console: buffer and show origin of guest PV writes

Guests other than domain 0 using the console output have previously been
controlled by the VERBOSE #define, but with no designation of which
guest's output was on the console. This patch converts the HVM output
buffering to be used by all domains except the hardware domain (dom0):
stripping non-printable characters, line buffering the output, and
prefixing it with the domain ID. This is especially useful for debugging
stub domains during early boot.

Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Acked-by: Keir Fraser <keir@xen.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
index ae6a3b843b..0013a8d8ce 100644
--- a/xen/include/xen/sched.h
+++ b/xen/include/xen/sched.h
@@ -341,6 +341,12 @@ struct domain
     /* Control-plane tools handle for this domain. */
     xen_domain_handle_t handle;
 
+    /* hvm_print_line() and guest_console_write() logging. */
+#define DOMAIN_PBUF_SIZE 80
+    char       *pbuf;
+    unsigned    pbuf_idx;
+    spinlock_t  pbuf_lock;
+
     /* OProfile support. */
     struct xenoprof *xenoprof;
     int32_t time_offset_seconds;