Re: [Xen-devel] [PATCH][VT] Patch to allow VMX domainsto be destroyedor shut down cleanly

[Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>]

On 19 Sep 2005, at 11:52, Jiang, Yunhong wrote:

> > I think it's more correct to do get/put in vmx_set_cr0 (at that point
> > we can know what format the pagetables should be, for example
> > (32/32p/64). But I think it's a bigger cleanup patch.
> Do you mean put all get/put on vmx_set_cr0 ? even for paging enabled 
> case?
No, I mean that get/put on cr3 change (or guest destruction) should be 
gated on CR0_PG. Then, additionally, get or put is required when CR0_PG 
is toggled.
> And there is one more issue .If the guest is destroyed before the 
> kernel enabling paging, how about the page pointed by cr3? It may 
> cause one referece count left. The reason is, currently when destroy 
> domain, only domain->guest_table is released. However, if the paging 
> is not enabled, then the get_page on vmx_set_cr0 has no corresponding 
> put_page, which may cause problem. Hope comments on this point.
Doing what I describe above would fix this: CR0_PG would be clear, so 
put_page() would not happen.
> > Whatever you go for: please send a complete tested patch. :-)
> Sure！
Thanks!

 -- Keir


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