linux-kernel - Re: [PATCH v2] x86/irq: Probe for PIC presence before allocating descs for legacy IRQs

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

Message-ID: <alpine.DEB.2.11.1511162229520.3761@nanos>
Date:	Mon, 16 Nov 2015 22:39:01 +0100 (CET)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	Boris Ostrovsky <boris.ostrovsky@...cle.com>
cc:	Vitaly Kuznetsov <vkuznets@...hat.com>, x86@...nel.org,
	Ingo Molnar <mingo@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Jiang Liu <jiang.liu@...ux.intel.com>,
	"K. Y. Srinivasan" <kys@...rosoft.com>,
	linux-kernel@...r.kernel.org, xen-devel <xen-devel@...ts.xen.org>
Subject: Re: [PATCH v2] x86/irq: Probe for PIC presence before allocating
 descs for legacy IRQs

On Mon, 16 Nov 2015, Boris Ostrovsky wrote:
> Xen expects legacy interrupts to be there (pretty much for the same reason as
> Hyper-V does) and with this change arch_probe_nr_irqs() returns zero and no
> descriptors are allocated.

Right, because everything which has a PIT gets them and everything
which does not have a PIT does not.

> We can allocate those descriptors as needed in xen_irq_init() (if we know that
> IRQs are legacy), although that would look somewhat ugly and out of place.

Why preallocating them in xen_irq_init()? You simply can remove the
NR_IRQS_LEGACY checks in xen_allocate_irq_gsi/xen_free_irq(), right?

Thanks,

	tglx
--
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/