Commit-ID: b828b79fcced0e66492590707649dbfaea6435e6 Gitweb: http://git.kernel.org/tip/b828b79fcced0e66492590707649dbfaea6435e6 Author: Andy Lutomirski <[email protected]> AuthorDate: Sat, 2 Apr 2016 07:01:40 -0700 Committer: Ingo Molnar <[email protected]> CommitDate: Wed, 13 Apr 2016 11:37:46 +0200
x86/msr: Set the return value to zero when native_rdmsr_safe() fails This will cause unchecked native_rdmsr_safe() failures to return deterministic results. Tested-by: Boris Ostrovsky <[email protected]> Signed-off-by: Andy Lutomirski <[email protected]> Acked-by: Linus Torvalds <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Arjan van de Ven <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: KVM list <[email protected]> Cc: Paolo Bonzini <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: xen-devel <[email protected]> Link: http://lkml.kernel.org/r/515fb611449a755312a476cfe11675906e7ddf6c.1459605520.git.l...@kernel.org Signed-off-by: Ingo Molnar <[email protected]> --- arch/x86/include/asm/msr.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/msr.h b/arch/x86/include/asm/msr.h index 00050c0..7dc1d8f 100644 --- a/arch/x86/include/asm/msr.h +++ b/arch/x86/include/asm/msr.h @@ -101,7 +101,10 @@ static inline unsigned long long native_read_msr_safe(unsigned int msr, asm volatile("2: rdmsr ; xor %[err],%[err]\n" "1:\n\t" ".section .fixup,\"ax\"\n\t" - "3: mov %[fault],%[err] ; jmp 1b\n\t" + "3: mov %[fault],%[err]\n\t" + "xorl %%eax, %%eax\n\t" + "xorl %%edx, %%edx\n\t" + "jmp 1b\n\t" ".previous\n\t" _ASM_EXTABLE(2b, 3b) : [err] "=r" (*err), EAX_EDX_RET(val, low, high)
