Re: [Xen-devel] [PATCH] xen/pass-through: fold host PCI command register writes

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Fri, 15 May 2015, Jan Beulich wrote:
> The code introduced to address XSA-126 allows simplification of other
> code in xen_pt_initfn(): All we need to do is update "cmd" suitably,
> as it'll be written back to the host register near the end of the
> function anyway.
> 
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

Reviewed-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>

I'll add it to my queue.


> --- a/hw/xen/xen_pt.c
> +++ b/hw/xen/xen_pt.c
> @@ -698,10 +698,7 @@ static int xen_pt_initfn(PCIDevice *d)
>                     machine_irq, pirq, rc);
>  
>          /* Disable PCI intx assertion (turn on bit10 of devctl) */
> -        xen_host_pci_set_word(&s->real_device,
> -                              PCI_COMMAND,
> -                              pci_get_word(s->dev.config + PCI_COMMAND)
> -                              | PCI_COMMAND_INTX_DISABLE);
> +        cmd |= PCI_COMMAND_INTX_DISABLE;
>          machine_irq = 0;
>          s->machine_irq = 0;
>      } else {
> @@ -723,9 +720,7 @@ static int xen_pt_initfn(PCIDevice *d)
>                         e_intx, rc);
>  
>              /* Disable PCI intx assertion (turn on bit10 of devctl) */
> -            xen_host_pci_set_word(&s->real_device, PCI_COMMAND,
> -                                  *(uint16_t *)(&s->dev.config[PCI_COMMAND])
> -                                  | PCI_COMMAND_INTX_DISABLE);
> +            cmd |= PCI_COMMAND_INTX_DISABLE;
>              xen_pt_mapped_machine_irq[machine_irq]--;
>  
>              if (xen_pt_mapped_machine_irq[machine_irq] == 0) {
> 
> 
> 

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