Re: [Xen-devel] [PATCH] x86/cpu: Fix SMAP check in PVOPS environments

[Ingo Molnar <mingo@xxxxxxxxxx>]

* Rusty Russell <rusty@xxxxxxxxxxxxxxx> wrote:

> As the comment in arch/x86/include/asm/paravirt_types.h says:
> 
>        * Get/set interrupt state.  save_fl and restore_fl are only
>        * expected to use X86_EFLAGS_IF; all other bits
>        * returned from save_fl are undefined, and may be ignored by
>        * restore_fl.

There should be no 'may' about this: under CONFIG_PARAVIRT_DEBUG=y the reminder 
of 
the flags should be cleared (or all bits should be set: that will instantly 
crash 
if restored verbatim), so that we trip up generic code that relies on non-IF 
restoration?

Thanks,

        Ingo

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