On 10/22/20 3:43 PM, Collin Walling wrote: > On 10/16/20 3:44 AM, Christian Borntraeger wrote: >> >> >> On 16.10.20 09:34, Janosch Frank wrote: >>> On 10/15/20 9:59 PM, Collin Walling wrote: >>>> The DIAGNOSE 0x0318 instruction must be reset on a normal and clear >>>> reset. However, this was missed for the clear reset case. >>>> >>>> Let's fix this by resetting the information during a normal reset. >>>> Since clear reset is a superset of normal reset, the info will >>>> still reset on a clear reset. >>> >>> The architecture really confuses me here but I think we don't want this >>> in the kernel VCPU reset handlers at all. >>> >>> This needs to be reset per VM *NOT* per VCPU. >>> Hence the resets are bound to diag308 and not SIGP. >>> >>> I.e. we need to clear it in QEMU's VM reset handler. >>> It's still early and I have yet to consume my first coffee, am I missing >>> something? >> >> I agree with Janosch. architecture indicates that this should only be reset >> for VM-wide resets, e.g. sigp orders 11 and 12 are explicitly mentioned >> to NOT reset the value. >> > > A few questions regarding how resets for diag318 should work here: > > The AR states that any copies retained by the diag318 should be set to 0 > on a clear reset and load normal -- I thought both of those resets were > implicitly called by diag308 as well? > > Should the register used to store diag318 info not be set to 0 *by KVM* > then? Should the values be set *by QEMU* and a subsequent sync_regs will > ensure things are sane on the KVM side? Just a FYI for the non-IBMers reading in: I have spoken to the author of the architecture and cleared up our way forward. * We need to clear on diag 308 subcodes 0,1,3,4 * SIGP does not alter diag318 data in any way * We need to set the cpnc on all VCPUs of the VM > >>> >>>> >>>> Signed-off-by: Collin Walling <walling@xxxxxxxxxxxxx> >>>> --- >>>> arch/s390/kvm/kvm-s390.c | 2 +- >>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>> >>>> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c >>>> index 6b74b92c1a58..b0cf8367e261 100644 >>>> --- a/arch/s390/kvm/kvm-s390.c >>>> +++ b/arch/s390/kvm/kvm-s390.c >>>> @@ -3516,6 +3516,7 @@ static void kvm_arch_vcpu_ioctl_normal_reset(struct kvm_vcpu *vcpu) >>>> vcpu->arch.sie_block->gpsw.mask &= ~PSW_MASK_RI; >>>> vcpu->arch.pfault_token = KVM_S390_PFAULT_TOKEN_INVALID; >>>> memset(vcpu->run->s.regs.riccb, 0, sizeof(vcpu->run->s.regs.riccb)); >>>> + vcpu->run->s.regs.diag318 = 0; >>>> >>>> kvm_clear_async_pf_completion_queue(vcpu); >>>> if (!kvm_s390_user_cpu_state_ctrl(vcpu->kvm)) >>>> @@ -3582,7 +3583,6 @@ static void kvm_arch_vcpu_ioctl_clear_reset(struct kvm_vcpu *vcpu) >>>> >>>> regs->etoken = 0; >>>> regs->etoken_extension = 0; >>>> - regs->diag318 = 0; >>>> } >>>> >>>> int kvm_arch_vcpu_ioctl_set_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs) >>>> >>> >>> > >
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