On 10.03.20 14:23, Christian Borntraeger wrote:
>
>
> On 10.03.20 14:21, David Hildenbrand wrote:
>> On 10.03.20 14:12, Christian Borntraeger wrote:
>>> When we do the initial CPU reset we must not only clear the registers
>>> in the internal data structures but also in kvm_run sync_regs. For
>>> modern userspace sync_regs is the only place that it looks at.
>>>
>>> Cc: stable@xxxxxxxxxxxxxxx
>>
>> # v?
>>
>>> Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
>>> ---
>>> arch/s390/kvm/kvm-s390.c | 18 +++++++++++++++++-
>>> 1 file changed, 17 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
>>> index d7ff30e45589..c2e6d4ba4e23 100644
>>> --- a/arch/s390/kvm/kvm-s390.c
>>> +++ b/arch/s390/kvm/kvm-s390.c
>>> @@ -3268,7 +3268,10 @@ static void kvm_arch_vcpu_ioctl_initial_reset(struct kvm_vcpu *vcpu)
>>> /* Initial reset is a superset of the normal reset */
>>> kvm_arch_vcpu_ioctl_normal_reset(vcpu);
>>>
>>> - /* this equals initial cpu reset in pop, but we don't switch to ESA */
>>> + /*
>>> + * This equals initial cpu reset in pop, but we don't switch to ESA.
>>> + * We do not only reset the internal data, but also ...
>>> + */
>>> vcpu->arch.sie_block->gpsw.mask = 0;
>>> vcpu->arch.sie_block->gpsw.addr = 0;
>>> kvm_s390_set_prefix(vcpu, 0);
>>> @@ -3278,6 +3281,19 @@ static void kvm_arch_vcpu_ioctl_initial_reset(struct kvm_vcpu *vcpu)
>>> memset(vcpu->arch.sie_block->gcr, 0, sizeof(vcpu->arch.sie_block->gcr));
>>> vcpu->arch.sie_block->gcr[0] = CR0_INITIAL_MASK;
>>> vcpu->arch.sie_block->gcr[14] = CR14_INITIAL_MASK;
>>> +
>>> + /* ... the data in sync regs */
>>> + memset(vcpu->run->s.regs.crs, 0, sizeof(vcpu->run->s.regs.crs));
>>> + vcpu->run->s.regs.ckc = 0;
>>> + vcpu->run->s.regs.crs[0] = CR0_INITIAL_MASK;
>>> + vcpu->run->s.regs.crs[14] = CR14_INITIAL_MASK;
>>> + vcpu->run->psw_addr = 0;
>>> + vcpu->run->psw_mask = 0;
>>> + vcpu->run->s.regs.todpr = 0;
>>> + vcpu->run->s.regs.cputm = 0;
>>> + vcpu->run->s.regs.ckc = 0;
>>> + vcpu->run->s.regs.pp = 0;
>>> + vcpu->run->s.regs.gbea = 1;
>>> vcpu->run->s.regs.fpc = 0;
>>> vcpu->arch.sie_block->gbea = 1;
>>> vcpu->arch.sie_block->pp = 0;
>>>
>>
>> Acked-by: David Hildenbrand <david@xxxxxxxxxx>
>>
>> However, I do wonder if that ioctl *originally* was designed for that -
>> IOW if this is rally a stable patch or just some change that makes
>> sense. IIRC, userspace/QEMU always did the right thing, no? There was no
>> documentation about the guarantees AFAIK.
>>
>
> Yes, I moved forth and back.
> Maybe removing cc stable and just adding
> Fixes: 7de3f1423ff ("KVM: s390: Add new reset vcpu API")
> is better then.
Makes sense.
--
Thanks,
David / dhildenb
