Paolo, have you forgot about this? Pavel Dovgalyuk
> -----Original Message----- > From: Paolo Bonzini [mailto:pbonz...@redhat.com] > Sent: Friday, May 11, 2018 12:14 PM > To: Pavel Dovgalyuk; qemu-devel@nongnu.org > Cc: arei.gong...@huawei.com; m...@redhat.com; ciro.santi...@gmail.com; > maria.klimushenk...@ispras.ru; dovga...@ispras.ru; kra...@redhat.com > Subject: Re: [PATCH] ps2: prevent changing irq state on save and load > > On 11/05/2018 10:16, Pavel Dovgalyuk wrote: > > Commit 2858ab09e6f708e381fc1a1cc87e747a690c4884 changed > > PS/2 keyboard/mouse buffers to the standard size. However, its state > > may change when migrating from the old buffer size and therefore irq needs > > updating. But this change made wrong, because it throws the whole queue > > if there are too much data instead of cropping it. > > > > That commit also updates irq (because the queue state may change). > > But updating the irq may change the VM state (and determinism of > > the execution). E.g., when replaying the execution, one may save > > the VM state and the state of the interrupt controller will be updated > > at the moment of saving, instead of using the recorded update events. > > > > This patch makes the queue update deterministic: it removes the update_irq > > call and crops the queue to prevent losing the characters and changing > > the required irq status. > > > > Signed-off-by: Pavel Dovgalyuk <pavel.dovga...@ispras.ru> > > --- > > hw/input/ps2.c | 8 ++++++-- > > 1 file changed, 6 insertions(+), 2 deletions(-) > > > > diff --git a/hw/input/ps2.c b/hw/input/ps2.c > > index 06f5d2a..8b1931b 100644 > > --- a/hw/input/ps2.c > > +++ b/hw/input/ps2.c > > @@ -837,7 +837,12 @@ static void ps2_common_post_load(PS2State *s) > > uint8_t tmp_data[PS2_QUEUE_SIZE]; > > > > /* set the useful data buffer queue size, < PS2_QUEUE_SIZE */ > > - size = (q->count < 0 || q->count > PS2_QUEUE_SIZE) ? 0 : q->count; > > + size = q->count; > > + if (q->count < 0) { > > + size = 0; > > + } else if (q->count > PS2_QUEUE_SIZE) { > > + size = PS2_QUEUE_SIZE; > > + } > > > > /* move the queue elements to the start of data array */ > > for (i = 0; i < size; i++) { > > @@ -852,7 +857,6 @@ static void ps2_common_post_load(PS2State *s) > > q->rptr = 0; > > q->wptr = size; > > q->count = size; > > - s->update_irq(s->update_arg, q->count != 0); > > } > > > > static void ps2_kbd_reset(void *opaque) > > > > Queued, thanks. > > Paolo
