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Re: [PATCH v4 2/4] xen/arm: optimize the size of struct vcpu
- To: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
- From: Jan Beulich <jbeulich@xxxxxxxx>
- Date: Mon, 5 Jan 2026 15:44:22 +0100
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- Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>, Julien Grall <julien@xxxxxxx>, Bertrand Marquis <bertrand.marquis@xxxxxxx>, Volodymyr Babchuk <Volodymyr_Babchuk@xxxxxxxx>, Andrew Cooper <andrew.cooper3@xxxxxxxxxx>, "Orzel, Michal" <michal.orzel@xxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxxx
- Delivery-date: Mon, 05 Jan 2026 14:44:34 +0000
- List-id: Xen developer discussion <xen-devel.lists.xenproject.org>
On 31.12.2025 09:27, Oleksii Kurochko wrote:
> On 12/29/25 12:10 PM, Orzel, Michal wrote:
>> On 29/12/2025 12:08, Orzel, Michal wrote:
>>> On 23/12/2025 18:01, Oleksii Kurochko wrote:
>>>> When CONFIG_NEW_VGIC=y and CONFIG_ARM_64=y, the size of struct vcpu
>>>> exceeds one page, which requires allocating two pages and led to the
>>>> introduction of MAX_PAGES_PER_VCPU.
>> Also, I think it would be better to drop MAX_PAGES_PER_VCPU in this patch.
>
> Then I'll update alloc_vcpu_struct() and free_vcpu_struct() to:
> struct vcpu *alloc_vcpu_struct(const struct domain *d)
> {
> struct vcpu *v;
>
> - BUILD_BUG_ON(sizeof(*v) > MAX_PAGES_PER_VCPU * PAGE_SIZE);
> - v = alloc_xenheap_pages(get_order_from_bytes(sizeof(*v)), 0);
> + BUILD_BUG_ON(sizeof(*v) > PAGE_SIZE);
> + v = alloc_xenheap_pages(0, 0);
Just one nit here: As (iirc) previously indicated by Andrew, please
avoid open-coding of alloc_xenheap_page().
Jan
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