linux-kernel - Re: [PATCH v3 1/2] xen/pci: Defer initialization of MSI ops on HVM guests until after x2APIC has been set up

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]

Date:	Tue, 25 Nov 2014 15:12:14 +0000
From:	Stefano Stabellini <stefano.stabellini@...citrix.com>
To:	Boris Ostrovsky <boris.ostrovsky@...cle.com>
CC:	Stefano Stabellini <stefano.stabellini@...citrix.com>,
	<david.vrabel@...rix.com>, <konrad.wilk@...cle.com>,
	<jun.nakajima@...el.com>, <linux-kernel@...r.kernel.org>,
	<xen-devel@...ts.xen.org>
Subject: Re: [PATCH v3 1/2] xen/pci: Defer initialization of MSI ops on HVM
 guests until after x2APIC has been set up

On Tue, 25 Nov 2014, Boris Ostrovsky wrote:
> On 11/25/2014 07:06 AM, Stefano Stabellini wrote:
> > On Mon, 24 Nov 2014, Boris Ostrovsky wrote:
> > > If the hardware supports APIC virtualization we may decide not to use
> > > pirqs
> > > and instead use APIC/x2APIC directly, meaning that we don't want to set
> > > x86_msi.setup_msi_irqs and x86_msi.teardown_msi_irq to Xen-specific
> > > routines.
> > > However, x2APIC is not set up by the time pci_xen_hvm_init() is called so
> > > we
> > > need to postpone setting these ops until later, when we know which APIC
> > > mode
> > > is used.
> > > 
> > > (Note that currently x2APIC is never initialized on HVM guests. This may
> > > change in the future)
> > I take that this is safe because no MSIs can be received at this point
> > (apic_post_init), right?
> 
> 
> Yes. At the time apic_post_init() is called PCI has not been probed yet.

Please add that to the commit message.

Acked-by: Stefano Stabellini <stefano.stabellini@...citrix.com>
--
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/