On 26.02.2010, at 14:21, Joerg Roedel wrote:
> On Fri, Feb 26, 2010 at 03:10:13PM +0200, Avi Kivity wrote:
>> On 02/26/2010 03:04 PM, Joerg Roedel wrote:
>>>
>>>> I'm still not convinced on this way of doing things. If it's static,
>>>> make it static. If it's dynamic, make it dynamic. Dynamically
>>>> generating a static list just sounds plain wrong to me.
>>> Stop. I had a static list in the first version of the patch. This list
>>> was fine except the fact that a developer needs to remember to update
>>> this list if the list of non-intercepted msrs is expanded. The whole
>>> reason for a dynamically built list is to take the task of maintaining
>>> the list away from the developer and remove a possible source of hard to
>>> find bugs. This is what the current approach does.
>>
>> The problem was the two lists. If you had a
>>
>> static struct svm_direct_access_msrs = {
>> u32 index;
>> bool longmode_only;
>> } direct_access_msrs = {
>> ...
>> };
>>
>> You could generate
>>
>> static unsigned *msrpm_offsets_longmode, *msrpm_offsets_legacy;
>>
>> as well as the original bitmaps at module init, no?
>
> True for the msrs the guest always has access too. But for the lbr-msrs
> the intercept bits may change at runtime. So an addtional flag is
> required to indicate if the bits should be cleared initially.
So the msrpm bitmap changes dynamically for each vcpu? Great, make it fully dynamic then, changing the vcpu->arch.msrpm only from within its vcpu context. No need for atomic ops.
Alex--
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