Re: [Xen-devel] [PATCH v4 1/5] x86/paravirt: Add _safe to the read_msr and write_msr PV hooks

[Borislav Petkov <bp@xxxxxxxxx>]

On Sat, Mar 12, 2016 at 10:08:48AM -0800, Andy Lutomirski wrote:
> These hooks match the _safe variants, so name them accordingly.
> This will make room for unsafe PV hooks.
> 
> Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx>
> ---
>  arch/x86/include/asm/paravirt.h       | 33 +++++++++++++++++----------------
>  arch/x86/include/asm/paravirt_types.h |  8 ++++----
>  arch/x86/kernel/paravirt.c            |  4 ++--
>  arch/x86/xen/enlighten.c              |  4 ++--
>  4 files changed, 25 insertions(+), 24 deletions(-)
> 
> diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
> index f6192502149e..2e49228ed9a3 100644
> --- a/arch/x86/include/asm/paravirt.h
> +++ b/arch/x86/include/asm/paravirt.h
> @@ -129,34 +129,35 @@ static inline void wbinvd(void)
>  
>  #define get_kernel_rpl()  (pv_info.kernel_rpl)
>  
> -static inline u64 paravirt_read_msr(unsigned msr, int *err)
> +static inline u64 paravirt_read_msr_safe(unsigned msr, int *err)
>  {
> -     return PVOP_CALL2(u64, pv_cpu_ops.read_msr, msr, err);
> +     return PVOP_CALL2(u64, pv_cpu_ops.read_msr_safe, msr, err);
>  }
>  
> -static inline int paravirt_write_msr(unsigned msr, unsigned low, unsigned 
> high)
> +static inline int paravirt_write_msr_safe(unsigned msr,
> +                                       unsigned low, unsigned high)
>  {
> -     return PVOP_CALL3(int, pv_cpu_ops.write_msr, msr, low, high);
> +     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(msr, &_err); \
> +     u64 _l = paravirt_read_msr_safe(msr, &_err);    \
>       val1 = (u32)_l;                         \
>       val2 = _l >> 32;                        \
>  } while (0)
>  
>  #define wrmsr(msr, val1, val2)                       \
>  do {                                         \
> -     paravirt_write_msr(msr, val1, val2);    \
> +     paravirt_write_msr_safe(msr, val1, val2);       \
>  } while (0)
>  
>  #define rdmsrl(msr, val)                     \
>  do {                                         \
>       int _err;                               \
> -     val = paravirt_read_msr(msr, &_err);    \
> +     val = paravirt_read_msr_safe(msr, &_err);       \
>  } while (0)
>  
>  static inline void wrmsrl(unsigned msr, u64 val)
> @@ -164,23 +165,23 @@ static inline void wrmsrl(unsigned msr, u64 val)
>       wrmsr(msr, (u32)val, (u32)(val>>32));
>  }
>  
> -#define wrmsr_safe(msr, a, b)        paravirt_write_msr(msr, a, b)
> +#define wrmsr_safe(msr, a, b)        paravirt_write_msr_safe(msr, a, b)
>  
>  /* rdmsr with exception handling */
> -#define rdmsr_safe(msr, a, b)                        \
> -({                                           \
> -     int _err;                               \
> -     u64 _l = paravirt_read_msr(msr, &_err); \
> -     (*a) = (u32)_l;                         \
> -     (*b) = _l >> 32;                        \
> -     _err;                                   \
> +#define rdmsr_safe(msr, a, b)                                \
> +({                                                   \
> +     int _err;                                       \
> +     u64 _l = paravirt_read_msr_safe(msr, &_err);    \
> +     (*a) = (u32)_l;                                 \
> +     (*b) = _l >> 32;                                \
> +     _err;                                           \
>  })
>  
>  static inline int rdmsrl_safe(unsigned msr, unsigned long long *p)
>  {
>       int err;
>  
> -     *p = paravirt_read_msr(msr, &err);
> +     *p = paravirt_read_msr_safe(msr, &err);
>       return err;
>  }
>  
> diff --git a/arch/x86/include/asm/paravirt_types.h 
> b/arch/x86/include/asm/paravirt_types.h
> index 77db5616a473..5a06cccd36f0 100644
> --- a/arch/x86/include/asm/paravirt_types.h
> +++ b/arch/x86/include/asm/paravirt_types.h
> @@ -155,10 +155,10 @@ struct pv_cpu_ops {
>       void (*cpuid)(unsigned int *eax, unsigned int *ebx,
>                     unsigned int *ecx, unsigned int *edx);
>  
> -     /* 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, unsigned low, unsigned high);
> +     /* MSR operations.
> +        err = 0/-EIO.  wrmsr returns 0/-EIO. */

Please fix the comment format while you're touching this :

        /*
         * A sentence.
         * Another sentence.
         */

Other than that:

Acked-by: Borislav Petkov <bp@xxxxxxx>

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.

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