Re: [Xen-devel] use tasklet to handle init/sipi?

["Zhang, Yang Z" <yang.z.zhang@xxxxxxxxx>]

Keir Fraser wrote on 2013-03-25:
> There are deadlock issues around directly locking and resetting a remote
> vcpu (e.g., buggy/malicious guest vcpu A sends INIT to vcpu B, and B does
> same to A).

Can you elaborate it? Does the lock impact hypervisor or just guest?
 
>  -- Keir
> On 25/03/2013 05:31, "Zhang, Yang Z" <yang.z.zhang@xxxxxxxxx> wrote:
> 
>> Hi, Keir,
>> 
>> I am looking into a issue and found cs:17457 changes to use tasklet to handle
>> init and sipi. And the comments only said "clean up". I wonder is there any
>> special reason to use tasklet to handle it? If no, I will send a patch to 
>> call
>> handler directly instead via tasklet.
>> The background is that with APICv, it assume all apic write is succeed and
>> don't care the return value of vlapic_reg_write(). But the above logic need
>> the caller to check return value. This obviously will break APICv.
>> 
>> # HG changeset patch
>> # User Keir Fraser <keir.fraser@xxxxxxxxxx>
>> # Date 1208270873 -3600
>> # Node ID e15be54059e4bde8f5916269dedff5fc3812686a
>> # Parent  6691ae150d104127c097fd9f3a6acccc5ce43c52
>> x86, hvm: Clean up handling of APIC INIT and SIPI messages.
>> Signed-off-by: Keir Fraser <keir.fraser@xxxxxxxxxx>
>> 
>> best regards
>> yang
>> 
>


Best regards,
Yang


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