If you wish to utilise a pidfd interface to refer to the current process or
thread it is rather cumbersome, requiring something like:
int pidfd = pidfd_open(getpid(), 0 or PIDFD_THREAD);
...
close(pidfd);
Or the equivalent call opening /proc/self. It is more convenient to use a
sentinel value to indicate to an interface that accepts a pidfd that we
simply wish to refer to the current process thread.
This series introduces sentinels for this purposes which can be passed as
the pidfd in this instance rather than having to establish a dummy fd for
this purpose.
It is useful to refer to both the current thread from the userland's
perspective for which we use PIDFD_SELF, and the current process from the
userland's perspective, for which we use PIDFD_SELF_PROCESS.
There is unfortunately some confusion between the kernel and userland as to
what constitutes a process - a thread from the userland perspective is a
process in userland, and a userland process is a thread group (more
specifically the thread group leader from the kernel perspective). We
therefore alias things thusly:
* PIDFD_SELF_THREAD aliased by PIDFD_SELF - use PIDTYPE_PID.
* PIDFD_SELF_THREAD_GROUP alised by PIDFD_SELF_PROCESS - use PIDTYPE_TGID.
In all of the kernel code we refer to PIDFD_SELF_THREAD and
PIDFD_SELF_THREAD_GROUP. However we expect users to use PIDFD_SELF and
PIDFD_SELF_PROCESS.
This matters for cases where, for instance, a user unshare()'s FDs or does
thread-specific signal handling and where the user would be hugely confused
if the FDs referenced or signal processed referred to the thread group
leader rather than the individual thread.
We ensure that pidfd_send_signal() and pidfd_getfd() work correctly, and
assert as much in selftests. All other interfaces except setns() will work
implicitly with this new interface, however it doesn't make sense to test
waitid(P_PIDFD, ...) as waiting on ourselves is a blocking operation.
In the case of setns() we explicitly disallow use of PIDFD_SELF* as it
doesn't make sense to obtain the namespaces of our own process, and it
would require work to implement this functionality there that would be of
no use.
We also do not provide the ability to utilise PIDFD_SELF* in ordinary fd
operations such as open() or poll(), as this would require extensive work
and be of no real use.
v5:
* Fixup self test dependencies on pidfd/pidfd.h.
v4:
* Avoid returning an fd in the __pidfd_get_pid() function as pointed out by
Christian, instead simply always pin the pid and maintain fd scope in the
helper alone.
* Add wrapper header file in tools/include/linux to allow for import of
UAPI pidfd.h header without encountering the collision between system
fcntl.h and linux/fcntl.h as discussed with Shuah and John.
* Fixup tests to import the UAPI pidfd.h header working around conflicts
between system fcntl.h and linux/fcntl.h which the UAPI pidfd.h imports,
as reported by Shuah.
* Use an int for pidfd_is_self_sentinel() to avoid any dependency on
stdbool.h in userland.
https://lore.kernel.org/linux-mm/cover.1729198898.git.lorenzo.stoakes@oracl…
v3:
* Do not fput() an invalid fd as reported by kernel test bot.
* Fix unintended churn from moving variable declaration.
https://lore.kernel.org/linux-mm/cover.1729073310.git.lorenzo.stoakes@oracl…
v2:
* Fix tests as reported by Shuah.
* Correct RFC version lore link.
https://lore.kernel.org/linux-mm/cover.1728643714.git.lorenzo.stoakes@oracl…
Non-RFC v1:
* Removed RFC tag - there seems to be general consensus that this change is
a good idea, but perhaps some debate to be had on implementation. It
seems sensible then to move forward with the RFC flag removed.
* Introduced PIDFD_SELF_THREAD, PIDFD_SELF_THREAD_GROUP and their aliases
PIDFD_SELF and PIDFD_SELF_PROCESS respectively.
* Updated testing accordingly.
https://lore.kernel.org/linux-mm/cover.1728578231.git.lorenzo.stoakes@oracl…
RFC version:
https://lore.kernel.org/linux-mm/cover.1727644404.git.lorenzo.stoakes@oracl…
Lorenzo Stoakes (5):
pidfd: extend pidfd_get_pid() and de-duplicate pid lookup
pidfd: add PIDFD_SELF_* sentinels to refer to own thread/process
tools: testing: separate out wait_for_pid() into helper header
selftests: pidfd: add pidfd.h UAPI wrapper
selftests: pidfd: add tests for PIDFD_SELF_*
include/linux/pid.h | 34 ++++-
include/uapi/linux/pidfd.h | 15 ++
kernel/exit.c | 3 +-
kernel/nsproxy.c | 1 +
kernel/pid.c | 65 +++++---
kernel/signal.c | 29 +---
tools/include/linux/pidfd.h | 14 ++
tools/testing/selftests/cgroup/test_kill.c | 2 +-
.../pid_namespace/regression_enomem.c | 2 +-
tools/testing/selftests/pidfd/Makefile | 3 +-
tools/testing/selftests/pidfd/pidfd.h | 28 +---
.../selftests/pidfd/pidfd_getfd_test.c | 141 ++++++++++++++++++
tools/testing/selftests/pidfd/pidfd_helpers.h | 39 +++++
.../selftests/pidfd/pidfd_setns_test.c | 11 ++
tools/testing/selftests/pidfd/pidfd_test.c | 76 ++++++++--
15 files changed, 375 insertions(+), 88 deletions(-)
create mode 100644 tools/include/linux/pidfd.h
create mode 100644 tools/testing/selftests/pidfd/pidfd_helpers.h
--
2.47.0
Use a less populated IP range to run the tests, as suggested by Petr in
Link: https://lore.kernel.org/netdev/87ikvukv3s.fsf@nvidia.com/.
Suggested-by: Petr Machata <petrm(a)nvidia.com>
Signed-off-by: Breno Leitao <leitao(a)debian.org>
---
tools/testing/selftests/drivers/net/netcons_basic.sh | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/drivers/net/netcons_basic.sh b/tools/testing/selftests/drivers/net/netcons_basic.sh
index 06021b2059b7..4ad1e216c6b0 100755
--- a/tools/testing/selftests/drivers/net/netcons_basic.sh
+++ b/tools/testing/selftests/drivers/net/netcons_basic.sh
@@ -20,9 +20,9 @@ SCRIPTDIR=$(dirname "$(readlink -e "${BASH_SOURCE[0]}")")
# Simple script to test dynamic targets in netconsole
SRCIF="" # to be populated later
-SRCIP=192.168.1.1
+SRCIP=192.168.2.1
DSTIF="" # to be populated later
-DSTIP=192.168.1.2
+DSTIP=192.168.2.2
PORT="6666"
MSG="netconsole selftest"
--
2.43.5
Following the previous vIOMMU series, this adds another vDEVICE structure,
representing the association from an iommufd_device to an iommufd_viommu.
This gives the whole architecture a new "v" layer:
_______________________________________________________________________
| iommufd (with vIOMMU/vDEVICE) |
| _____________ _____________ |
| | | | | |
| |----------------| vIOMMU |<---| vDEVICE |<------| |
| | | | |_____________| | |
| | ______ | | _____________ ___|____ |
| | | | | | | | | | |
| | | IOAS |<---|(HWPT_PAGING)|<---| HWPT_NESTED |<--| DEVICE | |
| | |______| |_____________| |_____________| |________| |
|______|________|______________|__________________|_______________|_____|
| | | | |
______v_____ | ______v_____ ______v_____ ___v__
| struct | | PFN | (paging) | | (nested) | |struct|
|iommu_device| |------>|iommu_domain|<----|iommu_domain|<----|device|
|____________| storage|____________| |____________| |______|
This vDEVICE object is used to collect and store all vIOMMU-related device
information/attributes in a VM. As an initial series for vDEVICE, add only
the virt_id to the vDEVICE, which is a vIOMMU specific device ID in a VM:
e.g. vSID of ARM SMMUv3, vDeviceID of AMD IOMMU, and vID of Intel VT-d to
a Context Table. This virt_id helps IOMMU drivers to link the vID to a pID
of the device against the physical IOMMU instance. This is essential for a
vIOMMU-based invalidation, where the request contains a device's vID for a
device cache flush, e.g. ATC invalidation.
Therefore, with this vDEVICE object, support a vIOMMU-based invalidation,
by reusing IOMMUFD_CMD_HWPT_INVALIDATE for a vIOMMU object to flush cache
with a given driver data.
As for the implementation of the series, add driver support in ARM SMMUv3
for a real world use case.
This series is on Github:
https://github.com/nicolinc/iommufd/commits/iommufd_viommu_p2-v4
For testing, try this "with-rmr" branch:
https://github.com/nicolinc/iommufd/commits/iommufd_viommu_p2-v4-with-rmr
Paring QEMU branch for testing:
https://github.com/nicolinc/qemu/commits/wip/for_iommufd_viommu_p2-v4
Changelog
v4
* Added missing brackets in switch-case
* Fixed the unreleased idev refcount issue
* Reworked the iommufd_vdevice_alloc allocator
* Dropped support for IOMMU_VIOMMU_TYPE_DEFAULT
* Added missing TEST_LENGTH and fail_nth coverages
* Added a verification to the driver-allocated vDEVICE object
* Added an iommufd_vdevice_abort for a missing mutex protection
* Added a u64 structure arm_vsmmu_invalidation_cmd for user command
conversion
v3
https://lore.kernel.org/all/cover.1728491532.git.nicolinc@nvidia.com/
* Added Jason's Reviewed-by
* Split this invalidation part out of the part-1 series
* Repurposed VDEV_ID ioctl to a wider vDEVICE structure and ioctl
* Reduced viommu_api functions by allowing drivers to access viommu
and vdevice structure directly
* Dropped vdevs_rwsem by using xa_lock instead
* Dropped arm_smmu_cache_invalidate_user
v2
https://lore.kernel.org/all/cover.1724776335.git.nicolinc@nvidia.com/
* Limited vdev_id to one per idev
* Added a rw_sem to protect the vdev_id list
* Reworked driver-level APIs with proper lockings
* Added a new viommu_api file for IOMMUFD_DRIVER config
* Dropped useless iommu_dev point from the viommu structure
* Added missing index numnbers to new types in the uAPI header
* Dropped IOMMU_VIOMMU_INVALIDATE uAPI; Instead, reuse the HWPT one
* Reworked mock_viommu_cache_invalidate() using the new iommu helper
* Reordered details of set/unset_vdev_id handlers for proper lockings
v1
https://lore.kernel.org/all/cover.1723061377.git.nicolinc@nvidia.com/
Thanks!
Nicolin
Jason Gunthorpe (2):
iommu: Add iommu_copy_struct_from_full_user_array helper
iommu/arm-smmu-v3: Allow ATS for IOMMU_DOMAIN_NESTED
Nicolin Chen (12):
iommufd/viommu: Introduce IOMMUFD_OBJ_VDEVICE and its related struct
iommufd/viommu: Add IOMMU_VDEVICE_ALLOC ioctl
iommufd/selftest: Add IOMMU_VDEVICE_ALLOC test coverage
iommu/viommu: Add cache_invalidate to iommufd_viommu_ops
iommufd/hw_pagetable: Enforce cache invalidation op on vIOMMU-based
hwpt_nested
iommufd: Allow hwpt_id to carry viommu_id for IOMMU_HWPT_INVALIDATE
iommufd/viommu: Add vdev_to_dev helper
iommufd/selftest: Add mock_viommu_cache_invalidate
iommufd/selftest: Add IOMMU_TEST_OP_DEV_CHECK_CACHE test command
iommufd/selftest: Add vIOMMU coverage for IOMMU_HWPT_INVALIDATE ioctl
Documentation: userspace-api: iommufd: Update vDEVICE
iommu/arm-smmu-v3: Add arm_vsmmu_cache_invalidate
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 9 +-
drivers/iommu/iommufd/iommufd_private.h | 12 ++
drivers/iommu/iommufd/iommufd_test.h | 30 +++
include/linux/iommu.h | 49 ++++-
include/linux/iommufd.h | 50 +++++
include/uapi/linux/iommufd.h | 61 +++++-
tools/testing/selftests/iommu/iommufd_utils.h | 83 +++++++
.../arm/arm-smmu-v3/arm-smmu-v3-iommufd.c | 162 +++++++++++++-
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 32 ++-
drivers/iommu/iommufd/device.c | 11 +
drivers/iommu/iommufd/driver.c | 7 +
drivers/iommu/iommufd/hw_pagetable.c | 36 +++-
drivers/iommu/iommufd/main.c | 7 +
drivers/iommu/iommufd/selftest.c | 115 +++++++++-
drivers/iommu/iommufd/viommu.c | 108 ++++++++++
tools/testing/selftests/iommu/iommufd.c | 204 +++++++++++++++++-
.../selftests/iommu/iommufd_fail_nth.c | 4 +
Documentation/userspace-api/iommufd.rst | 41 +++-
18 files changed, 983 insertions(+), 38 deletions(-)
--
2.43.0
If you wish to utilise a pidfd interface to refer to the current process or
thread it is rather cumbersome, requiring something like:
int pidfd = pidfd_open(getpid(), 0 or PIDFD_THREAD);
...
close(pidfd);
Or the equivalent call opening /proc/self. It is more convenient to use a
sentinel value to indicate to an interface that accepts a pidfd that we
simply wish to refer to the current process thread.
This series introduces sentinels for this purposes which can be passed as
the pidfd in this instance rather than having to establish a dummy fd for
this purpose.
It is useful to refer to both the current thread from the userland's
perspective for which we use PIDFD_SELF, and the current process from the
userland's perspective, for which we use PIDFD_SELF_PROCESS.
There is unfortunately some confusion between the kernel and userland as to
what constitutes a process - a thread from the userland perspective is a
process in userland, and a userland process is a thread group (more
specifically the thread group leader from the kernel perspective). We
therefore alias things thusly:
* PIDFD_SELF_THREAD aliased by PIDFD_SELF - use PIDTYPE_PID.
* PIDFD_SELF_THREAD_GROUP alised by PIDFD_SELF_PROCESS - use PIDTYPE_TGID.
In all of the kernel code we refer to PIDFD_SELF_THREAD and
PIDFD_SELF_THREAD_GROUP. However we expect users to use PIDFD_SELF and
PIDFD_SELF_PROCESS.
This matters for cases where, for instance, a user unshare()'s FDs or does
thread-specific signal handling and where the user would be hugely confused
if the FDs referenced or signal processed referred to the thread group
leader rather than the individual thread.
We ensure that pidfd_send_signal() and pidfd_getfd() work correctly, and
assert as much in selftests. All other interfaces except setns() will work
implicitly with this new interface, however it doesn't make sense to test
waitid(P_PIDFD, ...) as waiting on ourselves is a blocking operation.
In the case of setns() we explicitly disallow use of PIDFD_SELF* as it
doesn't make sense to obtain the namespaces of our own process, and it
would require work to implement this functionality there that would be of
no use.
We also do not provide the ability to utilise PIDFD_SELF* in ordinary fd
operations such as open() or poll(), as this would require extensive work
and be of no real use.
v4:
* Avoid returning an fd in the __pidfd_get_pid() function as pointed out by
Christian, instead simply always pin the pid and maintain fd scope in the
helper alone.
* Add wrapper header file in tools/include/linux to allow for import of
UAPI pidfd.h header without encountering the collision between system
fcntl.h and linux/fcntl.h as discussed with Shuah and John.
* Fixup tests to import the UAPI pidfd.h header working around conflicts
between system fcntl.h and linux/fcntl.h which the UAPI pidfd.h imports,
as reported by Shuah.
* Use an int for pidfd_is_self_sentinel() to avoid any dependency on
stdbool.h in userland.
v3:
* Do not fput() an invalid fd as reported by kernel test bot.
* Fix unintended churn from moving variable declaration.
https://lore.kernel.org/linux-mm/cover.1729073310.git.lorenzo.stoakes@oracl…
v2:
* Fix tests as reported by Shuah.
* Correct RFC version lore link.
https://lore.kernel.org/linux-mm/cover.1728643714.git.lorenzo.stoakes@oracl…
Non-RFC v1:
* Removed RFC tag - there seems to be general consensus that this change is
a good idea, but perhaps some debate to be had on implementation. It
seems sensible then to move forward with the RFC flag removed.
* Introduced PIDFD_SELF_THREAD, PIDFD_SELF_THREAD_GROUP and their aliases
PIDFD_SELF and PIDFD_SELF_PROCESS respectively.
* Updated testing accordingly.
https://lore.kernel.org/linux-mm/cover.1728578231.git.lorenzo.stoakes@oracl…
RFC version:
https://lore.kernel.org/linux-mm/cover.1727644404.git.lorenzo.stoakes@oracl…
Lorenzo Stoakes (4):
pidfd: extend pidfd_get_pid() and de-duplicate pid lookup
pidfd: add PIDFD_SELF_* sentinels to refer to own thread/process
selftests: pidfd: add pidfd.h UAPI wrapper
selftests: pidfd: add tests for PIDFD_SELF_*
include/linux/pid.h | 34 ++++-
include/uapi/linux/pidfd.h | 15 ++
kernel/exit.c | 3 +-
kernel/nsproxy.c | 1 +
kernel/pid.c | 65 +++++---
kernel/signal.c | 29 +---
tools/include/linux/pidfd.h | 14 ++
tools/testing/selftests/pidfd/Makefile | 3 +-
tools/testing/selftests/pidfd/pidfd.h | 2 +
.../selftests/pidfd/pidfd_getfd_test.c | 141 ++++++++++++++++++
.../selftests/pidfd/pidfd_setns_test.c | 11 ++
tools/testing/selftests/pidfd/pidfd_test.c | 76 ++++++++--
12 files changed, 333 insertions(+), 61 deletions(-)
create mode 100644 tools/include/linux/pidfd.h
--
2.46.2