RE: [PATCH v1 2/2] colo-compare: Record packet creation time by QEMU_CLOCK_REALTIME

[Zhang, Chen]

> -----Original Message-----
> From: Derek Su <dereksu@qnap.com>
> Sent: Saturday, September 12, 2020 3:05 AM
> To: qemu-devel@nongnu.org
> Cc: Zhang, Chen <chen.zhang@intel.com>; lizhijian@cn.fujitsu.com;
> jasowang@redhat.com; Derek Su <dereksu@qnap.com>
> Subject: [PATCH v1 2/2] colo-compare: Record packet creation time by
> QEMU_CLOCK_REALTIME
> 
> Record packet creation time by QEMU_CLOCK_REALTIME instead of
> QEMU_CLOCK_HOST. The time difference between `now` and packet
> `creation_ms` has the possibility of an unexpected negative value and results
> in wrong comparison after changing the host clock.
> 

Hi Derek,

I think this issue caused by other code in this file use the 
qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL);
I will change all code to QEMU_CLOCK_HOST to fix it with the patch 1/2. 

Thanks
Zhang Chen

> Signed-off-by: Derek Su <dereksu@qnap.com>
> ---
>  net/colo-compare.c | 2 +-
>  net/colo.c         | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/net/colo-compare.c b/net/colo-compare.c index
> c4de86ef34..29d7f986e3 100644
> --- a/net/colo-compare.c
> +++ b/net/colo-compare.c
> @@ -621,7 +621,7 @@ static int colo_packet_compare_other(Packet *spkt,
> Packet *ppkt)
> 
>  static int colo_old_packet_check_one(Packet *pkt, void *user_data)  {
> -    int64_t now = qemu_clock_get_ms(QEMU_CLOCK_HOST);
> +    int64_t now = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
>      uint32_t check_time = *(uint32_t *)user_data;
> 
>      if ((now - pkt->creation_ms) > check_time) { diff --git a/net/colo.c
> b/net/colo.c index a6c66d829a..0441910169 100644
> --- a/net/colo.c
> +++ b/net/colo.c
> @@ -164,7 +164,7 @@ Packet *packet_new(const void *data, int size, int
> vnet_hdr_len)
> 
>      pkt->data = g_memdup(data, size);
>      pkt->size = size;
> -    pkt->creation_ms = qemu_clock_get_ms(QEMU_CLOCK_HOST);
> +    pkt->creation_ms = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
>      pkt->vnet_hdr_len = vnet_hdr_len;
>      pkt->tcp_seq = 0;
>      pkt->tcp_ack = 0;
> --
> 2.25.1