[Devel] [PATCH RHEL7 COMMIT] kvm: fix RH rebase fallouts: wake up SynIC message waiters

[Konstantin Khorenko]

The commit is pushed to "branch-rh7-3.10.0-514.10.2.vz7.29.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-514.10.2.vz7.29.5
------>
commit b0f4bdc62001156ff1e402676e49cec59df3934f
Author: Roman Kagan <rkagan at virtuozzo.com>
Date:   Mon Mar 20 17:45:47 2017 +0400

    kvm: fix RH rebase fallouts: wake up SynIC message waiters
    
    When rebasing to a more recent RH upstream, the split nature of
    kvm_arch_irq_routing_update / kvm_arch_post_irq_routing_update was lost.
    
    As a result, in current VZ kernels the ACK notifiers aren't attached to
    Hyper-V synthetic interrupts, which causes the userspace that observed
    contention on the SynIC message page and went to sleep, to never be
    woken up again.
    
    Signed-off-by: Roman Kagan <rkagan at virtuozzo.com>
---
 arch/x86/kvm/irq_comm.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/irq_comm.c b/arch/x86/kvm/irq_comm.c
index c2d61d8..2bfb9a6 100644
--- a/arch/x86/kvm/irq_comm.c
+++ b/arch/x86/kvm/irq_comm.c
@@ -399,11 +399,11 @@ int kvm_arch_set_irq(struct kvm_kernel_irq_routing_entry *irq, struct kvm *kvm,
 	}
 }
 
-void kvm_arch_irq_routing_update(struct kvm *kvm)
+void kvm_arch_post_irq_routing_update(struct kvm *kvm)
 {
-	if (ioapic_in_kernel(kvm) || !irqchip_in_kernel(kvm))
+	if (!irqchip_split(kvm))
 		return;
-	kvm_hv_irq_routing_update(kvm);
+	kvm_make_scan_ioapic_request(kvm);
 }
 
 void kvm_scan_ioapic_routes(struct kvm_vcpu *vcpu, u64 *eoi_exit_bitmap)
@@ -435,3 +435,8 @@ void kvm_scan_ioapic_routes(struct kvm_vcpu *vcpu, u64 *eoi_exit_bitmap)
 	}
 	srcu_read_unlock(&kvm->irq_srcu, idx);
 }
+
+void kvm_arch_irq_routing_update(struct kvm *kvm)
+{
+	kvm_hv_irq_routing_update(kvm);
+}