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From: David Woodhouse <dwmw2@infradead.org>
To: Sean Christopherson <seanjc@google.com>
Cc: Dongli Zhang <dongli.zhang@oracle.com>,
	Joe Jin <joe.jin@oracle.com>,
	x86@kernel.org, kvm@vger.kernel.org,
	linux-kernel@vger.kernel.org, pbonzini@redhat.com,
	tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
	dave.hansen@linux.intel.com
Subject: Re: [PATCH RFC 1/1] KVM: x86: add param to update master clock periodically
Date: Wed, 04 Oct 2023 09:06:14 +0100	[thread overview]
Message-ID: <d00c8a58b366419abf94bfcdc96710390f0416aa.camel@infradead.org> (raw)
In-Reply-To: <ZRysuu8YJg0cLCt4@google.com>

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On Tue, 2023-10-03 at 17:07 -0700, Sean Christopherson wrote:
> 
> The issue is that the timekeeping code doesn't provide a notification mechanism
> to *just* get updates for things like suspend/reume.  We could maybe do something
> in KVM like unregister the notifier if the TSC is constant, and manually refresh
> on suspend/resume.  But that's pretty gross too, and I'd definitely be concerned
> that we missed something.

Or *in* the existing notifier, just do the maths (correctly!) and don't
update KVM's raw_clock data if the only thing that's really changed is
the passage of time?

On the whole, it's better if your other patch works to avoid the drift
in the first place. I'll test it...

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  reply	other threads:[~2023-10-04  8:06 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-26 23:06 [PATCH RFC 1/1] KVM: x86: add param to update master clock periodically Dongli Zhang
2023-09-27  0:29 ` Joe Jin
2023-09-27  0:36   ` Dongli Zhang
2023-09-28 16:18     ` Sean Christopherson
2023-09-29 20:15       ` Dongli Zhang
2023-10-02  8:33         ` David Woodhouse
2023-10-02 16:37           ` Sean Christopherson
2023-10-02 17:17             ` Dongli Zhang
2023-10-02 18:18               ` Sean Christopherson
2023-10-02 21:06                 ` Peter Zijlstra
2023-10-02 21:16                   ` Peter Zijlstra
2023-10-02 18:16             ` David Woodhouse
2023-10-03  0:53               ` Sean Christopherson
2023-10-03  1:32                 ` Dongli Zhang
2023-10-03  1:49                   ` Sean Christopherson
2023-10-03  2:07                     ` Dongli Zhang
2023-10-03 21:00                       ` Sean Christopherson
2023-10-03  5:54                 ` David Woodhouse
2023-10-04  0:04                   ` Sean Christopherson
2023-10-04 10:01                     ` David Woodhouse
2023-10-04 18:06                       ` Sean Christopherson
2023-10-04 19:13                         ` Dongli Zhang
2023-10-11  0:20                           ` Sean Christopherson
2023-10-11  7:18                             ` David Woodhouse
2023-10-13 18:07                               ` Sean Christopherson
2023-10-13 18:21                                 ` David Woodhouse
2023-10-13 19:02                                   ` Sean Christopherson
2023-10-13 19:12                                     ` David Woodhouse
2023-10-13 20:03                                       ` Sean Christopherson
2023-10-13 20:12                                 ` Dongli Zhang
2023-10-13 23:26                                   ` Sean Christopherson
2023-10-14  9:49                                     ` David Woodhouse
2023-10-16 15:47                                       ` Dongli Zhang
2023-10-16 16:25                                         ` David Woodhouse
2023-10-16 17:04                                           ` Dongli Zhang
2023-10-16 18:49                                           ` Sean Christopherson
2023-10-16 22:04                                             ` Dongli Zhang
2023-10-16 22:48                                               ` Sean Christopherson
2023-10-17 16:18                                                 ` Dongli Zhang
2023-10-03  9:12                 ` David Woodhouse
2023-10-04  0:07                   ` Sean Christopherson
2023-10-04  8:06                     ` David Woodhouse [this message]
2023-10-03 14:29                 ` David Woodhouse
2023-10-04  0:10                   ` Sean Christopherson

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