From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Glauber de Oliveira Costa <gcosta@redhat.com>
Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org,
rusty@rustcorp.com.au, ak@suse.de, mingo@elte.hu,
chrisw@sous-sol.org, avi@qumranet.com, anthony@codemonkey.ws,
virtualization@lists.linux-foundation.org, lguest@ozlabs.org,
kvm-devel@lists.sourceforge.net, zach@vmware.com,
tglx@linutronix.de, jun.nakajima@intel.com, glommer@gmail.com,
Steven Rostedt <rostedt@goodmis.org>
Subject: Re: [PATCH 3/16] read/write_crX, clts and wbinvd for 64-bit paravirt
Date: Thu, 01 Nov 2007 08:30:59 -0700 [thread overview]
Message-ID: <4729F133.3060308@goop.org> (raw)
In-Reply-To: <4729D92E.2030108@redhat.com>
Glauber de Oliveira Costa wrote:
> I in fact have seen bugs with mixed reads and writes to the same cr,
> (cr4), but adding the volatile
> flag to the read function seemed to fix it.
Well, volatile will make a read be repeated rather than caching the
previous value, but it has no effect on ordering.
> Yet, I agree with you that
> the theorectical problem exists for the reorder, and your proposed fix
> seems fine (although if we're really desperate about memory usage, we
> can use a char instead a int and save 3 bytes!)
Sure. Ideally the compiler would never even generate a reference to it,
and it could just be extern, but in practice the compiler will generate
references sometimes.
J
next prev parent reply other threads:[~2007-11-01 15:31 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-31 19:14 [PATCH 0/7] (Re-)introducing pvops for x86_64 - Real pvops work part Glauber de Oliveira Costa
2007-10-31 19:14 ` [PATCH 1/16] Wipe out traditional opt from x86_64 Makefile Glauber de Oliveira Costa
2007-10-31 19:14 ` [PATCH 2/16] paravirt hooks at entry functions Glauber de Oliveira Costa
2007-10-31 19:14 ` [PATCH 3/16] read/write_crX, clts and wbinvd for 64-bit paravirt Glauber de Oliveira Costa
2007-10-31 19:14 ` [PATCH 4/16] provide native irq initialization function Glauber de Oliveira Costa
2007-10-31 19:14 ` [PATCH 5/16] report ring kernel is running without paravirt Glauber de Oliveira Costa
2007-10-31 19:14 ` [PATCH 6/16] export math_state_restore Glauber de Oliveira Costa
2007-10-31 19:14 ` [PATCH 7/16] native versions for set pagetables Glauber de Oliveira Costa
2007-10-31 19:14 ` [PATCH 8/16] add native functions for descriptors handling Glauber de Oliveira Costa
2007-10-31 19:14 ` [PATCH 9/16] This patch add provisions for time related functions so they Glauber de Oliveira Costa
2007-10-31 19:14 ` [PATCH 10/16] export cpu_gdt_descr Glauber de Oliveira Costa
2007-10-31 19:14 ` [PATCH 11/16] turn priviled operation into a macro in head_64.S Glauber de Oliveira Costa
2007-10-31 19:14 ` [PATCH 12/16] tweak io_64.h for paravirt Glauber de Oliveira Costa
2007-10-31 19:14 ` [PATCH 13/16] native versions for page table entries values Glauber de Oliveira Costa
2007-10-31 19:14 ` [PATCH 14/16] prepare x86_64 architecture initialization for paravirt Glauber de Oliveira Costa
2007-10-31 19:15 ` [PATCH 15/16] consolidation of paravirt for 32 and 64 bits Glauber de Oliveira Costa
2007-10-31 19:15 ` [PATCH 16/16] make vsmp a paravirt client Glauber de Oliveira Costa
2007-11-01 4:38 ` Jeremy Fitzhardinge
2007-11-01 4:50 ` [PATCH 11/16] turn priviled operation into a macro in head_64.S Jeremy Fitzhardinge
2007-11-01 13:50 ` Glauber de Oliveira Costa
2007-11-01 4:48 ` [PATCH 3/16] read/write_crX, clts and wbinvd for 64-bit paravirt Jeremy Fitzhardinge
2007-11-01 13:48 ` Glauber de Oliveira Costa
2007-11-01 15:30 ` Jeremy Fitzhardinge [this message]
2007-11-01 16:07 ` Keir Fraser
2007-11-01 16:13 ` Glauber de Oliveira Costa
2007-11-01 17:41 ` Jeremy Fitzhardinge
2007-11-01 16:55 ` [Lguest] " Zachary Amsden
2007-11-02 1:21 ` Jeremy Fitzhardinge
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