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

From: Boris Ostrovsky
Date: Fri Feb 26 2016 - 11:09:50 EST


On 02/26/2016 10:39 AM, Stefano Stabellini wrote:
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?

Sure, that sounds good.

(BTW, I didn't mean that my R-b was conditional on this)


-boris



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,
};