Re: [Xen-ia64-devel] [PATCH] Strange problem with virtual aliases

[Isaku Yamahata <yamahata@xxxxxxxxxxxxx>]

On Thu, Nov 30, 2006 at 05:39:24PM +1100, Matthew Chapman wrote:

> Unfortunately, that is not what the code actually does... it does not
> update the ppn to point to the same PAGE_SIZE part of the big page as
> the ifa is pointing to.

Correct.


> The one-entry TLB contains the *untranslated* PTE supplied to itc, so it
> doesn't depend on the p2m mapping... it doesn't seem to depend on
> anything that could change in the retry loop, which is why I put it
> outside.  Of course I may have misunderstood the purpose of
> p2m_entry_retry().
> 
> In terms of ordering with respect to ptc.g on another vcpu...  as far as
> the guest is concerned, it is executing itc on the this vcpu, and ptc.g
> on another.  It can't know what the relative ordering of those two
> operations will be, so there may be a "stale entry" inserted by the itc.
> (Which is why Linux necessarily rechecks and purges after.)

Sounds good.

-- 
yamahata

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