public inbox for kvm@vger.kernel.org
 help / color / mirror / Atom feed
From: Andi Kleen <ak@linux.intel.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: kvm@vger.kernel.org
Subject: Re: qemu polling KVM_IRQ_LINE_STATUS when stopped
Date: Fri, 20 Oct 2017 07:09:17 -0700	[thread overview]
Message-ID: <20171020140917.GH5109@tassilo.jf.intel.com> (raw)
In-Reply-To: <22d62b58-725b-9065-1f6d-081972ca32c3@redhat.com>

> Unfortunately that's not possible in general.  Windows uses the periodic
> timer to track wall time (!), so if you do that your clock is going to
> be late when you resume the guest.

But when the guest cannot execute instructions 
it cannot see whatever the handler does.

So the handler could always catch up after stopping for longer,
without making any difference.

> 
> But yeah, we might have to figure out a way to do that for non-Windows
> guests.  But why is the RTC periodic timer on at all in your setup?

Sorry this one was actually a Windows guest.

I'll check the Linux guests too.

-Andi

  reply	other threads:[~2017-10-20 14:10 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-10-17 21:34 qemu polling KVM_IRQ_LINE_STATUS when stopped Andi Kleen
2017-10-18  7:47 ` Paolo Bonzini
2017-10-18 17:49   ` Andi Kleen
2017-10-18 19:24     ` Paolo Bonzini
2017-10-20  0:34       ` Andi Kleen
2017-10-20  8:32         ` Paolo Bonzini
2017-10-20 14:09           ` Andi Kleen [this message]
2017-10-20 15:12             ` Paolo Bonzini
2017-10-20 20:50               ` Andi Kleen
2017-10-20 22:51                 ` Paolo Bonzini
2020-06-25 14:26                   ` Kevin Locke
2020-06-25 16:28                     ` Andi Kleen
2020-06-25 18:41                     ` Paolo Bonzini
2020-06-25 18:56                       ` Kevin Locke
2020-06-25 19:17                         ` Paolo Bonzini
2020-06-25 20:10                           ` Kevin Locke
2020-06-26 15:14                       ` Kevin Locke

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=20171020140917.GH5109@tassilo.jf.intel.com \
    --to=ak@linux.intel.com \
    --cc=kvm@vger.kernel.org \
    --cc=pbonzini@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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox