linux-kernel - [PATCH 9/9] selftests/x86/avx: Add AVX test

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Message-ID: <20250226010731.2456-10-chang.seok.bae@intel.com>
Date: Tue, 25 Feb 2025 17:07:29 -0800
From: "Chang S. Bae" <chang.seok.bae@...el.com>
To: linux-kernel@...r.kernel.org,
	linux-kselftest@...r.kernel.org
Cc: x86@...nel.org,
	tglx@...utronix.de,
	mingo@...hat.com,
	bp@...en8.de,
	dave.hansen@...ux.intel.com,
	shuah@...nel.org,
	chang.seok.bae@...el.com
Subject: [PATCH 9/9] selftests/x86/avx: Add AVX test

Add xstate testing specifically for those vector register states,
validating kernel's context switching and ensuring ABI compliance.
Use the established xstate testing framework.

Signed-off-by: Chang S. Bae <chang.seok.bae@...el.com>
---
Alternatively, this invocation could be placed directly in
xstate.c::main(). However, the current test file naming convention, which
clearly specifies the tested area, seems reasonable. Adding avx.c
considerably aligns with that convention.

The test output should be like this for ZMM_Hi256 as an example:
$ avx_64
...
[RUN]   AVX-512 ZMM_Hi256: check context switches, 10 iterations, 5 threads.
[OK]    No incorrect case was found.
[RUN]   AVX-512 ZMM_Hi256: inject xstate via ptrace().
[OK]    'xfeatures' in SW reserved area was correctly written
[OK]    xstate was correctly updated.
[RUN]   AVX-512 ZMM_Hi256: load xstate and raise SIGUSR1
[OK]    'magic1' is valid
[OK]    'xfeatures' in SW reserved area is valid
[OK]    'xfeatures' in XSAVE header is valid
[OK]    xstate delivery was successful
[OK]    'magic2' is valid
[RUN]   AVX-512 ZMM_Hi256: load new xstate from sighandler and check it after sigreturn
[OK]    xstate was restored correctly

But systems without AVX-512 will look like:
...
The kernel does not support feature number: 5
The kernel does not support feature number: 6
The kernel does not support feature number: 7
---
 tools/testing/selftests/x86/Makefile |  4 +++-
 tools/testing/selftests/x86/avx.c    | 12 ++++++++++++
 2 files changed, 15 insertions(+), 1 deletion(-)
 create mode 100644 tools/testing/selftests/x86/avx.c

diff --git a/tools/testing/selftests/x86/Makefile b/tools/testing/selftests/x86/Makefile
index f15efdc6aef7..28422c32cc8f 100644
--- a/tools/testing/selftests/x86/Makefile
+++ b/tools/testing/selftests/x86/Makefile
@@ -19,7 +19,7 @@ TARGETS_C_32BIT_ONLY := entry_from_vm86 test_syscall_vdso unwind_vdso \
 			test_FCMOV test_FCOMI test_FISTTP \
 			vdso_restorer
 TARGETS_C_64BIT_ONLY := fsgsbase sysret_rip syscall_numbering \
-			corrupt_xstate_header amx lam test_shadow_stack
+			corrupt_xstate_header amx lam test_shadow_stack avx
 # Some selftests require 32bit support enabled also on 64bit systems
 TARGETS_C_32BIT_NEEDED := ldt_gdt ptrace_syscall
 
@@ -133,4 +133,6 @@ $(OUTPUT)/check_initial_reg_state_64: CFLAGS += -Wl,-ereal_start -static
 $(OUTPUT)/nx_stack_32: CFLAGS += -Wl,-z,noexecstack
 $(OUTPUT)/nx_stack_64: CFLAGS += -Wl,-z,noexecstack
 
+$(OUTPUT)/avx_64: CFLAGS += -mno-avx -mno-avx512f
 $(OUTPUT)/amx_64: EXTRA_FILES += xstate.c
+$(OUTPUT)/avx_64: EXTRA_FILES += xstate.c
diff --git a/tools/testing/selftests/x86/avx.c b/tools/testing/selftests/x86/avx.c
new file mode 100644
index 000000000000..11d5367c235f
--- /dev/null
+++ b/tools/testing/selftests/x86/avx.c
@@ -0,0 +1,12 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#define _GNU_SOURCE /* Required for inline xstate helpers */
+#include "xstate.h"
+
+int main(void)
+{
+	test_xstate(XFEATURE_YMM);
+	test_xstate(XFEATURE_OPMASK);
+	test_xstate(XFEATURE_ZMM_Hi256);
+	test_xstate(XFEATURE_Hi16_ZMM);
+}
-- 
2.45.2