Re: [Xen-devel] [PATCH 02/18] xen/arm: Implement PSCI system suspend call (virtual interface)

[Julien Grall <julien.grall@xxxxxxx>]

Hi,

On 13/11/2018 20:39, Stefano Stabellini wrote:
> On Mon, 12 Nov 2018, Julien Grall wrote:
> > > > However, what is the issue with saving all the registers here?
> > > We need to save arguments that are provided by a guest with system
> > > suspend PSCI call. These arguments are the entry point that needs to
> > > be saved in program counter and context ID that needs to be saved in
> > > x0/r0. We don't have these arguments here. Context switch happens
> > > after processing the system suspend PSCI call, so it's too late.
> > It does not feel right to modify ctxt_switch{from,to} for suspend/resume. If
> > you want to reset the vCPU state before blocking the vCPU, then you should
> > instead
> You missed the end of the suggestion here
Whoops. I meant that instead you should save the context of the vCPU in advance 
or reset the vCPU using the system registers directly.
But my preference is to reset the vCPU when you receive the wake-up interrupt.

Cheers,

--
Julien Grall

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