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Subject[PATCH 8/10] change write msr functions interface
Date
This patche changes the native_write_msr() and friends interface
to explicitly take 2 32-bit registers instead of a 64-bit value.
The change will ease the merge with 64-bit code. As the 64-bit
value will be passed as two registers anyway in i386,
the PVOP_CALL interface has to account for that and use low/high parameters
It would force the x86_64 version to be different.

The change does not make i386 generated code less efficient. As said above,
it would get the values from two registers anyway.

Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com>
---
include/asm-x86/msr.h | 19 ++++++++++---------
include/asm-x86/paravirt.h | 2 +-
2 files changed, 11 insertions(+), 10 deletions(-)
diff --git a/include/asm-x86/msr.h b/include/asm-x86/msr.h
index ce2a257..9c695c7 100644
--- a/include/asm-x86/msr.h
+++ b/include/asm-x86/msr.h
@@ -59,13 +59,14 @@ static inline unsigned long long native_read_msr_safe(unsigned int msr,
return val;
}

-static inline void native_write_msr(unsigned int msr, unsigned long long val)
+static inline void native_write_msr(unsigned int msr,
+ unsigned low, unsigned high)
{
- asm volatile("wrmsr" : : "c" (msr), "A"(val));
+ asm volatile("wrmsr" : : "c" (msr), "a"(low), "d" (high));
}

static inline int native_write_msr_safe(unsigned int msr,
- unsigned long long val)
+ unsigned low, unsigned high)
{
int err;
asm volatile("2: wrmsr ; xorl %0,%0\n"
@@ -78,7 +79,7 @@ static inline int native_write_msr_safe(unsigned int msr,
" .long 2b,3b\n\t"
".previous"
: "=a" (err)
- : "c" (msr), "0" ((u32)val), "d" ((u32)(val>>32)),
+ : "c" (msr), "0" (low), "d" (high),
"i" (-EFAULT));
return err;
}
@@ -114,20 +115,20 @@ static inline unsigned long long native_read_pmc(int counter)
(val2) = (u32)(__val >> 32); \
} while(0)

-static inline void wrmsr(u32 __msr, u32 __low, u32 __high)
+static inline void wrmsr(unsigned msr, unsigned low, unsigned high)
{
- native_write_msr(__msr, ((u64)__high << 32) | __low);
+ native_write_msr(msr, low, high);
}

#define rdmsrl(msr,val) \
((val) = native_read_msr(msr))

-#define wrmsrl(msr,val) native_write_msr(msr, val)
+#define wrmsrl(msr,val) native_write_msr(msr, (u32)val, (u32)(val >> 32))

/* wrmsr with exception handling */
-static inline int wrmsr_safe(u32 __msr, u32 __low, u32 __high)
+static inline int wrmsr_safe(unsigned msr, unsigned low, unsigned high)
{
- return native_write_msr_safe(__msr, ((u64)__high << 32) | __low);
+ return native_write_msr_safe(msr, low, high);
}

/* rdmsr with exception handling */
diff --git a/include/asm-x86/paravirt.h b/include/asm-x86/paravirt.h
index 4a7be97..6f837bb 100644
--- a/include/asm-x86/paravirt.h
+++ b/include/asm-x86/paravirt.h
@@ -115,7 +115,7 @@ struct pv_cpu_ops {
/* MSR, PMC and TSR operations.
err = 0/-EFAULT. wrmsr returns 0/-EFAULT. */
u64 (*read_msr)(unsigned int msr, int *err);
- int (*write_msr)(unsigned int msr, u64 val);
+ int (*write_msr)(unsigned int msr, unsigned low, unsigned high);

u64 (*read_tsc)(void);
u64 (*read_pmc)(int counter);
--
1.4.4.2


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