On 06/02/2020 15.39, David Hildenbrand wrote:
> On 03.02.20 14:19, Christian Borntraeger wrote:
>> From: Janosch Frank <frankja@xxxxxxxxxxxxx>
>>
>> For protected VMs, the VCPU resets are done by the Ultravisor, as KVM
>> has no access to the VCPU registers.
>>
>> As the Ultravisor will only accept a call for the reset that is
>> needed, we need to fence the UV calls when chaining resets.
>>
>> Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
>> ---
>> arch/s390/kvm/kvm-s390.c | 20 ++++++++++++++++++++
>> 1 file changed, 20 insertions(+)
>>
>> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
>> index 3e4716b3fc02..f7a3f84be064 100644
>> --- a/arch/s390/kvm/kvm-s390.c
>> +++ b/arch/s390/kvm/kvm-s390.c
>> @@ -4699,6 +4699,7 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
>> void __user *argp = (void __user *)arg;
>> int idx;
>> long r;
>> + u32 ret;
>>
>> vcpu_load(vcpu);
>>
>> @@ -4720,14 +4721,33 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
>> case KVM_S390_CLEAR_RESET:
>> r = 0;
>> kvm_arch_vcpu_ioctl_clear_reset(vcpu);
>> + if (kvm_s390_pv_handle_cpu(vcpu)) {
>> + r = uv_cmd_nodata(kvm_s390_pv_handle_cpu(vcpu),
>> + UVC_CMD_CPU_RESET_CLEAR, &ret);
>> + VCPU_EVENT(vcpu, 3, "PROTVIRT RESET CLEAR VCPU: cpu %d rc %x rrc %x",
>> + vcpu->vcpu_id, ret >> 16, ret & 0x0000ffff);
>> + }
>> break;
>> case KVM_S390_INITIAL_RESET:
>> r = 0;
>> kvm_arch_vcpu_ioctl_initial_reset(vcpu);
>> + if (kvm_s390_pv_handle_cpu(vcpu)) {
>> + r = uv_cmd_nodata(kvm_s390_pv_handle_cpu(vcpu),
>> + UVC_CMD_CPU_RESET_INITIAL,
>> + &ret);
>> + VCPU_EVENT(vcpu, 3, "PROTVIRT RESET INITIAL VCPU: cpu %d rc %x rrc %x",
>> + vcpu->vcpu_id, ret >> 16, ret & 0x0000ffff);
>> + }
>> break;
>> case KVM_S390_NORMAL_RESET:
>> r = 0;
>> kvm_arch_vcpu_ioctl_normal_reset(vcpu);
>> + if (kvm_s390_pv_handle_cpu(vcpu)) {
>> + r = uv_cmd_nodata(kvm_s390_pv_handle_cpu(vcpu),
>> + UVC_CMD_CPU_RESET, &ret);
>> + VCPU_EVENT(vcpu, 3, "PROTVIRT RESET NORMAL VCPU: cpu %d rc %x rrc %x",
>> + vcpu->vcpu_id, ret >> 16, ret & 0x0000ffff);
>> + }
>> break;
>> case KVM_SET_ONE_REG:
>> case KVM_GET_ONE_REG: {
>>
>
> Any reason why to not put that into the actual kvm_arch_vcpu_ioctl_*
> functions?
Because they are chained and you must not chain the UV calls.
Thomas
