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

[Steven Maresca <steve@xxxxxxxxxxxx>]

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.

Steve

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