From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Peter Maydell <peter.maydell@linaro.org>
Cc: Michael Roth <mdroth@linux.vnet.ibm.com>,
QEMU Developers <qemu-devel@nongnu.org>,
Mike Day <ncmike@ncultra.org>, Paul Mackerras <paulus@samba.org>,
tyreld@linux.vnet.ibm.com, nfont@linux.vnet.ibm.com,
"qemu-ppc@nongnu.org" <qemu-ppc@nongnu.org>
Subject: Re: [Qemu-devel] [Qemu-ppc] [PATCH v2 10/14] pci: allow 0 address for PCI IO regions
Date: Wed, 11 Dec 2013 10:03:21 +1100 [thread overview]
Message-ID: <1386716601.32037.83.camel@pasglop> (raw)
In-Reply-To: <CAFEAcA_j=rP0xAnoc_eaK8XW8T5EjVvDsT=z0NvVyDWNf8FMjg@mail.gmail.com>
On Tue, 2013-12-10 at 22:14 +0000, Peter Maydell wrote:
> Googling again brought up this mailing list thread:
>
> http://www.pcisig.com/reflector/msg00459.html
>
> which includes what is supposedly a quote from the PCI 2.1 spec:
>
> # "Note: A Base Address register does not contain a valid
> # address when it is equal to "0""
>
> (I don't have access to the 2.1 version to check.)
>
> This text seems to have been removed from the 2.2 spec.
I have seen practical cases of both:
- Systems where the FW sets up a BAR to 0 and considers it valid
- Adapters that treat a BAR set to 0 as disabled
There's no win here. However it makes sense for qemu not to treat 0
as a special value, it's not necessary.
Cheers,
Ben.
next prev parent reply other threads:[~2013-12-10 23:03 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-05 22:32 [Qemu-devel] [PATCH v2 00/14] spapr: add support for pci hotplug Michael Roth
2013-12-05 22:32 ` [Qemu-devel] [PATCH v2 01/14] spapr: populate DRC entries for root dt node Michael Roth
2013-12-16 2:59 ` Alexey Kardashevskiy
2013-12-16 4:54 ` Alexey Kardashevskiy
2014-01-16 20:51 ` Michael Roth
2014-01-20 2:58 ` Alexey Kardashevskiy
2014-01-20 14:12 ` Mike Day
2014-01-20 17:24 ` Michael Roth
2014-01-20 17:59 ` Mike Day
2014-01-20 18:51 ` Michael Roth
2013-12-05 22:32 ` [Qemu-devel] [PATCH v2 02/14] spapr_pci: populate DRC dt entries for PHBs Michael Roth
2013-12-05 22:32 ` [Qemu-devel] [PATCH v2 03/14] spapr: add helper to retrieve a PHB/device DrcEntry Michael Roth
2013-12-05 22:32 ` [Qemu-devel] [PATCH v2 04/14] spapr_pci: add set-indicator RTAS interface Michael Roth
2013-12-16 4:26 ` Alexey Kardashevskiy
2014-01-16 20:54 ` Michael Roth
2013-12-05 22:32 ` [Qemu-devel] [PATCH v2 05/14] spapr_pci: add get/set-power-level RTAS interfaces Michael Roth
2013-12-16 3:09 ` Alexey Kardashevskiy
2014-01-16 21:01 ` Michael Roth
2013-12-05 22:32 ` [Qemu-devel] [PATCH v2 06/14] spapr_pci: add get-sensor-state RTAS interface Michael Roth
2013-12-05 22:32 ` [Qemu-devel] [PATCH v2 07/14] spapr_pci: add ibm, configure-connector " Michael Roth
2013-12-05 22:32 ` [Qemu-devel] [PATCH v2 08/14] memory: add memory_region_find_subregion Michael Roth
2013-12-05 22:33 ` [Qemu-devel] [PATCH v2 09/14] pci: make pci_bar useable outside pci.c Michael Roth
2013-12-05 22:33 ` [Qemu-devel] [PATCH v2 10/14] pci: allow 0 address for PCI IO regions Michael Roth
2013-12-05 23:33 ` Peter Maydell
2013-12-10 21:42 ` Michael Roth
2013-12-10 22:14 ` Peter Maydell
2013-12-10 23:03 ` Benjamin Herrenschmidt [this message]
2013-12-12 14:34 ` Michael S. Tsirkin
2013-12-05 22:33 ` [Qemu-devel] [PATCH v2 11/14] spapr_pci: enable basic hotplug operations Michael Roth
2013-12-16 4:36 ` Alexey Kardashevskiy
2014-01-16 21:22 ` Michael Roth
2013-12-05 22:33 ` [Qemu-devel] [PATCH v2 12/14] spapr_events: re-use EPOW event infrastructure for hotplug events Michael Roth
2013-12-16 5:05 ` Alexey Kardashevskiy
2014-01-16 21:32 ` Michael Roth
2013-12-05 22:33 ` [Qemu-devel] [PATCH v2 13/14] spapr_events: event-scan RTAS interface Michael Roth
2013-12-16 4:57 ` Alexey Kardashevskiy
2013-12-05 22:33 ` [Qemu-devel] [PATCH v2 14/14] spapr_pci: emit hotplug add/remove events during hotplug Michael Roth
2013-12-16 5:06 ` Alexey Kardashevskiy
2014-01-10 8:29 ` [Qemu-devel] [PATCH v2 00/14] spapr: add support for pci hotplug Alexey Kardashevskiy
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