On 06.06.2012, at 17:52, Alexander Graf wrote:
> On 06/06/2012 02:28 PM, Avi Kivity wrote:
>> On 06/01/2012 01:20 PM, Paul Mackerras wrote:
>>> At the moment we call kvmppc_pin_guest_page() in kvmppc_update_vpa()
>>> with two spinlocks held: the vcore lock and the vcpu->vpa_update_lock.
>>> This is not good, since kvmppc_pin_guest_page() calls down_read() and
>>> get_user_pages_fast(), both of which can sleep. This bug was introduced
>>> in 2e25aa5f ("KVM: PPC: Book3S HV: Make virtual processor area
>>> registration more robust").
>>>
>>> This arranges to drop those spinlocks before calling
>>> kvmppc_pin_guest_page() and re-take them afterwards. Dropping the
>>> vcore lock in kvmppc_run_core() means we have to set the vcore_state
>>> field to VCORE_RUNNING before we drop the lock, so that other vcpus
>>> won't try to run this vcore.
>>>
>>> Signed-off-by: Paul Mackerras<paulus@xxxxxxxxx>
>>> ---
>>> Since this bug is in Linus' tree, and it can cause a scheduling while
>>> atomic bug message, can we send this to Linus for inclusion in 3.5,
>>> after review of course?
>>>
>> Sure, Alex?
>
> Yup, reviewed and tested. Looks ready to go into the tree to me. Can you pull it in the short way please?
Avi?
Alex
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