Re: [PATCH v5 08/10] domain: introduce GADDR based runstate area registration alternative

[Julien Grall <julien@xxxxxxx>]

Hi,

On 02/10/2023 16:11, Roger Pau Monne wrote:
> From: Jan Beulich <jbeulich@xxxxxxxx>
>
> The registration by virtual/linear address has downsides: At least on
> x86 the access is expensive for HVM/PVH domains. Furthermore for 64-bit
> PV domains the area is inaccessible (and hence cannot be updated by Xen)
> when in guest-user mode.
>
> Introduce a new vCPU operation allowing to register the runstate area by
> guest-physical address.
>
> An at least theoretical downside to using physically registered areas is
> that PV then won't see dirty (and perhaps also accessed) bits set in its
> respective page table entries.
>
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
> Reviewed-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
Acked-by: Julien Grall <jgrall@xxxxxxxxxx>

Cheers,

--
Julien Grall