Re: [PATCH 04/16] x86/srat: vmap the pages for acpi_slit

From: Jan Beulich <jbeulich@suse.com>
To: Hongyan Xia <hx242@xen.org>
Cc: julien@xen.org, "Andrew Cooper" <andrew.cooper3@citrix.com>,
	"Wei Liu" <wl@xen.org>, "Roger Pau Monné" <roger.pau@citrix.com>,
	xen-devel@lists.xenproject.org
Subject: Re: [PATCH 04/16] x86/srat: vmap the pages for acpi_slit
Date: Mon, 30 Nov 2020 11:16:11 +0100	[thread overview]
Message-ID: <d41fee35-8889-3ab8-2a5e-f4b442747362@suse.com> (raw)
In-Reply-To: <f4226fafcd333c0274fcee24601c280bf6494417.1588278317.git.hongyxia@amazon.com>

On 30.04.2020 22:44, Hongyan Xia wrote:
> --- a/xen/arch/x86/srat.c
> +++ b/xen/arch/x86/srat.c
> @@ -196,7 +196,8 @@ void __init acpi_numa_slit_init(struct acpi_table_slit *slit)
>  		return;
>  	}
>  	mfn = alloc_boot_pages(PFN_UP(slit->header.length), 1);
> -	acpi_slit = mfn_to_virt(mfn_x(mfn));
> +	acpi_slit = vmap_boot_pages(mfn, PFN_UP(slit->header.length));
> +	BUG_ON(!acpi_slit);
>  	memcpy(acpi_slit, slit, slit->header.length);
>  }

I'm not sure in how far this series is still to be considered
active / pending; I still have it in my inbox as something to
look at in any event. If it is, then I think the latest by this
patch it becomes clear that we either want to make vmalloc()
boot-allocator capable, or introduce e.g. vmalloc_boot().
Having this recurring pattern including the somewhat odd
vmap_boot_pages() is imo not the best way forward. It would
then also no longer be necessary to allocate contiguous pages,
as none of the users up to here appear to have such a need.

Jan