Re: [PATCH 1/3] Implement emulator_write_phys()

From: Anthony Liguori
Date: Mon Aug 27 2007 - 14:09:58 EST



On Mon, 2007-08-27 at 18:45 +0300, Avi Kivity wrote:
> Anthony Liguori wrote:
> > Since a hypercall may span two pages and is a gva, we need a function to write
> > to a gva that may span multiple pages. emulator_write_phys() seems like the
> > logical choice for this.
> >
> > @@ -962,8 +962,35 @@ static int emulator_write_std(unsigned long addr,
> > unsigned int bytes,
> > struct kvm_vcpu *vcpu
>
> I think that emulator_write_emulated(), except for being awkwardly
> named, should do the job. We have enough APIs.

I'll drop this patch. My mistakenly thought emulator_write_emulated()
took a GPA. Thanks!

Regards,

Anthony Liguori

> But! We may not overwrite the hypercall instruction while a vcpu may be
> executing, since there's no atomicity guarantee for code fetch. We have
> to to be out of guest mode while writing that insn.
>

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