Commit 4985ce15 authored Apr 02, 2016 by Andy Lutomirski Committed by Ingo Molnar Apr 13, 2016

x86/paravirt: Make "unsafe" MSR accesses unsafe even if PARAVIRT=y



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>

parent dd2f4a00

arch/x86/include/asm/paravirt.h

+3 −6

Original line number	Diff line number	Diff line
		@@ -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)