August 2024 - Linux-kselftest-mirror

[PATCH v6 0/2] Add test to distinguish between thread's signal mask and ucontext_t

by Dev Jain

This patch series is motivated by the following observation: Raise a signal, jump to signal handler. The ucontext_t structure dumped by kernel to userspace has a uc_sigmask field having the mask of blocked signals. If you run a fresh minimalistic program doing this, this field is empty, even if you block some signals while registering the handler with sigaction(). Here is what the man-pages have to say: sigaction(2): "sa_mask specifies a mask of signals which should be blocked (i.e., added to the signal mask of the thread in which the signal handler is invoked) during execution of the signal handler. In addition, the signal which triggered the handler will be blocked, unless the SA_NODEFER flag is used." signal(7): Under "Execution of signal handlers", (1.3) implies: "The thread's current signal mask is accessible via the ucontext_t object that is pointed to by the third argument of the signal handler." But, (1.4) states: "Any signals specified in act->sa_mask when registering the handler with sigprocmask(2) are added to the thread's signal mask. The signal being delivered is also added to the signal mask, unless SA_NODEFER was specified when registering the handler. These signals are thus blocked while the handler executes." There clearly is no distinction being made in the man pages between "Thread's signal mask" and ucontext_t; this logically should imply that a signal blocked by populating struct sigaction should be visible in ucontext_t. Here is what the kernel code does (for Aarch64): do_signal() -> handle_signal() -> sigmask_to_save(), which returns &current->blocked, is passed to setup_rt_frame() -> setup_sigframe() -> __copy_to_user(). Hence, &current->blocked is copied to ucontext_t exposed to userspace. Returning back to handle_signal(), signal_setup_done() -> signal_delivered() -> sigorsets() and set_current_blocked() are responsible for using information from struct ksignal ksig, which was populated through the sigaction() system call in kernel/signal.c: copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa)), to update &current->blocked; hence, the set of blocked signals for the current thread is updated AFTER the kernel dumps ucontext_t to userspace. Assuming that the above is indeed the intended behaviour, because it semantically makes sense, since the signals blocked using sigaction() remain blocked only till the execution of the handler, and not in the context present before jumping to the handler (but nothing can be confirmed from the man-pages), the series introduces a test for mangling with uc_sigmask. I will send a separate series to fix the man-pages. The proposed selftest has been tested out on Aarch32, Aarch64 and x86_64. v5->v6: - Drop renaming of sas.c - Include the explanation from the cover letter in the changelog for the second patch v4->v5: - Remove a redundant print statement v3->v4: - Allocate sigsets as automatic variables to avoid malloc() v2->v3: - ucontext describes current state -> ucontext describes interrupted context - Add a comment for blockage of USR2 even after return from handler - Describe blockage of signals in a better way v1->v2: - Replace all occurrences of SIGPIPE with SIGSEGV - Fixed a mismatch between code comment and ksft log - Add a testcase: Raise the same signal again; it must not be queued - Remove unneeded <assert.h>, <unistd.h> - Give a detailed test description in the comments; also describe the exact meaning of delivered and blocked - Handle errors for all libc functions/syscalls - Mention tests in Makefile and .gitignore in alphabetical order v1: - https://lore.kernel.org/all/20240607122319.768640-1-dev.jain@arm.com/ Dev Jain (2): selftests: Rename sigaltstack to generic signal selftests: Add a test mangling with uc_sigmask tools/testing/selftests/Makefile | 2 +- .../{sigaltstack => signal}/.gitignore | 1 + .../{sigaltstack => signal}/Makefile | 3 +- .../current_stack_pointer.h | 0 .../selftests/signal/mangle_uc_sigmask.c | 184 ++++++++++++++++++ .../selftests/{sigaltstack => signal}/sas.c | 0 6 files changed, 188 insertions(+), 2 deletions(-) rename tools/testing/selftests/{sigaltstack => signal}/.gitignore (70%) rename tools/testing/selftests/{sigaltstack => signal}/Makefile (56%) rename tools/testing/selftests/{sigaltstack => signal}/current_stack_pointer.h (100%) create mode 100644 tools/testing/selftests/signal/mangle_uc_sigmask.c rename tools/testing/selftests/{sigaltstack => signal}/sas.c (100%) -- 2.30.2

11 months, 2 weeks

3
16
0 0

[PATCH v5 0/3] tracing: Support poll on event hist file

by Masami Hiramatsu (Google)

Hi, Here is the v5 patch to support polling on event 'hist' file. The previous version is here; https://lore.kernel.org/all/172377544331.67914.7474878424159759789.stgit@de… This version just update the comment in poll.c and add Shuah's Reviewed-by. Background ---------- There has been interest in allowing user programs to monitor kernel events in real time. Ftrace provides `trace_pipe` interface to wait on events in the ring buffer, but it is needed to wait until filling up a page with events in the ring buffer. We can also peek the `trace` file periodically, but that is inefficient way to monitor a randomely happening event. Overview -------- This patch set allows user to `poll`(or `select`, `epoll`) on event histogram interface. As you know each event has its own `hist` file which shows histograms generated by trigger action. So user can set a new hist trigger on any event you want to monitor, and poll on the `hist` file until it is updated. There are 2 poll events are supported, POLLIN and POLLPRI. POLLIN means that there are any readable update on `hist` file and this event will be flashed only when you call read(). So, this is useful if you want to read the histogram periodically. The other POLLPRI event is for monitoring trace event. Like the POLLIN, this will be returned when the histogram is updated, but you don't need to read() the file and use poll() again. Note that this waits for histogram update (not event arrival), thus you must set a histogram on the event at first. Usage ----- Here is an example usage: ---- TRACEFS=/sys/kernel/tracing EVENT=$TRACEFS/events/sched/sched_process_free # setup histogram trigger and enable event echo "hist:key=comm" >> $EVENT/trigger echo 1 > $EVENT/enable # Wait for update poll pri $EVENT/hist # Event arrived. echo "process free event is comming" tail $TRACEFS/trace ---- The 'poll' command is in the selftest patch. You can take this series also from here; https://git.kernel.org/pub/scm/linux/kernel/git/mhiramat/linux.git/log/?h=t… Thank you, --- Masami Hiramatsu (Google) (3): tracing/hist: Add poll(POLLIN) support on hist file tracing/hist: Support POLLPRI event for poll on histogram selftests/tracing: Add hist poll() support test include/linux/trace_events.h | 5 + kernel/trace/trace_events.c | 18 ++++ kernel/trace/trace_events_hist.c | 101 +++++++++++++++++++- tools/testing/selftests/ftrace/Makefile | 2 tools/testing/selftests/ftrace/poll.c | 74 +++++++++++++++ .../ftrace/test.d/trigger/trigger-hist-poll.tc | 74 +++++++++++++++ 6 files changed, 271 insertions(+), 3 deletions(-) create mode 100644 tools/testing/selftests/ftrace/poll.c create mode 100644 tools/testing/selftests/ftrace/test.d/trigger/trigger-hist-poll.tc -- Masami Hiramatsu (Google) <mhiramat(a)kernel.org>

11 months, 2 weeks

2
4
0 0

[PATCH RFT v9 0/8] fork: Support shadow stacks in clone3()

by Mark Brown

The kernel has recently added support for shadow stacks, currently x86 only using their CET feature but both arm64 and RISC-V have equivalent features (GCS and Zicfiss respectively), I am actively working on GCS[1]. With shadow stacks the hardware maintains an additional stack containing only the return addresses for branch instructions which is not generally writeable by userspace and ensures that any returns are to the recorded addresses. This provides some protection against ROP attacks and making it easier to collect call stacks. These shadow stacks are allocated in the address space of the userspace process. Our API for shadow stacks does not currently offer userspace any flexiblity for managing the allocation of shadow stacks for newly created threads, instead the kernel allocates a new shadow stack with the same size as the normal stack whenever a thread is created with the feature enabled. The stacks allocated in this way are freed by the kernel when the thread exits or shadow stacks are disabled for the thread. This lack of flexibility and control isn't ideal, in the vast majority of cases the shadow stack will be over allocated and the implicit allocation and deallocation is not consistent with other interfaces. As far as I can tell the interface is done in this manner mainly because the shadow stack patches were in development since before clone3() was implemented. Since clone3() is readily extensible let's add support for specifying a shadow stack when creating a new thread or process in a similar manner to how the normal stack is specified, keeping the current implicit allocation behaviour if one is not specified either with clone3() or through the use of clone(). The user must provide a shadow stack address and size, this must point to memory mapped for use as a shadow stackby map_shadow_stack() with a shadow stack token at the top of the stack. Please note that the x86 portions of this code are build tested only, I don't appear to have a system that can run CET avaible to me, I have done testing with an integration into my pending work for GCS. There is some possibility that the arm64 implementation may require the use of clone3() and explicit userspace allocation of shadow stacks, this is still under discussion. Please further note that the token consumption done by clone3() is not currently implemented in an atomic fashion, Rick indicated that he would look into fixing this if people are OK with the implementation. A new architecture feature Kconfig option for shadow stacks is added as here, this was suggested as part of the review comments for the arm64 GCS series and since we need to detect if shadow stacks are supported it seemed sensible to roll it in here. [1] https://lore.kernel.org/r/20231009-arm64-gcs-v6-0-78e55deaa4dd@kernel.org/ Signed-off-by: Mark Brown <broonie(a)kernel.org> --- Changes in v9: - Pull token validation earlier and report problems with an error return to parent rather than signal delivery to the child. - Verify that the top of the supplied shadow stack is VM_SHADOW_STACK. - Rework token validation to only do the page mapping once. - Drop no longer needed support for testing for signals in selftest. - Fix typo in comments. - Link to v8: https://lore.kernel.org/r/20240808-clone3-shadow-stack-v8-0-0acf37caf14c@ke… Changes in v8: - Fix token verification with user specified shadow stack. - Don't track user managed shadow stacks for child processes. - Link to v7: https://lore.kernel.org/r/20240731-clone3-shadow-stack-v7-0-a9532eebfb1d@ke… Changes in v7: - Rebase onto v6.11-rc1. - Typo fixes. - Link to v6: https://lore.kernel.org/r/20240623-clone3-shadow-stack-v6-0-9ee7783b1fb9@ke… Changes in v6: - Rebase onto v6.10-rc3. - Ensure we don't try to free the parent shadow stack in error paths of x86 arch code. - Spelling fixes in userspace API document. - Additional cleanups and improvements to the clone3() tests to support the shadow stack tests. - Link to v5: https://lore.kernel.org/r/20240203-clone3-shadow-stack-v5-0-322c69598e4b@ke… Changes in v5: - Rebase onto v6.8-rc2. - Rework ABI to have the user allocate the shadow stack memory with map_shadow_stack() and a token. - Force inlining of the x86 shadow stack enablement. - Move shadow stack enablement out into a shared header for reuse by other tests. - Link to v4: https://lore.kernel.org/r/20231128-clone3-shadow-stack-v4-0-8b28ffe4f676@ke… Changes in v4: - Formatting changes. - Use a define for minimum shadow stack size and move some basic validation to fork.c. - Link to v3: https://lore.kernel.org/r/20231120-clone3-shadow-stack-v3-0-a7b8ed3e2acc@ke… Changes in v3: - Rebase onto v6.7-rc2. - Remove stale shadow_stack in internal kargs. - If a shadow stack is specified unconditionally use it regardless of CLONE_ parameters. - Force enable shadow stacks in the selftest. - Update changelogs for RISC-V feature rename. - Link to v2: https://lore.kernel.org/r/20231114-clone3-shadow-stack-v2-0-b613f8681155@ke… Changes in v2: - Rebase onto v6.7-rc1. - Remove ability to provide preallocated shadow stack, just specify the desired size. - Link to v1: https://lore.kernel.org/r/20231023-clone3-shadow-stack-v1-0-d867d0b5d4d0@ke… --- Mark Brown (8): Documentation: userspace-api: Add shadow stack API documentation selftests: Provide helper header for shadow stack testing mm: Introduce ARCH_HAS_USER_SHADOW_STACK fork: Add shadow stack support to clone3() selftests/clone3: Remove redundant flushes of output streams selftests/clone3: Factor more of main loop into test_clone3() selftests/clone3: Allow tests to flag if -E2BIG is a valid error code selftests/clone3: Test shadow stack support Documentation/userspace-api/index.rst | 1 + Documentation/userspace-api/shadow_stack.rst | 41 ++++ arch/x86/Kconfig | 1 + arch/x86/include/asm/shstk.h | 11 +- arch/x86/kernel/process.c | 2 +- arch/x86/kernel/shstk.c | 103 +++++++--- fs/proc/task_mmu.c | 2 +- include/linux/mm.h | 2 +- include/linux/sched/task.h | 18 ++ include/uapi/linux/sched.h | 13 +- kernel/fork.c | 114 +++++++++-- mm/Kconfig | 6 + tools/testing/selftests/clone3/clone3.c | 230 ++++++++++++++++++---- tools/testing/selftests/clone3/clone3_selftests.h | 40 +++- tools/testing/selftests/ksft_shstk.h | 63 ++++++ 15 files changed, 560 insertions(+), 87 deletions(-) --- base-commit: 8400291e289ee6b2bf9779ff1c83a291501f017b change-id: 20231019-clone3-shadow-stack-15d40d2bf536 Best regards, -- Mark Brown <broonie(a)kernel.org>

11 months, 2 weeks

5
27
0 0

[PATCH v3] kselftest/devices/probe: Fix SyntaxWarning in regex strings for Python3

by Alessandro Zanni

Insert raw strings to prevent Python3 from interpreting string literals as Unicode strings and "\d" as invalid escaped sequence. Fix the warnings: tools/testing/selftests/devices/probe/test_discoverable_devices.py:48: SyntaxWarning: invalid escape sequence '\d' usb_controller_sysfs_dir = "usb[\d]+" tools/testing/selftests/devices/probe/test_discoverable_devices.py: 94: SyntaxWarning: invalid escape sequence '\d' re_usb_version = re.compile("PRODUCT=.*/(\d)/.*") Fixes: dacf1d7a78bf ("kselftest: Add test to verify probe of devices from discoverable buses") Reviewed-by: Nícolas F. R. A. Prado <nfraprado(a)collabora.com> Signed-off-by: Alessandro Zanni <alessandro.zanni87(a)gmail.com> --- Notes: v3: Reduce changelog lines lengthy, add warning messages v2: Imperative mode description, add previous commit tag fix .../selftests/devices/probe/test_discoverable_devices.py | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/devices/probe/test_discoverable_devices.py b/tools/testing/selftests/devices/probe/test_discoverable_devices.py index d94a74b8a054..d7a2bb91c807 100755 --- a/tools/testing/selftests/devices/probe/test_discoverable_devices.py +++ b/tools/testing/selftests/devices/probe/test_discoverable_devices.py @@ -45,7 +45,7 @@ def find_pci_controller_dirs(): def find_usb_controller_dirs(): - usb_controller_sysfs_dir = "usb[\d]+" + usb_controller_sysfs_dir = r"usb[\d]+" dir_regex = re.compile(usb_controller_sysfs_dir) for d in os.scandir(sysfs_usb_devices): @@ -91,7 +91,7 @@ def get_acpi_uid(sysfs_dev_dir): def get_usb_version(sysfs_dev_dir): - re_usb_version = re.compile("PRODUCT=.*/(\d)/.*") + re_usb_version = re.compile(r"PRODUCT=.*/(\d)/.*") with open(os.path.join(sysfs_dev_dir, "uevent")) as f: return int(re_usb_version.search(f.read()).group(1)) -- 2.43.0

11 months, 2 weeks

2
2
0 0

[PATCH] Improve timer_create failure message

by Gianfranco Trad

Improve timer_create failure message to give more information to the user. Signed-off-by: Gianfranco Trad <gianf.trad(a)gmail.com> --- tools/testing/selftests/timers/alarmtimer-suspend.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/timers/alarmtimer-suspend.c b/tools/testing/selftests/timers/alarmtimer-suspend.c index ad52e608b88e..74acdb87d4f4 100644 --- a/tools/testing/selftests/timers/alarmtimer-suspend.c +++ b/tools/testing/selftests/timers/alarmtimer-suspend.c @@ -28,6 +28,7 @@ #include <signal.h> #include <stdlib.h> #include <pthread.h> +#include <errno.h> #include "../kselftest.h" #define CLOCK_REALTIME 0 @@ -142,8 +143,8 @@ int main(void) alarmcount = 0; if (timer_create(alarm_clock_id, &se, &tm1) == -1) { - printf("timer_create failed, %s unsupported?\n", - clockstring(alarm_clock_id)); + printf("timer_create failed, %s unsupported?: %s\n", + clockstring(alarm_clock_id), strerror(errno)); break; } -- 2.43.0

11 months, 3 weeks

4
5
0 0

[PATCH v2 00/25] Enable FRED with KVM VMX

by Xin Li

This patch set enables the Intel flexible return and event delivery (FRED) architecture with KVM VMX to allow guests to utilize FRED. The FRED architecture defines simple new transitions that change privilege level (ring transitions). The FRED architecture was designed with the following goals: 1) Improve overall performance and response time by replacing event delivery through the interrupt descriptor table (IDT event delivery) and event return by the IRET instruction with lower latency transitions. 2) Improve software robustness by ensuring that event delivery establishes the full supervisor context and that event return establishes the full user context. The new transitions defined by the FRED architecture are FRED event delivery and, for returning from events, two FRED return instructions. FRED event delivery can effect a transition from ring 3 to ring 0, but it is used also to deliver events incident to ring 0. One FRED instruction (ERETU) effects a return from ring 0 to ring 3, while the other (ERETS) returns while remaining in ring 0. Collectively, FRED event delivery and the FRED return instructions are FRED transitions. Intel VMX architecture is extended to run FRED guests, and the major changes are: 1) New VMCS fields for FRED context management, which includes two new event data VMCS fields, eight new guest FRED context VMCS fields and eight new host FRED context VMCS fields. 2) VMX nested-exception support for proper virtualization of stack levels introduced with FRED architecture. Search for the latest FRED spec in most search engines with this search pattern: site:intel.com FRED (flexible return and event delivery) specification As the native FRED patches are committed in the tip tree "x86/fred" branch: https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/log/?h=x86/fred, and we have received a good amount of review comments for v1, it's time to send out v2 based on this branch for further help from the community. Patch 1-2 are cleanups to VMX basic and misc MSRs, which were sent out earlier as a preparation for FRED changes: https://lore.kernel.org/kvm/20240206182032.1596-1-xin3.li@intel.com/T/#u Patch 3-15 add FRED support to VMX. Patch 16-21 add FRED support to nested VMX. Patch 22 exposes FRED and its baseline features to KVM guests. Patch 23-25 add FRED selftests. There is also a counterpart qemu patch set for FRED at: https://lore.kernel.org/qemu-devel/20231109072012.8078-1-xin3.li@intel.com/…, which works with this patch set to allow KVM to run FRED guests. Changes since v1: * Always load the secondary VM exit controls (Sean Christopherson). * Remove FRED VM entry/exit controls consistency checks in setup_vmcs_config() (Sean Christopherson). * Clear FRED VM entry/exit controls if FRED is not enumerated (Chao Gao). * Use guest_can_use() to trace FRED enumeration in a vcpu (Chao Gao). * Enable FRED MSRs intercept if FRED is no longer enumerated in CPUID (Chao Gao). * Move guest FRED states init into __vmx_vcpu_reset() (Chao Gao). * Don't use guest_cpuid_has() in vmx_prepare_switch_to_{host,guest}(), which are called from IRQ-disabled context (Chao Gao). * Reset msr_guest_fred_rsp0 in __vmx_vcpu_reset() (Chao Gao). * Fail host requested FRED MSRs access if KVM cannot virtualize FRED (Chao Gao). * Handle the case FRED MSRs are valid but KVM cannot virtualize FRED (Chao Gao). * Add sanity checks when writing to FRED MSRs. * Explain why it is ok to only check CR4.FRED in kvm_is_fred_enabled() (Chao Gao). * Document event data should be equal to CR2/DR6/IA32_XFD_ERR instead of using WARN_ON() (Chao Gao). * Zero event data if a #NM was not caused by extended feature disable (Chao Gao). * Set the nested flag when there is an original interrupt (Chao Gao). * Dump guest FRED states only if guest has FRED enabled (Nikolay Borisov). * Add a prerequisite to SHADOW_FIELD_R[OW] macros * Remove hyperv TLFS related changes (Jeremi Piotrowski). * Use kvm_cpu_cap_has() instead of cpu_feature_enabled() to decouple KVM's capability to virtualize a feature and host's enabling of a feature (Chao Gao). Xin Li (25): KVM: VMX: Cleanup VMX basic information defines and usages KVM: VMX: Cleanup VMX misc information defines and usages KVM: VMX: Add support for the secondary VM exit controls KVM: x86: Mark CR4.FRED as not reserved KVM: VMX: Initialize FRED VM entry/exit controls in vmcs_config KVM: VMX: Defer enabling FRED MSRs save/load until after set CPUID KVM: VMX: Set intercept for FRED MSRs KVM: VMX: Initialize VMCS FRED fields KVM: VMX: Switch FRED RSP0 between host and guest KVM: VMX: Add support for FRED context save/restore KVM: x86: Add kvm_is_fred_enabled() KVM: VMX: Handle FRED event data KVM: VMX: Handle VMX nested exception for FRED KVM: VMX: Disable FRED if FRED consistency checks fail KVM: VMX: Dump FRED context in dump_vmcs() KVM: VMX: Invoke vmx_set_cpu_caps() before nested setup KVM: nVMX: Add support for the secondary VM exit controls KVM: nVMX: Add a prerequisite to SHADOW_FIELD_R[OW] macros KVM: nVMX: Add FRED VMCS fields KVM: nVMX: Add support for VMX FRED controls KVM: nVMX: Add VMCS FRED states checking KVM: x86: Allow FRED/LKGS/WRMSRNS to be exposed to guests KVM: selftests: Run debug_regs test with FRED enabled KVM: selftests: Add a new VM guest mode to run user level code KVM: selftests: Add fred exception tests Documentation/virt/kvm/x86/nested-vmx.rst | 19 + arch/x86/include/asm/kvm_host.h | 8 +- arch/x86/include/asm/msr-index.h | 15 +- arch/x86/include/asm/vmx.h | 59 ++- arch/x86/kvm/cpuid.c | 4 +- arch/x86/kvm/governed_features.h | 1 + arch/x86/kvm/kvm_cache_regs.h | 17 + arch/x86/kvm/svm/svm.c | 4 +- arch/x86/kvm/vmx/capabilities.h | 30 +- arch/x86/kvm/vmx/nested.c | 329 ++++++++++++--- arch/x86/kvm/vmx/nested.h | 2 +- arch/x86/kvm/vmx/vmcs.h | 1 + arch/x86/kvm/vmx/vmcs12.c | 19 + arch/x86/kvm/vmx/vmcs12.h | 38 ++ arch/x86/kvm/vmx/vmcs_shadow_fields.h | 80 ++-- arch/x86/kvm/vmx/vmx.c | 385 +++++++++++++++--- arch/x86/kvm/vmx/vmx.h | 15 +- arch/x86/kvm/x86.c | 103 ++++- arch/x86/kvm/x86.h | 5 +- tools/testing/selftests/kvm/Makefile | 1 + .../selftests/kvm/include/kvm_util_base.h | 1 + .../selftests/kvm/include/x86_64/processor.h | 36 ++ tools/testing/selftests/kvm/lib/kvm_util.c | 5 +- .../selftests/kvm/lib/x86_64/processor.c | 15 +- tools/testing/selftests/kvm/lib/x86_64/vmx.c | 4 +- .../testing/selftests/kvm/x86_64/debug_regs.c | 50 ++- .../testing/selftests/kvm/x86_64/fred_test.c | 297 ++++++++++++++ 27 files changed, 1320 insertions(+), 223 deletions(-) create mode 100644 tools/testing/selftests/kvm/x86_64/fred_test.c base-commit: e13841907b8fda0ae0ce1ec03684665f578416a8 -- 2.43.0

11 months, 3 weeks

8
93
0 0

[PATCH v3 0/5] KVM: s390: selftests: Add regression tests for CPU subfunctions

by Hariharan Mari

This patch series introduces a set of regression tests for various s390x CPU subfunctions in KVM. The tests ensure that the KVM implementation accurately reflects the behavior of actual CPU instructions for these subfunctions. The series adds tests for a total of 15 instructions across five patches, covering a range of operations including sorting, compression, and various cryptographic functions. Each patch follows a consistent testing pattern: 1. Obtain the KVM_S390_VM_CPU_MACHINE_SUBFUNC attribute for the VM. 2. Execute the relevant asm instructions. 3. Compare KVM-reported results with direct instruction execution results. Testing has been performed on s390x hardware with KVM support. All tests pass successfully, verifying the correct implementation of these subfunctions in KVM. --- v2: * Fix facility_bit type from bool to int v3: * Global variable in the header is moved to facility.c file in selftests/kvm/lib/s390x/ * Fixed the line length * Fixed single line comments and multiline comments * Renamed the PLO macro * Removed the unnecessary type cast where Implicit type promotion applies --- Hariharan Mari (5): KVM: s390: selftests: Add regression tests for SORTL and DFLTCC CPU subfunctions KVM: s390: selftests: Add regression tests for PRNO, KDSA and KMA crypto subfunctions KVM: s390: selftests: Add regression tests for KMCTR, KMF, KMO and PCC crypto subfunctions KVM: s390: selftests: Add regression tests for KMAC, KMC, KM, KIMD and KLMD crypto subfunctions KVM: s390: selftests: Add regression tests for PLO subfunctions tools/testing/selftests/kvm/Makefile | 2 + .../selftests/kvm/include/s390x/facility.h | 50 +++ .../selftests/kvm/lib/s390x/facility.c | 14 + .../kvm/s390x/cpumodel_subfuncs_test.c | 286 ++++++++++++++++++ 4 files changed, 352 insertions(+) create mode 100644 tools/testing/selftests/kvm/include/s390x/facility.h create mode 100644 tools/testing/selftests/kvm/lib/s390x/facility.c create mode 100644 tools/testing/selftests/kvm/s390x/cpumodel_subfuncs_test.c -- 2.45.2

11 months, 4 weeks

3
8
0 0

[RFC PATCH v1 0/4] Add support for the Bus Lock Threshold

by Manali Shukla

Malicious guests can cause bus locks to degrade the performance of a system. Non-WB (write-back) and misaligned locked RMW (read-modify-write) instructions are referred to as "bus locks" and require system wide synchronization among all processors to guarantee the atomicity. The bus locks can impose notable performance penalties for all processors within the system. Support for the Bus Lock Threshold is indicated by CPUID Fn8000_000A_EDX[29] BusLockThreshold=1, the VMCB provides a Bus Lock Threshold enable bit and an unsigned 16-bit Bus Lock Threshold count. VMCB intercept bit VMCB Offset Bits Function 14h 5 Intercept bus lock operations Bus lock threshold count VMCB Offset Bits Function 120h 15:0 Bus lock counter During VMRUN, the bus lock threshold count is fetched and stored in an internal count register. Prior to executing a bus lock within the guest, the processor verifies the count in the bus lock register. If the count is greater than zero, the processor executes the bus lock, reducing the count. However, if the count is zero, the bus lock operation is not performed, and instead, a Bus Lock Threshold #VMEXIT is triggered to transfer control to the Virtual Machine Monitor (VMM). A Bus Lock Threshold #VMEXIT is reported to the VMM with VMEXIT code 0xA5h, VMEXIT_BUSLOCK. EXITINFO1 and EXITINFO2 are set to 0 on a VMEXIT_BUSLOCK. On a #VMEXIT, the processor writes the current value of the Bus Lock Threshold Counter to the VMCB. More details about the Bus Lock Threshold feature can be found in AMD APM [1]. Patches are prepared on kvm-x86/svm (704ec48fc2fb) Testing done: - Added a selftest for the Bus Lock Threadshold functionality. - Tested the Bus Lock Threshold functionality on SEV and SEV-ES guests. - Tested the Bus Lock Threshold functionality on nested guests. Qemu changes can be found on: Repo: https://github.com/AMDESE/qemu.git Branch: buslock_threshold Qemu commandline to use the bus lock threshold functionality: qemu-system-x86_64 -enable-kvm -cpu EPYC-Turin,+svm -M q35,bus-lock-ratelimit=10 \ .. [1]: AMD64 Architecture Programmer's Manual Pub. 24593, April 2024, Vol 2, 15.14.5 Bus Lock Threshold. https://bugzilla.kernel.org/attachment.cgi?id=306250 Manali Shukla (2): x86/cpufeatures: Add CPUID feature bit for the Bus Lock Threshold KVM: x86: nSVM: Implement support for nested Bus Lock Threshold Nikunj A Dadhania (2): KVM: SVM: Enable Bus lock threshold exit KVM: selftests: Add bus lock exit test arch/x86/include/asm/cpufeatures.h | 1 + arch/x86/include/asm/svm.h | 5 +- arch/x86/include/uapi/asm/svm.h | 2 + arch/x86/kvm/governed_features.h | 1 + arch/x86/kvm/svm/nested.c | 25 ++++ arch/x86/kvm/svm/svm.c | 48 ++++++++ arch/x86/kvm/svm/svm.h | 1 + arch/x86/kvm/x86.h | 1 + tools/testing/selftests/kvm/Makefile | 1 + .../selftests/kvm/x86_64/svm_buslock_test.c | 114 ++++++++++++++++++ 10 files changed, 198 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/kvm/x86_64/svm_buslock_test.c base-commit: 704ec48fc2fbd4e41ec982662ad5bf1eee33eeb2 -- 2.34.1

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[PATCH v4 0/2] selftests/resctrl: SNC kernel support discovery

by Maciej Wieczor-Retman

Changes v4: - Printing SNC warnings at the start of every test. - Printing SNC warnings at the end of every relevant test. - Remove global snc_mode variable, consolidate snc detection functions into one. - Correct minor mistakes. Changes v3: - Reworked patch 2. - Changed minor things in patch 1 like function name and made corrections to the patch message. Changes v2: - Removed patches 2 and 3 since now this part will be supported by the kernel. Sub-Numa Clustering (SNC) allows splitting CPU cores, caches and memory into multiple NUMA nodes. When enabled, NUMA-aware applications can achieve better performance on bigger server platforms. SNC support in the kernel was merged into x86/cache [1]. With SNC enabled and kernel support in place all the tests will function normally (aside from effective cache size). There might be a problem when SNC is enabled but the system is still using an older kernel version without SNC support. Currently the only message displayed in that situation is a guess that SNC might be enabled and is causing issues. That message also is displayed whenever the test fails on an Intel platform. Add a mechanism to discover kernel support for SNC which will add more meaning and certainty to the error message. Add runtime SNC mode detection and verify how reliable that information is. Series was tested on Ice Lake server platforms with SNC disabled, SNC-2 and SNC-4. The tests were also ran with and without kernel support for SNC. Series applies cleanly on kselftest/next. [1] https://lore.kernel.org/all/20240628215619.76401-1-tony.luck@intel.com/ Previous versions of this series: [v1] https://lore.kernel.org/all/cover.1709721159.git.maciej.wieczor-retman@inte… [v2] https://lore.kernel.org/all/cover.1715769576.git.maciej.wieczor-retman@inte… [v3] https://lore.kernel.org/all/cover.1719842207.git.maciej.wieczor-retman@inte… Maciej Wieczor-Retman (2): selftests/resctrl: Adjust effective L3 cache size with SNC enabled selftests/resctrl: Adjust SNC support messages tools/testing/selftests/resctrl/cat_test.c | 8 ++ tools/testing/selftests/resctrl/cmt_test.c | 10 +- tools/testing/selftests/resctrl/mba_test.c | 7 + tools/testing/selftests/resctrl/mbm_test.c | 9 +- tools/testing/selftests/resctrl/resctrl.h | 7 + .../testing/selftests/resctrl/resctrl_tests.c | 8 +- tools/testing/selftests/resctrl/resctrlfs.c | 130 ++++++++++++++++++ 7 files changed, 174 insertions(+), 5 deletions(-) -- 2.45.2

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[PATCH] selftests: riscv: Allow mmap test to compile on 32-bit

by Charlie Jenkins

Macros needed for 32-bit compilations were hidden behind 64-bit riscv ifdefs. Fix the 32-bit compilations by moving macros to allow the memory_layout test to run on 32-bit. Signed-off-by: Charlie Jenkins <charlie(a)rivosinc.com> Fixes: 73d05262a2ca ("selftests: riscv: Generalize mm selftests") --- tools/testing/selftests/riscv/mm/mmap_test.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/riscv/mm/mmap_test.h b/tools/testing/selftests/riscv/mm/mmap_test.h index 3b29ca3bb3d4..1c3313c201d5 100644 --- a/tools/testing/selftests/riscv/mm/mmap_test.h +++ b/tools/testing/selftests/riscv/mm/mmap_test.h @@ -48,11 +48,11 @@ uint32_t random_addresses[] = { }; #endif -// Only works on 64 bit -#if __riscv_xlen == 64 #define PROT (PROT_READ | PROT_WRITE) #define FLAGS (MAP_PRIVATE | MAP_ANONYMOUS) +// Only works on 64 bit +#if __riscv_xlen == 64 /* mmap must return a value that doesn't use more bits than the hint address. */ static inline unsigned long get_max_value(unsigned long input) { @@ -80,6 +80,8 @@ static inline unsigned long get_max_value(unsigned long input) }) #endif /* __riscv_xlen == 64 */ +#define TEST_MMAPS do { } while (0) + static inline int memory_layout(void) { void *value1 = mmap(NULL, sizeof(int), PROT, FLAGS, 0, 0); --- base-commit: 8400291e289ee6b2bf9779ff1c83a291501f017b change-id: 20240807-mmap_tests__fixes-651cc2b5fead -- - Charlie

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Linux-kselftest-mirror August 2024