From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>
Subject: Re: [PATCH 2 of 3] apic: remove 'enabled_via_apicbase' variable
Date: Wed, 18 May 2011 16:45:37 -0400 [thread overview]
Message-ID: <20110518204537.GB7647@dumpdata.com> (raw)
In-Reply-To: <4DD42D9E.7030700@citrix.com>
> >So if you don't have x2apic, then it is wrong to disable the LAPIC mode?
> >What about older hardware?
> I guess I wasn't very clear in my description. In older hardware
> without x2apic, it is correct to simply twiddle the ENABLE bit in
> the APICBASE MSR. However, with x2apic mode enabled, setting the
> ENABLE bit from 1 to 0 while leaving the EXTD bit set will result in
> a protection fault which will propagate to a general protection
> fault the same codepath will be called in the fault handler. As a
> result, the current code in disable_local_APIC will result in a GPF
> if the BIOS boots with LAPICs disabled (fine as per the spec for
> compatibility) and xen decided to take advantage of x2apic mode.
Ok. You might also point to the appropiate section of the x2APIC
spec about this. I think it is 2.7.1.2
next prev parent reply other threads:[~2011-05-18 20:45 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-18 18:08 [PATCH 0 of 3] Fix kexec path in xen (take 2) Andrew Cooper
2011-05-18 18:08 ` [PATCH 1 of 3] apic: record local apic state on boot Andrew Cooper
2011-05-18 18:49 ` Konrad Rzeszutek Wilk
2011-05-18 20:27 ` Andrew Cooper
2011-05-18 20:43 ` Konrad Rzeszutek Wilk
2011-05-19 0:56 ` Tian, Kevin
2011-05-19 8:34 ` Ian Campbell
2011-05-19 16:21 ` Konrad Rzeszutek Wilk
2011-05-19 0:54 ` Tian, Kevin
2011-05-18 23:40 ` Keir Fraser
2011-05-19 11:14 ` Andrew Cooper
2011-05-19 14:26 ` Konrad Rzeszutek Wilk
2011-05-19 14:43 ` Andrew Cooper
2011-05-18 18:08 ` [PATCH 2 of 3] apic: remove 'enabled_via_apicbase' variable Andrew Cooper
2011-05-18 18:53 ` Konrad Rzeszutek Wilk
2011-05-18 20:35 ` Andrew Cooper
2011-05-18 20:45 ` Konrad Rzeszutek Wilk [this message]
2011-05-19 3:31 ` Tian, Kevin
2011-05-18 18:08 ` [PATCH 3 of 3] kexec: disable iommu jumping into the kdump kernel Andrew Cooper
2011-05-18 18:49 ` Konrad Rzeszutek Wilk
2011-05-18 20:48 ` Andrew Cooper
2011-05-18 20:57 ` Konrad Rzeszutek Wilk
2011-05-18 21:24 ` Andrew Cooper
2011-05-19 14:32 ` Konrad Rzeszutek Wilk
2011-05-20 0:33 ` Kay, Allen M
2011-05-20 21:55 ` Kay, Allen M
2011-05-18 18:39 ` [PATCH 0 of 3] Fix kexec path in xen (take 2) Konrad Rzeszutek Wilk
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