| Message ID | 1483969570-3154-9-git-send-email-eric.auger@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Joerg, On 09/01/2017 14:45, Eric Auger wrote: > A new iommu-group sysfs attribute file is introduced. It contains > the list of reserved regions for the iommu-group. Each reserved > region is described on a separate line: > - first field is the start IOVA address, > - second is the end IOVA address, > - third is the type. > > Signed-off-by: Eric Auger <eric.auger@redhat.com> > > --- > v6 -> v7: > - also report the type of the reserved region as a string > - updated ABI documentation > > v3 -> v4: > - add cast to long long int when printing to avoid warning on > i386 > - change S_IRUGO into 0444 > - remove sort. The list is natively sorted now. > > The file layout is inspired of /sys/bus/pci/devices/BDF/resource. > I also read Documentation/filesystems/sysfs.txt so I expect this > to be frowned upon. > --- > .../ABI/testing/sysfs-kernel-iommu_groups | 12 +++++++ > drivers/iommu/iommu.c | 38 ++++++++++++++++++++++ > 2 files changed, 50 insertions(+) > > diff --git a/Documentation/ABI/testing/sysfs-kernel-iommu_groups b/Documentation/ABI/testing/sysfs-kernel-iommu_groups > index 9b31556..35c64e0 100644 > --- a/Documentation/ABI/testing/sysfs-kernel-iommu_groups > +++ b/Documentation/ABI/testing/sysfs-kernel-iommu_groups > @@ -12,3 +12,15 @@ Description: /sys/kernel/iommu_groups/ contains a number of sub- > file if the IOMMU driver has chosen to register a more > common name for the group. > Users: > + > +What: /sys/kernel/iommu_groups/reserved_regions > +Date: January 2017 > +KernelVersion: v4.11 > +Contact: Eric Auger <eric.auger@redhat.com> > +Description: /sys/kernel/iommu_groups/reserved_regions list IOVA > + regions that are reserved. Not necessarily all > + reserved regions are listed. This is typically used to > + output direct-mapped, MSI, non mappable regions. Each > + region is described on a single line: the 1st field is > + the base IOVA, the second is the end IOVA and the third > + field describes the type of the region. > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > index 640056b..0123daa 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -68,6 +68,12 @@ struct iommu_group_attribute { > const char *buf, size_t count); > }; > > +static const char * const iommu_group_resv_type_string[] = { > + [IOMMU_RESV_DIRECT] = "direct", > + [IOMMU_RESV_RESERVED] = "reserved", > + [IOMMU_RESV_MSI] = "msi", > +}; > + > #define IOMMU_GROUP_ATTR(_name, _mode, _show, _store) \ > struct iommu_group_attribute iommu_group_attr_##_name = \ > __ATTR(_name, _mode, _show, _store) > @@ -231,8 +237,33 @@ int iommu_get_group_resv_regions(struct iommu_group *group, > } > EXPORT_SYMBOL_GPL(iommu_get_group_resv_regions); > > +static ssize_t iommu_group_show_resv_regions(struct iommu_group *group, > + char *buf) > +{ > + struct iommu_resv_region *region, *next; > + struct list_head group_resv_regions; > + char *str = buf; > + > + INIT_LIST_HEAD(&group_resv_regions); > + iommu_get_group_resv_regions(group, &group_resv_regions); > + > + list_for_each_entry_safe(region, next, &group_resv_regions, list) { > + str += sprintf(str, "0x%016llx 0x%016llx %s\n", > + (long long int)region->start, > + (long long int)(region->start + > + region->length - 1), > + iommu_group_resv_type_string[region->type]); > + kfree(region); > + } > + > + return (str - buf); > +} > + > static IOMMU_GROUP_ATTR(name, S_IRUGO, iommu_group_show_name, NULL); > > +static IOMMU_GROUP_ATTR(reserved_regions, 0444, > + iommu_group_show_resv_regions, NULL); > + > static void iommu_group_release(struct kobject *kobj) > { > struct iommu_group *group = to_iommu_group(kobj); > @@ -247,6 +278,8 @@ static void iommu_group_release(struct kobject *kobj) > if (group->default_domain) > iommu_domain_free(group->default_domain); > > + iommu_group_remove_file(group, &iommu_group_attr_reserved_regions); The /sys/kernel/iommu_groups/n directory seems to be removed before this gets called and this may produce a WARNING when devices get removed from the group. I intend to remove the call since I have the feeling everything gets cleaned up properly. Do you see any issue? Thanks Eric [ 350.753618] iommu: Removing device 0000:01:10.0 from group 7 [ 350.759331] kernfs: can not remove 'reserved_regions', no directory [ 350.765603] ------------[ cut here ]------------ [ 350.770216] WARNING: CPU: 3 PID: 2617 at fs/kernfs/dir.c:1406 kernfs_remove_by_name_ns+0x8c/0x98 ../.. [ 351.028154] [<ffff00000828819c>] kernfs_remove_by_name_ns+0x8c/0x98 [ 351.034414] [<ffff000008289bf8>] sysfs_remove_file_ns+0x14/0x1c [ 351.040325] [<ffff00000856d918>] iommu_group_release+0x68/0x9c [ 351.046150] [<ffff0000083d152c>] kobject_cleanup+0x8c/0x194 [ 351.051715] [<ffff0000083d13c8>] kobject_put+0x44/0x6c [ 351.056844] [<ffff0000083d1490>] kobject_del+0x40/0x50 [ 351.061974] [<ffff0000083d1508>] kobject_cleanup+0x68/0x194 [ 351.067538] [<ffff0000083d13c8>] kobject_put+0x44/0x6c [ 351.072668] [<ffff00000856df30>] iommu_group_remove_device+0x128/0x1d4 [ 351.079187] [<ffff000008575eb0>] arm_smmu_remove_device+0x12c/0x158 > + > kfree(group->name); > kfree(group); > } > @@ -310,6 +343,11 @@ struct iommu_group *iommu_group_alloc(void) > */ > kobject_put(&group->kobj); > > + ret = iommu_group_create_file(group, > + &iommu_group_attr_reserved_regions); > + if (ret) > + return ERR_PTR(ret); > + > pr_debug("Allocated group %d\n", group->id); > > return group; >
On Tue, Jan 10, 2017 at 05:20:34PM +0100, Auger Eric wrote: > The /sys/kernel/iommu_groups/n directory seems to be removed before this > gets called and this may produce a WARNING when devices get removed from > the group. I intend to remove the call since I have the feeling > everything gets cleaned up properly. A feeling is not enough, please check that in the code. Joerg
Hi Joerg, On 10/01/2017 18:14, Joerg Roedel wrote: > On Tue, Jan 10, 2017 at 05:20:34PM +0100, Auger Eric wrote: >> The /sys/kernel/iommu_groups/n directory seems to be removed before this >> gets called and this may produce a WARNING when devices get removed from >> the group. I intend to remove the call since I have the feeling >> everything gets cleaned up properly. > > A feeling is not enough, please check that in the code. So my understanding is on group's kobject_release we have: kobject_release |_ kobject_cleanup |_ kobject_del |_ sysfs_remove_dir |_ kernfs_remove |_ _kernfs_remove ../.. |_ ktype release (iommu_group_release) _kernfs_remove() calls kernfs_put() on all descendant nodes, leading to the whole directory cleanup. In iommu_group_release I called sysfs_remove_file on the reserved_regions attribute file. My understanding is its job is identifical as what was done previously and the node was already destroyed hence the warning. sysfs_remove_file |_ sysfs_remove_file_ns |_ kernfs_remove_by_name_ns |_kernfs_remove So my understanding is it is safe to remove it. Thanks Eric > > > Joerg > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >
diff --git a/Documentation/ABI/testing/sysfs-kernel-iommu_groups b/Documentation/ABI/testing/sysfs-kernel-iommu_groups index 9b31556..35c64e0 100644 --- a/Documentation/ABI/testing/sysfs-kernel-iommu_groups +++ b/Documentation/ABI/testing/sysfs-kernel-iommu_groups @@ -12,3 +12,15 @@ Description: /sys/kernel/iommu_groups/ contains a number of sub- file if the IOMMU driver has chosen to register a more common name for the group. Users: + +What: /sys/kernel/iommu_groups/reserved_regions +Date: January 2017 +KernelVersion: v4.11 +Contact: Eric Auger <eric.auger@redhat.com> +Description: /sys/kernel/iommu_groups/reserved_regions list IOVA + regions that are reserved. Not necessarily all + reserved regions are listed. This is typically used to + output direct-mapped, MSI, non mappable regions. Each + region is described on a single line: the 1st field is + the base IOVA, the second is the end IOVA and the third + field describes the type of the region. diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 640056b..0123daa 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -68,6 +68,12 @@ struct iommu_group_attribute { const char *buf, size_t count); }; +static const char * const iommu_group_resv_type_string[] = { + [IOMMU_RESV_DIRECT] = "direct", + [IOMMU_RESV_RESERVED] = "reserved", + [IOMMU_RESV_MSI] = "msi", +}; + #define IOMMU_GROUP_ATTR(_name, _mode, _show, _store) \ struct iommu_group_attribute iommu_group_attr_##_name = \ __ATTR(_name, _mode, _show, _store) @@ -231,8 +237,33 @@ int iommu_get_group_resv_regions(struct iommu_group *group, } EXPORT_SYMBOL_GPL(iommu_get_group_resv_regions); +static ssize_t iommu_group_show_resv_regions(struct iommu_group *group, + char *buf) +{ + struct iommu_resv_region *region, *next; + struct list_head group_resv_regions; + char *str = buf; + + INIT_LIST_HEAD(&group_resv_regions); + iommu_get_group_resv_regions(group, &group_resv_regions); + + list_for_each_entry_safe(region, next, &group_resv_regions, list) { + str += sprintf(str, "0x%016llx 0x%016llx %s\n", + (long long int)region->start, + (long long int)(region->start + + region->length - 1), + iommu_group_resv_type_string[region->type]); + kfree(region); + } + + return (str - buf); +} + static IOMMU_GROUP_ATTR(name, S_IRUGO, iommu_group_show_name, NULL); +static IOMMU_GROUP_ATTR(reserved_regions, 0444, + iommu_group_show_resv_regions, NULL); + static void iommu_group_release(struct kobject *kobj) { struct iommu_group *group = to_iommu_group(kobj); @@ -247,6 +278,8 @@ static void iommu_group_release(struct kobject *kobj) if (group->default_domain) iommu_domain_free(group->default_domain); + iommu_group_remove_file(group, &iommu_group_attr_reserved_regions); + kfree(group->name); kfree(group); } @@ -310,6 +343,11 @@ struct iommu_group *iommu_group_alloc(void) */ kobject_put(&group->kobj); + ret = iommu_group_create_file(group, + &iommu_group_attr_reserved_regions); + if (ret) + return ERR_PTR(ret); + pr_debug("Allocated group %d\n", group->id); return group;
A new iommu-group sysfs attribute file is introduced. It contains the list of reserved regions for the iommu-group. Each reserved region is described on a separate line: - first field is the start IOVA address, - second is the end IOVA address, - third is the type. Signed-off-by: Eric Auger <eric.auger@redhat.com> --- v6 -> v7: - also report the type of the reserved region as a string - updated ABI documentation v3 -> v4: - add cast to long long int when printing to avoid warning on i386 - change S_IRUGO into 0444 - remove sort. The list is natively sorted now. The file layout is inspired of /sys/bus/pci/devices/BDF/resource. I also read Documentation/filesystems/sysfs.txt so I expect this to be frowned upon. --- .../ABI/testing/sysfs-kernel-iommu_groups | 12 +++++++ drivers/iommu/iommu.c | 38 ++++++++++++++++++++++ 2 files changed, 50 insertions(+)