linux-kernel - Re: [PATCH] decouple x2apic from irq remapping

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:	Thu, 19 Feb 2009 12:30:18 +0100
From:	Ingo Molnar <mingo@...e.hu>
To:	Gleb Natapov <gleb@...hat.com>
Cc:	linux-kernel@...r.kernel.org, yinghai@...nel.org,
	"H. Peter Anvin" <hpa@...or.com>,
	Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH] decouple x2apic from irq remapping


* Gleb Natapov <gleb@...hat.com> wrote:

> Hi,
> 
> Currently x2apic is used only if interrupt remapping can be enabled,
> but if all apic ids are smaller then 255 there is no reason to
> enable interrupt remapping at all. Although there is not real HW that has
> x2apic but does not have IR the decoupling is useful since we want to
> emulate x2apic interface in KVM (it is more vitalization friendly), but
> we don't want to emulate IR just for that.
> 
> According to Intel docs BIOS should pass control to OS in x2apic mode 
> if there are apics with id > 255 and in xapic otherwise, so the proposed
> patch requires IR configuration only if BIOS switched apic to x2apic
> mode.
> 
> The patch is against tip:x86/apic.

Applied to tip:x86/apic, thanks Gleb!

	Ingo
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/