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Re: [PATCH v6 8/8] s390: guest support for diagnose 0x318
From: |
David Hildenbrand |
Subject: |
Re: [PATCH v6 8/8] s390: guest support for diagnose 0x318 |
Date: |
Wed, 16 Sep 2020 10:21:16 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 |
On 16.09.20 10:11, Thomas Huth wrote:
> On 15/09/2020 21.44, Collin Walling wrote:
>> DIAGNOSE 0x318 (diag318) is an s390 instruction that allows the storage
>> of diagnostic information that is collected by the firmware in the case
>> of hardware/firmware service events.
>>
>> QEMU handles the instruction by storing the info in the CPU state. A
>> subsequent register sync will communicate the data to the hypervisor.
>>
>> QEMU handles the migration via a VM State Description.
>>
>> This feature depends on the Extended-Length SCCB (els) feature. If
>> els is not present, then a warning will be printed and the SCLP bit
>> that allows the Linux kernel to execute the instruction will not be
>> set.
>>
>> Availability of this instruction is determined by byte 134 (aka fac134)
>> bit 0 of the SCLP Read Info block. This coincidentally expands into the
>> space used for CPU entries, which means VMs running with the diag318
>> capability may not be able to read information regarding all CPUs
>> unless the guest kernel supports an extended-length SCCB.
>>
>> This feature is not supported in protected virtualization mode.
>>
>> Signed-off-by: Collin Walling <walling@linux.ibm.com>
>> Acked-by: Janosch Frank <frankja@linux.ibm.com>
>> ---
>> hw/s390x/sclp.c | 5 ++++
>> include/hw/s390x/sclp.h | 8 ++++++
>> target/s390x/cpu.h | 2 ++
>> target/s390x/cpu_features.h | 1 +
>> target/s390x/cpu_features_def.h.inc | 3 +++
>> target/s390x/cpu_models.c | 1 +
>> target/s390x/gen-features.c | 1 +
>> target/s390x/kvm.c | 39 +++++++++++++++++++++++++++++
>> target/s390x/machine.c | 17 +++++++++++++
>> 9 files changed, 77 insertions(+)
>
> Acked-by: Thomas Huth <thuth@redhat.com>
>
> (I hope David could still comment on the CPU model stuff ... it looks ok
> to me here, but I got that wrong a couple of times in the past already...)
>
Had a skim over it and it looks good to me!
Acked-by: David Hildenbrand <david@redhat.com>
--
Thanks,
David / dhildenb
- [PATCH v6 2/8] s390/sclp: rework sclp boundary checks, (continued)
- [PATCH v6 2/8] s390/sclp: rework sclp boundary checks, Collin Walling, 2020/09/15
- [PATCH v6 5/8] s390/sclp: use cpu offset to locate cpu entries, Collin Walling, 2020/09/15
- [PATCH v6 7/8] s390/kvm: header sync for diag318, Collin Walling, 2020/09/15
- [PATCH v6 6/8] s390/sclp: add extended-length sccb support for kvm guest, Collin Walling, 2020/09/15
- [PATCH v6 8/8] s390: guest support for diagnose 0x318, Collin Walling, 2020/09/15
- Re: [PATCH v6 0/8] s390: Extended-Length SCCB & DIAGNOSE 0x318, no-reply, 2020/09/15
- Re: [PATCH v6 0/8] s390: Extended-Length SCCB & DIAGNOSE 0x318, Cornelia Huck, 2020/09/16