When X86_FEATURE_WAITPKG(CPUID.7.0:ECX.WAITPKG[bit 5]) supported,
".byte 0x66, 0x0f, 0xae, 0xf0" sequence no longer represents clwb
instruction with invalid operand but tpause instruction with %eax
as input register.
Execute tpause with invalid input triggers #GP with below customed
qemu command line:
qemu -kernel x86/memory.flat -overcommit cpu-pm=on ...
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@xxxxxxxxx>
---
x86/memory.c | 7 -------
1 file changed, 7 deletions(-)
diff --git a/x86/memory.c b/x86/memory.c
index 8f61020..351e7c0 100644
--- a/x86/memory.c
+++ b/x86/memory.c
@@ -67,13 +67,6 @@ int main(int ac, char **av)
asm volatile(".byte 0x66, 0x0f, 0xae, 0x33" : : "b" (&target));
report(ud == expected, "clwb (%s)", expected ? "ABSENT" : "present");
- ud = 0;
- /* clwb requires a memory operand, the following is NOT a valid
- * CLWB instruction (modrm == 0xF0).
- */
- asm volatile(".byte 0x66, 0x0f, 0xae, 0xf0");
- report(ud, "invalid clwb");
-
expected = !this_cpu_has(X86_FEATURE_PCOMMIT); /* PCOMMIT */
ud = 0;
/* pcommit: */
--
2.25.1
