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Re: [Qemu-devel] [PATCH/s390-next 3/3] s390x/flic: migrate ais states
From: |
Christian Borntraeger |
Subject: |
Re: [Qemu-devel] [PATCH/s390-next 3/3] s390x/flic: migrate ais states |
Date: |
Thu, 13 Jul 2017 15:58:30 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.0 |
On 07/13/2017 03:10 PM, Cornelia Huck wrote:
> On Thu, 13 Jul 2017 15:02:08 +0200
> Christian Borntraeger <address@hidden> wrote:
>
>> On 07/13/2017 02:27 PM, Cornelia Huck wrote:
>>> On Thu, 13 Jul 2017 12:40:29 +0200
>>> Christian Borntraeger <address@hidden> wrote:
>>>
>>>> From: Yi Min Zhao <address@hidden>
>>>>
>>>> During migration we should transfer ais states to the target guest.
>>>> This patch introduces a subsection to kvm_s390_flic_vmstate and new
>>>> vmsd for qemu_flic. The ais states need to be migrated only when
>>>> ais is supported.
>>>>
>>>> Signed-off-by: Yi Min Zhao <address@hidden>
>>>> Signed-off-by: Christian Borntraeger <address@hidden>
>>>> ---
>>>> hw/intc/s390_flic.c | 20 ++++++++++++
>>>> hw/intc/s390_flic_kvm.c | 75
>>>> ++++++++++++++++++++++++++++++++++++++++++++
>>>> include/hw/s390x/s390_flic.h | 1 +
>>>> 3 files changed, 96 insertions(+)
>
>>>> +static int kvm_flic_ais_post_load(void *opaque, int version_id)
>>>> +{
>>>> + KVMS390FLICStateMigTmp *tmp = opaque;
>>>> + KVMS390FLICState *flic = tmp->parent;
>>>> + struct kvm_s390_ais_all ais = {
>>>> + .simm = tmp->simm,
>>>> + .nimm = tmp->nimm,
>>>> + };
>>>> + struct kvm_device_attr attr = {
>>>> + .group = KVM_DEV_FLIC_AISM_ALL,
>>>> + .addr = (uint64_t)&ais,
>>>> + };
>>>> +
>>>> + if (!ais_needed(flic)) {
>>>> + return -ENOSYS;
>>>> + }
>>>
>>> I do not understand this... does that mean that
>>> - we should never get here or
>>> - we should not try to change the fields or
>>> - I need coffee?
>>
>> My understanding is that this should not happen with a normal setup,
>> but it can happen if the user does something "wrong". For example
>> use qemu without libvirt and with -cpu host (which is not migration safe)
>> and do a migration from a host that has AIS to a host that has no AIS.
>> In that case the target system will reject the migration (late, but hopefully
>> not too late).
>
> A comment would be helpful here.
Something like
diff --git a/hw/intc/s390_flic_kvm.c b/hw/intc/s390_flic_kvm.c
index 4cf73ee..9b8dbd1 100644
--- a/hw/intc/s390_flic_kvm.c
+++ b/hw/intc/s390_flic_kvm.c
@@ -452,6 +452,12 @@ static int kvm_flic_ais_post_load(void *opaque, int
version_id)
.addr = (uint64_t)&ais,
};
+ /* This can happen when the user mis-configures its guests in an
+ * incompatible fashion or without a CPU model. For example using
+ * qemu with -cpu host (which is not migration safe) and do a
+ * migration from a host that has AIS to a host that has no AIS.
+ * In that case the target system will reject the migration here.
+ */
if (!ais_needed(flic)) {
return -ENOSYS;
}
- Re: [Qemu-devel] [PATCH/s390-next 2/3] s390x/cpumodel: add zpci, aen and ais facilities, (continued)
- Re: [Qemu-devel] [PATCH/s390-next 2/3] s390x/cpumodel: add zpci, aen and ais facilities, Christian Borntraeger, 2017/07/13
- Re: [Qemu-devel] [PATCH/s390-next 2/3] s390x/cpumodel: add zpci, aen and ais facilities, Cornelia Huck, 2017/07/13
- Re: [Qemu-devel] [PATCH/s390-next 2/3] s390x/cpumodel: add zpci, aen and ais facilities, Halil Pasic, 2017/07/13
[Qemu-devel] [PATCH/s390-next 3/3] s390x/flic: migrate ais states, Christian Borntraeger, 2017/07/13
Re: [Qemu-devel] [PATCH/s390-next 3/3] s390x/flic: migrate ais states, Halil Pasic, 2017/07/13
Re: [Qemu-devel] [PATCH/s390-next 3/3] s390x/flic: migrate ais states, Dr. David Alan Gilbert, 2017/07/13
Re: [Qemu-devel] [PATCH/s390-next 3/3] s390x/flic: migrate ais states, Christian Borntraeger, 2017/07/13
Re: [Qemu-devel] [PATCH/s390-next 3/3] s390x/flic: migrate ais states, Dr. David Alan Gilbert, 2017/07/13
Re: [Qemu-devel] [PATCH/s390-next 3/3] s390x/flic: migrate ais states, Halil Pasic, 2017/07/13
Re: [Qemu-devel] [PATCH/s390-next 3/3] s390x/flic: migrate ais states, Dr. David Alan Gilbert, 2017/07/13
Re: [Qemu-devel] [PATCH/s390-next 3/3] s390x/flic: migrate ais states, Juan Quintela, 2017/07/18
Re: [Qemu-devel] [PATCH/s390-next 3/3] s390x/flic: migrate ais states, Dr. David Alan Gilbert, 2017/07/18
Re: [Qemu-devel] [PATCH/s390-next 3/3] s390x/flic: migrate ais states, Halil Pasic, 2017/07/18