On Tue, 17 Jan 2017, Borislav Petkov wrote:
> diff --git a/arch/x86/include/asm/microcode.h
> b/arch/x86/include/asm/microcode.h
> index 38711df3bcb5..fbecea6e46e2 100644
> --- a/arch/x86/include/asm/microcode.h
> +++ b/arch/x86/include/asm/microcode.h
> @@ -5,20 +5,33 @@
> #include <linux/earlycpio.h>
> #include <linux/initrd.h>
>
> -#define native_rdmsr(msr, val1, val2) \
> +static inline unsigned long long __rdmsr(unsigned int msr)
> +{
> + DECLARE_ARGS(val, low, high);
> +
> + asm volatile("1: rdmsr\n"
> + "2:\n"
> + : EAX_EDX_RET(val, low, high) : "c" (msr));
> + return EAX_EDX_VAL(val, low, high);
> +}
> +
> +#define microcode_rdmsr(msr, val1, val2) \
> do { \
> - u64 __val = native_read_msr((msr)); \
> + u64 __val = __rdmsr((msr)); \
> (void)((val1) = (u32)__val); \
> (void)((val2) = (u32)(__val >> 32)); \
> } while (0)
>
> -#define native_wrmsr(msr, low, high) \
> - native_write_msr(msr, low, high)
> +static inline void microcode_wrmsr(unsigned int msr, u64 val)
> +{
> + u32 low, high;
> +
> + low = (u32)val;
> + high = (u32)(val >> 32);
>
> -#define native_wrmsrl(msr, val) \
> - native_write_msr((msr), \
> - (u32)((u64)(val)), \
> - (u32)((u64)(val) >> 32))
> + asm volatile("wrmsr\n"
> + :: "c" (msr), "a"(low), "d" (high) : "memory");
> +}
msr.h already has:
wrmsr_notrace() so adding wrmsrl_notrace() to it should be a nobrainer.
Providing rdmsr_notrace() in msr.h is a natural extension of the existing
interfaces.
That would get rid of all the extra microcode specific MSR accessors which
are just yet another copy of stuff in msr.h.
Thanks,
tglx
