From: Vitaly Kuznetsov <vkuznets@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>,
Juan Quintela <quintela@redhat.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
"Dr. David Alan Gilbert" <dgilbert@redhat.com>,
qemu-devel@nongnu.org,
Antoine Damhet <antoine.damhet@blade-group.com>
Subject: Re: [BUG] Migration hv_time rollback
Date: Wed, 16 Sep 2020 15:17:00 +0200 [thread overview]
Message-ID: <87363hj1yr.fsf@vitty.brq.redhat.com> (raw)
In-Reply-To: <37b1b2b7-40f5-d0b1-2709-df9fe24fc65f@redhat.com>
Paolo Bonzini <pbonzini@redhat.com> writes:
> On 16/09/20 13:29, Dr. David Alan Gilbert wrote:
>>> I have tracked the bug to the fact that `kvmclock` is not exposed and
>>> disabled from qemu PoV but is in fact used by `hv-time` (in KVM).
>>>
>>> I think we should enable the `kvmclock` (qemu device) if `hv-time` is
>>> present and add Hyper-V support for the `kvmclock_current_nsec`
>>> function.
>
> Yes, this seems correct. I would have to check but it may even be
> better to _always_ send kvmclock data in the live migration stream.
>
The question I have is: with 'kvm=off', do we actually restore TSC
reading on migration? (and I guess the answer is 'no' or Hyper-V TSC
page would 'just work' I guess). So yea, maybe dropping the
'cpu->env.features[FEAT_KVM]' check is the right fix.
--
Vitaly
prev parent reply other threads:[~2020-09-16 13:18 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-16 9:06 [BUG] Migration hv_time rollback Antoine Damhet
2020-09-16 11:29 ` Dr. David Alan Gilbert
2020-09-16 11:59 ` Vitaly Kuznetsov
2020-09-16 12:14 ` Antoine Damhet
2020-09-16 11:59 ` Antoine Damhet
2020-09-16 12:16 ` Vitaly Kuznetsov
2020-09-16 12:50 ` Vitaly Kuznetsov
2020-09-16 13:25 ` Antoine Damhet
2020-09-16 13:05 ` Paolo Bonzini
2020-09-16 13:17 ` Vitaly Kuznetsov [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87363hj1yr.fsf@vitty.brq.redhat.com \
--to=vkuznets@redhat.com \
--cc=antoine.damhet@blade-group.com \
--cc=dgilbert@redhat.com \
--cc=mst@redhat.com \
--cc=mtosatti@redhat.com \
--cc=pbonzini@redhat.com \
--cc=qemu-devel@nongnu.org \
--cc=quintela@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.