivers/iommu/iommu.c

  1679	
  1680	static int iommu_group_do_dma_attach(struct device *dev, void *data)
  1681	{
  1682		struct iommu_domain *domain = data;
  1683		int ret = 0;
  1684	
> 1685		if (!iommu_is_attach_deferred(group->domain, dev))
  1686			ret = __iommu_attach_device(group->domain, dev);
  1687	
  1688		return ret;
  1689	}
  1690	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

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