summaryrefslogtreecommitdiffstats
path: root/arch/x86/include/asm/msr.h
diff options
context:
space:
mode:
authorAndy Lutomirski <luto@kernel.org>2016-04-02 16:01:40 +0200
committerIngo Molnar <mingo@kernel.org>2016-04-13 11:37:46 +0200
commitb828b79fcced0e66492590707649dbfaea6435e6 (patch)
treeb7e03be5be31ee11357f156890c04975118524de /arch/x86/include/asm/msr.h
parentx86/paravirt: Make "unsafe" MSR accesses unsafe even if PARAVIRT=y (diff)
downloadlinux-b828b79fcced0e66492590707649dbfaea6435e6.tar.xz
linux-b828b79fcced0e66492590707649dbfaea6435e6.zip
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 <boris.ostrovsky@oracle.com> Signed-off-by: Andy Lutomirski <luto@kernel.org> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: KVM list <kvm@vger.kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: xen-devel <Xen-devel@lists.xen.org> Link: http://lkml.kernel.org/r/515fb611449a755312a476cfe11675906e7ddf6c.1459605520.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/include/asm/msr.h')
-rw-r--r--arch/x86/include/asm/msr.h5
1 files changed, 4 insertions, 1 deletions
diff --git a/arch/x86/include/asm/msr.h b/arch/x86/include/asm/msr.h
index 00050c034a13..7dc1d8fef7fd 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)