March 2023 - Linux-kselftest-mirror

[KTAP V2 PATCH] ktap_v2: add skip test result

by Rae Moar

Add the test result "skip" to KTAP version 2 as an alternative way to indicate a test was skipped. The current spec uses the "#SKIP" directive to indicate that a test was skipped. However, the "#SKIP" directive is not always evident when quickly skimming through KTAP results. The "skip" result would provide an alternative that could make it clearer that a test has not successfully passed because it was skipped. Before: KTAP version 1 1..1 KTAP version 1 1..2 ok 1 case_1 ok 2 case_2 #SKIP ok 1 suite After: KTAP version 2 1..1 KTAP version 2 1..2 ok 1 case_1 skip 2 case_2 ok 1 suite Here is a link to a version of the KUnit parser that is able to parse the skip test result for KTAP version 2. Note this parser is still able to parse the "#SKIP" directive. Link: https://kunit-review.googlesource.com/c/linux/+/5689 Signed-off-by: Rae Moar <rmoar(a)google.com> --- Note: this patch is based on Frank's ktap_spec_version_2 branch. Documentation/dev-tools/ktap.rst | 27 ++++++++++++++++++--------- 1 file changed, 18 insertions(+), 9 deletions(-) diff --git a/Documentation/dev-tools/ktap.rst b/Documentation/dev-tools/ktap.rst index ff77f4aaa6ef..f48aa00db8f0 100644 --- a/Documentation/dev-tools/ktap.rst +++ b/Documentation/dev-tools/ktap.rst @@ -74,7 +74,8 @@ They are required and must have the format: <result> <number> [<description>][ # [<directive>] [<diagnostic data>]] The result can be either "ok", which indicates the test case passed, -or "not ok", which indicates that the test case failed. +"not ok", which indicates that the test case failed, or "skip", which indicates +the test case did not run. <number> represents the number of the test being performed. The first test must have the number 1 and the number then must increase by 1 for each additional @@ -91,12 +92,13 @@ A directive is a keyword that indicates a different outcome for a test other than passed and failed. The directive is optional, and consists of a single keyword preceding the diagnostic data. In the event that a parser encounters a directive it doesn't support, it should fall back to the "ok" / "not ok" -result. +/ "skip" result. Currently accepted directives are: -- "SKIP", which indicates a test was skipped (note the result of the test case - result line can be either "ok" or "not ok" if the SKIP directive is used) +- "SKIP", which indicates a test was skipped (note this is an alternative to + the "skip" result type and if the SKIP directive is used, the + result can be any type - "ok", "not ok", or "skip") - "TODO", which indicates that a test is not expected to pass at the moment, e.g. because the feature it is testing is known to be broken. While this directive is inherited from TAP, its use in the kernel is discouraged. @@ -110,7 +112,7 @@ Currently accepted directives are: The diagnostic data is a plain-text field which contains any additional details about why this result was produced. This is typically an error message for ERROR -or failed tests, or a description of missing dependencies for a SKIP result. +or failed tests, or a description of missing dependencies for a skipped test. The diagnostic data field is optional, and results which have neither a directive nor any diagnostic data do not need to include the "#" field @@ -130,11 +132,18 @@ The test "test_case_name" failed. :: - ok 1 test # SKIP necessary dependency unavailable + skip 1 test # necessary dependency unavailable -The test "test" was SKIPPED with the diagnostic message "necessary dependency +The test "test" was skipped with the diagnostic message "necessary dependency unavailable". +:: + + ok 1 test_2 # SKIP this test should not run + +The test "test_2" was skipped with the diagnostic message "this test +should not run". + :: not ok 1 test # TIMEOUT 30 seconds @@ -225,7 +234,7 @@ An example format with multiple levels of nested testing: not ok 1 test_1 ok 2 test_2 not ok 1 test_3 - ok 2 test_4 # SKIP + skip 2 test_4 not ok 1 example_test_1 ok 2 example_test_2 @@ -262,7 +271,7 @@ Example KTAP output ok 1 example_test_1 KTAP version 2 1..2 - ok 1 test_1 # SKIP test_1 skipped + skip 1 test_1 # test_1 skipped ok 2 test_2 ok 2 example_test_2 KTAP version 2 base-commit: 906f02e42adfbd5ae70d328ee71656ecb602aaf5 -- 2.40.0.rc1.284.g88254d51c5-goog

1 year, 9 months

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Re: [PATCH] selftests: cgroup: Fix exception handling in test_memcg_oom_group_score_events()

by David Vernet

On Sun, Mar 26, 2023 at 10:15:31AM +0200, Markus Elfring wrote: [...] > >> > >> Fixes: a987785dcd6c8ae2915460582aebd6481c81eb67 ("Add tests for memory.oom.group") > > > > Fixes what in the what now? > > 1. Check repetition (which can be undesirable) > > 2. Can a cg_destroy() call ever work as expected if a cg_create() call failed? Perhaps next time you can answer your own question by spending 30 seconds actually reading the code you're "fixing": int cg_destroy(const char *cgroup) { int ret; retry: ret = rmdir(cgroup); if (ret && errno == EBUSY) { cg_killall(cgroup); usleep(100); goto retry; } if (ret && errno == ENOENT) <<< that case is explicitly handled here ret = 0; return ret; }

1 year, 9 months

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[PATCH 0/5] cgroup/cpuset: Miscellaneous updates

by Waiman Long

This patch series includes miscellaneous update to the cpuset and its testing code. Patch 2 is actually a follow-up of commit 3fb906e7fabb ("cgroup/cpuset: Don't filter offline CPUs in cpuset_cpus_allowed() for top cpuset tasks"). Patches 3-4 are for handling corner cases when dealing with task_cpu_possible_mask(). Waiman Long (5): cgroup/cpuset: Skip task update if hotplug doesn't affect current cpuset cgroup/cpuset: Include offline CPUs when tasks' cpumasks in top_cpuset are updated cgroup/cpuset: Find another usable CPU if none found in current cpuset cgroup/cpuset: Add CONFIG_DEBUG_CPUSETS config for cpuset testing cgroup/cpuset: Minor updates to test_cpuset_prs.sh init/Kconfig | 5 + kernel/cgroup/cpuset.c | 155 +++++++++++++++++- .../selftests/cgroup/test_cpuset_prs.sh | 25 +-- 3 files changed, 165 insertions(+), 20 deletions(-) -- 2.31.1

1 year, 9 months

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Re: [PATCH] selftests: cgroup: Fix exception handling in test_memcg_oom_group_score_events()

by Lorenzo Stoakes

On Sat, Mar 25, 2023 at 07:30:21PM +0100, Markus Elfring wrote: > Date: Sat, 25 Mar 2023 19:11:13 +0100 > > The label “cleanup” was used to jump to another pointer check despite of > the detail in the implementation of the function > “test_memcg_oom_group_score_events” that it was determined already > that a corresponding variable contained a null pointer. This is poorly writte and confusing. Something like 'avoid unnecessary null check/cg_destroy() invocation' would be far clearer. > > 1. Thus return directly after a call of the function “cg_name” failed. > This feels superfluious. > 2. Use an additional label. This also feels superfluious. > > 3. Delete a questionable check. This seems superfluois and frankly, rude. It's not questionable, it's readable, you should try to avoid language like 'questionable' when the purpose of the check is obvious. > > > This issue was detected by using the Coccinelle software. > > Fixes: a987785dcd6c8ae2915460582aebd6481c81eb67 ("Add tests for memory.oom.group") Fixes what in the what now? This is not a bug fix, it's a 'questionable' refactoring. > Signed-off-by: Markus Elfring <elfring(a)users.sourceforge.net> > --- > tools/testing/selftests/cgroup/test_memcontrol.c | 9 ++++----- > 1 file changed, 4 insertions(+), 5 deletions(-) > > diff --git a/tools/testing/selftests/cgroup/test_memcontrol.c b/tools/testing/selftests/cgroup/test_memcontrol.c > index f4f7c0aef702..afcd1752413e 100644 > --- a/tools/testing/selftests/cgroup/test_memcontrol.c > +++ b/tools/testing/selftests/cgroup/test_memcontrol.c > @@ -1242,12 +1242,11 @@ static int test_memcg_oom_group_score_events(const char *root) > int safe_pid; > > memcg = cg_name(root, "memcg_test_0"); > - > if (!memcg) > - goto cleanup; > + return ret; > > if (cg_create(memcg)) > - goto cleanup; > + goto free_cg; > > if (cg_write(memcg, "memory.max", "50M")) > goto cleanup; > @@ -1275,8 +1274,8 @@ static int test_memcg_oom_group_score_events(const char *root) > ret = KSFT_PASS; > > cleanup: > - if (memcg) > - cg_destroy(memcg); > + cg_destroy(memcg); > +free_cg: > free(memcg); > > return ret; > -- > 2.40.0 > > I dislike this patch, it adds complexity for no discernible purpose and actively makes the code _less_ readable and in a self-test of all places (!) Not all pedantic Coccinelle results are actionable. Remember that it's humans who are reading the code. Your email client/scripting is still somehow broken, I couldn't get b4 to pull it correctly and it seems to have a duplicate message ID. You really need to take a look at that (git send-email should do this fine for example). Please try to filter the output of Coccinelle and instead of spamming thousands of pointless patches that add no value, try to choose those that do add value. My advice overall would be to just stop.

1 year, 9 months

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Running KUnit using the wrapper script

by Mark Brown

I've been trying to do some stuff with KUnit but I can't seem to find a current tree where KUnit builds. Running on Debian stable starting from a clean -next tree and running: ./tools/testing/kunit/kunit.py config ./tools/testing/kunit/kunit.py build based on Documentation/dev-tools/kunit/start.rst. However I get: [00:42:59] Configuring KUnit Kernel ... [00:42:59] Building KUnit Kernel ... Populating config with: $ make ARCH=um O=.kunit olddefconfig Building with: $ make ARCH=um O=.kunit --jobs=8 ERROR:root:In file included from /usr/include/stdlib.h:1013, from ../arch/x86/um/os-Linux/registers.c:8: /usr/include/x86_64-linux-gnu/bits/stdlib-float.h: In function ‘atof’: /usr/include/x86_64-linux-gnu/bits/stdlib-float.h:26:1: error: SSE register return with SSE disabled 26 | { | ^ make[4]: *** [../scripts/Makefile.build:252: arch/x86/um/os-Linux/registers.o] Error 1 make[3]: *** [../scripts/Makefile.build:494: arch/x86/um/os-Linux] Error 2 make[3]: *** Waiting for unfinished jobs.... In file included from /usr/include/stdlib.h:1013, from ../arch/um/drivers/fd.c:7: /usr/include/x86_64-linux-gnu/bits/stdlib-float.h: In function ‘atof’: /usr/include/x86_64-linux-gnu/bits/stdlib-float.h:26:1: error: SSE register return with SSE disabled 26 | { | ^ make[3]: *** [../scripts/Makefile.build:252: arch/um/drivers/fd.o] Error 1 make[3]: *** Waiting for unfinished jobs.... In file included from /usr/include/stdlib.h:1013, from ../arch/um/os-Linux/skas/process.c:7: /usr/include/x86_64-linux-gnu/bits/stdlib-float.h: In function ‘atof’: /usr/include/x86_64-linux-gnu/bits/stdlib-float.h:26:1: error: SSE register return with SSE disabled 26 | { | ^ make[4]: *** [../scripts/Makefile.build:252: arch/um/os-Linux/skas/process.o] Error 1 make[3]: *** [../scripts/Makefile.build:494: arch/um/os-Linux/skas] Error 2 make[2]: *** [../scripts/Makefile.build:494: arch/um/os-Linux] Error 2 make[2]: *** Waiting for unfinished jobs.... make[2]: *** [../scripts/Makefile.build:494: arch/x86/um] Error 2 make[2]: *** [../scripts/Makefile.build:494: arch/um/drivers] Error 2 In file included from /usr/include/stdlib.h:1013, from arch/um/kernel/config.c:7: /usr/include/x86_64-linux-gnu/bits/stdlib-float.h: In function ‘atof’: /usr/include/x86_64-linux-gnu/bits/stdlib-float.h:26:1: error: SSE register return with SSE disabled 26 | { | ^ make[3]: *** [../scripts/Makefile.build:252: arch/um/kernel/config.o] Error 1 make[3]: *** Waiting for unfinished jobs.... make[2]: *** [../scripts/Makefile.build:494: arch/um/kernel] Error 2 make[1]: *** [/home/broonie/git/bisect/Makefile:2028: .] Error 2 make: *** [Makefile:226: __sub-make] Error 2 [00:43:20] Elapsed time: 20.233s which isn't ideal. v6.2 is also broken, albeit differently: ERROR:root:`.exit.text' referenced in section `.uml.exitcall.exit' of arch/um/drivers/virtio_uml.o: defined in discarded section `.exit.text' of arch/um/drivers/virtio_uml.o collect2: error: ld returned 1 exit status make[2]: *** [../scripts/Makefile.vmlinux:35: vmlinux] Error 1 make[1]: *** [/home/broonie/git/linux/Makefile:1264: vmlinux] Error 2 make: *** [Makefile:242: __sub-make] Error 2 which makes bisecting a bit of an issue. The kunit-fixes, kunit and kunit-next trees in -next have the former error. Can anyone point me at a tree/config/commands that's suitable for working on KUnit at the minute?

1 year, 9 months

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[PATCH] selftests: prctl: Add new prctl test for PR_SET_VMA action

by Ivan Orlov

This patch will add the new test, which covers the prctl call with PR_SET_VMA command. The test tries to give a name to the anonymous VMA within the process memory map, and then checks the result of the operation by parsing 'maps' virtual file. Additionally, the test tries to call the prctl PR_SET_VMA command with invalid arguments, and checks the error codes for correctness. At the moment anonymous VMA naming through prctl call functionality is not covered with any tests, so I think implementing it makes sense. Signed-off-by: Ivan Orlov <ivan.orlov0322(a)gmail.com> --- tools/testing/selftests/Makefile | 1 + tools/testing/selftests/prctl/.gitignore | 1 + tools/testing/selftests/prctl/Makefile | 2 +- tools/testing/selftests/prctl/config | 1 + .../selftests/prctl/set-anon-vma-name-test.c | 104 ++++++++++++++++++ 5 files changed, 108 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/prctl/config create mode 100644 tools/testing/selftests/prctl/set-anon-vma-name-test.c diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile index 13a6837a0c6b..dc2bfeaf4da7 100644 --- a/tools/testing/selftests/Makefile +++ b/tools/testing/selftests/Makefile @@ -89,6 +89,7 @@ TARGETS += vDSO TARGETS += mm TARGETS += x86 TARGETS += zram +TARGETS += prctl #Please keep the TARGETS list alphabetically sorted # Run "make quicktest=1 run_tests" or # "make quicktest=1 kselftest" from top level Makefile diff --git a/tools/testing/selftests/prctl/.gitignore b/tools/testing/selftests/prctl/.gitignore index 91af2b631bc9..7a657b25f686 100644 --- a/tools/testing/selftests/prctl/.gitignore +++ b/tools/testing/selftests/prctl/.gitignore @@ -2,3 +2,4 @@ disable-tsc-ctxt-sw-stress-test disable-tsc-on-off-stress-test disable-tsc-test +set-anon-vma-name-test diff --git a/tools/testing/selftests/prctl/Makefile b/tools/testing/selftests/prctl/Makefile index c7923b205222..c058b81eeb41 100644 --- a/tools/testing/selftests/prctl/Makefile +++ b/tools/testing/selftests/prctl/Makefile @@ -5,7 +5,7 @@ ARCH ?= $(shell echo $(uname_M) | sed -e s/i.86/x86/ -e s/x86_64/x86/) ifeq ($(ARCH),x86) TEST_PROGS := disable-tsc-ctxt-sw-stress-test disable-tsc-on-off-stress-test \ - disable-tsc-test + disable-tsc-test set-anon-vma-name-test all: $(TEST_PROGS) include ../lib.mk diff --git a/tools/testing/selftests/prctl/config b/tools/testing/selftests/prctl/config new file mode 100644 index 000000000000..c6ed03c544e5 --- /dev/null +++ b/tools/testing/selftests/prctl/config @@ -0,0 +1 @@ +CONFIG_ANON_VMA_NAME=y diff --git a/tools/testing/selftests/prctl/set-anon-vma-name-test.c b/tools/testing/selftests/prctl/set-anon-vma-name-test.c new file mode 100644 index 000000000000..26d853c5a0c1 --- /dev/null +++ b/tools/testing/selftests/prctl/set-anon-vma-name-test.c @@ -0,0 +1,104 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * This test covers the anonymous VMA naming functionality through prctl calls + */ + +#include <errno.h> +#include <sys/prctl.h> +#include <stdio.h> +#include <stdlib.h> +#include <sys/mman.h> +#include <string.h> + +#include "../kselftest_harness.h" + +#define AREA_SIZE 1024 + +#define GOOD_NAME "goodname" +#define BAD_NAME "badname\1" + +#ifndef PR_SET_VMA +#define PR_SET_VMA 0x53564d41 +#define PR_SET_VMA_ANON_NAME 0 +#endif + + +int rename_vma(unsigned long addr, unsigned long size, char *name) +{ + int res; + + res = prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, addr, size, name); + if (res < 0) + return -errno; + return res; +} + +int was_renaming_successful(char *target_name, unsigned long ptr) +{ + FILE *maps_file; + + char line_buf[512], name[128], mode[8]; + unsigned long start_addr, end_addr, offset; + unsigned int major_id, minor_id, node_id; + + char target_buf[128]; + int res = 0, sscanf_res; + + // The entry name in maps will be in format [anon:<target_name>] + sprintf(target_buf, "[anon:%s]", target_name); + maps_file = fopen("/proc/self/maps", "r"); + if (!maps_file) { + printf("## /proc/self/maps file opening error\n"); + return 0; + } + + // Parse the maps file to find the entry we renamed + while (fgets(line_buf, sizeof(line_buf), maps_file)) { + sscanf_res = sscanf(line_buf, "%lx-%lx %7s %lx %u:%u %u %s", &start_addr, + &end_addr, mode, &offset, &major_id, + &minor_id, &node_id, name); + if (sscanf_res == EOF) { + res = 0; + printf("## EOF while parsing the maps file\n"); + break; + } + if (!strcmp(name, target_buf) && start_addr == ptr) { + res = 1; + break; + } + } + fclose(maps_file); + return res; +} + +FIXTURE(vma) { + void *ptr_anon, *ptr_not_anon; +}; + +FIXTURE_SETUP(vma) { + self->ptr_anon = mmap(NULL, AREA_SIZE, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, 0, 0); + ASSERT_NE(self->ptr_anon, NULL); + self->ptr_not_anon = mmap(NULL, AREA_SIZE, PROT_READ | PROT_WRITE, + MAP_PRIVATE, 0, 0); + ASSERT_NE(self->ptr_not_anon, NULL); +} + +FIXTURE_TEARDOWN(vma) { + munmap(self->ptr_anon, AREA_SIZE); + munmap(self->ptr_not_anon, AREA_SIZE); +} + +TEST_F(vma, renaming) { + TH_LOG("Try to rename the VMA with correct parameters"); + EXPECT_GE(rename_vma((unsigned long)self->ptr_anon, AREA_SIZE, GOOD_NAME), 0); + EXPECT_TRUE(was_renaming_successful(GOOD_NAME, (unsigned long)self->ptr_anon)); + + TH_LOG("Try to pass invalid name (with non-printable character \\1) to rename the VMA"); + EXPECT_EQ(rename_vma((unsigned long)self->ptr_anon, AREA_SIZE, BAD_NAME), -EINVAL); + + TH_LOG("Try to rename non-anonynous VMA"); + EXPECT_EQ(rename_vma((unsigned long) self->ptr_not_anon, AREA_SIZE, GOOD_NAME), -EINVAL); +} + +TEST_HARNESS_MAIN -- 2.34.1

1 year, 9 months

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[PATCH bpf-next v2 0/2] bpf: add bound tracking for BPF_MOD

by Xu Kuohai

From: Xu Kuohai <xukuohai(a)huawei.com> dst_reg is marked as unknown when BPF_MOD instruction is verified, causing the following bpf prog to be incorrectly rejected. 0: r0 = 0 1: r0 %= 1 // r0 is marked as unknown 2: r1 = 0 3: r1 += 1 4: if r1 < r0 goto pc-2 // verifier concludes the loop is unbounded 5: exit To teach verifier to accept the above prog, this series adds bound tracking for BPF_MOD. v2: - fix build warning reported by kernel test robot <lkp(a)intel.com> [0] - add two more cases and update commit message [0] https://lore.kernel.org/oe-kbuild-all/202303060036.zK05OC5M-lkp@intel.com v1: https://lore.kernel.org/bpf/20230306033119.2634976-1-xukuohai@huaweicloud.c… Xu Kuohai (2): bpf: add bound tracking for BPF_MOD selftests/bpf: check if verifier tracks dst_reg bound for BPF_MOD kernel/bpf/verifier.c | 98 ++++++- tools/testing/selftests/bpf/verifier/mod.c | 320 +++++++++++++++++++++ 2 files changed, 413 insertions(+), 5 deletions(-) create mode 100644 tools/testing/selftests/bpf/verifier/mod.c -- 2.30.2

1 year, 9 months

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[PATCH] selftests: kvm: Add 'malloc' failure check in vcpu_save_state

by Ivan Orlov

There is a 'malloc' call in vcpu_save_state function, which can be unsuccessful. This patch will add the malloc failure checking to avoid possible null dereference and give more information about test fail reasons. Signed-off-by: Ivan Orlov <ivan.orlov0322(a)gmail.com> --- tools/testing/selftests/kvm/lib/x86_64/processor.c | 1 + 1 file changed, 1 insertion(+) diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c index c39a4353ba19..827647ff3d41 100644 --- a/tools/testing/selftests/kvm/lib/x86_64/processor.c +++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c @@ -954,6 +954,7 @@ struct kvm_x86_state *vcpu_save_state(struct kvm_vcpu *vcpu) vcpu_run_complete_io(vcpu); state = malloc(sizeof(*state) + msr_list->nmsrs * sizeof(state->msrs.entries[0])); + TEST_ASSERT(state, "-ENOMEM when allocating kvm state"); vcpu_events_get(vcpu, &state->events); vcpu_mp_state_get(vcpu, &state->mp_state); -- 2.34.1

1 year, 9 months

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[PATCH v3 00/13] Overhauling amx_test

by Mingwei Zhang

In this version, I have integrated Aaron's changes to the amx_test. In addition, we also integrated one fix patch for a kernel warning due to xsave address issue. Patch 1: Fix a host FPU kernel warning due to missing XTILEDATA in xinit. Patch 2-8: Overhaul amx_test. These patches were basically from v2. Patch 9-13: Overhaul amx_test from Aaron. I modified the changelog a little bit. v2 -> v3: - integrate Aaron's 5 commits with minor changes on commit message. - Add one fix patch for a kernel warning. v2: https://lore.kernel.org/all/20230214184606.510551-1-mizhang@google.com/ Aaron Lewis (5): KVM: selftests: x86: Assert that XTILE is XSAVE-enabled KVM: selftests: x86: Assert that both XTILE{CFG,DATA} are XSAVE-enabled KVM: selftests: x86: Remove redundant check that XSAVE is supported KVM: selftests: x86: Check that the palette table exists before using it KVM: selftests: x86: Check that XTILEDATA supports XFD Mingwei Zhang (8): x86/fpu/xstate: Avoid getting xstate address of init_fpstate if fpstate contains the component KVM: selftests: x86: Add a working xstate data structure KVM: selftests: x86: Fix an error in comment of amx_test KVM: selftests: x86: Add check of CR0.TS in the #NM handler in amx_test KVM: selftests: x86: Add the XFD check to IA32_XFD in #NM handler KVM: selftests: x86: Fix the checks to XFD_ERR using and operation KVM: selftests: x86: Enable checking on xcomp_bv in amx_test KVM: selftests: x86: Repeat the checking of xheader when IA32_XFD[XTILEDATA] is set in amx_test arch/x86/kernel/fpu/xstate.c | 10 ++- .../selftests/kvm/include/x86_64/processor.h | 14 ++++ tools/testing/selftests/kvm/x86_64/amx_test.c | 80 +++++++++---------- 3 files changed, 59 insertions(+), 45 deletions(-) -- 2.39.2.637.g21b0678d19-goog

1 year, 9 months

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[PATCH v2 1/1] KVM: selftests: Adjust VM's initial stack address to align with SysV ABI spec

by Ackerley Tng

Align the guest stack to match calling sequence requirements in section "The Stack Frame" of the System V ABI AMD64 Architecture Processor Supplement, which requires the value (%rsp + 8), NOT %rsp, to be a multiple of 16 when control is transferred to the function entry point. I.e. in a normal function call, %rsp needs to be 16-byte aligned _before_ CALL, not after. This fixes unexpected #GPs in guest code when the compiler uses SSE instructions, e.g. to initialize memory, as many SSE instructions require memory operands (including those on the stack) to be 16-byte-aligned. Signed-off-by: Ackerley Tng <ackerleytng(a)google.com> --- This patch is a follow-up from discussions at https://lore.kernel.org/lkml/20230121001542.2472357-9-ackerleytng@google.co… v1 -> v2: Cleaned the patch up after getting comments from Sean in v1: https://lore.kernel.org/lkml/Y%2FfHLdvKHlK6D%2F1v@google.com/ Please also see https://lore.kernel.org/lkml/20230227174654.94641-1-ackerleytng@google.com/ regarding providing alignment macros for selftests. --- .../selftests/kvm/lib/x86_64/processor.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c index ae1e573d94ce..a0669d31bb85 100644 --- a/tools/testing/selftests/kvm/lib/x86_64/processor.c +++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c @@ -5,6 +5,7 @@ * Copyright (C) 2018, Google LLC. */ +#include "linux/bitmap.h" #include "test_util.h" #include "kvm_util.h" #include "processor.h" @@ -573,6 +574,21 @@ struct kvm_vcpu *vm_arch_vcpu_add(struct kvm_vm *vm, uint32_t vcpu_id, DEFAULT_GUEST_STACK_VADDR_MIN, MEM_REGION_DATA); + stack_vaddr += DEFAULT_STACK_PGS * getpagesize(); + + /* + * Align stack to match calling sequence requirements in section "The + * Stack Frame" of the System V ABI AMD64 Architecture Processor + * Supplement, which requires the value (%rsp + 8) to be a multiple of + * 16 when control is transferred to the function entry point. + * + * If this code is ever used to launch a vCPU with 32-bit entry point it + * may need to subtract 4 bytes instead of 8 bytes. + */ + TEST_ASSERT(IS_ALIGNED(stack_vaddr, PAGE_SIZE), + "__vm_vaddr_alloc() did not provide a page-aligned address"); + stack_vaddr -= 8; + vcpu = __vm_vcpu_add(vm, vcpu_id); vcpu_init_cpuid(vcpu, kvm_get_supported_cpuid()); vcpu_setup(vm, vcpu); @@ -580,7 +596,7 @@ struct kvm_vcpu *vm_arch_vcpu_add(struct kvm_vm *vm, uint32_t vcpu_id, /* Setup guest general purpose registers */ vcpu_regs_get(vcpu, &regs); regs.rflags = regs.rflags | 0x2; - regs.rsp = stack_vaddr + (DEFAULT_STACK_PGS * getpagesize()); + regs.rsp = stack_vaddr; regs.rip = (unsigned long) guest_code; vcpu_regs_set(vcpu, &regs); -- 2.39.2.722.g9855ee24e9-goog

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Linux-kselftest-mirror March 2023