summaryrefslogtreecommitdiff
path: root/arch
diff options
context:
space:
mode:
authorPaul Mackerras <paulus@ozlabs.org>2017-06-20 08:46:12 +0300
committerPaul Mackerras <paulus@ozlabs.org>2017-06-20 08:46:12 +0300
commitee3308a254ec339b8d7c29e20274391685e58de1 (patch)
tree7c2e984406d99ade0b292c6a527ee8c80f0c7eb4 /arch
parent579006944e0d675361e987c646b83d2d1725966c (diff)
downloadlinux-ee3308a254ec339b8d7c29e20274391685e58de1.tar.xz
KVM: PPC: Book3S HV: Don't sleep if XIVE interrupt pending on POWER9
On a POWER9 system, it is possible for an interrupt to become pending for a VCPU when that VCPU is about to cede (execute a H_CEDE hypercall) and has already disabled interrupts, or in the H_CEDE processing up to the point where the XIVE context is pulled from the hardware. In such a case, the H_CEDE should not sleep, but should return immediately to the guest. However, the conditions tested in kvmppc_vcpu_woken() don't include the condition that a XIVE interrupt is pending, so the VCPU could sleep until the next decrementer interrupt. To fix this, we add a new xive_interrupt_pending() helper which looks in the XIVE context that was pulled from the hardware to see if the priority of any pending interrupt is higher (numerically lower than) the CPU priority. If so then kvmppc_vcpu_woken() will return true. If the XIVE context has never been used, then both the pipr and the cppr fields will be zero and the test will indicate that no interrupt is pending. Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/powerpc/kvm/book3s_hv.c17
1 files changed, 16 insertions, 1 deletions
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 8ecf226084af..f6a846c4f984 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -2845,10 +2845,25 @@ static void shrink_halt_poll_ns(struct kvmppc_vcore *vc)
vc->halt_poll_ns /= halt_poll_ns_shrink;
}
+#ifdef CONFIG_KVM_XICS
+static inline bool xive_interrupt_pending(struct kvm_vcpu *vcpu)
+{
+ if (!xive_enabled())
+ return false;
+ return vcpu->arch.xive_saved_state.pipr <
+ vcpu->arch.xive_saved_state.cppr;
+}
+#else
+static inline bool xive_interrupt_pending(struct kvm_vcpu *vcpu)
+{
+ return false;
+}
+#endif /* CONFIG_KVM_XICS */
+
static bool kvmppc_vcpu_woken(struct kvm_vcpu *vcpu)
{
if (vcpu->arch.pending_exceptions || vcpu->arch.prodded ||
- kvmppc_doorbell_pending(vcpu))
+ kvmppc_doorbell_pending(vcpu) || xive_interrupt_pending(vcpu))
return true;
return false;