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Re: [Xen-devel] [PATCH] mem_event: fix regression affecting CR3, CR4 memory events



At 21:21 -0400 on 10 Sep (1347312087), Andres Lagar-Cavilla wrote:
> 
> On Sep 10, 2012, at 6:06 PM, Steven Maresca wrote:
> 
> > On Mon, Sep 10, 2012 at 5:39 PM, Keir Fraser <keir@xxxxxxx> wrote:
> >> On 10/09/2012 22:20, "Steven Maresca" <steve@xxxxxxxxxxxx> wrote:
> >> 
> >>> Given the refactoring in the commit related to the regression
> >>> http://xenbits.xen.org/hg/xen-unstable.hg/rev/1276926e3795, it seemed
> >>> (to me anyway) that inserting calls as shown in the patch would be
> >>> cleaner, but I can definitely come up with some drawbacks.  However, I
> >>> wanted to get this fixed for 4.2 if at all possible, so I wanted to
> >>> send regardless.
> >>> 
> >>> In terms of drawbacks, this will require some ifdefs for x86_64, for 
> >>> example.
> >>> 
> >>> Any suggestions for the cleanest means of achieving the same in vmx.c?
> >> 
> >> I don't understand this at all. The original commit moved some CR handling
> >> to common HVM code. Your patch adds some mem_event calls into that common
> >> HVM code. What would need to be "achieved" in vmx.c? What ifdefs would be
> >> required for x86_64?
> >> 
> >> -- Keir
> >> 
> >> 
> > 
> > Keir,
> > 
> > In the process of moving CR handling to common code, that commit
> > removed calls to hvm_memory_event_cr3() and hvm_memory_event_cr4().
> > Without some patch restoring the calls to those two functions, current
> > xen-unstable and xen-4.2-testing only reference them as function
> > prototypes and function definitions -- there are no calls whatsoever.
> > 
> > I only mentioned an ifdef relative to x86_64 because of the #ifdef
> > __x86_64__  around the function definitions. ( I know in the hvm.h
> > itself they're just empty inline functions if not __x86_64__. )
> > 
> > Regarding vmx.c: hvm_memory_event_cr0 is called within vmx_cr_access.
> > The patch I sent restoring the calls to hvm_memory_event_cr4 and
> > hvm_memory_event_cr3 could be treated similarly, that's all.
> 
> The patch looks ok to me.
> Acked-by: Andres Lagar-Cavilla <andres@xxxxxxxxxxxxxxxx>
> 

Acked-by: Tim Deegan <tim@xxxxxxx>

Tim.

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