On Tue, Oct 26, 2021 at 6:36 PM Pavel Dovgalyuk
<pavel.dovgal...@ispras.ru> wrote:
>
> Setting timers randomly when vmstate is loaded breaks
> execution determinism.
> Therefore this patch allows saving mit and autoneg timers
> for e1000. It makes execution deterministic and allows
> snapshotting and reverse debugging in icount mode.
>
> Signed-off-by: Pavel Dovgalyuk <pavel.dovgal...@ispras.ru>
> ---
> hw/net/e1000.c | 61
> ++++++++++++++++++++++++++++++++++++++++++++++----------
> 1 file changed, 50 insertions(+), 11 deletions(-)
>
> diff --git a/hw/net/e1000.c b/hw/net/e1000.c
> index a30546c5d5..2f706f7298 100644
> --- a/hw/net/e1000.c
> +++ b/hw/net/e1000.c
> @@ -37,6 +37,7 @@
> #include "qemu/iov.h"
> #include "qemu/module.h"
> #include "qemu/range.h"
> +#include "sysemu/replay.h"
>
> #include "e1000x_common.h"
> #include "trace.h"
> @@ -1407,7 +1408,7 @@ static int e1000_pre_save(void *opaque)
> * complete auto-negotiation immediately. This allows us to look
> * at MII_SR_AUTONEG_COMPLETE to infer link status on load.
> */
> - if (nc->link_down && have_autoneg(s)) {
> + if (replay_mode == REPLAY_MODE_NONE && nc->link_down && have_autoneg(s))
> {
> s->phy_reg[PHY_STATUS] |= MII_SR_AUTONEG_COMPLETE;
> }
>
> @@ -1438,22 +1439,12 @@ static int e1000_post_load(void *opaque, int
> version_id)
> s->mac_reg[TADV] = 0;
> s->mit_irq_level = false;
> }
> - s->mit_ide = 0;
> - s->mit_timer_on = true;
> - timer_mod(s->mit_timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + 1);
>
> /* nc.link_down can't be migrated, so infer link_down according
> * to link status bit in mac_reg[STATUS].
> * Alternatively, restart link negotiation if it was in progress. */
> nc->link_down = (s->mac_reg[STATUS] & E1000_STATUS_LU) == 0;
>
> - if (have_autoneg(s) &&
> - !(s->phy_reg[PHY_STATUS] & MII_SR_AUTONEG_COMPLETE)) {
> - nc->link_down = false;
> - timer_mod(s->autoneg_timer,
> - qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 500);
> - }
So we won't get those timers armed after migration unconditionally. Is
this intended?
Thanks
> -
> s->tx.props = s->mig_props;
> if (!s->received_tx_tso) {
> /* We received only one set of offload data (tx.props)
> @@ -1472,6 +1463,13 @@ static int e1000_tx_tso_post_load(void *opaque, int
> version_id)
> return 0;
> }
>
> +static int e1000_mit_timer_post_load(void *opaque, int version_id)
> +{
> + E1000State *s = opaque;
> + s->mit_timer_on = true;
> + return 0;
> +}
> +
> static bool e1000_mit_state_needed(void *opaque)
> {
> E1000State *s = opaque;
> @@ -1493,6 +1491,21 @@ static bool e1000_tso_state_needed(void *opaque)
> return chkflag(TSO);
> }
>
> +static bool e1000_mit_timer_needed(void *opaque)
> +{
> + E1000State *s = opaque;
> +
> + return s->mit_timer_on;
> +}
> +
> +static bool e1000_autoneg_timer_needed(void *opaque)
> +{
> + E1000State *s = opaque;
> +
> + return have_autoneg(s)
> + && !(s->phy_reg[PHY_STATUS] & MII_SR_AUTONEG_COMPLETE);
> +}
> +
> static const VMStateDescription vmstate_e1000_mit_state = {
> .name = "e1000/mit_state",
> .version_id = 1,
> @@ -1541,6 +1554,30 @@ static const VMStateDescription
> vmstate_e1000_tx_tso_state = {
> }
> };
>
> +static const VMStateDescription vmstate_e1000_mit_timer = {
> + .name = "e1000/mit_timer",
> + .version_id = 1,
> + .minimum_version_id = 1,
> + .needed = e1000_mit_timer_needed,
> + .post_load = e1000_mit_timer_post_load,
> + .fields = (VMStateField[]) {
> + VMSTATE_TIMER_PTR(mit_timer, E1000State),
> + VMSTATE_UINT32(mit_ide, E1000State),
> + VMSTATE_END_OF_LIST()
> + }
> +};
> +
> +static const VMStateDescription vmstate_e1000_autoneg_timer = {
> + .name = "e1000/autoneg_timer",
> + .version_id = 1,
> + .minimum_version_id = 1,
> + .needed = e1000_autoneg_timer_needed,
> + .fields = (VMStateField[]) {
> + VMSTATE_TIMER_PTR(autoneg_timer, E1000State),
> + VMSTATE_END_OF_LIST()
> + }
> +};
> +
> static const VMStateDescription vmstate_e1000 = {
> .name = "e1000",
> .version_id = 2,
> @@ -1622,6 +1659,8 @@ static const VMStateDescription vmstate_e1000 = {
> &vmstate_e1000_mit_state,
> &vmstate_e1000_full_mac_state,
> &vmstate_e1000_tx_tso_state,
> + &vmstate_e1000_mit_timer,
> + &vmstate_e1000_autoneg_timer,
> NULL
> }
> };
>
