linux-kernel - Re: [PATCH 2/2] xen-pciback: also support disabling of bus-mastering and memory-write-invalidate

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Date:	Wed, 11 Mar 2015 10:42:05 -0400
From:	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
To:	Jan Beulich <JBeulich@...e.com>
Cc:	David Vrabel <david.vrabel@...rix.com>,
	Boris Ostrovsky <boris.ostrovsky@...cle.com>,
	xen-devel <xen-devel@...ts.xenproject.org>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] xen-pciback: also support disabling of bus-mastering
 and memory-write-invalidate

On Wed, Mar 11, 2015 at 01:52:00PM +0000, Jan Beulich wrote:
> It's not clear to me why only the enabling operation got handled so
> far.

Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
> 
> Signed-off-by: Jan Beulich <jbeulich@...e.com>
> ---
>  drivers/xen/xen-pciback/conf_space_header.c |   16 +++++++++++++++-
>  1 file changed, 15 insertions(+), 1 deletion(-)
> 
> --- 4.0-rc3-xen-pciback.orig/drivers/xen/xen-pciback/conf_space_header.c
> +++ 4.0-rc3-xen-pciback/drivers/xen/xen-pciback/conf_space_header.c
> @@ -88,9 +88,15 @@ static int command_write(struct pci_dev 
>  			printk(KERN_DEBUG DRV_NAME ": %s: set bus master\n",
>  			       pci_name(dev));
>  		pci_set_master(dev);
> +	} else if (dev->is_busmaster && !is_master_cmd(value)) {
> +		if (unlikely(verbose_request))
> +			printk(KERN_DEBUG DRV_NAME ": %s: clear bus master\n",
> +			       pci_name(dev));
> +		pci_clear_master(dev);
>  	}
>  
> -	if (value & PCI_COMMAND_INVALIDATE) {
> +	if (!(cmd->val & PCI_COMMAND_INVALIDATE) &&
> +	    (value & PCI_COMMAND_INVALIDATE)) {
>  		if (unlikely(verbose_request))
>  			printk(KERN_DEBUG
>  			       DRV_NAME ": %s: enable memory-write-invalidate\n",
> @@ -101,6 +107,13 @@ static int command_write(struct pci_dev 
>  				pci_name(dev), err);
>  			value &= ~PCI_COMMAND_INVALIDATE;
>  		}
> +	} else if ((cmd->val & PCI_COMMAND_INVALIDATE) &&
> +		   !(value & PCI_COMMAND_INVALIDATE)) {
> +		if (unlikely(verbose_request))
> +			printk(KERN_DEBUG
> +			       DRV_NAME ": %s: disable memory-write-invalidate\n",
> +			       pci_name(dev));
> +		pci_clear_mwi(dev);
>  	}
>  
>  	cmd->val = value;
> 
> 
> 
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