On 2015.5.6 1:21, David Vrabel wrote:
> On 05/05/15 14:19, Ouyang Zhaowei (Charles) wrote:
>>
>>
>> On 2015.5.5 17:09, David Vrabel wrote:
>>> On 04/05/15 03:56, Ouyang Zhaowei (Charles) wrote:
>>>> The hypervisor continues assuming that vcpu_info is stored in per-cpu data
>>>> which was set up by xen_vcpu_setup(),
>>>> while on canceled suspend, the call to xen_hvm_init_shared_info() will now
>>>> make the guest think that vcpu_info
>>>> is in the shared page, so we do not call xen_hvm_init_shared_info() on
>>>> suspend canceled.
>>>
>>> I don't understand what the impact of this fix is. Can you include this
>>> in the commit message?
>>>
>>> David
>>
>> Sure, please let me know if there is anything not clear enough.
>>
>> vcpu_info would be reset to wrong place on canceled suspend on PVOPS VM
>> which has multi-cpu
>>
>> The hypervisor continues assuming that vcpu_info is stored in per-cpu data
>> which was set up by xen_vcpu_setup(),
>> while on canceled suspend, the call to xen_hvm_init_shared_info() will make
>> the guest think that vcpu_info
>> is in the shared page. This will cause non-boot cpus keep checking a wrong
>> vcpu_info address and can not handle
>> irqs any more after suspend canceled, for example after we do "xl save
>> -c/restore", PVOPS VM can not be resumed
>> as the cpus can not finish their irqs.
>
> Ok, so it's only cancelled suspends that are affected. Can you make the
> clear in the commit and resubmit. This looks like something that should
> be tagged for stable as well.
>
> David
OK, thanks
>
>>
>>>
>>>> Signed-off-by: Charles Ouyang <ouyangzhao...@huawei.com>
>>>> Reviewed-by: Boris Ostrovsky <boris.ostrov...@oracle.com>
>>>> ---
>>>> arch/x86/xen/suspend.c | 3 ++-
>>>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/arch/x86/xen/suspend.c b/arch/x86/xen/suspend.c
>>>> index d949769..b2bed45 100644
>>>> --- a/arch/x86/xen/suspend.c
>>>> +++ b/arch/x86/xen/suspend.c
>>>> @@ -32,7 +32,8 @@ static void xen_hvm_post_suspend(int suspend_cancelled)
>>>> {
>>>> #ifdef CONFIG_XEN_PVHVM
>>>> int cpu;
>>>> - xen_hvm_init_shared_info();
>>>> + if (!suspend_cancelled)
>>>> + xen_hvm_init_shared_info();
>>>> xen_callback_vector();
>>>> xen_unplug_emulated_devices();
>>>> if (xen_feature(XENFEAT_hvm_safe_pvclock)) {
>>>>
>>>
>>>
>>> .
>>>
>>
>
>
> .
>
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