This splits the preparation works of the iommu and the Intel iommu driver
out from the iommufd pasid attach/replace series. [1]
To support domain replacement, the definition of the set_dev_pasid op
needs to be enhanced. Meanwhile, the existing set_dev_pasid callbacks
should be extended as well to suit the new definition.
This series first prepares the Intel iommu set_dev_pasid op for the new
definition, adds the missing set_dev_pasid support for nested domain, makes
ARM SMMUv3 set_dev_pasid op to suit the new definition, and in the end
enhances the definition of set_dev_pasid op. The AMD set_dev_pasid callback
is extended to fail if the caller tries to do domain replacement to meet the
new definition of set_dev_pasid op. AMD iommu driver would support it later
per Vasant [2].
[1] https://lore.kernel.org/linux-iommu/20240412081516.31168-1-yi.l.liu@intel.c…
[2] https://lore.kernel.org/linux-iommu/fa9c4fc3-9365-465e-8926-b4d2d6361b9c@am…
v2:
- Make ARM SMMUv3 set_dev_pasid op support domain replacement (Jason)
- Drop patch 03 of v1 (Kevin)
- Multiple tweaks in VT-d driver (Kevin)
v1: https://lore.kernel.org/linux-iommu/20240628085538.47049-1-yi.l.liu@intel.c…
Regards,
Yi Liu
Jason Gunthorpe (1):
iommu/arm-smmu-v3: Make smmuv3 set_dev_pasid() op support replace
Lu Baolu (1):
iommu/vt-d: Add set_dev_pasid callback for nested domain
Yi Liu (4):
iommu: Pass old domain to set_dev_pasid op
iommu/vt-d: Move intel_drain_pasid_prq() into
intel_pasid_tear_down_entry()
iommu/vt-d: Make intel_iommu_set_dev_pasid() to handle domain
replacement
iommu: Make set_dev_pasid op support domain replacement
drivers/iommu/amd/amd_iommu.h | 3 +-
drivers/iommu/amd/pasid.c | 6 +-
.../iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c | 5 +-
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 8 +-
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 2 +-
drivers/iommu/intel/iommu.c | 122 ++++++++++++------
drivers/iommu/intel/iommu.h | 3 +
drivers/iommu/intel/nested.c | 1 +
drivers/iommu/intel/pasid.c | 13 +-
drivers/iommu/intel/pasid.h | 8 +-
drivers/iommu/intel/svm.c | 6 +-
drivers/iommu/iommu.c | 3 +-
include/linux/iommu.h | 5 +-
13 files changed, 129 insertions(+), 56 deletions(-)
--
2.34.1
Userland library functions such as allocators and threading implementations
often require regions of memory to act as 'guard pages' - mappings which,
when accessed, result in a fatal signal being sent to the accessing
process.
The current means by which these are implemented is via a PROT_NONE mmap()
mapping, which provides the required semantics however incur an overhead of
a VMA for each such region.
With a great many processes and threads, this can rapidly add up and incur
a significant memory penalty. It also has the added problem of preventing
merges that might otherwise be permitted.
This series takes a different approach - an idea suggested by Vlasimil
Babka (and before him David Hildenbrand and Jann Horn - perhaps more - the
provenance becomes a little tricky to ascertain after this - please forgive
any omissions!) - rather than locating the guard pages at the VMA layer,
instead placing them in page tables mapping the required ranges.
Early testing of the prototype version of this code suggests a 5 times
speed up in memory mapping invocations (in conjunction with use of
process_madvise()) and a 13% reduction in VMAs on an entirely idle android
system and unoptimised code.
We expect with optimisation and a loaded system with a larger number of
guard pages this could significantly increase, but in any case these
numbers are encouraging.
This way, rather than having separate VMAs specifying which parts of a
range are guard pages, instead we have a VMA spanning the entire range of
memory a user is permitted to access and including ranges which are to be
'guarded'.
After mapping this, a user can specify which parts of the range should
result in a fatal signal when accessed.
By restricting the ability to specify guard pages to memory mapped by
existing VMAs, we can rely on the mappings being torn down when the
mappings are ultimately unmapped and everything works simply as if the
memory were not faulted in, from the point of view of the containing VMAs.
This mechanism in effect poisons memory ranges similar to hardware memory
poisoning, only it is an entirely software-controlled form of poisoning.
Any poisoned region of memory is also able to 'unpoisoned', that is, to
have its poison markers removed.
The mechanism is implemented via madvise() behaviour - MADV_GUARD_POISON
which simply poisons ranges - and MADV_GUARD_UNPOISON - which clears this
poisoning.
Poisoning can be performed across multiple VMAs and any existing mappings
will be cleared, that is zapped, before installing the poisoned page table
mappings.
There is no concept of 'nested' poisoning, multiple attempts to poison a
range will, after the first poisoning, have no effect.
Importantly, unpoisoning of poisoned ranges has no effect on non-poisoned
memory, so a user can safely unpoison a range of memory and clear only
poison page table mappings leaving the rest intact.
The actual mechanism by which the page table entries are specified makes
use of existing logic - PTE markers, which are used for the userfaultfd
UFFDIO_POISON mechanism.
Unfortunately PTE_MARKER_POISONED is not suited for the guard page
mechanism as it results in VM_FAULT_HWPOISON semantics in the fault
handler, so we add our own specific PTE_MARKER_GUARD and adapt existing
logic to handle it.
We also extend the generic page walk mechanism to allow for installation of
PTEs (carefully restricted to memory management logic only to prevent
unwanted abuse).
We ensure that zapping performed by, for instance, MADV_DONTNEED, does not
remove guard poison markers, nor does forking (except when VM_WIPEONFORK is
specified for a VMA which implies a total removal of memory
characteristics).
It's important to note that the guard page implementation is emphatically
NOT a security feature, so a user can remove the poisoning if they wish. We
simply implement it in such a way as to provide the least surprising
behaviour.
An extensive set of self-tests are provided which ensure behaviour is as
expected and additionally self-documents expected behaviour of poisoned
ranges.
Suggested-by: Vlastimil Babka <vbabka(a)suze.cz>
Suggested-by: Jann Horn <jannh(a)google.com>
Suggested-by: David Hildenbrand <david(a)redhat.com>
Lorenzo Stoakes (4):
mm: pagewalk: add the ability to install PTEs
mm: add PTE_MARKER_GUARD PTE marker
mm: madvise: implement lightweight guard page mechanism
selftests/mm: add self tests for guard page feature
arch/alpha/include/uapi/asm/mman.h | 3 +
arch/mips/include/uapi/asm/mman.h | 3 +
arch/parisc/include/uapi/asm/mman.h | 3 +
arch/xtensa/include/uapi/asm/mman.h | 3 +
include/linux/mm_inline.h | 2 +-
include/linux/pagewalk.h | 18 +-
include/linux/swapops.h | 26 +-
include/uapi/asm-generic/mman-common.h | 3 +
mm/hugetlb.c | 3 +
mm/internal.h | 6 +
mm/madvise.c | 158 +++
mm/memory.c | 18 +-
mm/mprotect.c | 3 +-
mm/mseal.c | 1 +
mm/pagewalk.c | 174 ++--
tools/testing/selftests/mm/.gitignore | 1 +
tools/testing/selftests/mm/Makefile | 1 +
tools/testing/selftests/mm/guard-pages.c | 1168 ++++++++++++++++++++++
18 files changed, 1525 insertions(+), 69 deletions(-)
create mode 100644 tools/testing/selftests/mm/guard-pages.c
--
2.46.2
Hello all,
This patch series offers improvements to the way .BTF_ids section data is
created and later patched by resolve_btfids.
Patch #1 simplifies the byte-order translation in resolve_btfids while
making it more resilient to future .BTF_ids encoding updates.
Patch #2 makes sure all BTF ID data is 4-byte aligned, and not only the
.BTF_ids used for vmlinux.
Patch #3 syncs the above changes in btf_ids.h to tools/include, obviating
a previous alignment fix in selftests/bpf.
Feedback and suggestions are welcome!
Best regards,
Tony
Tony Ambardar (3):
tools/resolve_btfids: Simplify handling cross-endian compilation
bpf: btf: Ensure natural alignment of .BTF_ids section
tools/bpf, selftests/bpf : Sync btf_ids.h to tools
include/linux/btf_ids.h | 1 +
tools/bpf/resolve_btfids/main.c | 60 +++++---------
tools/include/linux/btf_ids.h | 80 +++++++++++++++++--
.../selftests/bpf/prog_tests/resolve_btfids.c | 6 --
4 files changed, 97 insertions(+), 50 deletions(-)
--
2.34.1
From: Jeff Xu <jeffxu(a)chromium.org>
Pedro Falcato's optimization [1] for checking sealed VMAs, which replaces
the can_modify_mm() function with an in-loop check, necessitates an update
to the mseal.rst documentation to reflect this change.
Furthermore, the document has received offline comments regarding the code
sample and suggestions for sentence clarification to enhance reader
comprehension.
[1] https://lore.kernel.org/linux-mm/20240817-mseal-depessimize-v3-0-d8d2e037df…
Jeff Xu (1):
mseal: update mseal.rst
Documentation/userspace-api/mseal.rst | 290 ++++++++++++--------------
1 file changed, 136 insertions(+), 154 deletions(-)
--
2.46.1.824.gd892dcdcdd-goog
PASID (Process Address Space ID) is a PCIe extension to tag the DMA
transactions out of a physical device, and most modern IOMMU hardware
have supported PASID granular address translation. So a PASID-capable
device can be attached to multiple hwpts (a.k.a. domains), and each
attachment is tagged with a pasid.
This series is based on the preparation series [1] [2], it first adds a
missing iommu API to replace the domain for a pasid. Based on the iommu
pasid attach/ replace/detach APIs, this series adds iommufd APIs for device
drivers to attach/replace/detach pasid to/from hwpt per userspace's request,
and adds selftest to validate the iommufd APIs.
While this series has a missing part which is to enforce the domain
allocation with special flag if it will be used by PASID [3]. This is due
to special requirements by AMD. Since it is still in mailing discussion [4],
so let's mark it here. Once it's finalized, this series needs to enforce
the domain flag check to ensure the AMD pasid support is not broken from
day-1.
The completed code can be found in the below link [5]. Heads up! The existing
iommufd selftest was broken, there was a fix [6] to it, but not been
upstreamed yet. If want to run the iommufd selftest, please apply that fix.
Sorry for the inconvenience.
[1] https://lore.kernel.org/linux-iommu/20240912130427.10119-1-yi.l.liu@intel.c…
[2] https://lore.kernel.org/linux-iommu/20240912130653.11028-1-yi.l.liu@intel.c…
[3] https://lore.kernel.org/linux-iommu/20240822124433.GD3468552@ziepe.ca/
[4] https://lore.kernel.org/linux-iommu/20240911101911.6269-3-vasant.hegde@amd.…
[5] https://github.com/yiliu1765/iommufd/tree/iommufd_pasid
[6] https://lore.kernel.org/linux-iommu/20240111073213.180020-1-baolu.lu@linux.…
Change log:
v4:
- Replace remove_dev_pasid() by supporting set_dev_pasid() for blocking domain (Kevin)
- This is done by the preparation series "Support attaching PASID to the blocked_domain"
- Misc tweaks to foil the merging of the iommufd iopf series. Three new patches are added:
- iommufd: Always pass iommu_attach_handle to iommu core
- iommufd: Move the iommufd_handle helpers to iommufd_private.h
- iommufd: Refactor __fault_domain_replace_dev() to be a wrapper of iommu_replace_group_handle()
- Renmae patch 03 of v3 to be "iommufd: Support pasid attach/replace"
- Add test case for attaching/replacing iopf-capable hwpt to pasid
v3: https://lore.kernel.org/kvm/20240628090557.50898-1-yi.l.liu@intel.com/
- Split the set_dev_pasid op enhancements for domain replacement to be a
separate series "Make set_dev_pasid op supportting domain replacement" [1].
The below changes are made in the separate series.
*) set_dev_pasid() callback should keep the old config if failed to attach to
a domain. This simplifies the caller a lot as caller does not need to attach
it back to old domain explicitly. This also avoids some corner cases in which
the core may do duplicated domain attachment as described in below link (Jason)
https://lore.kernel.org/linux-iommu/BN9PR11MB52768C98314A95AFCD2FA6478C0F2@…
*) Drop patch 10 of v2 as it's a bug fix and can be submitted separately (Kevin)
*) Rebase on top of Baolu's domain_alloc_paging refactor series (Jason)
- Drop the attach_data which includes attach_fn and pasid, insteadly passing the
pasid through the device attach path. (Jason)
- Add a pasid-num-bits property to mock dev to make pasid selftest work (Kevin)
v2: https://lore.kernel.org/linux-iommu/20240412081516.31168-1-yi.l.liu@intel.c…
- Domain replace for pasid should be handled in set_dev_pasid() callbacks
instead of remove_dev_pasid and call set_dev_pasid afteward in iommu
layer (Jason)
- Make xarray operations more self-contained in iommufd pasid attach/replace/detach
(Jason)
- Tweak the dev_iommu_get_max_pasids() to allow iommu driver to populate the
max_pasids. This makes the iommufd selftest simpler to meet the max_pasids
check in iommu_attach_device_pasid() (Jason)
v1: https://lore.kernel.org/kvm/20231127063428.127436-1-yi.l.liu@intel.com/#r
- Implemnet iommu_replace_device_pasid() to fall back to the original domain
if this replacement failed (Kevin)
- Add check in do_attach() to check corressponding attach_fn per the pasid value.
rfc: https://lore.kernel.org/linux-iommu/20230926092651.17041-1-yi.l.liu@intel.c…
Regards,
Yi Liu
Yi Liu (10):
iommu: Introduce a replace API for device pasid
iommufd: Refactor __fault_domain_replace_dev() to be a wrapper of
iommu_replace_group_handle()
iommufd: Move the iommufd_handle helpers to iommufd_private.h
iommufd: Always pass iommu_attach_handle to iommu core
iommufd: Pass pasid through the device attach/replace path
iommufd: Support pasid attach/replace
iommufd/selftest: Add set_dev_pasid and remove_dev_pasid in mock iommu
iommufd/selftest: Add a helper to get test device
iommufd/selftest: Add test ops to test pasid attach/detach
iommufd/selftest: Add coverage for iommufd pasid attach/detach
drivers/iommu/iommu-priv.h | 4 +
drivers/iommu/iommu.c | 90 +++++-
drivers/iommu/iommufd/Makefile | 1 +
drivers/iommu/iommufd/device.c | 46 ++--
drivers/iommu/iommufd/fault.c | 90 ++----
drivers/iommu/iommufd/hw_pagetable.c | 5 +-
drivers/iommu/iommufd/iommufd_private.h | 129 ++++++++-
drivers/iommu/iommufd/iommufd_test.h | 30 ++
drivers/iommu/iommufd/pasid.c | 157 +++++++++++
drivers/iommu/iommufd/selftest.c | 208 +++++++++++++-
include/linux/iommufd.h | 7 +
tools/testing/selftests/iommu/iommufd.c | 256 ++++++++++++++++++
.../selftests/iommu/iommufd_fail_nth.c | 29 +-
tools/testing/selftests/iommu/iommufd_utils.h | 78 ++++++
14 files changed, 1005 insertions(+), 125 deletions(-)
create mode 100644 drivers/iommu/iommufd/pasid.c
--
2.34.1
v25: https://patchwork.kernel.org/project/netdevbpf/list/?series=885396&state=*
===
Major changes:
- Moved devmem.h and mp_dmabuf_devmem.h to internal header files.
- Changed the page_pool_params to take in a queue_idx rather than
a struct netdev_rx_queue.
- Added WARN_ON_ONCE around __skb_checksum readability check and added
check to skb_checksum_help().
Other more minor feedback addressed as well.
v24: https://patchwork.kernel.org/project/netdevbpf/list/?series=884556&state=*
====
No major changes. Mostly addressing issues in the error paths of dmabuf
binding, and code cleanups/improvements from reviewers:
Changes:
- Fix failing ynl regen error.
- Error path fixes & extack error messages in dmabuf binding.
- Code cleanup in introspection.
- gitignore ynl.d generated file.
Full devmem TCP changes including the full GVE driver implementation is
here:
https://github.com/mina/linux/commits/tcpdevmem-v24/
v23: https://patchwork.kernel.org/project/netdevbpf/list/?series=882978&state=*
====
Fixing relatively minor issues called out in v22. (thanks again!)
Mostly code cleanups, extack error messages, and minor reworks. Nothing
major really changed, so the exact changes per commit is called in the
commit messages.
Full devmem TCP changes including the full GVE driver implementation is
here:
https://github.com/mina/linux/commits/tcpdevmem-v23/
v22: https://patchwork.kernel.org/project/netdevbpf/list/?series=881158&state=*
====
v22 aims to resolve the pending issue pointed to in v21, which is the
interaction with xdp. In this series I rebase on top of the minor
refactor which refactors propagating xdp configuration to slave devices:
https://patchwork.kernel.org/project/netdevbpf/list/?series=881994&state=*
I then disable setting xdp on devices using memory providers, and
propagating xdp configuration to devices using memory providers.
Full devmem TCP changes including the full GVE driver implementation is
here:
https://github.com/mina/linux/commits/tcpdevmem-v22/
v21: https://patchwork.kernel.org/project/netdevbpf/list/?series=880735&state=*
====
v20 addressed some comments and resolved a test failure, but introduced
an unfortunate build error with a config edge case I wasn't testing. v21
simply resolves that error.
Major Changes:
- Resolve build error with CONFIG_PAGE_POOL=n && CONFIG_NET=y
Full devmem TCP changes including the full GVE driver implementation is
here:
https://github.com/mina/linux/commits/tcpdevmem-v21/
v20: https://patchwork.kernel.org/project/netdevbpf/list/?series=879373&state=*
====
v20 aims to resolve a couple of bug reports against v19, and addresses
some review comments around the page_pool_check_memory_provider
mechanism.
Major changes:
- Test edge cases such as header split disabled in selftest.
- Change `offset = 0` back to `offset = offset - start` to resolve issue
found in RX path by Taehee (thanks!)
- Address a few comments around page_pool_check_memory_provider() from
Pavel & Jakub.
- Removed some unnecessary includes across various patches in the
series.
- Removed unnecessary EXPORT_SYMBOL(page_pool_mem_providers) (Jakub).
- Fix regression caused by incorrect dev_get_max_mp_channel check, along
with rename (Jakub).
Full devmem TCP changes including the full GVE driver implementation is
here:
https://github.com/mina/linux/commits/tcpdevmem-v20/
v19: https://patchwork.kernel.org/project/netdevbpf/list/?series=876852&state=*
====
v18 got a thorough review (thanks!), and this iteration addresses the
feedback.
Major changes:
- Prevent deactivating mp bound queues.
- Prevent installing xdp on mp bound netdevs, or installing mps on xdp
installed netdevs.
- Fix corner cases in netlink API vis-a-vis missing attributes.
- Iron out the unreadable netmem driver support story. To be honest, the
conversation with Jakub & Pavel got a bit confusing for me. I've
implemented an approach in this set that makes sense to me, and
AFAICT, addresses the requirements. It may be good as-is, or it
may be a conversation starter/continuer. To be honest IMO there
are many ways to skin this cat and I don't see an extremely strong
reason to go for one approach over another. Here is one approach you
may like.
- Don't reset niov dma_addr on allocation & free.
- Add some tests to the selftest that catches some of the issues around
missing netlink attributes or deactivating mp-bound queues.
Full devmem TCP changes including the full GVE driver implementation is
here:
https://github.com/mina/linux/commits/tcpdevmem-v19/
v18: https://patchwork.kernel.org/project/netdevbpf/list/?series=874848&state=*
====
v17 got minor feedback: (a) to beef up the description on patch 1 and (b)
to remove the leading underscores in the header definition.
I applied (a). (b) seems to be against current conventions so I did not
apply before further discussion.
Full devmem TCP changes including the full GVE driver implementation is
here:
https://github.com/mina/linux/commits/tcpdevmem-v17/
v17: https://patchwork.kernel.org/project/netdevbpf/list/?series=869900&state=*
====
v16 also got a very thorough review and some testing (thanks again!).
Thes version addresses all the concerns reported on v15, in terms of
feedback and issues reported.
Major changes:
- Use ASSERT_RTNL.
- Moved around some of the page_pool helpers definitions so I can hide
some netmem helpers in private files as Jakub suggested.
- Don't make every net_iov hold a ref on the binding as Jakub suggested.
- Fix issue reported by Taehee where we access queues after they have
been freed.
Full devmem TCP changes including the full GVE driver implementation is
here:
https://github.com/mina/linux/commits/tcpdevmem-v17/
v16: https://patchwork.kernel.org/project/netdevbpf/list/?series=866353&state=*
====
v15 got a thorough review and some testing, and this version addresses almost
all the feedback. Some more minor comments where the authors said it
could be done later, I left out.
Major changes:
- Addition of dma-buf introspection to page-pool-get and queue-get.
- Fixes to selftests suggested by Taehee.
- Fixes to documentation suggested by Donald.
- A couple of suggestions and fixes to TCP patches by Eric and David.
- Fixes to number assignements suggested by Arnd.
- Use rtnl_lock()ing to guard against queue reconfiguration while the
page_pool initialization is happening. (Jakub).
- Fixes to a few warnings reproduced by Taehee.
- Fixes to dma-buf binding suggested by Taehee and Jakub.
- Fixes to netlink UAPI suggested by Jakub
- Applied a number of Reviewed-bys and Acked-bys (including ones I lost
from v13+).
Full devmem TCP changes including the full GVE driver implementation is
here:
https://github.com/mina/linux/commits/tcpdevmem-v16/
One caveat: Taehee reproduced a KASAN warning and reported it here:
https://lore.kernel.org/netdev/CAMArcTUdCxOBYGF3vpbq=eBvqZfnc44KBaQTN7H-wqd…
I estimate the issue to be minor and easily fixable:
https://lore.kernel.org/netdev/CAHS8izNgaqC--GGE2xd85QB=utUnOHmioCsDd1TNxJW…
I hope to be able to follow up with a fix to net tree as net-next closes
imminently, but if this iteration doesn't make it in, I will repost with
a fix squashed after net-next reopens, no problem.
v15: https://patchwork.kernel.org/project/netdevbpf/list/?series=865481&state=*
====
No material changes in this version, only a fix to linking against
libynl.a from the last version. Per Jakub's instructions I've pulled one
of his patches into this series, and now use the new libynl.a correctly,
I hope.
As usual, the full devmem TCP changes including the full GVE driver
implementation is here:
https://github.com/mina/linux/commits/tcpdevmem-v15/
v14: https://patchwork.kernel.org/project/netdevbpf/list/?series=865135&archive=…
====
No material changes in this version. Only rebase and re-verification on
top of net-next. v13, I think, raced with commit ebad6d0334793
("net/ipv4: Use nested-BH locking for ipv4_tcp_sk.") being merged to
net-next that caused a patchwork failure to apply. This series should
apply cleanly on commit c4532232fa2a4 ("selftests: net: remove unneeded
IP_GRE config").
I did not wait the customary 24hr as Jakub said it's OK to repost as soon
as I build test the rebased version:
https://lore.kernel.org/netdev/20240625075926.146d769d@kernel.org/
v13: https://patchwork.kernel.org/project/netdevbpf/list/?series=861406&archive=…
====
Major changes:
--------------
This iteration addresses Pavel's review comments, applies his
reviewed-by's, and seeks to fix the patchwork build error (sorry!).
As usual, the full devmem TCP changes including the full GVE driver
implementation is here:
https://github.com/mina/linux/commits/tcpdevmem-v13/
v12: https://patchwork.kernel.org/project/netdevbpf/list/?series=859747&state=*
====
Major changes:
--------------
This iteration only addresses one minor comment from Pavel with regards
to the trace printing of netmem, and the patchwork build error
introduced in v11 because I missed doing an allmodconfig build, sorry.
Other than that v11, AFAICT, received no feedback. There is one
discussion about how the specifics of plugging io uring memory through
the page pool, but not relevant to content in this particular patchset,
AFAICT.
As usual, the full devmem TCP changes including the full GVE driver
implementation is here:
https://github.com/mina/linux/commits/tcpdevmem-v12/
v11: https://patchwork.kernel.org/project/netdevbpf/list/?series=857457&state=*
====
Major Changes:
--------------
v11 addresses feedback received in v10. The major change is the removal
of the memory provider ops as requested by Christoph. We still
accomplish the same thing, but utilizing direct function calls with if
statements rather than generic ops.
Additionally address sparse warnings, bugs and review comments from
folks that reviewed.
As usual, the full devmem TCP changes including the full GVE driver
implementation is here:
https://github.com/mina/linux/commits/tcpdevmem-v11/
Detailed changelog:
-------------------
- Fixes in netdev_rx_queue_restart() from Pavel & David.
- Remove commit e650e8c3a36f5 ("net: page_pool: create hooks for
custom page providers") from the series to address Christoph's
feedback and rebased other patches on the series on this change.
- Fixed build errors with CONFIG_DMA_SHARED_BUFFER &&
!CONFIG_GENERIC_ALLOCATOR build.
- Fixed sparse warnings pointed out by Paolo.
- Drop unnecessary gro_pull_from_frag0 checks.
- Added Bagas reviewed-by to docs.
v10: https://patchwork.kernel.org/project/netdevbpf/list/?series=852422&state=*
====
Major Changes:
--------------
v9 was sent right before the merge window closed (sorry!). v10 is almost
a re-send of the series now that the merge window re-opened. Only
rebased to latest net-next and addressed some minor iterative comments
received on v9.
As usual, the full devmem TCP changes including the full GVE driver
implementation is here:
https://github.com/mina/linux/commits/tcpdevmem-v10/
Detailed changelog:
-------------------
- Fixed tokens leaking in DONTNEED setsockopt (Nikolay).
- Moved net_iov_dma_addr() to devmem.c and made it a devmem specific
helpers (David).
- Rename hook alloc_pages to alloc_netmems as alloc_pages is now
preprocessor macro defined and causes a build error.
v9:
===
Major Changes:
--------------
GVE queue API has been merged. Submitting this version as non-RFC after
rebasing on top of the merged API, and dropped the out of tree queue API
I was carrying on github. Addressed the little feedback v8 has received.
Detailed changelog:
------------------
- Added new patch from David Wei to this series for
netdev_rx_queue_restart()
- Fixed sparse error.
- Removed CONFIG_ checks in netmem_is_net_iov()
- Flipped skb->readable to skb->unreadable
- Minor fixes to selftests & docs.
RFC v8:
=======
Major Changes:
--------------
- Fixed build error generated by patch-by-patch build.
- Applied docs suggestions from Randy.
RFC v7:
=======
Major Changes:
--------------
This revision largely rebases on top of net-next and addresses the feedback
RFCv6 received from folks, namely Jakub, Yunsheng, Arnd, David, & Pavel.
The series remains in RFC because the queue-API ndos defined in this
series are not yet implemented. I have a GVE implementation I carry out
of tree for my testing. A upstreamable GVE implementation is in the
works. Aside from that, in my estimation all the patches are ready for
review/merge. Please do take a look.
As usual the full devmem TCP changes including the full GVE driver
implementation is here:
https://github.com/mina/linux/commits/tcpdevmem-v7/
Detailed changelog:
- Use admin-perm in netlink API.
- Addressed feedback from Jakub with regards to netlink API
implementation.
- Renamed devmem.c functions to something more appropriate for that
file.
- Improve the performance seen through the page_pool benchmark.
- Fix the value definition of all the SO_DEVMEM_* uapi.
- Various fixes to documentation.
Perf - page-pool benchmark:
---------------------------
Improved performance of bench_page_pool_simple.ko tests compared to v6:
https://pastebin.com/raw/v5dYRg8L
net-next base: 8 cycle fast path.
RFC v6: 10 cycle fast path.
RFC v7: 9 cycle fast path.
RFC v7 with CONFIG_DMA_SHARED_BUFFER disabled: 8 cycle fast path,
same as baseline.
Perf - Devmem TCP benchmark:
---------------------
Perf is about the same regardless of the changes in v7, namely the
removal of the static_branch_unlikely to improve the page_pool benchmark
performance:
189/200gbps bi-directional throughput with RX devmem TCP and regular TCP
TX i.e. ~95% line rate.
RFC v6:
=======
Major Changes:
--------------
This revision largely rebases on top of net-next and addresses the little
feedback RFCv5 received.
The series remains in RFC because the queue-API ndos defined in this
series are not yet implemented. I have a GVE implementation I carry out
of tree for my testing. A upstreamable GVE implementation is in the
works. Aside from that, in my estimation all the patches are ready for
review/merge. Please do take a look.
As usual the full devmem TCP changes including the full GVE driver
implementation is here:
https://github.com/mina/linux/commits/tcpdevmem-v6/
This version also comes with some performance data recorded in the cover
letter (see below changelog).
Detailed changelog:
- Rebased on top of the merged netmem_ref changes.
- Converted skb->dmabuf to skb->readable (Pavel). Pavel's original
suggestion was to remove the skb->dmabuf flag entirely, but when I
looked into it closely, I found the issue that if we remove the flag
we have to dereference the shinfo(skb) pointer to obtain the first
frag to tell whether an skb is readable or not. This can cause a
performance regression if it dirties the cache line when the
shinfo(skb) was not really needed. Instead, I converted the skb->dmabuf
flag into a generic skb->readable flag which can be re-used by io_uring
0-copy RX.
- Squashed a few locking optimizations from Eric Dumazet in the RX path
and the DEVMEM_DONTNEED setsockopt.
- Expanded the tests a bit. Added validation for invalid scenarios and
added some more coverage.
Perf - page-pool benchmark:
---------------------------
bench_page_pool_simple.ko tests with and without these changes:
https://pastebin.com/raw/ncHDwAbn
AFAIK the number that really matters in the perf tests is the
'tasklet_page_pool01_fast_path Per elem'. This one measures at about 8
cycles without the changes but there is some 1 cycle noise in some
results.
With the patches this regresses to 9 cycles with the changes but there
is 1 cycle noise occasionally running this test repeatedly.
Lastly I tried disable the static_branch_unlikely() in
netmem_is_net_iov() check. To my surprise disabling the
static_branch_unlikely() check reduces the fast path back to 8 cycles,
but the 1 cycle noise remains.
Perf - Devmem TCP benchmark:
---------------------
189/200gbps bi-directional throughput with RX devmem TCP and regular TCP
TX i.e. ~95% line rate.
Major changes in RFC v5:
========================
1. Rebased on top of 'Abstract page from net stack' series and used the
new netmem type to refer to LSB set pointers instead of re-using
struct page.
2. Downgraded this series back to RFC and called it RFC v5. This is
because this series is now dependent on 'Abstract page from net
stack'[1] and the queue API. Both are removed from the series to
reduce the patch # and those bits are fairly independent or
pre-requisite work.
3. Reworked the page_pool devmem support to use netmem and for some
more unified handling.
4. Reworked the reference counting of net_iov (renamed from
page_pool_iov) to use pp_ref_count for refcounting.
The full changes including the dependent series and GVE page pool
support is here:
https://github.com/mina/linux/commits/tcpdevmem-rfcv5/
[1] https://patchwork.kernel.org/project/netdevbpf/list/?series=810774
Major changes in v1:
====================
1. Implemented MVP queue API ndos to remove the userspace-visible
driver reset.
2. Fixed issues in the napi_pp_put_page() devmem frag unref path.
3. Removed RFC tag.
Many smaller addressed comments across all the patches (patches have
individual change log).
Full tree including the rest of the GVE driver changes:
https://github.com/mina/linux/commits/tcpdevmem-v1
Changes in RFC v3:
==================
1. Pulled in the memory-provider dependency from Jakub's RFC[1] to make the
series reviewable and mergeable.
2. Implemented multi-rx-queue binding which was a todo in v2.
3. Fix to cmsg handling.
The sticking point in RFC v2[2] was the device reset required to refill
the device rx-queues after the dmabuf bind/unbind. The solution
suggested as I understand is a subset of the per-queue management ops
Jakub suggested or similar:
https://lore.kernel.org/netdev/20230815171638.4c057dcd@kernel.org/
This is not addressed in this revision, because:
1. This point was discussed at netconf & netdev and there is openness to
using the current approach of requiring a device reset.
2. Implementing individual queue resetting seems to be difficult for my
test bed with GVE. My prototype to test this ran into issues with the
rx-queues not coming back up properly if reset individually. At the
moment I'm unsure if it's a mistake in the POC or a genuine issue in
the virtualization stack behind GVE, which currently doesn't test
individual rx-queue restart.
3. Our usecases are not bothered by requiring a device reset to refill
the buffer queues, and we'd like to support NICs that run into this
limitation with resetting individual queues.
My thought is that drivers that have trouble with per-queue configs can
use the support in this series, while drivers that support new netdev
ops to reset individual queues can automatically reset the queue as
part of the dma-buf bind/unbind.
The same approach with device resets is presented again for consideration
with other sticking points addressed.
This proposal includes the rx devmem path only proposed for merge. For a
snapshot of my entire tree which includes the GVE POC page pool support &
device memory support:
https://github.com/torvalds/linux/compare/master...mina:linux:tcpdevmem-v3
[1] https://lore.kernel.org/netdev/f8270765-a27b-6ccf-33ea-cda097168d79@redhat.…
[2] https://lore.kernel.org/netdev/CAHS8izOVJGJH5WF68OsRWFKJid1_huzzUK+hpKbLcL4…
Changes in RFC v2:
==================
The sticking point in RFC v1[1] was the dma-buf pages approach we used to
deliver the device memory to the TCP stack. RFC v2 is a proof-of-concept
that attempts to resolve this by implementing scatterlist support in the
networking stack, such that we can import the dma-buf scatterlist
directly. This is the approach proposed at a high level here[2].
Detailed changes:
1. Replaced dma-buf pages approach with importing scatterlist into the
page pool.
2. Replace the dma-buf pages centric API with a netlink API.
3. Removed the TX path implementation - there is no issue with
implementing the TX path with scatterlist approach, but leaving
out the TX path makes it easier to review.
4. Functionality is tested with this proposal, but I have not conducted
perf testing yet. I'm not sure there are regressions, but I removed
perf claims from the cover letter until they can be re-confirmed.
5. Added Signed-off-by: contributors to the implementation.
6. Fixed some bugs with the RX path since RFC v1.
Any feedback welcome, but specifically the biggest pending questions
needing feedback IMO are:
1. Feedback on the scatterlist-based approach in general.
2. Netlink API (Patch 1 & 2).
3. Approach to handle all the drivers that expect to receive pages from
the page pool (Patch 6).
[1] https://lore.kernel.org/netdev/dfe4bae7-13a0-3c5d-d671-f61b375cb0b4@gmail.c…
[2] https://lore.kernel.org/netdev/CAHS8izPm6XRS54LdCDZVd0C75tA1zHSu6jLVO8nzTLX…
==================
* TL;DR:
Device memory TCP (devmem TCP) is a proposal for transferring data to and/or
from device memory efficiently, without bouncing the data to a host memory
buffer.
* Problem:
A large amount of data transfers have device memory as the source and/or
destination. Accelerators drastically increased the volume of such transfers.
Some examples include:
- ML accelerators transferring large amounts of training data from storage into
GPU/TPU memory. In some cases ML training setup time can be as long as 50% of
TPU compute time, improving data transfer throughput & efficiency can help
improving GPU/TPU utilization.
- Distributed training, where ML accelerators, such as GPUs on different hosts,
exchange data among them.
- Distributed raw block storage applications transfer large amounts of data with
remote SSDs, much of this data does not require host processing.
Today, the majority of the Device-to-Device data transfers the network are
implemented as the following low level operations: Device-to-Host copy,
Host-to-Host network transfer, and Host-to-Device copy.
The implementation is suboptimal, especially for bulk data transfers, and can
put significant strains on system resources, such as host memory bandwidth,
PCIe bandwidth, etc. One important reason behind the current state is the
kernel’s lack of semantics to express device to network transfers.
* Proposal:
In this patch series we attempt to optimize this use case by implementing
socket APIs that enable the user to:
1. send device memory across the network directly, and
2. receive incoming network packets directly into device memory.
Packet _payloads_ go directly from the NIC to device memory for receive and from
device memory to NIC for transmit.
Packet _headers_ go to/from host memory and are processed by the TCP/IP stack
normally. The NIC _must_ support header split to achieve this.
Advantages:
- Alleviate host memory bandwidth pressure, compared to existing
network-transfer + device-copy semantics.
- Alleviate PCIe BW pressure, by limiting data transfer to the lowest level
of the PCIe tree, compared to traditional path which sends data through the
root complex.
* Patch overview:
** Part 1: netlink API
Gives user ability to bind dma-buf to an RX queue.
** Part 2: scatterlist support
Currently the standard for device memory sharing is DMABUF, which doesn't
generate struct pages. On the other hand, networking stack (skbs, drivers, and
page pool) operate on pages. We have 2 options:
1. Generate struct pages for dmabuf device memory, or,
2. Modify the networking stack to process scatterlist.
Approach #1 was attempted in RFC v1. RFC v2 implements approach #2.
** part 3: page pool support
We piggy back on page pool memory providers proposal:
https://github.com/kuba-moo/linux/tree/pp-providers
It allows the page pool to define a memory provider that provides the
page allocation and freeing. It helps abstract most of the device memory
TCP changes from the driver.
** part 4: support for unreadable skb frags
Page pool iovs are not accessible by the host; we implement changes
throughput the networking stack to correctly handle skbs with unreadable
frags.
** Part 5: recvmsg() APIs
We define user APIs for the user to send and receive device memory.
Not included with this series is the GVE devmem TCP support, just to
simplify the review. Code available here if desired:
https://github.com/mina/linux/tree/tcpdevmem
This series is built on top of net-next with Jakub's pp-providers changes
cherry-picked.
* NIC dependencies:
1. (strict) Devmem TCP require the NIC to support header split, i.e. the
capability to split incoming packets into a header + payload and to put
each into a separate buffer. Devmem TCP works by using device memory
for the packet payload, and host memory for the packet headers.
2. (optional) Devmem TCP works better with flow steering support & RSS support,
i.e. the NIC's ability to steer flows into certain rx queues. This allows the
sysadmin to enable devmem TCP on a subset of the rx queues, and steer
devmem TCP traffic onto these queues and non devmem TCP elsewhere.
The NIC I have access to with these properties is the GVE with DQO support
running in Google Cloud, but any NIC that supports these features would suffice.
I may be able to help reviewers bring up devmem TCP on their NICs.
* Testing:
The series includes a udmabuf kselftest that show a simple use case of
devmem TCP and validates the entire data path end to end without
a dependency on a specific dmabuf provider.
** Test Setup
Kernel: net-next with this series and memory provider API cherry-picked
locally.
Hardware: Google Cloud A3 VMs.
NIC: GVE with header split & RSS & flow steering support.
Cc: Pavel Begunkov <asml.silence(a)gmail.com>
Cc: David Wei <dw(a)davidwei.uk>
Cc: Jason Gunthorpe <jgg(a)ziepe.ca>
Cc: Yunsheng Lin <linyunsheng(a)huawei.com>
Cc: Shailend Chand <shailend(a)google.com>
Cc: Harshitha Ramamurthy <hramamurthy(a)google.com>
Cc: Shakeel Butt <shakeel.butt(a)linux.dev>
Cc: Jeroen de Borst <jeroendb(a)google.com>
Cc: Praveen Kaligineedi <pkaligineedi(a)google.com>
Cc: Bagas Sanjaya <bagasdotme(a)gmail.com>
Cc: Steven Rostedt <rostedt(a)goodmis.org>
Cc: Christoph Hellwig <hch(a)infradead.org>
Cc: Nikolay Aleksandrov <razor(a)blackwall.org>
Cc: Taehee Yoo <ap420073(a)gmail.com>
Cc: Donald Hunter <donald.hunter(a)gmail.com>
Mina Almasry (13):
netdev: add netdev_rx_queue_restart()
net: netdev netlink api to bind dma-buf to a net device
netdev: support binding dma-buf to netdevice
netdev: netdevice devmem allocator
page_pool: devmem support
memory-provider: dmabuf devmem memory provider
net: support non paged skb frags
net: add support for skbs with unreadable frags
tcp: RX path for devmem TCP
net: add SO_DEVMEM_DONTNEED setsockopt to release RX frags
net: add devmem TCP documentation
selftests: add ncdevmem, netcat for devmem TCP
netdev: add dmabuf introspection
Documentation/netlink/specs/netdev.yaml | 61 +++
Documentation/networking/devmem.rst | 269 +++++++++++
Documentation/networking/index.rst | 1 +
arch/alpha/include/uapi/asm/socket.h | 6 +
arch/mips/include/uapi/asm/socket.h | 6 +
arch/parisc/include/uapi/asm/socket.h | 6 +
arch/sparc/include/uapi/asm/socket.h | 6 +
include/linux/netdevice.h | 2 +
include/linux/skbuff.h | 61 ++-
include/linux/skbuff_ref.h | 9 +-
include/linux/socket.h | 1 +
include/net/netdev_rx_queue.h | 5 +
include/net/netmem.h | 132 +++++-
include/net/page_pool/helpers.h | 39 +-
include/net/page_pool/types.h | 23 +-
include/net/sock.h | 2 +
include/net/tcp.h | 3 +-
include/trace/events/page_pool.h | 12 +-
include/uapi/asm-generic/socket.h | 6 +
include/uapi/linux/netdev.h | 13 +
include/uapi/linux/uio.h | 17 +
net/Kconfig | 5 +
net/core/Makefile | 2 +
net/core/datagram.c | 6 +
net/core/dev.c | 33 +-
net/core/devmem.c | 389 ++++++++++++++++
net/core/devmem.h | 180 ++++++++
net/core/gro.c | 3 +-
net/core/mp_dmabuf_devmem.h | 44 ++
net/core/netdev-genl-gen.c | 23 +
net/core/netdev-genl-gen.h | 6 +
net/core/netdev-genl.c | 139 +++++-
net/core/netdev_rx_queue.c | 81 ++++
net/core/netmem_priv.h | 31 ++
net/core/page_pool.c | 120 +++--
net/core/page_pool_priv.h | 46 ++
net/core/page_pool_user.c | 32 +-
net/core/skbuff.c | 77 +++-
net/core/sock.c | 68 +++
net/ethtool/common.c | 8 +
net/ipv4/esp4.c | 3 +-
net/ipv4/tcp.c | 263 ++++++++++-
net/ipv4/tcp_input.c | 13 +-
net/ipv4/tcp_ipv4.c | 16 +
net/ipv4/tcp_minisocks.c | 2 +
net/ipv4/tcp_output.c | 5 +-
net/ipv6/esp6.c | 3 +-
net/packet/af_packet.c | 4 +-
net/xdp/xsk_buff_pool.c | 5 +
tools/include/uapi/linux/netdev.h | 13 +
tools/net/ynl/lib/.gitignore | 1 +
tools/testing/selftests/net/.gitignore | 1 +
tools/testing/selftests/net/Makefile | 9 +
tools/testing/selftests/net/ncdevmem.c | 570 ++++++++++++++++++++++++
54 files changed, 2757 insertions(+), 124 deletions(-)
create mode 100644 Documentation/networking/devmem.rst
create mode 100644 net/core/devmem.c
create mode 100644 net/core/devmem.h
create mode 100644 net/core/mp_dmabuf_devmem.h
create mode 100644 net/core/netdev_rx_queue.c
create mode 100644 net/core/netmem_priv.h
create mode 100644 tools/testing/selftests/net/ncdevmem.c
--
2.46.0.469.g59c65b2a67-goog
Currently, sk_lookup allows an ebpf program to run on the ingress socket
lookup path, and accept traffic not only on a range of addresses, but
also on a range of ports. At Cloudflare we use sk_lookup for two main
cases:
1. Sharing a single port between multiple services - i.e. two services
(or more) use disjoint IP ranges but share the same port;
2. Receiving traffic on all ports - i.e. a service which accepts traffic
on specific IP ranges but any port [1].
However, one main challenge we face while using sk_lookup for these use
cases is how to source return UDP traffic:
- On point 1. above, sometimes this range of addresses are not local
(i.e. there's no local routes for these in the server), which means we
need IP_TRANSPARENT set to be able to egress traffic from addresses
we've received traffic on (or simply IP_FREEBIND in the case of IPv6);
- And on point 2. above, allowing traffic to a range of ports means a
service could get traffic on multiple ports, but currently there's no
way to set the source UDP port egress traffic should be sourced from -
it's possible to receive the original destination port using the
IP_ORIGDSTADDR ancilliary message in recvmsg, but not set it in
sendmsg.
Both of these limitations can be worked around, but in a sub-optimal
way. Using IP_TRANSPARENT, for instance, requires special privileges.
And while one could use UDP connected sockets to send return traffic,
creating a connected socket for each different address a UDP traffic is
received on does have performance implications.
Given sk_lookup allows services to accept traffic on a range of
addresses or ports, it seems sensible to also allow return traffic to
proceed through as well, without needing extra configurations / set ups.
This patch set allows to do exactly this by performing a reverse socket
lookup on the egress path - where it looks to see if the egress socket
matches a socket in the attached sk_lookup ebpf program for the traffic
that's being sent. If it does, traffic is allowed to proceed.
The downsides to this is that this runs on the egress hot path, although
this work tries to minimise its impact by only performing the reverse
socket lookup when necessary. Further performance measurements are to be
taken, but we're reaching out early for feedback to see what the
technical concerns are and if we can address them.
[1] https://blog.cloudflare.com/how-we-built-spectrum/
Suggested-by: Jakub Sitnicki <jakub(a)cloudflare.com>
Signed-off-by: Tiago Lam <tiagolam(a)cloudflare.com>
---
Tiago Lam (3):
ipv4: Run a reverse sk_lookup on sendmsg.
ipv6: Run a reverse sk_lookup on sendmsg.
bpf: Add sk_lookup test to use ORIGDSTADDR cmsg.
include/net/ip.h | 1 +
net/ipv4/ip_sockglue.c | 11 ++++
net/ipv4/udp.c | 33 +++++++++-
net/ipv6/datagram.c | 76 ++++++++++++++++++++++
net/ipv6/udp.c | 8 ++-
tools/testing/selftests/bpf/prog_tests/sk_lookup.c | 70 +++++++++++++-------
6 files changed, 174 insertions(+), 25 deletions(-)
---
base-commit: da3ea35007d0af457a0afc87e84fddaebc4e0b63
change-id: 20240909-reverse-sk-lookup-f7bf36292bc4
Best regards,
--
Tiago Lam <tiagolam(a)cloudflare.com>
Hi all,
This is part of a hackathon organized by LKCAMP [1], focused on writing
tests using KUnit. We reached out a while ago asking for advice on what would
be a useful contribution [2] and ended up choosing data structures that did
not yet have tests.
This patch series depends on the patch that moves the KUnit tests on lib/
into lib/tests/ [3].
This patch adds tests for the kfifo data structure, defined in
include/linux/kfifo.h, and is inspired by the KUnit tests for the doubly
linked list in lib/tests/list-test.c (previously at lib/list-test.c) [4].
[1] https://lkcamp.dev/about/
[2] https://lore.kernel.org/all/Zktnt7rjKryTh9-N@arch/
[3] https://lore.kernel.org/all/20240720181025.work.002-kees@kernel.org/
[4] https://elixir.bootlin.com/linux/latest/source/lib/list-test.c
---
Changes in v2:
- Add MODULE_DESCRIPTION()
- Move the tests from lib/kfifo-test.c to lib/tests/kfifo_kunit.c
Diego Vieira (1):
lib/tests/kfifo_kunit.c: add tests for the kfifo structure
lib/Kconfig.debug | 14 +++
lib/tests/Makefile | 1 +
lib/tests/kfifo_kunit.c | 224 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 239 insertions(+)
create mode 100644 lib/tests/kfifo_kunit.c
--
2.34.1