From: Alejandro Vallejo <alejandro.garciavallejo@amd.com>
To: Milan Djokic <milan_djokic@epam.com>,
"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>,
Julien Grall <julien@xen.org>,
Bertrand Marquis <bertrand.marquis@arm.com>,
Michal Orzel <michal.orzel@amd.com>,
Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>,
Xen-devel <xen-devel-bounces@lists.xenproject.org>
Subject: Re: [PATCH] xen/arm: XEN_DOMCTL_get_address_size hypercall support
Date: Fri, 3 Oct 2025 12:05:18 +0200 [thread overview]
Message-ID: <DD8LPC6M7AOI.2YFMXY9IMGXJP@amd.com> (raw)
In-Reply-To: <39511522aae7dab5766ef2ebfed1d13abec8610e.1759324344.git.milan_djokic@epam.com>
On Wed Oct 1, 2025 at 10:01 PM CEST, Milan Djokic wrote:
> Signed-off-by: Milan Djokic <milan_djokic@epam.com>
>
> ---
> XEN_DOMCTL_get_address_size hypercall is not implemented for arm (only for x86)
> It would be useful to have this hypercall supported for arm64, in order to get
> current guest addressing mode
Why is this helpful? You're racing against the guest transitioning between 32
and 64 bits, so the result is stale by the time you read it.
Do you care about the instantanerous bitness of the vCPU or whether you
created a 32 or 64 bit guest?
> and also to verify that XEN_DOMCTL_set_address_size
> performs switch to target addressing mode (instead of relying on its returned error code only).
You can't use that in HVM. Even if you could, why would you? What's the ultimate
goal?
Cheers,
Alejandro
prev parent reply other threads:[~2025-10-03 10:05 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-01 20:01 [PATCH] xen/arm: XEN_DOMCTL_get_address_size hypercall support Milan Djokic
2025-10-02 10:10 ` Andrew Cooper
2025-10-02 11:10 ` Milan Djokic
2025-10-02 12:43 ` Julien Grall
2025-10-03 9:26 ` Milan Djokic
2025-10-02 18:27 ` Demi Marie Obenour
2025-10-03 10:00 ` Alejandro Vallejo
2025-10-03 10:14 ` Julien Grall
2025-10-03 16:03 ` Demi Marie Obenour
2025-10-06 11:28 ` Julien Grall
2025-10-03 10:05 ` Alejandro Vallejo [this message]
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