linux-kernel - RE: [PATCH 2/6] x86-mce: Modify CMCI storm exit to reenable instead of rediscover banks.

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Date:	Wed, 9 Jul 2014 20:20:41 +0000
From:	"Luck, Tony" <tony.luck@...el.com>
To:	Havard Skinnemoen <hskinnemoen@...gle.com>,
	Borislav Petkov <bp@...en8.de>
CC:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"Ewout van Bekkum" <ewout@...gle.com>
Subject: RE: [PATCH 2/6] x86-mce: Modify CMCI storm exit to reenable instead
 of rediscover banks.

> The CMCI storm handler previously called cmci_reenable() when exiting a
> CMCI storm. However, when entering a CMCI storm the bank ownership was
> not relinquished by the affected CPUs. The CMCIs were only disabled via
> cmci_storm_disable_banks(). The handler was updated to instead call a
> new function, cmci_storm_enable_banks(), to reenable CMCI on the already
> owned banks instead of rediscovering CMCI banks (which were still owned
> but disabled).

Won't this cause problems if we online a cpu during the storm. We will
re-run the discovery algorithm and some other cpu that shares the bank
will see MCi_CTL2{30} is zero and claim ownership.

-Tony
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