Date: Tue, 25 Nov 2008 20:19:46 -0800
From: Greg KH <greg@kroah.com>
To: Chris Wright <chrisw@sous-sol.org>
Cc: jbarnes@virtuousgeek.org, linux-pci@vger.kernel.org,
       linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
       allen.m.kay@intel.com, jun.nakajima@intel.com
Subject: Re: [PATCH 2/2] PCI: pci-stub module to reserve pci device
Message-ID: <20081126041946.GA18816@kroah.com>
References: <20081126033610.GB19881@sequoia.sous-sol.org> <20081126033839.GC19881@sequoia.sous-sol.org>
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On Tue, Nov 25, 2008 at 07:38:39PM -0800, Chris Wright wrote:
> When doing device assignment with KVM there's currently nothing to
> protect the device from having a driver in the host as well as the guest.
> This trivial module just binds the pci device on the host to a stub
> driver so that a real host driver can't bind to the device.  It has no
> pci id table, it supports only dynamic ids.
> 
>  # echo "8086 10f5" > /sys/bus/pci/drivers/pci-stub/new_id
>  # echo -n 0000:00:19.0 > /sys/bus/pci/drivers/e1000e/unbind
>  # echo -n 0000:00:19.0 > /sys/bus/pci/drivers/pci-stub/bind
>  # ls -l /sys/bus/pci/devices/0000:00:19.0/driver
>  lrwxrwxrwx 1 root root 0 2008-11-25 19:10 /sys/bus/pci/devices/0000:00:19.0/driver -> ../../../bus/pci/drivers/pci-stub

You might want to put this somewhere in the .c or documentation files
somewhere as well.

> 
> Cc: "Kay, Allen M" <allen.m.kay@intel.com>
> Cc: "Nakajima, Jun" <jun.nakajima@intel.com>
> Signed-off-by: Chris Wright <chrisw@sous-sol.org>
> ---
>  drivers/pci/Kconfig    |    9 +++++++++
>  drivers/pci/Makefile   |    2 ++
>  drivers/pci/pci-stub.c |   38 ++++++++++++++++++++++++++++++++++++++
>  3 files changed, 49 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/pci/pci-stub.c
> 
> diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
> index e1ca425..f6183df 100644
> --- a/drivers/pci/Kconfig
> +++ b/drivers/pci/Kconfig
> @@ -42,6 +42,15 @@ config PCI_DEBUG
>  
>  	  When in doubt, say N.
>  
> +config PCI_STUB
> +	tristate "PCI Stub driver"
> +	depends on PCI
> +	help
> +	  Say Y or M here if you want be able to reserve a PCI device
> +	  when it is going to be assigned to a guest.

"guest operating system"?  Otherwise, just "guest" doesn't mean much
here in this context.

Other than that minor thing, looks great.

Acked-by: Greg Kroah-Hartman <gregkh@suse.de>

thanks,

greg k-h
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