Re: [PATCH 06/13] KVM: x86: pass the whole hflags field to emulator and back

[Paolo Bonzini]

On 05/05/2015 17:47, Bandan Das wrote:
> > The hflags field will contain information about system management mode
> > and will be useful for the emulator.  Pass the entire field rather than
> > just the guest-mode information.
>
> With respect to maintaining maximum isolation between vcpu internals and
> the emulator,

Isolation is maintained.  hflags are simply parts of the processor state
that are not visible to the guest, you can choose to include them as
separate flags or in a single one.  Bundling them in a single flag makes
it a bit faster to pass around many of them.

While we do not need all of them in the emulator, that's in some cases a
limitation of the emulator.  For example, if we wanted to emulate
CLGI/STGI we would need either HF_GIF_MASK or another .  Likewise,
HF_NMI_MASK could replace emulator_set_nmi_mask (especially in v2 of the
series, which will add kvm_set_hflags).

However, if you prefer, I can change it to "bool smm_mode" + a new
smm_exit emulator callback.

Paolo

> why not just "bool smm_mode" ?
> 
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