On 05/11/2018 18:41, Michael Mueller wrote:
On 31.10.18 13:10, Pierre Morel wrote:
atomic_inc(&vcpu->kvm->arch.vcpus_in_sie);
+ if (vcpu->kvm->arch.gib_in_use)
+ vcpu->kvm->arch.gisa->iam = 0;
I am not sure that this is race free....
It is, I looked at the generated instructions.
Here we clear IAM, so an IPM can be set and should trigger an interrupt
in the guest
vcpu->arch.sie_block->icptcode = 0;
cpuflags = atomic_read(&vcpu->arch.sie_block->cpuflags);
@@ -3421,6 +3423,9 @@ static int vcpu_post_run(struct kvm_vcpu *vcpu,
int exit_reason)
vcpu->run->s.regs.gprs[15] = vcpu->arch.sie_block->gg15;
atomic_dec(&vcpu->kvm->arch.vcpus_in_sie);
+ if (vcpu->kvm->arch.gib_in_use &&
+ !atomic_fetch_andnot(0, &vcpu->kvm->arch.vcpus_in_sie))
+ vcpu->kvm->arch.gisa->iam = vcpu->kvm->arch.iam;
... with this. Is it?
the same here
No, here we set the IAM if the interrupt comes after the vCPU sleeps and
before we set the IAM we have a race window.
What I mean is: here we should check the IPM bit to be sure not to loose
an interrupt in case the IPM bit is also set.
if (exit_reason == -EINTR) {
VCPU_EVENT(vcpu, 3, "%s", "machine check");
--
Pierre Morel
Linux/KVM/QEMU in Böblingen - Germany
