From: Brian King <brking@linux.vnet.ibm.com>
To: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Jan Kiszka <jan.kiszka@siemens.com>,
linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
"Hans J. Koch" <hjk@hansjkoch.de>,
Greg Kroah-Hartman <gregkh@suse.de>,
"Michael S. Tsirkin" <mst@redhat.com>,
kvm@vger.kernel.org
Subject: Re: [PATCH 0/3] PCI: Rework config space locking, add INTx masking services
Date: Fri, 14 Oct 2011 10:44:11 -0500 [thread overview]
Message-ID: <4E9858CB.7080005@linux.vnet.ibm.com> (raw)
In-Reply-To: <20111006084853.033d8d0f@jbarnes-desktop>
On 10/06/2011 10:48 AM, Jesse Barnes wrote:
> On Mon, 12 Sep 2011 18:54:01 +0200
> Jan Kiszka <jan.kiszka@siemens.com> wrote:
>
>> This series tries to heal the currently broken locking scheme around PCI
>> config space accesses.
>>
>> We have an interface lock out access via sysfs, but that service wrongly
>> assumes it is only called by one instance at a time for some device. So
>> two loops doing
>>
>> echo 1 > /sys/bus/pci/devices/<some-device>/reset
>>
>> in parallel will trigger a kernel BUG at the moment.
>>
>> Besides synchronizing with user space, we also need to manage config
>> space access of generic PCI drivers. They need to mask legacy interrupt
>> lines while the specific driver runs in user space or a guest OS.
>>
>> The approach taken here is provide mutex-like locking for general
>> access - which still requires a special mechanism due to requirements of
>> the IBM Power RAID SCSI driver. Furthermore, INTx masking is now
>> available via the PCI core and synchronized via the internal pci_lock.
>>
>> Not sure who may want to take this, so I'm CC'ing broadly.
>
> ISTR a bunch of discussion about this (just back from lots of work
> travel and vacation, sorry I missed most of it).
>
> Is this the agreed upon way of handling it? If so, can I get some
> Reviewed/Acked-bys from people?
Acked-by: Brian King <brking@linux.vnet.ibm.com>
--
Brian King
Linux on Power Virtualization
IBM Linux Technology Center
next prev parent reply other threads:[~2011-10-14 15:44 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-12 16:54 [PATCH 0/3] PCI: Rework config space locking, add INTx masking services Jan Kiszka
2011-09-12 16:54 ` [PATCH 1/3] pci: Rework config space blocking services Jan Kiszka
2011-11-02 20:59 ` Jesse Barnes
2011-09-12 16:54 ` [PATCH 2/3] pci: Introduce INTx check & mask API Jan Kiszka
2011-09-12 16:54 ` [PATCH 3/3] uio: Convert uio_generic_pci to new intx masking API Jan Kiszka
2011-10-06 15:48 ` [PATCH 0/3] PCI: Rework config space locking, add INTx masking services Jesse Barnes
2011-10-14 14:48 ` Jan Kiszka
2011-10-25 12:32 ` Jan Kiszka
2011-10-14 15:44 ` Brian King [this message]
2011-10-16 14:25 ` Michael S. Tsirkin
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