Re: [Xen-devel] Re: how to handle paged hypercall args?

[Keir Fraser <keir@xxxxxxx>]

On 15/11/2010 09:53, "Jan Beulich" <JBeulich@xxxxxxxxxx> wrote:

>> Maybe Patrick can comment too, but my recollection of discussing this is
>> that we would have to propagate failures caused by paging at least as
>> far as the dom0 kernel, because otherwise a single-vcpu dom0 kernel
>> could deadlock with its one vcpu stuck in a hypercall (or continually
>> having it preempted and retried) and the paging binary that would
>> unstick it never getting scheduled.
> 
> How's Dom0 involved here? The hypercall arguments live in
> guest memory.

Yes, and you'd never turn on paging for dom0 itself. That would never work!

Changing every user of the guest accessor macros to retry via guest space is
really not tenable. We'd never get all the bugs out.

 -- Keir



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