x86/paravirt: Make "unsafe" MSR accesses unsafe even if PARAVIRT=y
authorAndy Lutomirski <luto@kernel.org>
Sat, 2 Apr 2016 14:01:39 +0000 (07:01 -0700)
committerIngo Molnar <mingo@kernel.org>
Wed, 13 Apr 2016 09:37:46 +0000 (11:37 +0200)
Enabling CONFIG_PARAVIRT had an unintended side effect: rdmsr() turned
into rdmsr_safe() and wrmsr() turned into wrmsr_safe(), even on bare
metal.  Undo that by using the new unsafe paravirt MSR callbacks.

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/414fabd6d3527703077c6c2a797223d0a9c3b081.1459605520.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
arch/x86/include/asm/paravirt.h

index 97839fa..3c73141 100644 (file)
@@ -152,24 +152,21 @@ static inline int paravirt_write_msr_safe(unsigned msr,
        return PVOP_CALL3(int, pv_cpu_ops.write_msr_safe, msr, low, high);
 }
 
-/* These should all do BUG_ON(_err), but our headers are too tangled. */
 #define rdmsr(msr, val1, val2)                 \
 do {                                           \
-       int _err;                               \
-       u64 _l = paravirt_read_msr_safe(msr, &_err);    \
+       u64 _l = paravirt_read_msr(msr);        \
        val1 = (u32)_l;                         \
        val2 = _l >> 32;                        \
 } while (0)
 
 #define wrmsr(msr, val1, val2)                 \
 do {                                           \
-       paravirt_write_msr_safe(msr, val1, val2);       \
+       paravirt_write_msr(msr, val1, val2);    \
 } while (0)
 
 #define rdmsrl(msr, val)                       \
 do {                                           \
-       int _err;                               \
-       val = paravirt_read_msr_safe(msr, &_err);       \
+       val = paravirt_read_msr(msr);           \
 } while (0)
 
 static inline void wrmsrl(unsigned msr, u64 val)