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From: Nicholas Piggin <npiggin@gmail.com>
To: Ganesh Goudar <ganeshgr@linux.ibm.com>,
	linuxppc-dev@lists.ozlabs.org, mpe@ellerman.id.au
Cc: aneesh.kumar@linux.ibm.com, mahesh@linux.vnet.ibm.com
Subject: Re: [PATCH] powerpc/mce: Avoid using addr_to_pfn in realmode
Date: Mon, 22 Jun 2020 12:16:11 +1000	[thread overview]
Message-ID: <1592791213.eqbgr0cksa.astroid@bobo.none> (raw)
In-Reply-To: <20200620124435.9900-1-ganeshgr@linux.ibm.com>

Excerpts from Ganesh Goudar's message of June 20, 2020 10:44 pm:
> When an UE or memory error exception is encountered the MCE handler
> tries to find the pfn using addr_to_pfn() which takes effective
> address as an argument, later pfn is used to poison the page where
> memory error occurred, recent rework in this area made addr_to_pfn
> to run in realmode, which can be fatal as it may try to access
> memory outside RMO region.
> 
> To fix this move the use of addr_to_pfn to save_mce_event(), which
> runs in virtual mode.

I'd rather this be done in the pseries mce handler rather than
change bare metal, and leaving save_mce_event as purely recording the 
event, decoding remains in its caller.

Radix guests also don't have an RMO, we could probably restrict that
pseries hack to hash. I want to get rid of it but it will take longer
to fix things properly.

Thanks,
Nick

      reply	other threads:[~2020-06-22  2:18 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-20 12:44 [PATCH] powerpc/mce: Avoid using addr_to_pfn in realmode Ganesh Goudar
2020-06-22  2:16 ` Nicholas Piggin [this message]

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