The vIOMMU object is designed to represent a slice of an IOMMU HW for its
virtualization features shared with or passed to user space (a VM mostly)
in a way of HW acceleration. This extended the HWPT-based design for more
advanced virtualization feature.
HW QUEUE introduced by this series as a part of the vIOMMU infrastructure
represents a HW accelerated queue/buffer for VM to use exclusively, e.g.
- NVIDIA's Virtual Command Queue
- AMD vIOMMU's Command Buffer, Event Log Buffer, and PPR Log Buffer
each of which allows its IOMMU HW to directly access a queue memory owned
by a guest VM and allows a guest OS to control the HW queue direclty, to
avoid VM Exit overheads to improve the performance.
Introduce IOMMUFD_OBJ_HW_QUEUE and its pairing IOMMUFD_CMD_HW_QUEUE_ALLOC
allowing VMM to forward the IOMMU-specific queue info, such as queue base
address, size, and etc.
Meanwhile, a guest-owned queue needs the guest kernel to control the queue
by reading/writing its consumer and producer indexes, via MMIO acceses to
the hardware MMIO registers. Introduce an mmap infrastructure for iommufd
to support passing through a piece of MMIO region from the host physical
address space to the guest physical address space. The mmap info (offset/
length) used by an mmap syscall must be pre-allocated and returned to the
user space via an output driver-data during an IOMMUFD_CMD_HW_QUEUE_ALLOC
call. Thus, it requires a driver-specific user data support in the vIOMMU
allocation flow.
As a real-world use case, this series implements a HW QUEUE support in the
tegra241-cmdqv driver for VCMDQs on NVIDIA Grace CPU. In another word, it
is also the Tegra CMDQV series Part-2 (user-space support), reworked from
Previous RFCv1:
https://lore.kernel.org/all/cover.1712978212.git.nicolinc@nvidia.com/
This enables the HW accelerated feature for NVIDIA Grace CPU. Compared to
the standard SMMUv3 operating in the nested translation mode trapping CMDQ
for TLBI and ATC_INV commands, this gives a huge performance improvement:
70% to 90% reductions of invalidation time were measured by various DMA
unmap tests running in a guest OS.
// Unmap latencies from "dma_map_benchmark -g @granule -t @threads",
// by toggling "/sys/kernel/debug/iommu/tegra241_cmdqv/bypass_vcmdq"
@granule | @threads | bypass_vcmdq=1 | bypass_vcmdq=0
4KB 1 35.7 us 5.3 us
16KB 1 41.8 us 6.8 us
64KB 1 68.9 us 9.9 us
128KB 1 109.0 us 12.6 us
256KB 1 187.1 us 18.0 us
4KB 2 96.9 us 6.8 us
16KB 2 97.8 us 7.5 us
64KB 2 151.5 us 10.7 us
128KB 2 257.8 us 12.7 us
256KB 2 443.0 us 17.9 us
This is on Github:
https://github.com/nicolinc/iommufd/commits/iommufd_hw_queue-v4
Paring QEMU branch for testing:
https://github.com/nicolinc/qemu/commits/wip/for_iommufd_hw_queue-v4
Changelog
v4
* Rebase on v6.15-rc5
* Add Reviewed-by from Vasant
* Rename "vQUEUE" to "HW QUEUE"
* Use "offset" and "length" for all mmap-related variables
* [iommufd] Use u64 for guest PA
* [iommufd] Fix typo in uAPI doc
* [iommufd] Rename immap_id to offset
* [iommufd] Drop the partial-size mmap support
* [iommufd] Do not replace WARN_ON with WARN_ON_ONCE
* [iommufd] Use "u64 base_addr" for queue base address
* [iommufd] Use u64 base_pfn/num_pfns for immap structure
* [iommufd] Correct the size passed in to mtree_alloc_range()
* [iommufd] Add IOMMUFD_VIOMMU_FLAG_HW_QUEUE_READS_PA to viommu_ops
v3
https://lore.kernel.org/all/cover.1746139811.git.nicolinc@nvidia.com/
* Add Reviewed-by from Baolu, Pranjal, and Alok
* Revise kdocs, uAPI docs, and commit logs
* Rename "vCMDQ" back to "vQUEUE" for AMD cases
* [tegra] Add tegra241_vcmdq_hw_flush_timeout()
* [tegra] Rename vsmmu_alloc to alloc_vintf_user
* [tegra] Use writel for SID replacement registers
* [tegra] Move mmap removal call to vsmmu_destroy op
* [tegra] Fix revert in tegra241_vintf_alloc_lvcmdq_user()
* [iommufd] Replace "& ~PAGE_MASK" with PAGE_ALIGNED()
* [iommufd] Add an object-type "owner" to immap structure
* [iommufd] Drop the ictx input in the new for-driver APIs
* [iommufd] Add iommufd_vma_ops to keep track of mmap lifecycle
* [iommufd] Add viommu-based iommufd_viommu_alloc/destroy_mmap helpers
* [iommufd] Rename iommufd_ctx_alloc/free_mmap to
_iommufd_alloc/destroy_mmap
v2
https://lore.kernel.org/all/cover.1745646960.git.nicolinc@nvidia.com/
* Add Reviewed-by from Jason
* [smmu] Fix vsmmu initial value
* [smmu] Support impl for hw_info
* [tegra] Rename "slot" to "vsid"
* [tegra] Update kdocs and commit logs
* [tegra] Map/unmap LVCMDQ dynamically
* [tegra] Refcount the previous LVCMDQ
* [tegra] Return -EEXIST if LVCMDQ exists
* [tegra] Simplify VINTF cleanup routine
* [tegra] Use vmid and s2_domain in vsmmu
* [tegra] Rename "mmap_pgoff" to "immap_id"
* [tegra] Add more addr and length validation
* [iommufd] Add more narrative to mmap's kdoc
* [iommufd] Add iommufd_struct_depend/undepend()
* [iommufd] Rename vcmdq_free op to vcmdq_destroy
* [iommufd] Fix bug in iommu_copy_struct_to_user()
* [iommufd] Drop is_io from iommufd_ctx_alloc_mmap()
* [iommufd] Test the queue memory for its contiguity
* [iommufd] Return -ENXIO if address or length fails
* [iommufd] Do not change @min_last in mock_viommu_alloc()
* [iommufd] Generalize TEGRA241_VCMDQ data in core structure
* [iommufd] Add selftest coverage for IOMMUFD_CMD_VCMDQ_ALLOC
* [iommufd] Add iopt_pin_pages() to prevent queue memory from unmapping
v1
https://lore.kernel.org/all/cover.1744353300.git.nicolinc@nvidia.com/
Thanks
Nicolin
Nicolin Chen (23):
iommufd/viommu: Add driver-allocated vDEVICE support
iommu: Pass in a driver-level user data structure to viommu_alloc op
iommufd/viommu: Allow driver-specific user data for a vIOMMU object
iommu: Add iommu_copy_struct_to_user helper
iommufd/driver: Let iommufd_viommu_alloc helper save ictx to
viommu->ictx
iommufd/driver: Add iommufd_struct_destroy to revert
iommufd_viommu_alloc
iommufd/selftest: Support user_data in mock_viommu_alloc
iommufd/selftest: Add covearge for viommu data
iommufd: Abstract iopt_pin_pages and iopt_unpin_pages helpers
iommufd/viommu: Introduce IOMMUFD_OBJ_HW_QUEUE and its related struct
iommufd/viommu: Add IOMMUFD_CMD_HW_QUEUE_ALLOC ioctl
iommufd/driver: Add iommufd_hw_queue_depend/undepend() helpers
iommufd/selftest: Add coverage for IOMMUFD_CMD_HW_QUEUE_ALLOC
iommufd: Add mmap interface
iommufd/selftest: Add coverage for the new mmap interface
Documentation: userspace-api: iommufd: Update HW QUEUE
iommu/arm-smmu-v3-iommufd: Add vsmmu_alloc impl op
iommu/arm-smmu-v3-iommufd: Support implementation-defined hw_info
iommu/tegra241-cmdqv: Use request_threaded_irq
iommu/tegra241-cmdqv: Simplify deinit flow in
tegra241_cmdqv_remove_vintf()
iommu/tegra241-cmdqv: Do not statically map LVCMDQs
iommu/tegra241-cmdqv: Add user-space use support
iommu/tegra241-cmdqv: Add IOMMU_VEVENTQ_TYPE_TEGRA241_CMDQV support
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 25 +-
drivers/iommu/iommufd/io_pagetable.h | 8 +
drivers/iommu/iommufd/iommufd_private.h | 28 +-
drivers/iommu/iommufd/iommufd_test.h | 20 +
include/linux/iommu.h | 43 +-
include/linux/iommufd.h | 186 ++++++-
include/uapi/linux/iommufd.h | 116 ++++-
tools/testing/selftests/iommu/iommufd_utils.h | 52 +-
.../arm/arm-smmu-v3/arm-smmu-v3-iommufd.c | 43 +-
.../iommu/arm/arm-smmu-v3/tegra241-cmdqv.c | 490 +++++++++++++++++-
drivers/iommu/iommufd/device.c | 117 +----
drivers/iommu/iommufd/driver.c | 94 ++++
drivers/iommu/iommufd/io_pagetable.c | 95 ++++
drivers/iommu/iommufd/main.c | 80 ++-
drivers/iommu/iommufd/selftest.c | 133 ++++-
drivers/iommu/iommufd/viommu.c | 121 ++++-
tools/testing/selftests/iommu/iommufd.c | 97 +++-
.../selftests/iommu/iommufd_fail_nth.c | 11 +-
Documentation/userspace-api/iommufd.rst | 12 +
19 files changed, 1577 insertions(+), 194 deletions(-)
base-commit: 92a09c47464d040866cf2b4cd052bc60555185fb
--
2.43.0
Problem
=======
When host APEI is unable to claim synchronous external abort (SEA)
during stage-2 guest abort, today KVM directly injects an async SError
into the VCPU then resumes it. The injected SError usually results in
unpleasant guest kernel panic.
One of the major situation of guest SEA is when VCPU consumes recoverable
uncorrected memory error (UER), which is not uncommon at all in modern
datacenter servers with large amounts of physical memory. Although SError
and guest panic is sufficient to stop the propagation of corrupted memory
there is still room to recover from memory UER in a more graceful manner.
Proposed Solution
=================
Alternatively KVM can replay the SEA to the faulting VCPU, via existing
KVM_SET_VCPU_EVENTS API. If the memory poison consumption or the fault
that cause SEA is not from guest kernel, the blast radius can be limited
to the consuming or faulting guest userspace process, so the VM can keep
running.
In addition, instead of doing under the hood without involving userspace,
there are benefits to redirect the SEA to VMM:
- VM customers care about the disruptions caused by memory errors, and
VMM usually has the responsibility to start the process of notifying
the customers of memory error events in their VMs. For example some
cloud provider emits a critical log in their observability UI [1], and
provides playbook for customers on how to mitigate disruptions to
their workloads.
- VMM can protect future memory error consumption or faults by unmapping
the poisoned pages from stage-2 page table with KVM userfault [2],
which is more performant than splitting the memslot that contains
the poisoned guest pages.
- VMM can keep track SEA events in the VM. When VMM thinks the status
on the host or the VM is bad enough, e.g. number of distinct SEAs
exceeds a threshold, it can restart the VM on another healthy host.
- Behavior parity with x86 architecture. When machine check exception
(MCE) is caused by VCPU, kernel or KVM signals userspace SIGBUS to
let VMM either recover from the MCE, or terminate itself with VM.
The prior RFC proposes to implement SIGBUS on arm64 as well, but
Marc preferred VCPU exit over signal [3]. However, implementation
aside, returning SEA to VMM is on par with returning MCE to VMM.
Once SEA is redirected to VMM, among other actions, VMM is encouraged
to inject external aborts into the faulting VCPU, which is already
supported by KVM on arm64, although not fully supported by
KVM_SET_VCPU_EVENTS but complemented in this patchset.
New UAPIs
=========
This patchset introduces following userspace-visiable changes to empower
VMM to control what happens next for guest SEA:
- KVM_CAP_ARM_SEA_TO_USER. If userspace enables this new capability at VM
creation, KVM will not inject SError while taking SEA, but VM exit to
userspace.
- KVM_EXIT_ARM_SEA. This is the VM exit reason VMM gets. The details
about the SEA is provided in arm_sea as much as possible, including
ESR value at EL2, if guest virtual and physical addresses (GPA and GVA)
are available and the values if available.
- KVM_CAP_ARM_INJECT_EXT_IABT. VMM today can inject external data abort
to VCPU via KVM_SET_VCPU_EVENTS API. However, in case of instruction
abort, VMM cannot inject it via KVM_SET_VCPU_EVENTS.
KVM_CAP_ARM_INJECT_EXT_IABT is just a natural extend to
KVM_CAP_ARM_INJECT_EXT_DABT that tells VMM KVM_SET_VCPU_EVENTS now
supports external instruction abort.
Patchset utilizes commit 26fbdf369227 ("KVM: arm64: Don't translate
FAR if invalid/unsafe") from [4], available already in kvmarm/next.
[4] makes KVM safely do address translation for HPFAR_EL2, including at
the event of SEA, and indicate if HPFAR_EL2 is valid in NS bit.
This patchset depends on [4] to tell userspace if GPA is valid and
its value if valid.
Patchset is based on commit 68ec8b4e84446 ("Merge branch
kvm-arm64/pkvm-6.16 into kvmarm-master/next")
[1] https://cloud.google.com/solutions/sap/docs/manage-host-errors
[2] https://lpc.events/event/18/contributions/1757/attachments/1442/3073/LPC_%2…
[3] https://lore.kernel.org/kvm/86pljbqqh0.wl-maz@kernel.org
[4] https://lore.kernel.org/all/174369514508.3034362.13165690020799838042.b4-ty…
Jiaqi Yan (5):
KVM: arm64: VM exit to userspace to handle SEA
KVM: arm64: Set FnV for VCPU when FAR_EL2 is invalid
KVM: selftests: Test for KVM_EXIT_ARM_SEA and KVM_CAP_ARM_SEA_TO_USER
KVM: selftests: Test for KVM_CAP_INJECT_EXT_IABT
Documentation: kvm: new uAPI for handling SEA
Raghavendra Rao Ananta (1):
KVM: arm64: Allow userspace to inject external instruction aborts
Documentation/virt/kvm/api.rst | 120 ++++++-
arch/arm64/include/asm/kvm_emulate.h | 12 +
arch/arm64/include/asm/kvm_host.h | 8 +
arch/arm64/include/asm/kvm_ras.h | 21 +-
arch/arm64/include/uapi/asm/kvm.h | 3 +-
arch/arm64/kvm/Makefile | 3 +-
arch/arm64/kvm/arm.c | 6 +
arch/arm64/kvm/guest.c | 13 +-
arch/arm64/kvm/inject_fault.c | 3 +
arch/arm64/kvm/kvm_ras.c | 54 +++
arch/arm64/kvm/mmu.c | 12 +-
include/uapi/linux/kvm.h | 12 +
tools/arch/arm64/include/uapi/asm/kvm.h | 3 +-
tools/testing/selftests/kvm/Makefile.kvm | 2 +
.../testing/selftests/kvm/arm64/inject_iabt.c | 100 ++++++
.../testing/selftests/kvm/arm64/sea_to_user.c | 324 ++++++++++++++++++
tools/testing/selftests/kvm/lib/kvm_util.c | 1 +
17 files changed, 654 insertions(+), 43 deletions(-)
create mode 100644 arch/arm64/kvm/kvm_ras.c
create mode 100644 tools/testing/selftests/kvm/arm64/inject_iabt.c
create mode 100644 tools/testing/selftests/kvm/arm64/sea_to_user.c
--
2.49.0.967.g6a0df3ecc3-goog
Enable CONFIG_INIT_STACK_ALL_PATTERN in all_tests.config. This helps
to detect use of uninitialized local variables.
This option found an uninitialized data bug in the cs_dsp test.
Signed-off-by: Richard Fitzgerald <rf(a)opensource.cirrus.com>
---
tools/testing/kunit/configs/all_tests.config | 1 +
1 file changed, 1 insertion(+)
diff --git a/tools/testing/kunit/configs/all_tests.config b/tools/testing/kunit/configs/all_tests.config
index cdd9782f9646..4a60bb71fe72 100644
--- a/tools/testing/kunit/configs/all_tests.config
+++ b/tools/testing/kunit/configs/all_tests.config
@@ -10,6 +10,7 @@ CONFIG_KUNIT_EXAMPLE_TEST=y
CONFIG_KUNIT_ALL_TESTS=y
CONFIG_FORTIFY_SOURCE=y
+CONFIG_INIT_STACK_ALL_PATTERN=y
CONFIG_IIO=y
--
2.39.5
This patch set aims to allow ublk server threads to better balance load
amongst themselves by decoupling server threads from ublk_queues/hctxs,
so that multiple threads can service I/Os that are issued from a single
CPU. This can improve performance for workloads in which ublk server CPU
is a bottleneck, and for which load is issued from CPUs which are not
balanced across ublk_queues/hctxs.
Performance
-----------
First create two ublk devices with:
ublkb0: ./kublk add -t null -q 2 --nthreads 2
ublkb1: ./kublk add -t null -q 2 --nthreads 2 --per_io_tasks
Then run load with:
taskset -c 1 fio/t/io_uring -r5 -p0 /dev/ublkb0: 1.90M IOPS
taskset -c 1 fio/t/io_uring -r5 -p0 /dev/ublkb1: 2.18M IOPS
Since ublkb1 has per-io-tasks, the second command is able to make use of
both ublk server worker threads and therefore has increased max
throughput.
Caveats:
- This testing was done on a system with 2 numa nodes, but the penalty
of having I/O cross a numa (or LLC) boundary in the per_io_tasks case
is quite high. So these numbers were obtained after moving all ublk
server threads and the application threads to CPUs on the same numa
node/LLC.
- One might expect the scaling to be linear - because ublkb1 can make
use of twice as many ublk server threads, it should be able to drive
twice the throughput. However this is not true (the improvement is
~15%), and needs further investigation.
Signed-off-by: Uday Shankar <ushankar(a)purestorage.com>
---
Changes in v8:
- Fix queue_rqs batch dispatch OOPS when dispatching a list of requests
associated to > 1 ublk_queue (Ming Lei, Caleb Sander Mateos)
- Simplify queue_rqs (Caleb Sander Mateos)
- Narrow a couple of types (Ming Lei)
- Add stress test for per io daemons (Ming Lei)
- Link to v7: https://lore.kernel.org/r/20250527-ublk_task_per_io-v7-0-cbdbaf283baa@pures…
Changes in v7:
- Fix queue_rqs batch dispatch for per-io daemons
- Kick round-robin tag allocation changes to a followup
- Add explicit feature flag for per-task daemons (Ming Lei, Caleb Sander
Mateos)
- Move some variable assignments to avoid redundant computation (Caleb
Sander Mateos)
- Switch from storing pointers in ublk_io to computing based on address
with container_of in a couple places (Ming Lei)
- Link to v6: https://lore.kernel.org/r/20250507-ublk_task_per_io-v6-0-a2a298783c01@pures…
Changes in v6:
- Add a feature flag for this feature, called UBLK_F_RR_TAGS (Ming Lei)
- Add test for this feature (Ming Lei)
- Add documentation for this feature (Ming Lei)
- Link to v5: https://lore.kernel.org/r/20250416-ublk_task_per_io-v5-0-9261ad7bff20@pures…
Changes in v5:
- Set io->task before ublk_mark_io_ready (Caleb Sander Mateos)
- Set io->task atomically, read it atomically when needed
- Return 0 on success from command-specific helpers in
__ublk_ch_uring_cmd (Caleb Sander Mateos)
- Rename ublk_handle_need_get_data to ublk_get_data (Caleb Sander
Mateos)
- Link to v4: https://lore.kernel.org/r/20250415-ublk_task_per_io-v4-0-54210b91a46f@pures…
Changes in v4:
- Drop "ublk: properly serialize all FETCH_REQs" since Ming is taking it
in another set
- Prevent data races by marking data structures which should be
read-only in the I/O path as const (Ming Lei)
- Link to v3: https://lore.kernel.org/r/20250410-ublk_task_per_io-v3-0-b811e8f4554a@pures…
Changes in v3:
- Check for UBLK_IO_FLAG_ACTIVE on I/O again after taking lock to ensure
that two concurrent FETCH_REQs on the same I/O can't succeed (Caleb
Sander Mateos)
- Link to v2: https://lore.kernel.org/r/20250408-ublk_task_per_io-v2-0-b97877e6fd50@pures…
Changes in v2:
- Remove changes split into other patches
- To ease error handling/synchronization, associate each I/O (instead of
each queue) to the last task that issues a FETCH_REQ against it. Only
that task is allowed to operate on the I/O.
- Link to v1: https://lore.kernel.org/r/20241002224437.3088981-1-ushankar@purestorage.com
---
Uday Shankar (9):
ublk: have a per-io daemon instead of a per-queue daemon
selftests: ublk: kublk: plumb q_id in io_uring user_data
selftests: ublk: kublk: tie sqe allocation to io instead of queue
selftests: ublk: kublk: lift queue initialization out of thread
selftests: ublk: kublk: move per-thread data out of ublk_queue
selftests: ublk: kublk: decouple ublk_queues from ublk server threads
selftests: ublk: add functional test for per io daemons
selftests: ublk: add stress test for per io daemons
Documentation: ublk: document UBLK_F_PER_IO_DAEMON
Documentation/block/ublk.rst | 35 ++-
drivers/block/ublk_drv.c | 111 +++----
include/uapi/linux/ublk_cmd.h | 9 +
tools/testing/selftests/ublk/Makefile | 2 +
tools/testing/selftests/ublk/fault_inject.c | 4 +-
tools/testing/selftests/ublk/file_backed.c | 20 +-
tools/testing/selftests/ublk/kublk.c | 344 ++++++++++++++-------
tools/testing/selftests/ublk/kublk.h | 73 +++--
tools/testing/selftests/ublk/null.c | 22 +-
tools/testing/selftests/ublk/stripe.c | 17 +-
tools/testing/selftests/ublk/test_common.sh | 5 +
tools/testing/selftests/ublk/test_generic_12.sh | 55 ++++
tools/testing/selftests/ublk/test_stress_06.sh | 36 +++
.../selftests/ublk/trace/count_ios_per_tid.bt | 11 +
14 files changed, 512 insertions(+), 232 deletions(-)
---
base-commit: 533c87e2ed742454957f14d7bef9f48d5a72e72d
change-id: 20250408-ublk_task_per_io-c693cf608d7a
Best regards,
--
Uday Shankar <ushankar(a)purestorage.com>
The anon_inode_test test fails to build due to attempting to include
a nonexisting overlayfs/wrapper.h:
anon_inode_test.c:10:10: fatal error: overlayfs/wrappers.h: No such file or directory
10 | #include "overlayfs/wrappers.h"
| ^~~~~~~~~~~~~~~~~~~~~~
This is due to 0bd92b9fe538 ("selftests/filesystems: move wrapper.h out
of overlayfs subdir") which was added in the vfs-6.16.selftests branch
which was based on -rc5 and does not contain the newly added test so
once things were merged into vfs.all in the build started failing - both
parent commits are fine.
Fixes: feaa00dbff45a ("Merge branch 'vfs-6.16.selftests' into vfs.all")
Signed-off-by: Mark Brown <broonie(a)kernel.org>
---
tools/testing/selftests/filesystems/anon_inode_test.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/testing/selftests/filesystems/anon_inode_test.c b/tools/testing/selftests/filesystems/anon_inode_test.c
index e8e0ef1460d2..73e0a4d4fb2f 100644
--- a/tools/testing/selftests/filesystems/anon_inode_test.c
+++ b/tools/testing/selftests/filesystems/anon_inode_test.c
@@ -7,7 +7,7 @@
#include <sys/stat.h>
#include "../kselftest_harness.h"
-#include "overlayfs/wrappers.h"
+#include "wrappers.h"
TEST(anon_inode_no_chown)
{
---
base-commit: feaa00dbff45ad9a0dcd04a92f88c745bf880f55
change-id: 20250516-selftests-anon-inode-build-007e206e8422
Best regards,
--
Mark Brown <broonie(a)kernel.org>
This picks up from Michal Rostecki's work[0]. Per Michal's guidance I
have omitted Co-authored tags, as the end result is quite different.
Link: https://lore.kernel.org/rust-for-linux/20240819153656.28807-2-vadorovsky@pr… [0]
Closes: https://github.com/Rust-for-Linux/linux/issues/1075
Signed-off-by: Tamir Duberstein <tamird(a)gmail.com>
---
Changes in v10:
- Rebase on cbeaa41dfe26b72639141e87183cb23e00d4b0dd.
- Implement Alice's suggestion to use a proc macro to work around orphan
rules otherwise preventing `core::ffi::CStr` to be directly printed
with `{}`.
- Link to v9: https://lore.kernel.org/r/20250317-cstr-core-v9-0-51d6cc522f62@gmail.com
Changes in v9:
- Rebase on rust-next.
- Restore `impl Display for BStr` which exists upstream[1].
- Link: https://doc.rust-lang.org/nightly/std/bstr/struct.ByteStr.html#impl-Display… [1]
- Link to v8: https://lore.kernel.org/r/20250203-cstr-core-v8-0-cb3f26e78686@gmail.com
Changes in v8:
- Move `{from,as}_char_ptr` back to `CStrExt`. This reduces the diff
some.
- Restore `from_bytes_with_nul_unchecked_mut`, `to_cstring`.
- Link to v7: https://lore.kernel.org/r/20250202-cstr-core-v7-0-da1802520438@gmail.com
Changes in v7:
- Rebased on mainline.
- Restore functionality added in commit a321f3ad0a5d ("rust: str: add
{make,to}_{upper,lower}case() to CString").
- Used `diff.algorithm patience` to improve diff readability.
- Link to v6: https://lore.kernel.org/r/20250202-cstr-core-v6-0-8469cd6d29fd@gmail.com
Changes in v6:
- Split the work into several commits for ease of review.
- Restore `{from,as}_char_ptr` to allow building on ARM (see commit
message).
- Add `CStrExt` to `kernel::prelude`. (Alice Ryhl)
- Remove `CStrExt::from_bytes_with_nul_unchecked_mut` and restore
`DerefMut for CString`. (Alice Ryhl)
- Rename and hide `kernel::c_str!` to encourage use of C-String
literals.
- Drop implementation and invocation changes in kunit.rs. (Trevor Gross)
- Drop docs on `Display` impl. (Trevor Gross)
- Rewrite docs in the style of the standard library.
- Restore the `test_cstr_debug` unit tests to demonstrate that the
implementation has changed.
Changes in v5:
- Keep the `test_cstr_display*` unit tests.
Changes in v4:
- Provide the `CStrExt` trait with `display()` method, which returns a
`CStrDisplay` wrapper with `Display` implementation. This addresses
the lack of `Display` implementation for `core::ffi::CStr`.
- Provide `from_bytes_with_nul_unchecked_mut()` method in `CStrExt`,
which might be useful and is going to prevent manual, unsafe casts.
- Fix a typo (s/preffered/prefered/).
Changes in v3:
- Fix the commit message.
- Remove redundant braces in `use`, when only one item is imported.
Changes in v2:
- Do not remove `c_str` macro. While it's preferred to use C-string
literals, there are two cases where `c_str` is helpful:
- When working with macros, which already return a Rust string literal
(e.g. `stringify!`).
- When building macros, where we want to take a Rust string literal as an
argument (for caller's convenience), but still use it as a C-string
internally.
- Use Rust literals as arguments in macros (`new_mutex`, `new_condvar`,
`new_mutex`). Use the `c_str` macro to convert these literals to C-string
literals.
- Use `c_str` in kunit.rs for converting the output of `stringify!` to a
`CStr`.
- Remove `DerefMut` implementation for `CString`.
---
Tamir Duberstein (5):
rust: retitle "Example" section as "Examples"
rust: support formatting of foreign types
rust: replace `CStr` with `core::ffi::CStr`
rust: replace `kernel::c_str!` with C-Strings
rust: remove core::ffi::CStr reexport
drivers/block/rnull.rs | 2 +-
drivers/gpu/drm/drm_panic_qr.rs | 5 +-
drivers/gpu/nova-core/driver.rs | 2 +-
drivers/gpu/nova-core/firmware.rs | 2 +-
drivers/net/phy/ax88796b_rust.rs | 8 +-
drivers/net/phy/qt2025.rs | 6 +-
rust/kernel/block/mq.rs | 2 +-
rust/kernel/device.rs | 9 +-
rust/kernel/devres.rs | 2 +-
rust/kernel/driver.rs | 4 +-
rust/kernel/error.rs | 10 +-
rust/kernel/faux.rs | 5 +-
rust/kernel/firmware.rs | 16 +-
rust/kernel/fmt.rs | 77 +++++++
rust/kernel/kunit.rs | 21 +-
rust/kernel/lib.rs | 3 +-
rust/kernel/miscdevice.rs | 5 +-
rust/kernel/net/phy.rs | 12 +-
rust/kernel/of.rs | 5 +-
rust/kernel/pci.rs | 2 +-
rust/kernel/platform.rs | 6 +-
rust/kernel/prelude.rs | 5 +-
rust/kernel/print.rs | 4 +-
rust/kernel/seq_file.rs | 6 +-
rust/kernel/str.rs | 415 ++++++++++-------------------------
rust/kernel/sync.rs | 7 +-
rust/kernel/sync/condvar.rs | 4 +-
rust/kernel/sync/lock.rs | 4 +-
rust/kernel/sync/lock/global.rs | 6 +-
rust/kernel/sync/poll.rs | 1 +
rust/kernel/workqueue.rs | 1 +
rust/macros/fmt.rs | 118 ++++++++++
rust/macros/kunit.rs | 6 +-
rust/macros/lib.rs | 21 +-
rust/macros/module.rs | 2 +-
samples/rust/rust_driver_faux.rs | 4 +-
samples/rust/rust_driver_pci.rs | 4 +-
samples/rust/rust_driver_platform.rs | 4 +-
samples/rust/rust_misc_device.rs | 3 +-
scripts/rustdoc_test_gen.rs | 2 +-
40 files changed, 426 insertions(+), 395 deletions(-)
---
base-commit: cbeaa41dfe26b72639141e87183cb23e00d4b0dd
change-id: 20250201-cstr-core-d4b9b69120cf
Best regards,
--
Tamir Duberstein <tamird(a)gmail.com>