Re: [Qemu-devel] [PATCH 08/12] pci: allow 0 address for PCI IO regions

From: Alexey Kardashevskiy <aik@ozlabs.ru>
To: Michael Roth <mdroth@linux.vnet.ibm.com>, qemu-devel@nongnu.org
Cc: ncmike@ncultra.org, nfont@linux.vnet.ibm.com,
	qemu-ppc@nongnu.org, agraf@suse.de, tyreld@linux.vnet.ibm.com
Subject: Re: [Qemu-devel] [PATCH 08/12] pci: allow 0 address for PCI IO regions
Date: Tue, 26 Aug 2014 19:14:27 +1000	[thread overview]
Message-ID: <53FC4FF3.6020906@ozlabs.ru> (raw)
In-Reply-To: <1408407718-10835-9-git-send-email-mdroth@linux.vnet.ibm.com>

On 08/19/2014 10:21 AM, Michael Roth wrote:
> Some kernels program a 0 address for io regions. PCI 3.0 spec
> section 6.2.5.1 doesn't seem to disallow this.

I remember there was discussion about it but I forgot :) Why does it have
to be a part of this patchset? Worth mentioning in the commit log I believe.

> 
> Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
> ---
>  hw/pci/pci.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/hw/pci/pci.c b/hw/pci/pci.c
> index 351d320..9578749 100644
> --- a/hw/pci/pci.c
> +++ b/hw/pci/pci.c
> @@ -1035,7 +1035,7 @@ static pcibus_t pci_bar_address(PCIDevice *d,
>          /* Check if 32 bit BAR wraps around explicitly.
>           * TODO: make priorities correct and remove this work around.
>           */
> -        if (last_addr <= new_addr || new_addr == 0 || last_addr >= UINT32_MAX) {
> +        if (last_addr <= new_addr || last_addr >= UINT32_MAX) {
>              return PCI_BAR_UNMAPPED;
>          }
>          return new_addr;
> 

-- 
Alexey