Re: [Xen-devel] [PATCH v2 2/3] hvc_xen: fix xenboot for DomUs

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Thu, 25 Feb 2016, Boris Ostrovsky wrote:
> On 02/25/2016 07:10 AM, Stefano Stabellini wrote:
> > The xenboot early console has been partially broken for DomU for a long
> > time: the output would only go to the hypervisor via hypercall
> > (HYPERVISOR_console_io), while it wouldn't actually go to the DomU
> > console. The reason is that domU_write_console would return early as no
> > xencons structs are configured for it.
> > 
> > Add an appropriate xencons struct for xenboot from the xenboot setup
> > callback.
> > 
> > Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
> > 
> > ---
> > Changes in v2:
> > - add return to xenboot_setup_console
> > ---
> >   drivers/tty/hvc/hvc_xen.c |   32 ++++++++++++++++++++++++++------
> >   1 file changed, 26 insertions(+), 6 deletions(-)
> > 
> > diff --git a/drivers/tty/hvc/hvc_xen.c b/drivers/tty/hvc/hvc_xen.c
> > index 68b8ec8..bf787aa 100644
> > --- a/drivers/tty/hvc/hvc_xen.c
> > +++ b/drivers/tty/hvc/hvc_xen.c
> > @@ -246,6 +246,18 @@ err:
> >     return -ENODEV;
> >   }
> >   +static int xen_early_pv_console_init(struct xencons_info *info, int
> > vtermno)
> 
> Nit: not sure whether "early" is the right word to use here: when called from
> xen_pv_console_init() it's not really on the early path.

What about xencons_info_pv_init?


> Other than that:
> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>

Thanks!


> > +{
> > +   info->evtchn = xen_start_info->console.domU.evtchn;
> > +   /* GFN == MFN for PV guest */
> > +   info->intf = gfn_to_virt(xen_start_info->console.domU.mfn);
> > +   info->vtermno = vtermno;
> > +
> > +   list_add_tail(&info->list, &xenconsoles);
> > +
> > +   return 0;
> > +}
> > +
> >   static int xen_pv_console_init(void)
> >   {
> >     struct xencons_info *info;
> > @@ -265,13 +277,8 @@ static int xen_pv_console_init(void)
> >             /* already configured */
> >             return 0;
> >     }
> > -   info->evtchn = xen_start_info->console.domU.evtchn;
> > -   /* GFN == MFN for PV guest */
> > -   info->intf = gfn_to_virt(xen_start_info->console.domU.mfn);
> > -   info->vtermno = HVC_COOKIE;
> > -
> >     spin_lock(&xencons_lock);
> > -   list_add_tail(&info->list, &xenconsoles);
> > +   xen_early_pv_console_init(info, HVC_COOKIE);
> >     spin_unlock(&xencons_lock);
> >             return 0;
> > @@ -599,6 +606,18 @@ static int xen_cons_init(void)
> >   console_initcall(xen_cons_init);
> >     #ifdef CONFIG_EARLY_PRINTK
> > +static int __init xenboot_setup_console(struct console *console, char
> > *string)
> > +{
> > +   static struct xencons_info xenboot;
> > +
> > +   if (xen_initial_domain())
> > +           return 0;
> > +   if (!xen_pv_domain())
> > +           return -ENODEV;
> > +
> > +   return xen_early_pv_console_init(&xenboot, 0);
> > +}
> > +
> >   static void xenboot_write_console(struct console *console, const char
> > *string,
> >                               unsigned len)
> >   {
> > @@ -629,6 +648,7 @@ static void xenboot_write_console(struct console
> > *console, const char *string,
> >   struct console xenboot_console = {
> >     .name           = "xenboot",
> >     .write          = xenboot_write_console,
> > +   .setup          = xenboot_setup_console,
> >     .flags          = CON_PRINTBUFFER | CON_BOOT | CON_ANYTIME,
> >     .index          = -1,
> >   };
> 

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