Re: [Xen-ia64-devel] [PATCH 2/9] [P2M/VP step 1] xen: introduce P2M conversion

[Isaku Yamahata <yamahata@xxxxxxxxxxxxx>]

On Wed, Apr 26, 2006 at 05:16:21PM +0200, Tristan Gingold wrote:

> why does domain_page_flush purge TC entries ?
> These entries map virtual addr to mp addr.  If you remove a page from the 
> domain, the next access will be trapped.

I feared the race between ia64_do_page_fault() and removing page.
Smp isn't supported yet for now, it doesn't make sense yet.
Actually I'm not sure and I felt some consideration is necessary
so that I added the comment, "XXX SMP", there.
Presumably xenLinux doesn't issue such a racy operation,
but it is possible in theory.


        cpu0                            cpu1
ia64_do_page_fault()
  translate_domain_pte()

                                        removing page.

  vcpu_itc_no_srlz()
  // bang!

-- 
yamahata

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