KVM: Disable manual dirty log when dirty ring enabled
KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 is for KVM_CLEAR_DIRTY_LOG, which is only useful for KVM_GET_DIRTY_LOG. Skip enabling it for kvm dirty ring. More importantly, KVM_DIRTY_LOG_INITIALLY_SET will not wr-protect all the pages initially, which is against how kvm dirty ring is used - there's no way for kvm dirty ring to re-protect a page before it's notified as being written first with a GFN entry in the ring! So when KVM_DIRTY_LOG_INITIALLY_SET is enabled with dirty ring, we'll see silent data loss after migration. Signed-off-by: Peter Xu <peterx@redhat.com> Message-Id: <20210506160549.130416-10-peterx@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
parent
2ea5cb0a47
commit
a81a592698
|
@ -2131,6 +2131,14 @@ static int kvm_init(MachineState *ms)
|
|||
s->coalesced_pio = s->coalesced_mmio &&
|
||||
kvm_check_extension(s, KVM_CAP_COALESCED_PIO);
|
||||
|
||||
/*
|
||||
* KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 is not needed when dirty ring is
|
||||
* enabled. More importantly, KVM_DIRTY_LOG_INITIALLY_SET will assume no
|
||||
* page is wr-protected initially, which is against how kvm dirty ring is
|
||||
* usage - kvm dirty ring requires all pages are wr-protected at the very
|
||||
* beginning. Enabling this feature for dirty ring causes data corruption.
|
||||
*/
|
||||
if (!s->kvm_dirty_ring_size) {
|
||||
dirty_log_manual_caps =
|
||||
kvm_check_extension(s, KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2);
|
||||
dirty_log_manual_caps &= (KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE |
|
||||
|
@ -2147,6 +2155,7 @@ static int kvm_init(MachineState *ms)
|
|||
s->manual_dirty_log_protect = 0;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
#ifdef KVM_CAP_VCPU_EVENTS
|
||||
s->vcpu_events = kvm_check_extension(s, KVM_CAP_VCPU_EVENTS);
|
||||
|
|
Loading…
Reference in New Issue