From mboxrd@z Thu Jan  1 00:00:00 1970
From: Keir Fraser <keir.xen@gmail.com>
Subject: Re: [PATCH 2/2] x86/microcode: enable boot time
 (pre-Dom0) loading
Date: Wed, 30 Nov 2011 09:05:29 +0000
Message-ID: <CAFBA259.26155%keir.xen@gmail.com>
References: <4ED6676F02000078000646BC@nat28.tlf.novell.com>
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To: Jan Beulich <JBeulich@suse.com>, "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>
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On 30/11/2011 16:27, "Jan Beulich" <JBeulich@suse.com> wrote:

> 
> In order to not convert the spin_lock() in microcode_update_cpu() (and
> then obviously also all other uses on microcode_mutex) to
> spin_lock_irqsave() (which would be undesirable for the hypercall
> context in which the function also runs), the boot time handling gets
> done using a tasklet (instead of using on_selected_cpus()).

Can you explain this some more? Why would the conversion to
spin_lock_irqsave be required when spin_lock is sufficient for current usage
from dom0 hypercall?

 -- Keir