This is a note to let you know that I've just added the patch titled
kvm: x86: correctly reset dest_map->vector when restoring LAPIC state
to the 4.7-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
kvm-x86-correctly-reset-dest_map-vector-when-restoring-lapic-state.patch
and it can be found in the queue-4.7 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From b0eaf4506f5f95d15d6731d72c0ddf4a2179eefa Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Date: Wed, 14 Sep 2016 23:39:12 +0200
Subject: kvm: x86: correctly reset dest_map->vector when restoring LAPIC state
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From: Paolo Bonzini <pbonzini@xxxxxxxxxx>
commit b0eaf4506f5f95d15d6731d72c0ddf4a2179eefa upstream.
When userspace sends KVM_SET_LAPIC, KVM schedules a check between
the vCPU's IRR and ISR and the IOAPIC redirection table, in order
to re-establish the IOAPIC's dest_map (the list of CPUs servicing
the real-time clock interrupt with the corresponding vectors).
However, __rtc_irq_eoi_tracking_restore_one was forgetting to
set dest_map->vectors. Because of this, the IOAPIC did not process
the real-time clock interrupt EOI, ioapic->rtc_status.pending_eoi
got stuck at a non-zero value, and further RTC interrupts were
reported to userspace as coalesced.
Fixes: 9e4aabe2bb3454c83dac8139cf9974503ee044db
Fixes: 4d99ba898dd0c521ca6cdfdde55c9b58aea3cb3d
Cc: Joerg Roedel <jroedel@xxxxxxx>
Cc: David Gilbert <dgilbert@xxxxxxxxxx>
Reviewed-by: Radim Krčmář <rkrcmar@xxxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kvm/ioapic.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
--- a/arch/x86/kvm/ioapic.c
+++ b/arch/x86/kvm/ioapic.c
@@ -109,6 +109,7 @@ static void __rtc_irq_eoi_tracking_resto
{
bool new_val, old_val;
struct kvm_ioapic *ioapic = vcpu->kvm->arch.vioapic;
+ struct dest_map *dest_map = &ioapic->rtc_status.dest_map;
union kvm_ioapic_redirect_entry *e;
e = &ioapic->redirtbl[RTC_GSI];
@@ -117,16 +118,17 @@ static void __rtc_irq_eoi_tracking_resto
return;
new_val = kvm_apic_pending_eoi(vcpu, e->fields.vector);
- old_val = test_bit(vcpu->vcpu_id, ioapic->rtc_status.dest_map.map);
+ old_val = test_bit(vcpu->vcpu_id, dest_map->map);
if (new_val == old_val)
return;
if (new_val) {
- __set_bit(vcpu->vcpu_id, ioapic->rtc_status.dest_map.map);
+ __set_bit(vcpu->vcpu_id, dest_map->map);
+ dest_map->vectors[vcpu->vcpu_id] = e->fields.vector;
ioapic->rtc_status.pending_eoi++;
} else {
- __clear_bit(vcpu->vcpu_id, ioapic->rtc_status.dest_map.map);
+ __clear_bit(vcpu->vcpu_id, dest_map->map);
ioapic->rtc_status.pending_eoi--;
rtc_status_pending_eoi_check_valid(ioapic);
}
Patches currently in stable-queue which might be from pbonzini@xxxxxxxxxx are
queue-4.7/mips-kvm-check-for-pfn-noslot-case.patch
queue-4.7/kvm-x86-correctly-reset-dest_map-vector-when-restoring-lapic-state.patch
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