xen_console: support the new extended xenstore protocol

Since CS 21994 on xen-unstable.hg and CS
466608f3a32e1f9808acdf832a5843af37e5fcec on qemu-xen-unstable.git, few
changes have been introduced to the PV console xenstore protocol, as
described by the document docs/misc/console.txt under xen-unstable.hg.

From the Qemu point of view, very few modifications are needed to
correctly support the protocol: read from xenstore the "output" node
that tell us what the output of the PV console is going to be.
In case the output is a tty, write to xenstore the device name.

Changes in v2:

- fix error paths: free malloc'ed strings and close the xenstore
connection before returning;

- remove useless snprintf in xenstore_store_pv_console_info if i == 0.

Changes in v3:

- replace xs_daemon_open/xs_daemon_close with xs_open/xs_close.

Changes in v4:

- add a compatibility implementation of xs_open/xs_close.

Changes in v5:

- fix code style.

[agraf] fix build error due to missing stub

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Alexander Graf <agraf@suse.de>

3 files changed, 23 insertions, 6 deletions

diff --git a/hw/xen.h b/hw/xen.h
index 95029bb164..e432705f45 100644
--- a/hw/xen.h
+++ b/hw/xen.h
@@ -41,6 +41,7 @@ qemu_irq *xen_interrupt_controller_init(void);
 int xen_init(void);
 int xen_hvm_init(void);
 void xen_vcpu_init(void);
+void xenstore_store_pv_console_info(int i, struct CharDriverState *chr);
 
 #if defined(NEED_CPU_H) && !defined(CONFIG_USER_ONLY)
 void xen_ram_alloc(ram_addr_t ram_addr, ram_addr_t size);
diff --git a/hw/xen_common.h b/hw/xen_common.h
index 2c79af64d0..0409ac7971 100644
--- a/hw/xen_common.h
+++ b/hw/xen_common.h
@@ -85,6 +85,18 @@ static inline int xc_domain_add_to_physmap(int xc_handle, uint32_t domid,
     return xc_memory_op(xc_handle, XENMEM_add_to_physmap, &xatp);
 }
 
+static inline struct xs_handle *xs_open(unsigned long flags)
+{
+    return xs_daemon_open();
+}
+
+static inline void xs_close(struct xs_handle *xsh)
+{
+    if (xsh != NULL) {
+        xs_daemon_close(xsh);
+    }
+}
+
 
 /* Xen 4.1 */
 #else
diff --git a/hw/xen_console.c b/hw/xen_console.c
index 2d613ee6e5..bdb8540542 100644
--- a/hw/xen_console.c
+++ b/hw/xen_console.c
@@ -179,8 +179,9 @@ static void xencons_send(struct XenConsole *con)
 static int con_init(struct XenDevice *xendev)
 {
     struct XenConsole *con = container_of(xendev, struct XenConsole, xendev);
-    char *type, *dom;
+    char *type, *dom, label[32];
     int ret = 0;
+    const char *output;
 
     /* setup */
     dom = xs_get_domain_path(xenstore, con->xendev.dom);
@@ -194,11 +195,14 @@ static int con_init(struct XenDevice *xendev)
         goto out;
     }
 
-    if (!serial_hds[con->xendev.dev])
-	xen_be_printf(xendev, 1, "WARNING: serial line %d not configured\n",
-                      con->xendev.dev);
-    else
-        con->chr = serial_hds[con->xendev.dev];
+    output = xenstore_read_str(con->console, "output");
+    /* output is a pty by default */
+    if (output == NULL) {
+        output = "pty";
+    }
+    snprintf(label, sizeof(label), "xencons%d", con->xendev.dev);
+    con->chr = qemu_chr_open(label, output, NULL);
+    xenstore_store_pv_console_info(con->xendev.dev, con->chr);
 
 out:
     qemu_free(type);