From: Avi Kivity <avi@redhat.com>
To: Marcelo Tosatti <mtosatti@redhat.com>
Cc: kvm <kvm@vger.kernel.org>, Amit Shah <amit.shah@redhat.com>,
Eric B Munson <emunson@mgebm.net>
Subject: Re: KVM: x86: fix pvclock guest stopped flag reporting
Date: Thu, 02 Aug 2012 18:42:25 +0300 [thread overview]
Message-ID: <501A9FE1.8090209@redhat.com> (raw)
In-Reply-To: <20120802153343.GA12119@amt.cnet>
On 08/02/2012 06:33 PM, Marcelo Tosatti wrote:
>
> kvm_guest_time_update unconditionally clears hv_clock.flags field,
> so the notification never reaches the guest.
>
> Fix it by allowing PVCLOCK_GUEST_STOPPED to passthrough.
>
> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 3a53bcc..e8ce10f 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -1217,7 +1217,9 @@ static int kvm_guest_time_update(struct kvm_vcpu *v)
> vcpu->hv_clock.system_time = kernel_ns + v->kvm->arch.kvmclock_offset;
> vcpu->last_kernel_ns = kernel_ns;
> vcpu->last_guest_tsc = tsc_timestamp;
> - vcpu->hv_clock.flags = 0;
> + /* only support PVCLOCK_GUEST_STOPPED flag ATM */
> + if (vcpu->hv_clock.flags != PVCLOCK_GUEST_STOPPED)
> + vcpu->hv_clock.flags = 0;
>
Seems a little risky. Should we store the flag in a separate bool and
mix it in instead of RMWing it?
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2012-08-02 15:42 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-02 15:33 KVM: x86: fix pvclock guest stopped flag reporting Marcelo Tosatti
2012-08-02 15:42 ` Avi Kivity [this message]
2012-08-02 15:43 ` Marcelo Tosatti
2012-08-02 15:52 ` Avi Kivity
2012-08-02 16:00 ` Marcelo Tosatti
2012-08-03 18:57 ` KVM: x86: fix pvclock guest stopped flag reporting (v2) Marcelo Tosatti
2012-08-07 12:16 ` Amit Shah
2012-08-07 13:18 ` Eric B Munson
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