virtio: docs, tests for 4.7

This merely has some documentation and a new test, seems safe to merge.
 
 Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost

Pull virtio docs and tests from Michael Tsirkin:
 "This merely has some documentation and a new test, seems safe to
  merge"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  tools/virtio: add noring tool
  tools/virtio/ringtest: fix run-on-all.sh to work without /dev/cpu
  tools/virtio/ringtest: add usage example to README
  MAINTAINERS: Add file patterns for virtio device tree bindings

MAINTAINERS

@@ -12148,6 +12148,7 @@ VIRTIO CORE, NET AND BLOCK DRIVERS
 M:	"Michael S. Tsirkin" <mst@redhat.com>
 L:	virtualization@lists.linux-foundation.org
 S:	Maintained
+F:	Documentation/devicetree/bindings/virtio/
 F:	drivers/virtio/
 F:	tools/virtio/
 F:	drivers/net/virtio_net.c

tools/virtio/ringtest/Makefile

@@ -1,6 +1,6 @@
 all:
 
-all: ring virtio_ring_0_9 virtio_ring_poll virtio_ring_inorder
+all: ring virtio_ring_0_9 virtio_ring_poll virtio_ring_inorder noring
 
 CFLAGS += -Wall
 CFLAGS += -pthread -O2 -ggdb
@@ -15,11 +15,13 @@ ring: ring.o main.o
 virtio_ring_0_9: virtio_ring_0_9.o main.o
 virtio_ring_poll: virtio_ring_poll.o main.o
 virtio_ring_inorder: virtio_ring_inorder.o main.o
+noring: noring.o main.o
 clean:
 	-rm main.o
 	-rm ring.o ring
 	-rm virtio_ring_0_9.o virtio_ring_0_9
 	-rm virtio_ring_poll.o virtio_ring_poll
 	-rm virtio_ring_inorder.o virtio_ring_inorder
+	-rm noring.o noring
 
 .PHONY: all clean

tools/virtio/ringtest/README

@@ -1,2 +1,6 @@
 Partial implementation of various ring layouts, useful to tune virtio design.
 Uses shared memory heavily.
+
+Typical use:
+
+# sh run-on-all.sh perf stat -r 10 --log-fd 1 -- ./ring

tools/virtio/ringtest/noring.c

@@ -0,0 +1,69 @@
+#define _GNU_SOURCE
+#include "main.h"
+#include <assert.h>
+
+/* stub implementation: useful for measuring overhead */
+void alloc_ring(void)
+{
+}
+
+/* guest side */
+int add_inbuf(unsigned len, void *buf, void *datap)
+{
+	return 0;
+}
+
+/*
+ * skb_array API provides no way for producer to find out whether a given
+ * buffer was consumed.  Our tests merely require that a successful get_buf
+ * implies that add_inbuf succeed in the past, and that add_inbuf will succeed,
+ * fake it accordingly.
+ */
+void *get_buf(unsigned *lenp, void **bufp)
+{
+	return "Buffer";
+}
+
+void poll_used(void)
+{
+}
+
+void disable_call()
+{
+	assert(0);
+}
+
+bool enable_call()
+{
+	assert(0);
+}
+
+void kick_available(void)
+{
+	assert(0);
+}
+
+/* host side */
+void disable_kick()
+{
+	assert(0);
+}
+
+bool enable_kick()
+{
+	assert(0);
+}
+
+void poll_avail(void)
+{
+}
+
+bool use_buf(unsigned *lenp, void **bufp)
+{
+	return true;
+}
+
+void call_used(void)
+{
+	assert(0);
+}

tools/virtio/ringtest/run-on-all.sh

@@ -3,10 +3,10 @@
 #use last CPU for host. Why not the first?
 #many devices tend to use cpu0 by default so
 #it tends to be busier
-HOST_AFFINITY=$(cd /dev/cpu; ls|grep -v '[a-z]'|sort -n|tail -1)
+HOST_AFFINITY=$(lscpu -p=cpu | tail -1)
 
 #run command on all cpus
-for cpu in $(cd /dev/cpu; ls|grep -v '[a-z]'|sort -n);
+for cpu in $(seq 0 $HOST_AFFINITY)
 do
 	#Don't run guest and host on same CPU
 	#It actually works ok if using signalling