Re: [Xen-devel] [PATCH v4 2/5] vpci: fix deferral of long operations

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 16.11.18 at 15:57, <roger.pau@xxxxxxxxxx> wrote:
> On Fri, Nov 16, 2018 at 05:11:39AM -0700, Jan Beulich wrote:
>> >>> On 14.11.18 at 12:57, <roger.pau@xxxxxxxxxx> wrote:
>> > @@ -182,6 +185,7 @@ static void defer_map(struct domain *d, struct pci_dev 
>> > *pdev,
>> >      curr->vpci.mem = mem;
>> >      curr->vpci.cmd = cmd;
>> >      curr->vpci.rom_only = rom_only;
>> > +    raise_softirq(SCHEDULE_SOFTIRQ);
>> >  }
>> 
>> Why is this needed? The description doesn't mention it.
> 
> vPCI needs to raise a shceduler softirq in order to prevent the guest
> from resuming execution after deferring a map/unmap operation. Without
> this the guest might just resume execution while having pending work
> if there's no scheduler softirq already pending.

Ah yes, but please again attach a brief comment to clarify this.

Jan



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