The arm64 Guarded Control Stack (GCS) feature provides support for
hardware protected stacks of return addresses, intended to provide
hardening against return oriented programming (ROP) attacks and to make
it easier to gather call stacks for applications such as profiling.
When GCS is active a secondary stack called the Guarded Control Stack is
maintained, protected with a memory attribute which means that it can
only be written with specific GCS operations. The current GCS pointer
can not be directly written to by userspace. When a BL is executed the
value stored in LR is also pushed onto the GCS, and when a RET is
executed the top of the GCS is popped and compared to LR with a fault
being raised if the values do not match. GCS operations may only be
performed on GCS pages, a data abort is generated if they are not.
The combination of hardware enforcement and lack of extra instructions
in the function entry and exit paths should result in something which
has less overhead and is more difficult to attack than a purely software
implementation like clang's shadow stacks.
This series implements support for use of GCS by userspace, along with
support for use of GCS within KVM guests. It does not enable use of GCS
by either EL1 or EL2, this will be implemented separately. Executables
are started without GCS and must use a prctl() to enable it, it is
expected that this will be done very early in application execution by
the dynamic linker or other startup code.
x86 has an equivalent feature called shadow stacks, this series depends
on the x86 patches for generic memory management support for the new
guarded/shadow stack page type and shares APIs as much as possible. As
there has been extensive discussion with the wider community around the
ABI for shadow stacks I have as far as practical kept implementation
decisions close to those for x86, anticipating that review would lead to
similar conclusions in the absence of strong reasoning for divergence.
The main divergence I am concious of is that x86 allows shadow stack to
be enabled and disabled repeatedly, freeing the shadow stack for the
thread whenever disabled, while this implementation keeps the GCS
allocated after disable but refuses to reenable it. This is to avoid
races with things actively walking the GCS during a disable, we do
anticipate that some systems will wish to disable GCS at runtime but are
not aware of any demand for subsequently reenabling it.
x86 uses an arch_prctl() to manage enable and disable, since only x86
and S/390 use arch_prctl() a generic prctl() was proposed[1] as part of a
patch set for the equivalent RISC-V zisslpcfi feature which I initially
adopted fairly directly but following review feedback has been revised
quite a bit.
There is an open issue with support for CRIU, on x86 this required the
ability to set the GCS mode via ptrace. This series supports
configuring mode bits other than enable/disable via ptrace but it needs
to be confirmed if this is sufficient.
There's a few bits where I'm not convinced with where I've placed
things, in particular the GCS write operation is in the GCS header not
in uaccess.h, I wasn't sure what was clearest there and am probably too
close to the code to have a clear opinion. The reporting of GCS in
/proc/PID/smaps is also a bit awkward.
The series depends on the x86 shadow stack support:
https://lore.kernel.org/lkml/20230227222957.24501-1-rick.p.edgecombe@intel.…
I've rebased this onto v6.5-rc4 but not included it in the series in
order to avoid confusion with Rick's work and cut down the size of the
series, you can see the branch at:
https://git.kernel.org/pub/scm/linux/kernel/git/broonie/misc.git arm64-gcs
[1] https://lore.kernel.org/lkml/20230213045351.3945824-1-debug@rivosinc.com/
Signed-off-by: Mark Brown <broonie(a)kernel.org>
---
Changes in v4:
- Implement flags for map_shadow_stack() allowing the cap and end of
stack marker to be enabled independently or not at all.
- Relax size and alignment requirements for map_shadow_stack().
- Add more blurb explaining the advantages of hardware enforcement.
- Link to v3: https://lore.kernel.org/r/20230731-arm64-gcs-v3-0-cddf9f980d98@kernel.org
Changes in v3:
- Rebase onto v6.5-rc4.
- Add a GCS barrier on context switch.
- Add a GCS stress test.
- Link to v2: https://lore.kernel.org/r/20230724-arm64-gcs-v2-0-dc2c1d44c2eb@kernel.org
Changes in v2:
- Rebase onto v6.5-rc3.
- Rework prctl() interface to allow each bit to be locked independently.
- map_shadow_stack() now places the cap token based on the size
requested by the caller not the actual space allocated.
- Mode changes other than enable via ptrace are now supported.
- Expand test coverage.
- Various smaller fixes and adjustments.
- Link to v1: https://lore.kernel.org/r/20230716-arm64-gcs-v1-0-bf567f93bba6@kernel.org
---
Mark Brown (36):
prctl: arch-agnostic prctl for shadow stack
arm64: Document boot requirements for Guarded Control Stacks
arm64/gcs: Document the ABI for Guarded Control Stacks
arm64/sysreg: Add new system registers for GCS
arm64/sysreg: Add definitions for architected GCS caps
arm64/gcs: Add manual encodings of GCS instructions
arm64/gcs: Provide copy_to_user_gcs()
arm64/cpufeature: Runtime detection of Guarded Control Stack (GCS)
arm64/mm: Allocate PIE slots for EL0 guarded control stack
mm: Define VM_SHADOW_STACK for arm64 when we support GCS
arm64/mm: Map pages for guarded control stack
KVM: arm64: Manage GCS registers for guests
arm64/gcs: Allow GCS usage at EL0 and EL1
arm64/idreg: Add overrride for GCS
arm64/hwcap: Add hwcap for GCS
arm64/traps: Handle GCS exceptions
arm64/mm: Handle GCS data aborts
arm64/gcs: Context switch GCS state for EL0
arm64/gcs: Allocate a new GCS for threads with GCS enabled
arm64/gcs: Implement shadow stack prctl() interface
arm64/mm: Implement map_shadow_stack()
arm64/signal: Set up and restore the GCS context for signal handlers
arm64/signal: Expose GCS state in signal frames
arm64/ptrace: Expose GCS via ptrace and core files
arm64: Add Kconfig for Guarded Control Stack (GCS)
kselftest/arm64: Verify the GCS hwcap
kselftest/arm64: Add GCS as a detected feature in the signal tests
kselftest/arm64: Add framework support for GCS to signal handling tests
kselftest/arm64: Allow signals tests to specify an expected si_code
kselftest/arm64: Always run signals tests with GCS enabled
kselftest/arm64: Add very basic GCS test program
kselftest/arm64: Add a GCS test program built with the system libc
kselftest/arm64: Add test coverage for GCS mode locking
selftests/arm64: Add GCS signal tests
kselftest/arm64: Add a GCS stress test
kselftest/arm64: Enable GCS for the FP stress tests
Documentation/admin-guide/kernel-parameters.txt | 3 +
Documentation/arch/arm64/booting.rst | 22 +
Documentation/arch/arm64/elf_hwcaps.rst | 3 +
Documentation/arch/arm64/gcs.rst | 228 +++++++++
Documentation/arch/arm64/index.rst | 1 +
Documentation/filesystems/proc.rst | 2 +-
arch/arm64/Kconfig | 19 +
arch/arm64/include/asm/cpufeature.h | 6 +
arch/arm64/include/asm/el2_setup.h | 17 +
arch/arm64/include/asm/esr.h | 28 +-
arch/arm64/include/asm/exception.h | 2 +
arch/arm64/include/asm/gcs.h | 106 ++++
arch/arm64/include/asm/hwcap.h | 1 +
arch/arm64/include/asm/kvm_arm.h | 4 +-
arch/arm64/include/asm/kvm_host.h | 12 +
arch/arm64/include/asm/pgtable-prot.h | 14 +-
arch/arm64/include/asm/processor.h | 7 +
arch/arm64/include/asm/sysreg.h | 20 +
arch/arm64/include/asm/uaccess.h | 42 ++
arch/arm64/include/uapi/asm/hwcap.h | 1 +
arch/arm64/include/uapi/asm/ptrace.h | 8 +
arch/arm64/include/uapi/asm/sigcontext.h | 9 +
arch/arm64/kernel/cpufeature.c | 19 +
arch/arm64/kernel/cpuinfo.c | 1 +
arch/arm64/kernel/entry-common.c | 23 +
arch/arm64/kernel/idreg-override.c | 2 +
arch/arm64/kernel/process.c | 85 ++++
arch/arm64/kernel/ptrace.c | 59 +++
arch/arm64/kernel/signal.c | 237 ++++++++-
arch/arm64/kernel/traps.c | 11 +
arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h | 17 +
arch/arm64/kvm/sys_regs.c | 22 +
arch/arm64/mm/Makefile | 1 +
arch/arm64/mm/fault.c | 78 ++-
arch/arm64/mm/gcs.c | 234 +++++++++
arch/arm64/mm/mmap.c | 12 +-
arch/arm64/tools/cpucaps | 1 +
arch/arm64/tools/sysreg | 55 +++
fs/proc/task_mmu.c | 3 +
include/linux/mm.h | 16 +-
include/linux/syscalls.h | 1 +
include/uapi/asm-generic/unistd.h | 5 +-
include/uapi/linux/elf.h | 1 +
include/uapi/linux/prctl.h | 22 +
kernel/sys.c | 30 ++
kernel/sys_ni.c | 1 +
tools/testing/selftests/arm64/Makefile | 2 +-
tools/testing/selftests/arm64/abi/hwcap.c | 19 +
tools/testing/selftests/arm64/fp/assembler.h | 15 +
tools/testing/selftests/arm64/fp/fpsimd-test.S | 2 +
tools/testing/selftests/arm64/fp/sve-test.S | 2 +
tools/testing/selftests/arm64/fp/za-test.S | 2 +
tools/testing/selftests/arm64/fp/zt-test.S | 2 +
tools/testing/selftests/arm64/gcs/.gitignore | 5 +
tools/testing/selftests/arm64/gcs/Makefile | 24 +
tools/testing/selftests/arm64/gcs/asm-offsets.h | 0
tools/testing/selftests/arm64/gcs/basic-gcs.c | 356 ++++++++++++++
tools/testing/selftests/arm64/gcs/gcs-locking.c | 200 ++++++++
.../selftests/arm64/gcs/gcs-stress-thread.S | 311 ++++++++++++
tools/testing/selftests/arm64/gcs/gcs-stress.c | 532 +++++++++++++++++++++
tools/testing/selftests/arm64/gcs/gcs-util.h | 87 ++++
tools/testing/selftests/arm64/gcs/libc-gcs.c | 500 +++++++++++++++++++
tools/testing/selftests/arm64/signal/.gitignore | 1 +
.../testing/selftests/arm64/signal/test_signals.c | 17 +-
.../testing/selftests/arm64/signal/test_signals.h | 6 +
.../selftests/arm64/signal/test_signals_utils.c | 32 +-
.../selftests/arm64/signal/test_signals_utils.h | 39 ++
.../arm64/signal/testcases/gcs_exception_fault.c | 59 +++
.../selftests/arm64/signal/testcases/gcs_frame.c | 78 +++
.../arm64/signal/testcases/gcs_write_fault.c | 67 +++
.../selftests/arm64/signal/testcases/testcases.c | 7 +
.../selftests/arm64/signal/testcases/testcases.h | 1 +
72 files changed, 3823 insertions(+), 34 deletions(-)
---
base-commit: ed0e1456f04be7a93c9a186e8e13aed78b555617
change-id: 20230303-arm64-gcs-e311ab0d8729
Best regards,
--
Mark Brown <broonie(a)kernel.org>
IOMMU hardwares that support nested translation would have two stages
address translation (normally mentioned as stage-1 and stage-2). The page
table formats of the stage-1 and stage-2 can be different. e.g., VT-d has
different page table formats for stage-1 and stage-2.
Nested parent domain is the iommu domain used to represent the stage-2
translation. In IOMMUFD, both stage-1 and stage-2 translation are tracked
as HWPT (a.k.a. iommu domain). Stage-2 HWPT is parent of stage-1 HWPT as
stage-1 cannot work alone in nested translation. In the cases of stage-1 and
stage-2 page table format are different, the parent HWPT should use exactly
the stage-2 page table format. However, the existing kernel hides the format
selection in iommu drivers, so the domain allocated via IOMMU_HWPT_ALLOC can
use either stage-1 page table format or stage-2 page table format, there is
no guarantees for it.
To enforce the page table format of the nested parent domain, this series
introduces a new iommu op (domain_alloc_user) which can accept user flags
to allocate domain as userspace requires. It also converts IOMMUFD to use
the new domain_alloc_user op for domain allocation if supported, then extends
the IOMMU_HWPT_ALLOC ioctl to pass down a NEST_PARENT flag to allocate a HWPT
which can be used as parent. This series implements the new op in Intel iommu
driver to have a complete picture. It is a preparation for adding nesting
support in IOMMUFD/IOMMU.
Complete code can be found:
https://github.com/yiliu1765/iommufd/tree/iommufd_alloc_user_v2
Change log:
v2:
- Require domain_alloc_user op if IOMMU_HWPT_ALLOC passes non-zero flags (Kevin)
- IOMMUFD core should check kernel known flags while iommu driver needs
to check supported flags as well (Jason)
- Minor tweaks per Baolu's comment
v1: https://lore.kernel.org/linux-iommu/20230919092523.39286-1-yi.l.liu@intel.c…
Regards,
Yi Liu
Yi Liu (6):
iommu: Add new iommu op to create domains owned by userspace
iommufd/hw_pagetable: Use domain_alloc_user op for domain allocation
iommufd/hw_pagetable: Accepts user flags for domain allocation
iommufd/hw_pagetable: Support allocating nested parent domain
iommufd/selftest: Add domain_alloc_user() support in iommu mock
iommu/vt-d: Add domain_alloc_user op
drivers/iommu/intel/iommu.c | 28 +++++++++++++++++
drivers/iommu/iommufd/device.c | 2 +-
drivers/iommu/iommufd/hw_pagetable.c | 31 ++++++++++++++-----
drivers/iommu/iommufd/iommufd_private.h | 3 +-
drivers/iommu/iommufd/selftest.c | 19 ++++++++++++
include/linux/iommu.h | 11 ++++++-
include/uapi/linux/iommufd.h | 12 ++++++-
tools/testing/selftests/iommu/iommufd.c | 24 +++++++++++---
.../selftests/iommu/iommufd_fail_nth.c | 2 +-
tools/testing/selftests/iommu/iommufd_utils.h | 11 +++++--
10 files changed, 124 insertions(+), 19 deletions(-)
--
2.34.1
This is to add Intel VT-d nested translation based on IOMMUFD nesting
infrastructure. As the iommufd nesting infrastructure series[1], iommu
core supports new ops to report iommu hardware information, allocate
domains with user data and invalidate stage-1 IOTLB when there is mapping
changed in stage-1 page table. The data required in the three paths are
vendor-specific, so
1) IOMMU_HWPT_TYPE_VTD_S1 is defined for the Intel VT-d stage-1 page
table, it will be used in the stage-1 domain allocation and IOTLB
syncing path. struct iommu_hwpt_vtd_s1 is defined to pass user_data
for the Intel VT-d stage-1 domain allocation.
struct iommu_hwpt_vtd_s1_invalidate is defined to pass the data for
the Intel VT-d stage-1 IOTLB invalidation.
2) IOMMU_HW_INFO_TYPE_INTEL_VTD and struct iommu_hw_info_vtd are defined
to report iommu hardware information for Intel VT-d.
With above IOMMUFD extensions, the intel iommu driver implements the three
paths to support nested translation.
The first Intel platform supporting nested translation is Sapphire
Rapids which, unfortunately, has a hardware errata [2] requiring special
treatment. This errata happens when a stage-1 page table page (either
level) is located in a stage-2 read-only region. In that case the IOMMU
hardware may ignore the stage-2 RO permission and still set the A/D bit
in stage-1 page table entries during page table walking.
A flag IOMMU_HW_INFO_VTD_ERRATA_772415_SPR17 is introduced to report
this errata to userspace. With that restriction the user should either
disable nested translation to favor RO stage-2 mappings or ensure no
RO stage-2 mapping to enable nested translation.
Intel-iommu driver is armed with necessary checks to prevent such mix
in patch12 of this series.
Qemu currently does add RO mappings though. The vfio agent in Qemu
simply maps all valid regions in the GPA address space which certainly
includes RO regions e.g. vbios.
In reality we don't know a usage relying on DMA reads from the BIOS
region. Hence finding a way to skip RO regions (e.g. via a discard manager)
in Qemu might be an acceptable tradeoff. The actual change needs more
discussion in Qemu community. For now we just hacked Qemu to test.
Complete code can be found in [3], corresponding QEMU could can be found
in [4].
[1] https://lore.kernel.org/linux-iommu/20230921075138.124099-1-yi.l.liu@intel.…
[2] https://www.intel.com/content/www/us/en/content-details/772415/content-deta…
[3] https://github.com/yiliu1765/iommufd/tree/iommufd_nesting
[4] https://github.com/yiliu1765/qemu/tree/zhenzhong/wip/iommufd_nesting_rfcv1
Change log:
v5:
- Add Kevin's r-b for patch 2, 3 ,5 8, 10
- Drop enforce_cache_coherency callback from the nested type domain ops (Kevin)
- Remove duplicate agaw check in patch 04 (Kevin)
- Remove duplicate domain_update_iommu_cap() in patch 06 (Kevin)
- Check parent's force_snooping to set pgsnp in the pasid entry (Kevin)
- uapi data structure check (Kevin)
- Simplify the errata handling as user can allocate nested parent domain
v4: https://lore.kernel.org/linux-iommu/20230724111335.107427-1-yi.l.liu@intel.…
- Remove ascii art tables (Jason)
- Drop EMT (Tina, Jason)
- Drop MTS and related definitions (Kevin)
- Rename macro IOMMU_VTD_PGTBL_ to IOMMU_VTD_S1_ (Kevin)
- Rename struct iommu_hwpt_intel_vtd_ to iommu_hwpt_vtd_ (Kevin)
- Rename struct iommu_hwpt_intel_vtd to iommu_hwpt_vtd_s1 (Kevin)
- Put the vendor specific hwpt alloc data structure before enuma iommu_hwpt_type (Kevin)
- Do not trim the higher page levels of S2 domain in nested domain attachment as the
S2 domain may have been used independently. (Kevin)
- Remove the first-stage pgd check against the maximum address of s2_domain as hw
can check it anyhow. It makes sense to check every pfns used in the stage-1 page
table. But it cannot make it. So just leave it to hw. (Kevin)
- Split the iotlb flush part into an order of uapi, helper and callback implementation (Kevin)
- Change the policy of VT-d nesting errata, disallow RO mapping once a domain is used
as parent domain of a nested domain. This removes the nested_users counting. (Kevin)
- Minor fix for "make htmldocs"
v3: https://lore.kernel.org/linux-iommu/20230511145110.27707-1-yi.l.liu@intel.c…
- Further split the patches into an order of adding helpers for nested
domain, iotlb flush, nested domain attachment and nested domain allocation
callback, then report the hw_info to userspace.
- Add batch support in cache invalidation from userspace
- Disallow nested translation usage if RO mappings exists in stage-2 domain
due to errata on readonly mappings on Sapphire Rapids platform.
v2: https://lore.kernel.org/linux-iommu/20230309082207.612346-1-yi.l.liu@intel.…
- The iommufd infrastructure is split to be separate series.
v1: https://lore.kernel.org/linux-iommu/20230209043153.14964-1-yi.l.liu@intel.c…
Regards,
Yi Liu
Lu Baolu (5):
iommu/vt-d: Extend dmar_domain to support nested domain
iommu/vt-d: Add helper for nested domain allocation
iommu/vt-d: Add helper to setup pasid nested translation
iommu/vt-d: Add nested domain allocation
iommu/vt-d: Disallow read-only mappings to nest parent domain
Yi Liu (6):
iommufd: Add data structure for Intel VT-d stage-1 domain allocation
iommu/vt-d: Make domain attach helpers to be extern
iommu/vt-d: Set the nested domain to a device
iommufd: Add data structure for Intel VT-d stage-1 cache invalidation
iommu/vt-d: Make iotlb flush helpers to be extern
iommu/vt-d: Add iotlb flush for nested domain
drivers/iommu/intel/Makefile | 2 +-
drivers/iommu/intel/iommu.c | 60 +++++++++----
drivers/iommu/intel/iommu.h | 51 +++++++++--
drivers/iommu/intel/nested.c | 162 +++++++++++++++++++++++++++++++++++
drivers/iommu/intel/pasid.c | 125 +++++++++++++++++++++++++++
drivers/iommu/intel/pasid.h | 2 +
include/uapi/linux/iommufd.h | 76 +++++++++++++++-
7 files changed, 452 insertions(+), 26 deletions(-)
create mode 100644 drivers/iommu/intel/nested.c
--
2.34.1
In order to use run_kselftest.sh the list of tests must be emitted to
populate kselftest-list.txt.
The powerpc Makefile is written to use EMIT_TESTS. But support for
EMIT_TESTS was dropped in commit d4e59a536f50 ("selftests: Use runner.sh
for emit targets"). Although prior to that commit a548de0fe8e1
("selftests: lib.mk: add test execute bit check to EMIT_TESTS") had
already broken run_kselftest.sh for powerpc due to the executable check
using the wrong path.
It can be fixed by replacing the EMIT_TESTS definitions with actual
emit_tests rules in the powerpc Makefiles. This makes run_kselftest.sh
able to run powerpc tests:
$ cd linux
$ export ARCH=powerpc
$ export CROSS_COMPILE=powerpc64le-linux-gnu-
$ make headers
$ make -j -C tools/testing/selftests install
$ grep -c "^powerpc" tools/testing/selftests/kselftest_install/kselftest-list.txt
182
Fixes: d4e59a536f50 ("selftests: Use runner.sh for emit targets")
Signed-off-by: Michael Ellerman <mpe(a)ellerman.id.au>
---
tools/testing/selftests/powerpc/Makefile | 7 +++----
tools/testing/selftests/powerpc/pmu/Makefile | 11 ++++++-----
2 files changed, 9 insertions(+), 9 deletions(-)
I'll plan to merge this via the powerpc tree.
cheers
diff --git a/tools/testing/selftests/powerpc/Makefile b/tools/testing/selftests/powerpc/Makefile
index 49f2ad1793fd..7ea42fa02eab 100644
--- a/tools/testing/selftests/powerpc/Makefile
+++ b/tools/testing/selftests/powerpc/Makefile
@@ -59,12 +59,11 @@ override define INSTALL_RULE
done;
endef
-override define EMIT_TESTS
+emit_tests:
+@for TARGET in $(SUB_DIRS); do \
BUILD_TARGET=$(OUTPUT)/$$TARGET; \
- $(MAKE) OUTPUT=$$BUILD_TARGET -s -C $$TARGET emit_tests;\
+ $(MAKE) OUTPUT=$$BUILD_TARGET -s -C $$TARGET $@;\
done;
-endef
override define CLEAN
+@for TARGET in $(SUB_DIRS); do \
@@ -77,4 +76,4 @@ endef
tags:
find . -name '*.c' -o -name '*.h' | xargs ctags
-.PHONY: tags $(SUB_DIRS)
+.PHONY: tags $(SUB_DIRS) emit_tests
diff --git a/tools/testing/selftests/powerpc/pmu/Makefile b/tools/testing/selftests/powerpc/pmu/Makefile
index 2b95e44d20ff..a284fa874a9f 100644
--- a/tools/testing/selftests/powerpc/pmu/Makefile
+++ b/tools/testing/selftests/powerpc/pmu/Makefile
@@ -30,13 +30,14 @@ override define RUN_TESTS
+TARGET=event_code_tests; BUILD_TARGET=$$OUTPUT/$$TARGET; $(MAKE) OUTPUT=$$BUILD_TARGET -C $$TARGET run_tests
endef
-DEFAULT_EMIT_TESTS := $(EMIT_TESTS)
-override define EMIT_TESTS
- $(DEFAULT_EMIT_TESTS)
+emit_tests:
+ for TEST in $(TEST_GEN_PROGS); do \
+ BASENAME_TEST=`basename $$TEST`; \
+ echo "$(COLLECTION):$$BASENAME_TEST"; \
+ done
+TARGET=ebb; BUILD_TARGET=$$OUTPUT/$$TARGET; $(MAKE) OUTPUT=$$BUILD_TARGET -s -C $$TARGET emit_tests
+TARGET=sampling_tests; BUILD_TARGET=$$OUTPUT/$$TARGET; $(MAKE) OUTPUT=$$BUILD_TARGET -s -C $$TARGET emit_tests
+TARGET=event_code_tests; BUILD_TARGET=$$OUTPUT/$$TARGET; $(MAKE) OUTPUT=$$BUILD_TARGET -s -C $$TARGET emit_tests
-endef
DEFAULT_INSTALL_RULE := $(INSTALL_RULE)
override define INSTALL_RULE
@@ -64,4 +65,4 @@ sampling_tests:
event_code_tests:
TARGET=$@; BUILD_TARGET=$$OUTPUT/$$TARGET; mkdir -p $$BUILD_TARGET; $(MAKE) OUTPUT=$$BUILD_TARGET -k -C $$TARGET all
-.PHONY: all run_tests ebb sampling_tests event_code_tests
+.PHONY: all run_tests ebb sampling_tests event_code_tests emit_tests
--
2.41.0
Rework how KVM limits guest-unsupported xfeatures to effectively hide
only when saving state for userspace (KVM_GET_XSAVE), i.e. to let userspace
load all host-supported xfeatures (via KVM_SET_XSAVE) irrespective of
what features have been exposed to the guest.
The effect on KVM_SET_XSAVE was knowingly done by commit ad856280ddea
("x86/kvm/fpu: Limit guest user_xfeatures to supported bits of XCR0"):
As a bonus, it will also fail if userspace tries to set fpu features
(with the KVM_SET_XSAVE ioctl) that are not compatible to the guest
configuration. Such features will never be returned by KVM_GET_XSAVE
or KVM_GET_XSAVE2.
Peventing userspace from doing stupid things is usually a good idea, but in
this case restricting KVM_SET_XSAVE actually exacerbated the problem that
commit ad856280ddea was fixing. As reported by Tyler, rejecting KVM_SET_XSAVE
for guest-unsupported xfeatures breaks live migration from a kernel without
commit ad856280ddea, to a kernel with ad856280ddea. I.e. from a kernel that
saves guest-unsupported xfeatures to a kernel that doesn't allow loading
guest-unuspported xfeatures.
To make matters even worse, QEMU doesn't terminate if KVM_SET_XSAVE fails,
and so the end result is that the live migration results (possibly silent)
guest data corruption instead of a failed migration.
Patch 1 refactors the FPU code to let KVM pass in a mask of which xfeatures
to save, patch 2 fixes KVM by passing in guest_supported_xcr0 instead of
modifying user_xfeatures directly.
Patches 3-5 are regression tests.
I have no objection if anyone wants patches 1 and 2 squashed together, I
split them purely to make review easier.
Note, this doesn't fix the scenario where a guest is migrated from a "bad"
to a "good" kernel and the target host doesn't support the over-saved set
of xfeatures. I don't see a way to safely handle that in the kernel without
an opt-in, which more or less defeats the purpose of handling it in KVM.
Sean Christopherson (5):
x86/fpu: Allow caller to constrain xfeatures when copying to uabi
buffer
KVM: x86: Constrain guest-supported xfeatures only at KVM_GET_XSAVE{2}
KVM: selftests: Touch relevant XSAVE state in guest for state test
KVM: selftests: Load XSAVE state into untouched vCPU during state test
KVM: selftests: Force load all supported XSAVE state in state test
arch/x86/include/asm/fpu/api.h | 3 +-
arch/x86/kernel/fpu/core.c | 5 +-
arch/x86/kernel/fpu/xstate.c | 12 +-
arch/x86/kernel/fpu/xstate.h | 3 +-
arch/x86/kvm/cpuid.c | 8 --
arch/x86/kvm/x86.c | 37 +++---
.../selftests/kvm/include/x86_64/processor.h | 23 ++++
.../testing/selftests/kvm/x86_64/state_test.c | 110 +++++++++++++++++-
8 files changed, 168 insertions(+), 33 deletions(-)
base-commit: 5804c19b80bf625c6a9925317f845e497434d6d3
--
2.42.0.582.g8ccd20d70d-goog
Changelog: v2 -> v3
* Minimal code refactoring
* Rebased on v6.6-rc1
RFC v1:
https://lore.kernel.org/all/20210611124154.56427-1-psampat@linux.ibm.com/
RFC v2:
https://lore.kernel.org/all/20230828061530.126588-2-aboorvad@linux.vnet.ibm…
Other related RFC:
https://lore.kernel.org/all/20210430082804.38018-1-psampat@linux.ibm.com/
Userspace selftest:
https://lkml.org/lkml/2020/9/2/356
----
A kernel module + userspace driver to estimate the wakeup latency
caused by going into stop states. The motivation behind this program is
to find significant deviations behind advertised latency and residency
values.
The patchset measures latencies for two kinds of events. IPIs and Timers
As this is a software-only mechanism, there will be additional latencies
of the kernel-firmware-hardware interactions. To account for that, the
program also measures a baseline latency on a 100 percent loaded CPU
and the latencies achieved must be in view relative to that.
To achieve this, we introduce a kernel module and expose its control
knobs through the debugfs interface that the selftests can engage with.
The kernel module provides the following interfaces within
/sys/kernel/debug/powerpc/latency_test/ for,
IPI test:
ipi_cpu_dest = Destination CPU for the IPI
ipi_cpu_src = Origin of the IPI
ipi_latency_ns = Measured latency time in ns
Timeout test:
timeout_cpu_src = CPU on which the timer to be queued
timeout_expected_ns = Timer duration
timeout_diff_ns = Difference of actual duration vs expected timer
Sample output is as follows:
# --IPI Latency Test---
# Baseline Avg IPI latency(ns): 2720
# Observed Avg IPI latency(ns) - State snooze: 2565
# Observed Avg IPI latency(ns) - State stop0_lite: 3856
# Observed Avg IPI latency(ns) - State stop0: 3670
# Observed Avg IPI latency(ns) - State stop1: 3872
# Observed Avg IPI latency(ns) - State stop2: 17421
# Observed Avg IPI latency(ns) - State stop4: 1003922
# Observed Avg IPI latency(ns) - State stop5: 1058870
#
# --Timeout Latency Test--
# Baseline Avg timeout diff(ns): 1435
# Observed Avg timeout diff(ns) - State snooze: 1709
# Observed Avg timeout diff(ns) - State stop0_lite: 2028
# Observed Avg timeout diff(ns) - State stop0: 1954
# Observed Avg timeout diff(ns) - State stop1: 1895
# Observed Avg timeout diff(ns) - State stop2: 14556
# Observed Avg timeout diff(ns) - State stop4: 873988
# Observed Avg timeout diff(ns) - State stop5: 959137
Aboorva Devarajan (2):
powerpc/cpuidle: cpuidle wakeup latency based on IPI and timer events
powerpc/selftest: Add support for cpuidle latency measurement
arch/powerpc/Kconfig.debug | 10 +
arch/powerpc/kernel/Makefile | 1 +
arch/powerpc/kernel/test_cpuidle_latency.c | 154 ++++++
tools/testing/selftests/powerpc/Makefile | 1 +
.../powerpc/cpuidle_latency/.gitignore | 2 +
.../powerpc/cpuidle_latency/Makefile | 6 +
.../cpuidle_latency/cpuidle_latency.sh | 443 ++++++++++++++++++
.../powerpc/cpuidle_latency/settings | 1 +
8 files changed, 618 insertions(+)
create mode 100644 arch/powerpc/kernel/test_cpuidle_latency.c
create mode 100644 tools/testing/selftests/powerpc/cpuidle_latency/.gitignore
create mode 100644 tools/testing/selftests/powerpc/cpuidle_latency/Makefile
create mode 100755 tools/testing/selftests/powerpc/cpuidle_latency/cpuidle_latency.sh
create mode 100644 tools/testing/selftests/powerpc/cpuidle_latency/settings
--
2.25.1
When execute the following command to test clone3 under !CONFIG_TIME_NS:
# make headers && cd tools/testing/selftests/clone3 && make && ./clone3
we can see the following error info:
# [7538] Trying clone3() with flags 0x80 (size 0)
# Invalid argument - Failed to create new process
# [7538] clone3() with flags says: -22 expected 0
not ok 18 [7538] Result (-22) is different than expected (0)
...
# Totals: pass:18 fail:1 xfail:0 xpass:0 skip:0 error:0
This is because if CONFIG_TIME_NS is not set, but the flag
CLONE_NEWTIME (0x80) is used to clone a time namespace, it
will return -EINVAL in copy_time_ns().
If kernel does not support CONFIG_TIME_NS, /proc/self/ns/time
will be not exist, and then we should skip clone3() test with
CLONE_NEWTIME.
With this patch under !CONFIG_TIME_NS:
# make headers && cd tools/testing/selftests/clone3 && make && ./clone3
...
# Time namespaces are not supported
ok 18 # SKIP Skipping clone3() with CLONE_NEWTIME
...
# Totals: pass:18 fail:0 xfail:0 xpass:0 skip:1 error:0
Fixes: 515bddf0ec41 ("selftests/clone3: test clone3 with CLONE_NEWTIME")
Suggested-by: Thomas Gleixner <tglx(a)linutronix.de>
Signed-off-by: Tiezhu Yang <yangtiezhu(a)loongson.cn>
---
v6: Rebase on 6.5-rc1 and update the commit message
tools/testing/selftests/clone3/clone3.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/clone3/clone3.c b/tools/testing/selftests/clone3/clone3.c
index e60cf4d..1c61e3c 100644
--- a/tools/testing/selftests/clone3/clone3.c
+++ b/tools/testing/selftests/clone3/clone3.c
@@ -196,7 +196,12 @@ int main(int argc, char *argv[])
CLONE3_ARGS_NO_TEST);
/* Do a clone3() in a new time namespace */
- test_clone3(CLONE_NEWTIME, 0, 0, CLONE3_ARGS_NO_TEST);
+ if (access("/proc/self/ns/time", F_OK) == 0) {
+ test_clone3(CLONE_NEWTIME, 0, 0, CLONE3_ARGS_NO_TEST);
+ } else {
+ ksft_print_msg("Time namespaces are not supported\n");
+ ksft_test_result_skip("Skipping clone3() with CLONE_NEWTIME\n");
+ }
/* Do a clone3() with exit signal (SIGCHLD) in flags */
test_clone3(SIGCHLD, 0, -EINVAL, CLONE3_ARGS_NO_TEST);
--
2.1.0
v2: Rebase on 6.5-rc1 and update the commit message
Tiezhu Yang (2):
selftests/vDSO: Add support for LoongArch
selftests/vDSO: Get version and name for all archs
tools/testing/selftests/vDSO/vdso_config.h | 6 ++++-
tools/testing/selftests/vDSO/vdso_test_getcpu.c | 16 +++++--------
.../selftests/vDSO/vdso_test_gettimeofday.c | 26 ++++++----------------
3 files changed, 18 insertions(+), 30 deletions(-)
--
2.1.0
Hi all,
This series implements the Permission Overlay Extension introduced in 2022
VMSA enhancements [1]. It is based on v6.6-rc3.
The Permission Overlay Extension allows to constrain permissions on memory
regions. This can be used from userspace (EL0) without a system call or TLB
invalidation.
POE is used to implement the Memory Protection Keys [2] Linux syscall.
The first few patches add the basic framework, then the PKEYS interface is
implemented, and then the selftests are made to work on arm64.
There was discussion about what the 'default' protection key value should be,
I used disallow-all (apart from pkey 0), which matches what x86 does.
Patch 15 contains a call to cpus_have_const_cap(), which I couldn't avoid
until Mark's patch to re-order when the alternatives were applied [3] is
committed.
The KVM part isn't tested yet.
I have tested the modified protection_keys test on x86_64 [4], but not PPC.
Hopefully I have CC'd everyone correctly.
Thanks,
Joey
Joey Gouly (20):
arm64/sysreg: add system register POR_EL{0,1}
arm64/sysreg: update CPACR_EL1 register
arm64: cpufeature: add Permission Overlay Extension cpucap
arm64: disable trapping of POR_EL0 to EL2
arm64: context switch POR_EL0 register
KVM: arm64: Save/restore POE registers
arm64: enable the Permission Overlay Extension for EL0
arm64: add POIndex defines
arm64: define VM_PKEY_BIT* for arm64
arm64: mask out POIndex when modifying a PTE
arm64: enable ARCH_HAS_PKEYS on arm64
arm64: handle PKEY/POE faults
arm64: stop using generic mm_hooks.h
arm64: implement PKEYS support
arm64: add POE signal support
arm64: enable PKEY support for CPUs with S1POE
arm64: enable POE and PIE to coexist
kselftest/arm64: move get_header()
selftests: mm: move fpregs printing
selftests: mm: make protection_keys test work on arm64
Documentation/arch/arm64/elf_hwcaps.rst | 3 +
arch/arm64/Kconfig | 1 +
arch/arm64/include/asm/el2_setup.h | 10 +-
arch/arm64/include/asm/hwcap.h | 1 +
arch/arm64/include/asm/kvm_host.h | 4 +
arch/arm64/include/asm/mman.h | 6 +-
arch/arm64/include/asm/mmu.h | 2 +
arch/arm64/include/asm/mmu_context.h | 51 ++++++-
arch/arm64/include/asm/pgtable-hwdef.h | 10 ++
arch/arm64/include/asm/pgtable-prot.h | 8 +-
arch/arm64/include/asm/pgtable.h | 28 +++-
arch/arm64/include/asm/pkeys.h | 110 ++++++++++++++
arch/arm64/include/asm/por.h | 33 +++++
arch/arm64/include/asm/processor.h | 1 +
arch/arm64/include/asm/sysreg.h | 16 ++
arch/arm64/include/asm/traps.h | 1 +
arch/arm64/include/uapi/asm/hwcap.h | 1 +
arch/arm64/include/uapi/asm/sigcontext.h | 7 +
arch/arm64/kernel/cpufeature.c | 15 ++
arch/arm64/kernel/cpuinfo.c | 1 +
arch/arm64/kernel/process.c | 16 ++
arch/arm64/kernel/signal.c | 51 +++++++
arch/arm64/kernel/traps.c | 12 +-
arch/arm64/kvm/sys_regs.c | 2 +
arch/arm64/mm/fault.c | 44 +++++-
arch/arm64/mm/mmap.c | 7 +
arch/arm64/mm/mmu.c | 38 +++++
arch/arm64/tools/cpucaps | 1 +
arch/arm64/tools/sysreg | 11 +-
fs/proc/task_mmu.c | 2 +
include/linux/mm.h | 11 +-
.../arm64/signal/testcases/testcases.c | 23 ---
.../arm64/signal/testcases/testcases.h | 26 +++-
tools/testing/selftests/mm/Makefile | 2 +-
tools/testing/selftests/mm/pkey-arm64.h | 138 ++++++++++++++++++
tools/testing/selftests/mm/pkey-helpers.h | 8 +
tools/testing/selftests/mm/pkey-powerpc.h | 3 +
tools/testing/selftests/mm/pkey-x86.h | 4 +
tools/testing/selftests/mm/protection_keys.c | 29 ++--
39 files changed, 685 insertions(+), 52 deletions(-)
create mode 100644 arch/arm64/include/asm/pkeys.h
create mode 100644 arch/arm64/include/asm/por.h
create mode 100644 tools/testing/selftests/mm/pkey-arm64.h
--
2.25.1
Zero out the buffer for readlink() since readlink() does not append a
terminating null byte to the buffer.
Fixes: 833c12ce0f430 ("selftests/x86/lam: Add inherit test cases for linear-address masking")
Signed-off-by: Binbin Wu <binbin.wu(a)linux.intel.com>
---
tools/testing/selftests/x86/lam.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/testing/selftests/x86/lam.c b/tools/testing/selftests/x86/lam.c
index eb0e46905bf9..9f06942a8e25 100644
--- a/tools/testing/selftests/x86/lam.c
+++ b/tools/testing/selftests/x86/lam.c
@@ -680,7 +680,7 @@ static int handle_execve(struct testcases *test)
perror("Fork failed.");
ret = 1;
} else if (pid == 0) {
- char path[PATH_MAX];
+ char path[PATH_MAX] = {0};
/* Set LAM mode in parent process */
if (set_lam(lam) != 0)
base-commit: ce9ecca0238b140b88f43859b211c9fdfd8e5b70
--
2.25.1