2018-04-23 19:50 GMT+08:00 Christian Borntraeger <borntraeger@xxxxxxxxxx>: > > > On 04/21/2018 02:38 AM, Wanpeng Li wrote: >> 2018-04-20 22:21 GMT+08:00 Cornelia Huck <cohuck@xxxxxxxxxx>: >>> On Fri, 20 Apr 2018 21:51:13 +0800 >>> Wanpeng Li <kernellwp@xxxxxxxxx> wrote: >>> >>>> 2018-04-20 15:15 GMT+08:00 Cornelia Huck <cohuck@xxxxxxxxxx>: >>>>> On Thu, 19 Apr 2018 17:47:28 -0700 >>>>> Wanpeng Li <kernellwp@xxxxxxxxx> wrote: >>>>> >>>>>> From: Wanpeng Li <wanpengli@xxxxxxxxxxx> >>>>>> >>>>>> Our virtual machines make use of device assignment by configuring >>>>>> 12 NVMe disks for high I/O performance. Each NVMe device has 129 >>>>>> MSI-X Table entries: >>>>>> Capabilities: [50] MSI-X: Enable+ Count=129 Masked-Vector table: BAR=0 offset=00002000 >>>>>> The windows virtual machines fail to boot since they will map the number of >>>>>> MSI-table entries that the NVMe hardware reported to the bus to msi routing >>>>>> table, this will exceed the 1024. This patch extends MAX_IRQ_ROUTES to 4096 >>>>>> for all archs, in the future this might be extended again if needed. >>>>>> >>>>>> Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx> >>>>>> Cc: Radim Krčmář <rkrcmar@xxxxxxxxxx> >>>>>> Cc: Tonny Lu <tonnylu@xxxxxxxxxxx> >>>>>> Cc: Cornelia Huck <cohuck@xxxxxxxxxx> >>>>>> Signed-off-by: Wanpeng Li <wanpengli@xxxxxxxxxxx> >>>>>> Signed-off-by: Tonny Lu <tonnylu@xxxxxxxxxxx> >>>>>> --- >>>>>> v1 -> v2: >>>>>> * extend MAX_IRQ_ROUTES to 4096 for all archs >>>>>> >>>>>> include/linux/kvm_host.h | 6 ------ >>>>>> 1 file changed, 6 deletions(-) >>>>>> >>>>>> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h >>>>>> index 6930c63..0a5c299 100644 >>>>>> --- a/include/linux/kvm_host.h >>>>>> +++ b/include/linux/kvm_host.h >>>>>> @@ -1045,13 +1045,7 @@ static inline int mmu_notifier_retry(struct kvm *kvm, unsigned long mmu_seq) >>>>>> >>>>>> #ifdef CONFIG_HAVE_KVM_IRQ_ROUTING >>>>>> >>>>>> -#ifdef CONFIG_S390 >>>>>> #define KVM_MAX_IRQ_ROUTES 4096 //FIXME: we can have more than that... >>>>> >>>>> What about /* might need extension/rework in the future */ instead of >>>>> the FIXME? >>>> >>>> Yeah, I guess the maintainers can help to fix it when applying. :) >>>> >>>>> >>>>> As far as I understand, 4096 should cover most architectures and the >>>>> sane end of s390 configurations, but will not be enough at the scarier >>>>> end of s390. (I'm not sure how much it matters in practice.) >>>>> >>>>> Do we want to make this a tuneable in the future? Do some kind of >>>>> dynamic allocation? Not sure whether it is worth the trouble. >>>> >>>> I think keep as it is currently. >>> >>> My main question here is how long this is enough... the number of >>> virtqueues per device is up to 1K from the initial 64, which makes it >>> possible to hit the 4K limit with fewer virtio devices than before (on >>> s390, each virtqueue uses a routing table entry). OTOH, we don't want >>> giant tables everywhere just to accommodate s390. >> >> I suspect there is no real scenario to futher extend for s390 since no >> guys report. >> >>> If the s390 maintainers tell me that nobody is doing the really insane >>> stuff, I'm happy as well :) >> >> Christian, any thoughts? > > For now this patch is a no-op for s390 so as long as nobody complains today we are good. > If it turns out to be "not enough" we can then add a configurable number or whatever. Thanks Christian. Paolo, could you pick this one w/ "/* might need extension/rework in the future */ instead of the FIXME" change or do you need I to send out a new version? :) Regards, Wanpeng Li
