Re: git: 4dd828c80828 - main - amd64: add kva_layout

From: Kristof Provost <kp_at_FreeBSD.org>
Date: Tue, 15 Jul 2025 08:52:35 UTC 
On 15 Jul 2025, at 0:03, Konstantin Belousov wrote:
> The branch main has been updated by kib:
>
> URL: https://cgit.FreeBSD.org/src/commit/?id=4dd828c80828637452a8a4e07a64e294c82e5d8b
>
> commit 4dd828c80828637452a8a4e07a64e294c82e5d8b
> Author:     Konstantin Belousov <kib@FreeBSD.org>
> AuthorDate: 2025-06-15 21:39:10 +0000
> Commit:     Konstantin Belousov <kib@FreeBSD.org>
> CommitDate: 2025-07-14 22:03:28 +0000
>
>     amd64: add kva_layout
>
>     Reviewed by:    markj
>     Tested by:      pho
>     Sponsored by:   The FreeBSD Foundation
>     Differential revision:  https://reviews.freebsd.org/D51085
> ---
..
> diff --git a/sys/amd64/include/vmparam.h b/sys/amd64/include/vmparam.h
> index 0cd9bb4fa7a4..f12e5217a44b 100644
> --- a/sys/amd64/include/vmparam.h
> +++ b/sys/amd64/include/vmparam.h
> @@ -181,12 +181,9 @@
>   * 0xffffffff80000000                        KERNBASE
>   */
>
> -#define	VM_MIN_KERNEL_ADDRESS	KV4ADDR(KPML4BASE, 0, 0, 0)
> -#define	VM_MAX_KERNEL_ADDRESS	KV4ADDR(KPML4BASE + NKPML4E - 1, \
> -					NPDPEPG-1, NPDEPG-1, NPTEPG-1)
> -
> -#define	DMAP_MIN_ADDRESS	KV4ADDR(DMPML4I, 0, 0, 0)
> -#define	DMAP_MAX_ADDRESS	KV4ADDR(DMPML4I + NDMPML4E, 0, 0, 0)
> +#define	VM_MIN_KERNEL_ADDRESS_LA48	KV4ADDR(KPML4BASE, 0, 0, 0)
> +#define	VM_MIN_KERNEL_ADDRESS		kva_layout.km_low
> +#define	VM_MAX_KERNEL_ADDRESS		kva_layout.km_high

The removal of DMAP_MIN_ADDRESS breaks the KASAN build.

This seems to fix it for me, but I’m not familiar enough with this code to be confident to commit it:

	diff --git a/sys/kern/subr_asan.c b/sys/kern/subr_asan.c
	index 0edb631d1475..31204bad8c30 100644
	--- a/sys/kern/subr_asan.c
	+++ b/sys/kern/subr_asan.c
	@@ -263,8 +263,8 @@ kasan_mark(const void *addr, size_t size, size_t redzsize, uint8_t code)
	        if (__predict_false(!kasan_enabled))
	                return;

	-       if ((vm_offset_t)addr >= DMAP_MIN_ADDRESS &&
	-           (vm_offset_t)addr < DMAP_MAX_ADDRESS)
	+       if ((vm_offset_t)addr >= kva_layout.dmap_low &&
	+           (vm_offset_t)addr < kva_layout.dmap_high)
	                return;

	        KASSERT((vm_offset_t)addr >= VM_MIN_KERNEL_ADDRESS &&

—
Kristof