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

[Kiryl Shutsemau <kas@kernel.org>]

On Thu, Mar 19, 2026 at 03:24:52PM +0800, Chao Gao wrote:
> On Wed, Mar 18, 2026 at 10:58:44AM +0000, Kiryl Shutsemau wrote:
> >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.
> 
> Sure. How about:
> 
> 		/*
> 		 * @sig is 4KB-aligned, but that does not imply PAGE_SIZE
> 		 * alignment when PAGE_SIZE != SZ_4K. Always include the
> 		 * in-page offset.
> 		 */

Ack.

-- 
  Kiryl Shutsemau / Kirill A. Shutemov