linux-kernel - Re: [PATCH] xen/x86: Do not call xen_init_time_ops() until shared

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Date:   Thu, 4 May 2017 08:37:30 +0200
From:   Juergen Gross <jgross@...e.com>
To:     Boris Ostrovsky <boris.ostrovsky@...cle.com>
Cc:     xen-devel@...ts.xenproject.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] xen/x86: Do not call xen_init_time_ops() until
 shared_info is initialized

On 03/05/17 22:20, Boris Ostrovsky wrote:
> Routines that are set by xen_init_time_ops() use shared_info's
> pvclock_vcpu_time_info area. This area is not properly available until
> shared_info is mapped in xen_setup_shared_info().
> 
> This became especially problematic due to commit dd759d93f4dd ("x86/timers:
> Add simple udelay calibration") where we end up reading tsc_to_system_mul
> from xen_dummy_shared_info (i.e. getting zero value) and then trying
> to divide by it in pvclock_tsc_khz().
> 
> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@...cle.com>

Reviewed-by: Juergen Gross <jgross@...e.com>


Thanks,

Juergen