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Re: [Qemu-devel] [PATCH v2 3/7] s390x/tcg: properly implement the TOD
From: |
David Hildenbrand |
Subject: |
Re: [Qemu-devel] [PATCH v2 3/7] s390x/tcg: properly implement the TOD |
Date: |
Thu, 21 Jun 2018 13:52:10 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 |
On 21.06.2018 13:44, Thomas Huth wrote:
> On 20.06.2018 12:08, David Hildenbrand wrote:
>> Right now, each CPU has its own TOD. Especially, the TOD will differ
>> based on creation time of a CPU - e.g. when hotplugging a CPU the times
>> will differ quite a lot, resulting in stall warnings in the guest.
>>
>> Let's use a single TOD by implementing our new TOD device. Prepare it
>> for TOD-clock epoch extension.
>>
>> Most importantly, whenever we set the TOD, we have to update the CKC
>> timer.
>>
>> Introduce "tcg_s390x.h" just like "kvm_s390x.h" for tcg specific
>> function declarations that should not go into cpu.h.
> [...]
>> diff --git a/hw/s390x/tod.c b/hw/s390x/tod.c
>> index c1b3438452..7495d8c057 100644
>> --- a/hw/s390x/tod.c
>> +++ b/hw/s390x/tod.c
>> @@ -30,6 +30,17 @@ void s390_init_tod(void)
>> qdev_init_nofail(DEVICE(obj));
>> }
>>
>> +S390TODState *s390_get_tod(void)
>> +{
>> + static S390TODState *ts;
>> +
>> + if (!ts) {
>> + ts = S390_TOD(object_resolve_path_type("", TYPE_S390_TOD, NULL));
>> + }
>> +
>> + return ts;
>> +}
>
> Could you please call that function s390_get_todstate or something
> similar? Otherwise it sounds like it could be used to retrieve the time,
> and not the state object.
Yes, makes sense! Thanks!
>
> Thomas
>
--
Thanks,
David / dhildenb
[Qemu-devel] [PATCH v2 3/7] s390x/tcg: properly implement the TOD, David Hildenbrand, 2018/06/20
Re: [Qemu-devel] [PATCH v2 3/7] s390x/tcg: properly implement the TOD, Thomas Huth, 2018/06/21
- Re: [Qemu-devel] [PATCH v2 3/7] s390x/tcg: properly implement the TOD,
David Hildenbrand <=
[Qemu-devel] [PATCH v2 5/7] s390x/tcg: implement SET CLOCK, David Hildenbrand, 2018/06/20
[Qemu-devel] [PATCH v2 7/7] s390x/tcg: fix CPU hotplug with single-threaded TCG, David Hildenbrand, 2018/06/20
[Qemu-devel] [PATCH v2 6/7] s390x/tcg: rearm the CKC timer during migration, David Hildenbrand, 2018/06/20