Re: [Qemu-devel] [PATCH v3 2/2] xen_platform: SUSE xenlinux unplug for emulated PCI

[Stefano Stabellini]

On Fri, 21 Oct 2016, Olaf Hering wrote:
> Implement SUSE specific unplug protocol for emulated PCI devices
> in PVonHVM guests. Its a simple 'outl(1, (ioaddr + 4));'.
> This protocol was implemented and used since Xen 3.0.4.
> It is used in all SUSE/SLES/openSUSE releases up to SLES11SP3 and
> openSUSE 12.3.
> In addition old (pre-2011) VMDP versions are handled as well.
> 
> Signed-off-by: Olaf Hering <address@hidden>

Reviewed-by: Stefano Stabellini <address@hidden>


>  hw/i386/xen/xen_platform.c | 27 ++++++++++++++++++++++++++-
>  1 file changed, 26 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/i386/xen/xen_platform.c b/hw/i386/xen/xen_platform.c
> index 91d8a7a..2e1e543 100644
> --- a/hw/i386/xen/xen_platform.c
> +++ b/hw/i386/xen/xen_platform.c
> @@ -311,13 +311,38 @@ static void xen_platform_ioport_writeb(void *opaque, 
> hwaddr addr,
>                                         uint64_t val, unsigned int size)
>  {
>      PCIXenPlatformState *s = opaque;
> +    PCIDevice *pci_dev = PCI_DEVICE(s);
>  
>      switch (addr) {
>      case 0: /* Platform flags */
>          platform_fixed_ioport_writeb(opaque, 0, (uint32_t)val);
>          break;
> +    case 4:
> +        if (val == 1) {
> +            /*
> +             * SUSE unplug for Xenlinux
> +             * xen-kmp used this since xen-3.0.4, instead the official 
> protocol
> +             * from xen-3.3+ It did an unconditional "outl(1, (ioaddr + 4));"
> +             * Pre VMDP 1.7 used 4 and 8 depending on how VMDP was 
> configured.
> +             * If VMDP was to control both disk and LAN it would use 4.
> +             * If it controlled just disk or just LAN, it would use 8 below.
> +             */
> +            pci_unplug_disks(pci_dev->bus);
> +            pci_unplug_nics(pci_dev->bus);
> +        }
> +        break;
>      case 8:
> -        log_writeb(s, (uint32_t)val);
> +        switch (val) {
> +        case 1:
> +            pci_unplug_disks(pci_dev->bus);
> +            break;
> +        case 2:
> +            pci_unplug_nics(pci_dev->bus);
> +            break;
> +        default:
> +            log_writeb(s, (uint32_t)val);
> +            break;
> +        }
>          break;
>      default:
>          break;
>