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SubjectRe: [PATCH 7/6] x86: __always_inline __{rd,wr}msr()
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On 1/7/21 2:18 AM, Peter Zijlstra wrote:
> On Thu, Jan 07, 2021 at 10:36:43AM +0100, Peter Zijlstra wrote:
>> On Wed, Jan 06, 2021 at 09:59:17AM -0800, Randy Dunlap wrote:
>>> On 1/6/21 6:36 AM, Peter Zijlstra wrote:
>>>> When the compiler fails to inline; we violate nonisntr:
>>>>
>>>> vmlinux.o: warning: objtool: __sev_es_nmi_complete()+0xc7: call to sev_es_wr_ghcb_msr() leaves .noinstr.text section
>>>
>>> I am still seeing (a variant of) this one:
>>>
>>> vmlinux.o: warning: objtool: __sev_es_nmi_complete()+0xce: call to __wrmsr.constprop.14() leaves .noinstr.text section
>>
>> Gah, sorry, I managed to mess up my .config :/ /me goes try again.
>
> OK, restored your original .config and that did indeed reproduce, the
> below cures it.
>
> ---
>
> Subject: x86: __always_inline __{rd,wr}msr()
> From: Peter Zijlstra <peterz@infradead.org>
> Date: Thu Jan 7 11:14:25 CET 2021
>
> When the compiler choses to not inline the trivial MSR helpers:
>
> vmlinux.o: warning: objtool: __sev_es_nmi_complete()+0xce: call to __wrmsr.constprop.14() leaves .noinstr.text section
>
> Reported-by: Randy Dunlap <rdunlap@infradead.org>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>

Acked-by: Randy Dunlap <rdunlap@infradead.org> # build-tested

Thanks.

> ---
> arch/x86/include/asm/msr.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> --- a/arch/x86/include/asm/msr.h
> +++ b/arch/x86/include/asm/msr.h
> @@ -86,7 +86,7 @@ static inline void do_trace_rdpmc(unsign
> * think of extending them - you will be slapped with a stinking trout or a frozen
> * shark will reach you, wherever you are! You've been warned.
> */
> -static inline unsigned long long notrace __rdmsr(unsigned int msr)
> +static __always_inline unsigned long long __rdmsr(unsigned int msr)
> {
> DECLARE_ARGS(val, low, high);
>
> @@ -98,7 +98,7 @@ static inline unsigned long long notrace
> return EAX_EDX_VAL(val, low, high);
> }
>
> -static inline void notrace __wrmsr(unsigned int msr, u32 low, u32 high)
> +static __always_inline void __wrmsr(unsigned int msr, u32 low, u32 high)
> {
> asm volatile("1: wrmsr\n"
> "2:\n"
>


--
~Randy

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