On 06/07/2012 09:21 AM, Borislav Petkov wrote:
On Wed, Jun 06, 2012 at 03:00:14PM -0700, H. Peter Anvin wrote:
On 06/01/2012 07:52 AM, Borislav Petkov wrote:
From: Andre Przywara<[email protected]>
f7f286a910221 ("x86/amd: Re-enable CPU topology extensions in case BIOS
has disabled it") wrongfully added code which used the AMD-specific
{rd,wr}msr variants for no real reason.
This caused boot panics on xen which wasn't initializing the
{rd,wr}msr_safe_regs pv_ops members properly.
This, in turn, caused a heated discussion leading to us reviewing all
uses of the AMD-specific variants and removing them where unneeded
(almost everywhere except an obscure K8 BIOS fix, see 6b0f43ddfa358).
Finally, this patch switches to the standard {rd,wr}msr*_safe* variants
which should've been used in the first place anyway and avoided unneeded
excitation with xen.
Signed-off-by: Andre Przywara<[email protected]>
Cc: Andreas Herrmann<[email protected]>
Cc: [email protected] # 3.4+
Link:<http://lkml.kernel.org/r/[email protected]>
[Boris: correct and expand commit message]
Signed-off-by: Borislav Petkov<[email protected]>
Why -stable? I though we had agreed that we didn't have an active
problem (unclean hack, yes, but not an active problem) in 3.4/3.5 as it
currently sits?
This is probably a leftover from the original patch, before Konrad's
patch got committed.
Yes, AFAICT, we need at least one fix for 3.4 where the original patch
f7f286a910221 broke xen.
So either this one or 1ab46fd319bc should be backported to stable, if
I'm not mistaken. If the second, I'll drop the stable tag from this one
and resend.
Konrad, what do you want wrt xen paravirt nullptr breakage for
3.4-stable?
Greg just sent out the review mail for 1ab46fd319bc, so we can drop the
stable tag from this one.
Regards,
Andre.
-------- Original Message --------
Subject: [ 21/82] x86, amd, xen: Avoid NULL pointer paravirt references
Date: Thu, 7 Jun 2012 13:03:57 +0900
From: Greg KH <[email protected]>
To: <[email protected]>, <[email protected]>
CC: <[email protected]>, <[email protected]>,
<[email protected]>, Andre Przywara <[email protected]>, "H.
Peter Anvin" <[email protected]>
3.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Konrad Rzeszutek Wilk <[email protected]>
commit 1ab46fd319bcf1fcd9fb6311727d532b580e4eba upstream.
Stub out MSR methods that aren't actually needed. This fixes a crash
as Xen Dom0 on AMD Trinity systems. A bigger patch should be added to
remove the paravirt machinery completely for the methods which
apparently have no users!
.....
--
Andre Przywara
AMD-OSRC (Dresden)
Tel: x29712
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