Re: [PATCH] make KVM conform to sucky rdmsr interface

Rusty Russell
2007-03-22T07:49:30Z

On Thu, 2007-03-22 at 09:20 +0200, Avi Kivity wrote:
> My rdmsr_safe (x86_64, i386 is similar/same) is

Erk. Andrew, please drop that patch, and take this one.

It was actually Jeremy's paravirt cleanup patch which changed the
calling convention of rdmsr_safe() to match rdmsr().

I went "oh it's that fucking rdmsr interface" and "fixed" kvm.

Sorry for the bad patch,
Rusty.
==
rdmsr_safe() takes pointers. rdmsr() modifies its arguments. What a
mess.

Fix rdmsr_safe() with !CONFIG_PARAVIRT.

Signed-off-by: Rusty Russell <rusty-8n+1lVoiYb80n/F98K4Iww@public.gmane.org>

diff -r a7f78e8eacc8 include/asm-i386/msr.h
--- a/include/asm-i386/msr.h Thu Mar 22 12:38:35 2007 +1100
+++ b/include/asm-i386/msr.h Thu Mar 22 18:40:35 2007 +1100
@@ -96,12 +96,12 @@ static inline void wrmsrl (unsigned long
(native_write_msr(msr, ((unsigned long long)val2 << 32) | val1))

/* rdmsr with exception handling */
-#define rdmsr_safe(msr,val1,val2) \
+#define rdmsr_safe(msr,p1,p2) \
({ \
int __err; \
- unsigned long long __val = native_read_msr(msr, &__err); \
- val1 = __val; \
- val2 = __val >> 32; \
+ unsigned long long __val = native_read_msr(msr, &__err);\
+ (*p1) = __val; \
+ (*p2) = __val >> 32; \
__err; \
})