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Subject[PATCH v2 1/2] hvc_xen: support PV on HVM consoles
Date
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
---
drivers/tty/hvc/hvc_xen.c | 84 +++++++++++++++++++++++++++++-------
include/xen/interface/hvm/params.h | 6 ++-
2 files changed, 73 insertions(+), 17 deletions(-)
diff --git a/drivers/tty/hvc/hvc_xen.c b/drivers/tty/hvc/hvc_xen.c
index 52fdf60..d5000aa 100644
--- a/drivers/tty/hvc/hvc_xen.c
+++ b/drivers/tty/hvc/hvc_xen.c
@@ -24,9 +24,12 @@
#include <linux/init.h>
#include <linux/types.h>

+#include <asm/io.h>
#include <asm/xen/hypervisor.h>

#include <xen/xen.h>
+#include <xen/interface/xen.h>
+#include <xen/hvm.h>
#include <xen/page.h>
#include <xen/events.h>
#include <xen/interface/io/console.h>
@@ -42,9 +45,13 @@ static int xencons_irq;
/* ------------------------------------------------------------------ */

static unsigned long console_pfn = ~0ul;
+static unsigned int console_evtchn = ~0ul;
+static struct xencons_interface *xencons_if = NULL;

static inline struct xencons_interface *xencons_interface(void)
{
+ if (xencons_if != NULL)
+ return xencons_if;
if (console_pfn == ~0ul)
return mfn_to_virt(xen_start_info->console.domU.mfn);
else
@@ -54,7 +61,10 @@ static inline struct xencons_interface *xencons_interface(void)
static inline void notify_daemon(void)
{
/* Use evtchn: this is called early, before irq is set up. */
- notify_remote_via_evtchn(xen_start_info->console.domU.evtchn);
+ if (console_evtchn == ~0ul)
+ notify_remote_via_evtchn(xen_start_info->console.domU.evtchn);
+ else
+ notify_remote_via_evtchn(console_evtchn);
}

static int __write_console(const char *data, int len)
@@ -157,28 +167,63 @@ static struct hv_ops dom0_hvc_ops = {
.notifier_hangup = notifier_hangup_irq,
};

+static int xen_hvm_console_init(void)
+{
+ int r;
+ uint64_t v = 0;
+ unsigned long mfn;
+
+ if (!xen_hvm_domain())
+ return -ENODEV;
+
+ if (xencons_if != NULL)
+ return -EBUSY;
+
+ r = hvm_get_parameter(HVM_PARAM_CONSOLE_EVTCHN, &v);
+ if (r < 0)
+ return -ENODEV;
+ console_evtchn = v;
+ hvm_get_parameter(HVM_PARAM_CONSOLE_PFN, &v);
+ if (r < 0)
+ return -ENODEV;
+ mfn = v;
+ xencons_if = ioremap(mfn << PAGE_SHIFT, PAGE_SIZE);
+ if (xencons_if == NULL)
+ return -ENODEV;
+
+ return 0;
+}
+
static int __init xen_hvc_init(void)
{
struct hvc_struct *hp;
struct hv_ops *ops;
+ int r;

- if (!xen_pv_domain())
+ if (!xen_domain())
return -ENODEV;

if (xen_initial_domain()) {
ops = &dom0_hvc_ops;
xencons_irq = bind_virq_to_irq(VIRQ_CONSOLE, 0);
} else {
- if (!xen_start_info->console.domU.evtchn)
- return -ENODEV;
-
ops = &domU_hvc_ops;
- xencons_irq = bind_evtchn_to_irq(xen_start_info->console.domU.evtchn);
+ if (xen_pv_domain()) {
+ if (!xen_start_info->console.domU.evtchn)
+ return -ENODEV;
+ console_pfn = mfn_to_pfn(xen_start_info->console.domU.mfn);
+ console_evtchn = xen_start_info->console.domU.evtchn;
+ } else {
+ r = xen_hvm_console_init();
+ if (r < 0)
+ return r;
+ }
+ xencons_irq = bind_evtchn_to_irq(console_evtchn);
+ if (xencons_irq < 0)
+ xencons_irq = 0; /* NO_IRQ */
+ else
+ irq_set_noprobe(xencons_irq);
}
- if (xencons_irq < 0)
- xencons_irq = 0; /* NO_IRQ */
- else
- irq_set_noprobe(xencons_irq);

hp = hvc_alloc(HVC_COOKIE, xencons_irq, ops, 256);
if (IS_ERR(hp))
@@ -186,15 +231,13 @@ static int __init xen_hvc_init(void)

hvc = hp;

- console_pfn = mfn_to_pfn(xen_start_info->console.domU.mfn);
-
return 0;
}

void xen_console_resume(void)
{
if (xencons_irq)
- rebind_evtchn_irq(xen_start_info->console.domU.evtchn, xencons_irq);
+ rebind_evtchn_irq(console_evtchn, xencons_irq);
}

static void __exit xen_hvc_fini(void)
@@ -205,16 +248,22 @@ static void __exit xen_hvc_fini(void)

static int xen_cons_init(void)
{
- struct hv_ops *ops;
+ const struct hv_ops *ops;

- if (!xen_pv_domain())
+ if (!xen_domain())
return 0;

if (xen_initial_domain())
ops = &dom0_hvc_ops;
- else
+ else {
ops = &domU_hvc_ops;

+ if (xen_pv_domain())
+ console_evtchn = xen_start_info->console.domU.evtchn;
+ else
+ xen_hvm_console_init();
+ }
+
hvc_instantiate(HVC_COOKIE, 0, ops);
return 0;
}
@@ -230,6 +279,9 @@ static void xenboot_write_console(struct console *console, const char *string,
unsigned int linelen, off = 0;
const char *pos;

+ if (!xen_pv_domain())
+ return;
+
dom0_write_console(0, string, len);

if (xen_initial_domain())
diff --git a/include/xen/interface/hvm/params.h b/include/xen/interface/hvm/params.h
index 1888d8c..1b4f923 100644
--- a/include/xen/interface/hvm/params.h
+++ b/include/xen/interface/hvm/params.h
@@ -90,6 +90,10 @@
/* Boolean: Enable aligning all periodic vpts to reduce interrupts */
#define HVM_PARAM_VPT_ALIGN 16

-#define HVM_NR_PARAMS 17
+/* Console debug shared memory ring and event channel */
+#define HVM_PARAM_CONSOLE_PFN 17
+#define HVM_PARAM_CONSOLE_EVTCHN 18
+
+#define HVM_NR_PARAMS 19

#endif /* __XEN_PUBLIC_HVM_PARAMS_H__ */
--
1.7.2.5


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