Re: [Xen-devel] [PATCH] add canonical address checks to HVM

["Jan Beulich" <jbeulich@xxxxxxxxxx>]

>>> Keir Fraser <keir@xxxxxxxxxxxxx> 01.12.06 09:07 >>>
>On 1/12/06 8:05 am, "Jan Beulich" <jbeulich@xxxxxxxxxx> wrote:
>
>> I think it might be a security issue:
>> - In MSR writes, are you certain there's not going to be any problem now or
>> in the future when the state gets actually loaded into CPU registers?
>> - In memory accesses, at least until no failures to read/write guest memory
>> are being ignored anymore.
>
>We should be defensive about guest reads/writes/MSR-accesses anyway. I.e.,
>we should at least accept faults on those accesses, and make sure the worst
>that happens is a domain crash.

That I take for granted. But it's far from optimal. I don't know about modern
Windows (has been too long since I was last looking at their handling of this),
but at least Linux takes precautions when doing potentially dangerous
accesses in so many places that it would seem unreasonable to crash a
domain when it could be passed a simple fault at the right point, and let it
decide for itself whether it wants to die.

Jan

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