Re: [PATCH RFC 03/10] domain: GADDR based shared guest area registration alternative - teardown

[Julien Grall <julien@xxxxxxx>]

Hi Jan,

On 19/10/2022 08:40, Jan Beulich wrote:
> In preparation of the introduction of new vCPU operations allowing to
> register the respective areas (one of the two is x86-specific) by
> guest-physical address, add the necessary domain cleanup hooks.
>
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
> ---
> RFC: Zapping the areas in pv_shim_shutdown() may not be strictly
>       necessary: Aiui unmap_vcpu_info() is called only because the vCPU
>       info area cannot be re-registered. Beyond that I guess the
>       assumption is that the areas would only be re-registered as they
>       were before. If that's not the case I wonder whether the guest
>       handles for both areas shouldn't also be zapped.
I don't know the code enough to be able to answer it.

The code itself looks good to me. With one remark below:

Reviewed-by: Julien Grall <jgrall@xxxxxxxxxx>

[...]

> @@ -1555,6 +1559,15 @@ void unmap_vcpu_info(struct vcpu *v)
>       put_page_and_type(mfn_to_page(mfn));
>   }
>   
> +/*
> + * This is only intended to be used for domain cleanup (or more generally only
> + * with at least the respective vCPU, if it's not the current one, reliably
> + * paused).
> + */
> +void unmap_guest_area(struct vcpu *v, struct guest_area *area)
> +{
IIUC, you will add the ASSERT() we discussed in patch #7 in this patch. 
I would be fine if you keep my reviewed-by.
Cheers,

--
Julien Grall