From: Matthew Rosato <mjrosato@linux.ibm.com>
To: Christian Borntraeger <borntraeger@de.ibm.com>,
Thomas Huth <thuth@redhat.com>, Cornelia Huck <cohuck@redhat.com>
Cc: Halil Pasic <pasic@linux.ibm.com>,
qemu-s390x@nongnu.org, qemu-devel@nongnu.org,
David Hildenbrand <david@redhat.com>
Subject: Re: [PATCH] target/s390x/kvm: Enable adapter interruption suppression again
Date: Thu, 16 Jan 2020 09:51:37 -0500 [thread overview]
Message-ID: <bc3edeb0-8c32-f750-7ccb-ae51eeadd5b3@linux.ibm.com> (raw)
In-Reply-To: <1e181d83-98ec-a8dd-2b43-0371b8eb65af@de.ibm.com>
On 1/16/20 8:22 AM, Christian Borntraeger wrote:
>
>
> On 16.01.20 13:55, Thomas Huth wrote:
>> On 16/01/2020 13.50, Cornelia Huck wrote:
>>> On Thu, 16 Jan 2020 13:20:26 +0100
>>> Thomas Huth <thuth@redhat.com> wrote:
>>>
>>>> The AIS feature has been disabled late in the v2.10 development
>>>> cycle since there were some issues with migration (see commit
>>>> 3f2d07b3b01ea61126b - "s390x/ais: for 2.10 stable: disable ais
>>>> facility"). We originally wanted to enable it again for newer
>>>> machine types, but apparently we forgot to do this so far. Let's
>>>> do it for the new s390-ccw-virtio-5.0 machine now.
>>>>
>>>> Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1756946
>>>> Signed-off-by: Thomas Huth <thuth@redhat.com>
>>>> ---
>>>> hw/s390x/s390-virtio-ccw.c | 4 ++++
>>>> include/hw/s390x/s390-virtio-ccw.h | 4 ++++
>>>> target/s390x/kvm.c | 11 ++++++++---
>>>> 3 files changed, 16 insertions(+), 3 deletions(-)
>>>>
>>>
>>>> @@ -365,10 +367,13 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
>>>> /*
>>>> * The migration interface for ais was introduced with kernel 4.13
>>>> * but the capability itself had been active since 4.12. As migration
>>>> - * support is considered necessary let's disable ais in the 2.10
>>>> - * machine.
>>>> + * support is considered necessary we only enable this for newer
>>>
>>> s/necessary we only enable this/necessary, we only try to enable this/
>>>
>>>> + * machine types and if KVM_CAP_S390_AIS_MIGRATION is available.
>>>
>>> maybe s/and if/if/
>>
>> Sure ... could you fix it up when picking up the patch (in case I don't
>> have to respin), or do you want me to send a v2?
>>
>>>> */
>>>> - /* kvm_vm_enable_cap(s, KVM_CAP_S390_AIS, 0); */
>>>> + if (smc->kvm_ais_allowed &&
>>>> + kvm_check_extension(s, KVM_CAP_S390_AIS_MIGRATION)) {
>>>> + kvm_vm_enable_cap(s, KVM_CAP_S390_AIS, 0);
>>>> + }
>>>>
>>>> kvm_set_max_memslot_size(KVM_SLOT_MAX_BYTES);
>>>> return 0;
>>>
>>> Looks good.
>>>
>>> Remind me again: ais only made a difference for pci devices, right? Is
>>> it enough to give this a quick whirl with virtio-pci devices?
>>
>> I don't remember the details, Christian, could you please answer this
>> question?
>
> Yes, IIRC AIS was there for PCI, but not for Crypto or virtio.
This matches my understanding as well.
> The patch looks sane, but it would be good if someone could try
> the AIS stuff.
>
> Matt, can you have a look?
Sure. But my PCI environment is currently down for a maintenance
window, will try again later today.
next prev parent reply other threads:[~2020-01-16 14:53 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-16 12:20 [PATCH] target/s390x/kvm: Enable adapter interruption suppression again Thomas Huth
2020-01-16 12:23 ` David Hildenbrand
2020-01-16 12:26 ` Thomas Huth
2020-01-16 12:28 ` David Hildenbrand
2020-01-16 12:38 ` Thomas Huth
2020-01-16 12:50 ` Cornelia Huck
2020-01-16 12:55 ` Thomas Huth
2020-01-16 13:22 ` Christian Borntraeger
2020-01-16 14:22 ` Cornelia Huck
2020-01-16 14:51 ` Matthew Rosato [this message]
2020-01-16 20:19 ` Matthew Rosato
2020-01-16 20:26 ` Cornelia Huck
2020-01-17 10:38 ` Thomas Huth
2020-01-17 11:05 ` Christian Borntraeger
2020-01-17 15:38 ` Thomas Huth
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