Re: [Xen-devel] [PATCH RFC V5 5/5] xen: Handle resumed instruction based on previous mem_event reply

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 06.08.14 at 17:58, <rcojocaru@xxxxxxxxxxxxxxx> wrote:
> --- a/xen/arch/x86/hvm/vmx/vmx.c
> +++ b/xen/arch/x86/hvm/vmx/vmx.c
> @@ -1698,6 +1698,18 @@ static void vmx_enable_intro_msr_interception(struct 
> domain *d)
>      }
>  }
>  
> +static bool_t vmx_exited_by_nested_pagefault(void)
> +{
> +    unsigned long exit_qualification;
> +
> +    __vmread(EXIT_QUALIFICATION, &exit_qualification);
> +
> +    if ( (exit_qualification & EPT_GLA_FAULT) == 0 )
> +        return 0;
> +
> +    return 1;
> +}

I think this and associated code will become unnecessary with the
changes Tamas is proposing.

> @@ -1443,6 +1444,36 @@ bool_t p2m_mem_access_check(paddr_t gpa, bool_t 
> gla_valid, unsigned long gla,
>              return 1;
>          }
>      }
> +    else if ( hvm_funcs.exited_by_nested_pagefault &&
> +        !hvm_funcs.exited_by_nested_pagefault() &&
> +        v->arch.mem_event.emulate_flags == 0 ) /* don't send a mem_event */

Indentation. Also the condition again strikes me as odd: If these really
are supposed to be to &&s, then the last condition should be checked
earlier (as being the cheaper check).

Jan


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