0001-kvm-x86-correctly-reset-dest_map-vector-when-restori.patch

   1 From b0eaf4506f5f95d15d6731d72c0ddf4a2179eefa Mon Sep 17 00:00:00 2001
   2 From: Paolo Bonzini <pbonzini@redhat.com>
   3 Date: Wed, 14 Sep 2016 23:39:12 +0200
   4 Subject: [PATCH] kvm: x86: correctly reset dest_map->vector when restoring
   5  LAPIC state
   6 MIME-Version: 1.0
   7 Content-Type: text/plain; charset=UTF-8
   8 Content-Transfer-Encoding: 8bit
   9
  10 When userspace sends KVM_SET_LAPIC, KVM schedules a check between
  11 the vCPU's IRR and ISR and the IOAPIC redirection table, in order
  12 to re-establish the IOAPIC's dest_map (the list of CPUs servicing
  13 the real-time clock interrupt with the corresponding vectors).
  14
  15 However, __rtc_irq_eoi_tracking_restore_one was forgetting to
  16 set dest_map->vectors.  Because of this, the IOAPIC did not process
  17 the real-time clock interrupt EOI, ioapic->rtc_status.pending_eoi
  18 got stuck at a non-zero value, and further RTC interrupts were
  19 reported to userspace as coalesced.
  20
  21 Fixes: 9e4aabe2bb3454c83dac8139cf9974503ee044db
  22 Fixes: 4d99ba898dd0c521ca6cdfdde55c9b58aea3cb3d
  23 Cc: stable@vger.kernel.org
  24 Cc: Joerg Roedel <jroedel@suse.de>
  25 Cc: David Gilbert <dgilbert@redhat.com>
  26 Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
  27 Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
  28 Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
  29 ---
  30  arch/x86/kvm/ioapic.c | 8 +++++---
  31  1 file changed, 5 insertions(+), 3 deletions(-)
  32
  33 diff --git a/arch/x86/kvm/ioapic.c b/arch/x86/kvm/ioapic.c
  34 index 5f42d03..c7220ba 100644
  35 --- a/arch/x86/kvm/ioapic.c
  36 +++ b/arch/x86/kvm/ioapic.c
  37 @@ -109,6 +109,7 @@ static void __rtc_irq_eoi_tracking_restore_one(struct kvm_vcpu *vcpu)
  38  {
  39         bool new_val, old_val;
  40         struct kvm_ioapic *ioapic = vcpu->kvm->arch.vioapic;
  41 +       struct dest_map *dest_map = &ioapic->rtc_status.dest_map;
  42         union kvm_ioapic_redirect_entry *e;
  43
  44         e = &ioapic->redirtbl[RTC_GSI];
  45 @@ -117,16 +118,17 @@ static void __rtc_irq_eoi_tracking_restore_one(struct kvm_vcpu *vcpu)
  46                 return;
  47
  48         new_val = kvm_apic_pending_eoi(vcpu, e->fields.vector);
  49 -       old_val = test_bit(vcpu->vcpu_id, ioapic->rtc_status.dest_map.map);
  50 +       old_val = test_bit(vcpu->vcpu_id, dest_map->map);
  51
  52         if (new_val == old_val)
  53                 return;
  54
  55         if (new_val) {
  56 -               __set_bit(vcpu->vcpu_id, ioapic->rtc_status.dest_map.map);
  57 +               __set_bit(vcpu->vcpu_id, dest_map->map);
  58 +               dest_map->vectors[vcpu->vcpu_id] = e->fields.vector;
  59                 ioapic->rtc_status.pending_eoi++;
  60         } else {
  61 -               __clear_bit(vcpu->vcpu_id, ioapic->rtc_status.dest_map.map);
  62 +               __clear_bit(vcpu->vcpu_id, dest_map->map);
  63                 ioapic->rtc_status.pending_eoi--;
  64                 rtc_status_pending_eoi_check_valid(ioapic);
  65         }
  66 --
  67 2.1.4
  68