Re: [PATCH v5 08/22] x86/virt/seamldr: Allocate and populate a module update request

From: Kiryl Shutsemau

Date: Wed Mar 18 2026 - 07:04:49 EST


On Wed, Mar 18, 2026 at 04:50:34PM +0800, Chao Gao wrote:
> >> + ptr = sig;
> >> + for (i = 0; i < sig_size / SZ_4K; i++) {
> >> + /*
> >> + * Don't assume @sig is page-aligned although it is 4KB-aligned.
> >> + * Always add the in-page offset to get the physical address.
> >> + */
> >
> >I don't follow this. If @sig is 4k aligned in VA, it is page aligned.
>
> Dan's concern was that PAGE_SIZE is not guaranteed to be 4096.
>
> I agree that PAGE_SIZE is 4K on x86 today. But to address that concern, I saw
> two options:
>
> 1. Add WARN_ON_ONCE(PAGE_SIZE != SZ_4K), or
> 2. Handle it as in the code above.
>
> I didn't find existing code using option 1 in x86, so I chose option 2.

Please, make it clear in the comment that you are talking about PAGE_SIZE != SZ_4K.

--
Kiryl Shutsemau / Kirill A. Shutemov