Re: [Xen-devel] [PATCH 22/25 v7] xen/arm: vpl011: Add support for vuart console in xenconsole

[Wei Liu]

On Mon, Aug 07, 2017 at 02:23:14PM +0530, Bhupinder Thakur wrote:
> This patch finally adds the support for vuart console. It adds
> two new fields in the console initialization:
> 
> - optional
> - use_gnttab
> 
> optional flag tells whether the console is optional.
> 
> use_gnttab tells whether the ring buffer should be allocated using
> grant table.
> 
> Signed-off-by: Bhupinder Thakur 

Acked-by: Wei Liu 

> @@ -665,7 +689,9 @@ static int console_create_ring(struct console *con)
>   if (ring_ref != con->ring_ref && con->ring_ref != -1)
>   console_unmap_interface(con);
>  
> - if (!con->interface && xgt_handle) {
> + if (!con->interface &&
> + xgt_handle &&
> + con->use_gnttab) {

You can join all these to one line.

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[Xen-devel] [PATCH 22/25 v7] xen/arm: vpl011: Add support for vuart console in xenconsole

[Bhupinder Thakur]

This patch finally adds the support for vuart console. It adds
two new fields in the console initialization:

- optional
- use_gnttab

optional flag tells whether the console is optional.

use_gnttab tells whether the ring buffer should be allocated using
grant table.

Signed-off-by: Bhupinder Thakur 
---
CC: Andrew Cooper 
CC: George Dunlap 
CC: Ian Jackson 
CC: Jan Beulich 
CC: Konrad Rzeszutek Wilk 
CC: Stefano Stabellini 
CC: Tim Deegan 
CC: Wei Liu 
CC: Julien Grall 

Changes since v6:
- Renames prefer_gnttab to use_gnttab

Changes since v4:
- Renamed VUART_CFLAGS- to CFLAGS_vuart- in the Makefile as per the convention.

 config/arm32.mk   |  1 +
 config/arm64.mk   |  1 +
 tools/console/Makefile|  3 ++-
 tools/console/daemon/io.c | 32 ++--
 4 files changed, 34 insertions(+), 3 deletions(-)

diff --git a/config/arm32.mk b/config/arm32.mk
index f95228e..b9f23fe 100644
--- a/config/arm32.mk
+++ b/config/arm32.mk
@@ -1,5 +1,6 @@
 CONFIG_ARM := y
 CONFIG_ARM_32 := y
+CONFIG_VUART_CONSOLE := y
 CONFIG_ARM_$(XEN_OS) := y
 
 CONFIG_XEN_INSTALL_SUFFIX :=
diff --git a/config/arm64.mk b/config/arm64.mk
index aa45772..861d0a4 100644
--- a/config/arm64.mk
+++ b/config/arm64.mk
@@ -1,5 +1,6 @@
 CONFIG_ARM := y
 CONFIG_ARM_64 := y
+CONFIG_VUART_CONSOLE := y
 CONFIG_ARM_$(XEN_OS) := y
 
 CONFIG_XEN_INSTALL_SUFFIX :=
diff --git a/tools/console/Makefile b/tools/console/Makefile
index abe77b2..e7ff8ff 100644
--- a/tools/console/Makefile
+++ b/tools/console/Makefile
@@ -11,6 +11,7 @@ LDLIBS += $(SOCKET_LIBS)
 
 LDLIBS_xenconsoled += $(UTIL_LIBS)
 LDLIBS_xenconsoled += -lrt
+CFLAGS_vuart-$(CONFIG_VUART_CONSOLE) = -DCONFIG_VUART_CONSOLE
 
 BIN  = xenconsoled xenconsole
 
@@ -28,7 +29,7 @@ clean:
 distclean: clean
 
 daemon/main.o: daemon/_paths.h
-daemon/io.o: CFLAGS += $(CFLAGS_libxenevtchn) $(CFLAGS_libxengnttab)
+daemon/io.o: CFLAGS += $(CFLAGS_libxenevtchn) $(CFLAGS_libxengnttab) 
$(CFLAGS_vuart-y)
 xenconsoled: $(patsubst %.c,%.o,$(wildcard daemon/*.c))
$(CC) $(LDFLAGS) $^ -o $@ $(LDLIBS) $(LDLIBS_libxenevtchn) 
$(LDLIBS_libxengnttab) $(LDLIBS_xenconsoled) $(APPEND_LDFLAGS)
 
diff --git a/tools/console/daemon/io.c b/tools/console/daemon/io.c
index 067eeb5..2817a49 100644
--- a/tools/console/daemon/io.c
+++ b/tools/console/daemon/io.c
@@ -107,12 +107,16 @@ struct console {
xenevtchn_port_or_error_t remote_port;
struct xencons_interface *interface;
struct domain *d;
+   bool optional;
+   bool use_gnttab;
 };
 
 struct console_data {
char *xsname;
char *ttyname;
char *log_suffix;
+   bool optional;
+   bool use_gnttab;
 };
 
 static struct console_data console_data[] = {
@@ -120,7 +124,18 @@ static struct console_data console_data[] = {
.xsname = "/console",
.ttyname = "tty",
.log_suffix = "",
+   .optional = false,
+   .use_gnttab = true,
},
+#if defined(CONFIG_VUART_CONSOLE)
+   {
+   .xsname = "/vuart/0",
+   .ttyname = "tty",
+   .log_suffix = "-vuart0",
+   .optional = true,
+   .use_gnttab = false,
+   },
+#endif
 };
 
 #define MAX_CONSOLE (sizeof(console_data)/sizeof(struct console_data))
@@ -650,8 +665,17 @@ static int console_create_ring(struct console *con)
"ring-ref", "%u", _ref,
"port", "%i", _port,
NULL);
-   if (err)
+
+   if (err) {
+   /*
+* This is a normal condition for optional consoles: they might 
not be
+* present on xenstore at all. In that case, just return 
without error.
+   */
+   if (con->optional)
+   err = 0;
+
goto out;
+   }
 
snprintf(path, sizeof(path), "%s/type", con->xspath);
type = xs_read(xs, XBT_NULL, path, NULL);
@@ -665,7 +689,9 @@ static int console_create_ring(struct console *con)
if (ring_ref != con->ring_ref && con->ring_ref != -1)
console_unmap_interface(con);
 
-   if (!con->interface && xgt_handle) {
+   if (!con->interface &&
+   xgt_handle &&
+   con->use_gnttab) {
/* Prefer using grant table */
con->interface = xengnttab_map_grant_ref(xgt_handle,
dom->domid, GNTTAB_RESERVED_CONSOLE,
@@ -784,6 +810,8 @@ static int console_init(struct console *con, struct domain 
*dom, void **data)
con->d = dom;
con->ttyname = (*con_data)->ttyname;
con->log_suffix = (*con_data)->log_suffix;
+   con->optional = (*con_data)->optional;
+   con->use_gnttab =