[PATCH v1 0/4] current plugins/next (reorg + hwprofile)

[PATCH v1 0/4] current plugins/next (reorg + hwprofile)

[Alex Bennée]

Hi,

This is the current state of my plugin tree. The biggest change is a
re-organisation moving a bunch of the more complex plugins into
contrib and just concentrating on the basic plugins for running the
tests. In the process I've updated the docs to describe what they do
in more detail. Finally the hwprofile plugin is a new plugin for
tracking HW access patterns.

Alex Bennée (4):
  hw/virtio/pci: include vdev name in registered PCI sections
  plugins: add API to return a name for a IO device
  plugins: move the more involved plugins to contrib
  plugins: new hwprofile plugin

 docs/devel/tcg-plugins.rst                    | 176 ++++++++++
 configure                                     |   2 +
 Makefile                                      |  11 +
 include/qemu/qemu-plugin.h                    |   6 +
 {tests/plugin => contrib/plugins}/hotblocks.c |   0
 {tests/plugin => contrib/plugins}/hotpages.c  |   0
 {tests/plugin => contrib/plugins}/howvec.c    |   0
 contrib/plugins/hwprofile.c                   | 305 ++++++++++++++++++
 {tests/plugin => contrib/plugins}/lockstep.c  |   0
 hw/virtio/virtio-pci.c                        |  22 +-
 plugins/api.c                                 |  20 ++
 MAINTAINERS                                   |   1 +
 contrib/plugins/Makefile                      |  43 +++
 tests/Makefile.include                        |   2 +-
 tests/plugin/meson.build                      |   4 +-
 tests/tcg/Makefile.target                     |   3 +-
 16 files changed, 582 insertions(+), 13 deletions(-)
 rename {tests/plugin => contrib/plugins}/hotblocks.c (100%)
 rename {tests/plugin => contrib/plugins}/hotpages.c (100%)
 rename {tests/plugin => contrib/plugins}/howvec.c (100%)
 create mode 100644 contrib/plugins/hwprofile.c
 rename {tests/plugin => contrib/plugins}/lockstep.c (100%)
 create mode 100644 contrib/plugins/Makefile

-- 
2.20.1

[PATCH v1 1/4] hw/virtio/pci: include vdev name in registered PCI sections

[Alex Bennée]

When viewing/debugging memory regions it is sometimes hard to figure
out which PCI device something belongs to. Make the names unique by
including the vdev name in the name string.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>

Message-Id: <20200713200415.26214-10-alex.bennee@linaro.org>
---
 hw/virtio/virtio-pci.c | 22 ++++++++++++++--------
 1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index 5bc769f685c..169d07ba20e 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -1421,7 +1421,8 @@ static void virtio_pci_device_write(void *opaque, hwaddr addr,
     }
 }
 
-static void virtio_pci_modern_regions_init(VirtIOPCIProxy *proxy)
+static void virtio_pci_modern_regions_init(VirtIOPCIProxy *proxy,
+                                           const char *vdev_name)
 {
     static const MemoryRegionOps common_ops = {
         .read = virtio_pci_common_read,
@@ -1468,36 +1469,41 @@ static void virtio_pci_modern_regions_init(VirtIOPCIProxy *proxy)
         },
         .endianness = DEVICE_LITTLE_ENDIAN,
     };
+    g_autoptr(GString) name = g_string_new(NULL);
 
-
+    g_string_printf(name, "virtio-pci-common-%s", vdev_name);
     memory_region_init_io(&proxy->common.mr, OBJECT(proxy),
                           &common_ops,
                           proxy,
-                          "virtio-pci-common",
+                          name->str,
                           proxy->common.size);
 
+    g_string_printf(name, "virtio-pci-isr-%s", vdev_name);
     memory_region_init_io(&proxy->isr.mr, OBJECT(proxy),
                           &isr_ops,
                           proxy,
-                          "virtio-pci-isr",
+                          name->str,
                           proxy->isr.size);
 
+    g_string_printf(name, "virtio-pci-device-%s", vdev_name);
     memory_region_init_io(&proxy->device.mr, OBJECT(proxy),
                           &device_ops,
                           proxy,
-                          "virtio-pci-device",
+                          name->str,
                           proxy->device.size);
 
+    g_string_printf(name, "virtio-pci-notify-%s", vdev_name);
     memory_region_init_io(&proxy->notify.mr, OBJECT(proxy),
                           &notify_ops,
                           proxy,
-                          "virtio-pci-notify",
+                          name->str,
                           proxy->notify.size);
 
+    g_string_printf(name, "virtio-pci-notify-pio-%s", vdev_name);
     memory_region_init_io(&proxy->notify_pio.mr, OBJECT(proxy),
                           &notify_pio_ops,
                           proxy,
-                          "virtio-pci-notify-pio",
+                          name->str,
                           proxy->notify_pio.size);
 }
 
@@ -1642,7 +1648,7 @@ static void virtio_pci_device_plugged(DeviceState *d, Error **errp)
 
         struct virtio_pci_cfg_cap *cfg_mask;
 
-        virtio_pci_modern_regions_init(proxy);
+        virtio_pci_modern_regions_init(proxy, vdev->name);
 
         virtio_pci_modern_mem_region_map(proxy, &proxy->common, &cap);
         virtio_pci_modern_mem_region_map(proxy, &proxy->isr, &cap);
-- 
2.20.1

[PATCH v1 2/4] plugins: add API to return a name for a IO device

[Alex Bennée]

This may well end up being anonymous but it should always be unique.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
[r-b provisional given change to g_intern_string]
Reviewed-by: Clement Deschamps <clement.deschamps@greensocs.com>
Reviewed-by: Emilio G. Cota <cota@braap.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

Message-Id: <20200713200415.26214-11-alex.bennee@linaro.org>
---
 include/qemu/qemu-plugin.h |  6 ++++++
 plugins/api.c              | 20 ++++++++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/include/qemu/qemu-plugin.h b/include/qemu/qemu-plugin.h
index bab8b0d4b3a..c98c18d6b05 100644
--- a/include/qemu/qemu-plugin.h
+++ b/include/qemu/qemu-plugin.h
@@ -335,6 +335,12 @@ struct qemu_plugin_hwaddr *qemu_plugin_get_hwaddr(qemu_plugin_meminfo_t info,
 bool qemu_plugin_hwaddr_is_io(const struct qemu_plugin_hwaddr *haddr);
 uint64_t qemu_plugin_hwaddr_device_offset(const struct qemu_plugin_hwaddr *haddr);
 
+/*
+ * Returns a string representing the device. The string is valid for
+ * the lifetime of the plugin.
+ */
+const char *qemu_plugin_hwaddr_device_name(const struct qemu_plugin_hwaddr *h);
+
 typedef void
 (*qemu_plugin_vcpu_mem_cb_t)(unsigned int vcpu_index,
                              qemu_plugin_meminfo_t info, uint64_t vaddr,
diff --git a/plugins/api.c b/plugins/api.c
index bbdc5a4eb46..4304e63f0cf 100644
--- a/plugins/api.c
+++ b/plugins/api.c
@@ -303,6 +303,26 @@ uint64_t qemu_plugin_hwaddr_device_offset(const struct qemu_plugin_hwaddr *haddr
     return 0;
 }
 
+const char *qemu_plugin_hwaddr_device_name(const struct qemu_plugin_hwaddr *h)
+{
+#ifdef CONFIG_SOFTMMU
+    if (h && h->is_io) {
+        MemoryRegionSection *mrs = h->v.io.section;
+        if (!mrs->mr->name) {
+            unsigned long maddr = 0xffffffff & (uintptr_t) mrs->mr;
+            g_autofree char *temp = g_strdup_printf("anon%08lx", maddr);
+            return g_intern_string(temp);
+        } else {
+            return g_intern_string(mrs->mr->name);
+        }
+    } else {
+        return g_intern_string("RAM");
+    }
+#else
+    return g_intern_string("Invalid");
+#endif
+}
+
 /*
  * Queries to the number and potential maximum number of vCPUs there
  * will be. This helps the plugin dimension per-vcpu arrays.
-- 
2.20.1

[PATCH v1 3/4] plugins: move the more involved plugins to contrib

[Alex Bennée]

We have an exploding complexity problem in the testing so lets just
move the more involved plugins into contrib. tests/plugins still exist
for the basic plugins that exercise the API. We restore the old
pre-meson style Makefile for contrib as it also doubles as a guide for
out-of-tree plugin builds.

While we are at it add some examples to the documentation and a
specific plugins build target.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
---
 docs/devel/tcg-plugins.rst                    | 142 ++++++++++++++++++
 configure                                     |   2 +
 Makefile                                      |  11 ++
 {tests/plugin => contrib/plugins}/hotblocks.c |   0
 {tests/plugin => contrib/plugins}/hotpages.c  |   0
 {tests/plugin => contrib/plugins}/howvec.c    |   0
 {tests/plugin => contrib/plugins}/lockstep.c  |   0
 MAINTAINERS                                   |   1 +
 contrib/plugins/Makefile                      |  42 ++++++
 tests/Makefile.include                        |   2 +-
 tests/plugin/meson.build                      |   4 +-
 tests/tcg/Makefile.target                     |   3 +-
 12 files changed, 202 insertions(+), 5 deletions(-)
 rename {tests/plugin => contrib/plugins}/hotblocks.c (100%)
 rename {tests/plugin => contrib/plugins}/hotpages.c (100%)
 rename {tests/plugin => contrib/plugins}/howvec.c (100%)
 rename {tests/plugin => contrib/plugins}/lockstep.c (100%)
 create mode 100644 contrib/plugins/Makefile

diff --git a/docs/devel/tcg-plugins.rst b/docs/devel/tcg-plugins.rst
index a05990906cc..e079695caf9 100644
--- a/docs/devel/tcg-plugins.rst
+++ b/docs/devel/tcg-plugins.rst
@@ -134,3 +134,145 @@ longer want to instrument the code. This operation is asynchronous
 which means callbacks may still occur after the uninstall operation is
 requested. The plugin isn't completely uninstalled until the safe work
 has executed while all vCPUs are quiescent.
+
+Example Plugins
+===============
+
+There are a number of plugins included with QEMU and you are
+encouraged to contribute them upstream. There is a `contrib/plugins`
+directory where they can go.
+
+- tests/plugins
+
+These are some basic plugins that are used to test and exercise the
+API during the `make check-tcg` target.
+
+- contrib/plugins/hotblocks.c
+
+The hotblocks plugin allows you to examine the where hot paths of
+execution are in your program. Once the program has finished you will
+get a sorted list of blocks reporting the starting PC, translation
+count, number of instructions and execution count. This will work best
+with linux-user execution as system emulation tends to generate
+re-translations as blocks from different programs get swapped in and
+out of system memory.
+
+If your program is single-threaded you can use the `inline` option for
+slightly faster (but not thread safe) counters.
+
+Example::
+
+  ./aarch64-linux-user/qemu-aarch64 -plugin contrib/plugins/libhotblocks.so -d plugin ./tests/tcg/aarch64-linux-user/sha1
+  SHA1=15dd99a1991e0b3826fede3deffc1feba42278e6
+  collected 903 entries in the hash table
+  pc, tcount, icount, ecount
+  0x0000000041ed10, 1, 5, 66087
+  0x000000004002b0, 1, 4, 66087
+  ...
+
+- contrib/plugins/hotpages.c
+
+Similar to hotblocks but this time tracks memory accesses::
+
+  ./aarch64-linux-user/qemu-aarch64 -plugin contrib/plugins/libhotpages.so -d plugin ./tests/tcg/aarch64-linux-user/sha1
+  SHA1=15dd99a1991e0b3826fede3deffc1feba42278e6
+  Addr, RCPUs, Reads, WCPUs, Writes
+  0x000055007fe000, 0x0001, 31747952, 0x0001, 8835161
+  0x000055007ff000, 0x0001, 29001054, 0x0001, 8780625
+  0x00005500800000, 0x0001, 687465, 0x0001, 335857
+  0x0000000048b000, 0x0001, 130594, 0x0001, 355
+  0x0000000048a000, 0x0001, 1826, 0x0001, 11
+
+- contrib/plugins/howvec.c
+
+This is an instruction classifier so can be used to count different
+types of instructions. It has a number of options to refine which get
+counted. You can give an argument for a class of instructions to break
+it down fully, so for example to see all the system registers
+accesses::
+
+  ./aarch64-softmmu/qemu-system-aarch64 $(QEMU_ARGS) \
+    -append "root=/dev/sda2 systemd.unit=benchmark.service" \
+    -smp 4 -plugin ./contrib/plugins/libhowvec.so,arg=sreg -d plugin
+
+which will lead to a sorted list after the class breakdown::
+
+  Instruction Classes:
+  Class:   UDEF                   not counted
+  Class:   SVE                    (68 hits)
+  Class:   PCrel addr             (47789483 hits)
+  Class:   Add/Sub (imm)          (192817388 hits)
+  Class:   Logical (imm)          (93852565 hits)
+  Class:   Move Wide (imm)        (76398116 hits)
+  Class:   Bitfield               (44706084 hits)
+  Class:   Extract                (5499257 hits)
+  Class:   Cond Branch (imm)      (147202932 hits)
+  Class:   Exception Gen          (193581 hits)
+  Class:     NOP                  not counted
+  Class:   Hints                  (6652291 hits)
+  Class:   Barriers               (8001661 hits)
+  Class:   PSTATE                 (1801695 hits)
+  Class:   System Insn            (6385349 hits)
+  Class:   System Reg             counted individually
+  Class:   Branch (reg)           (69497127 hits)
+  Class:   Branch (imm)           (84393665 hits)
+  Class:   Cmp & Branch           (110929659 hits)
+  Class:   Tst & Branch           (44681442 hits)
+  Class:   AdvSimd ldstmult       (736 hits)
+  Class:   ldst excl              (9098783 hits)
+  Class:   Load Reg (lit)         (87189424 hits)
+  Class:   ldst noalloc pair      (3264433 hits)
+  Class:   ldst pair              (412526434 hits)
+  Class:   ldst reg (imm)         (314734576 hits)
+  Class: Loads & Stores           (2117774 hits)
+  Class: Data Proc Reg            (223519077 hits)
+  Class: Scalar FP                (31657954 hits)
+  Individual Instructions:
+  Instr: mrs x0, sp_el0           (2682661 hits)  (op=0xd5384100/  System Reg)
+  Instr: mrs x1, tpidr_el2        (1789339 hits)  (op=0xd53cd041/  System Reg)
+  Instr: mrs x2, tpidr_el2        (1513494 hits)  (op=0xd53cd042/  System Reg)
+  Instr: mrs x0, tpidr_el2        (1490823 hits)  (op=0xd53cd040/  System Reg)
+  Instr: mrs x1, sp_el0           (933793 hits)   (op=0xd5384101/  System Reg)
+  Instr: mrs x2, sp_el0           (699516 hits)   (op=0xd5384102/  System Reg)
+  Instr: mrs x4, tpidr_el2        (528437 hits)   (op=0xd53cd044/  System Reg)
+  Instr: mrs x30, ttbr1_el1       (480776 hits)   (op=0xd538203e/  System Reg)
+  Instr: msr ttbr1_el1, x30       (480713 hits)   (op=0xd518203e/  System Reg)
+  Instr: msr vbar_el1, x30        (480671 hits)   (op=0xd518c01e/  System Reg)
+  ...
+
+To find the argument shorthand for the class you need to examine the
+source code of the plugin at the moment, specifically the `*opt`
+argument in the InsnClassExecCount tables.
+
+- contrib/plugins/lockstep.c
+
+This is a debugging tool for developers who want to find out when and
+where execution diverges after a subtle change to TCG code generation.
+It is not an exact science and results are likely to be mixed once
+asynchronous events are introduced. While the use of -icount can
+introduce determinism to the execution flow it doesn't always follow
+the translation sequence will be exactly the same. Typically this is
+caused by a timer firing to service the GUI causing a block to end
+early. However in some cases it has proved to be useful in pointing
+people at roughly where execution diverges. The only argument you need
+for the plugin is a path for the socket the two instances will
+communicate over::
+
+
+  ./sparc-softmmu/qemu-system-sparc -monitor none -parallel none \
+    -net none -M SS-20 -m 256 -kernel day11/zImage.elf \
+    -plugin ./contrib/plugins/liblockstep.so,arg=lockstep-sparc.sock \
+  -d plugin,nochain
+
+which will eventually report::
+
+  qemu-system-sparc: warning: nic lance.0 has no peer
+  @ 0x000000ffd06678 vs 0x000000ffd001e0 (2/1 since last)
+  @ 0x000000ffd07d9c vs 0x000000ffd06678 (3/1 since last)
+  Δ insn_count @ 0x000000ffd07d9c (809900609) vs 0x000000ffd06678 (809900612)
+    previously @ 0x000000ffd06678/10 (809900609 insns)
+    previously @ 0x000000ffd001e0/4 (809900599 insns)
+    previously @ 0x000000ffd080ac/2 (809900595 insns)
+    previously @ 0x000000ffd08098/5 (809900593 insns)
+    previously @ 0x000000ffd080c0/1 (809900588 insns)
+
diff --git a/configure b/configure
index f555923311f..2e4d3898012 100755
--- a/configure
+++ b/configure
@@ -8073,6 +8073,7 @@ DIRS="$DIRS tests/qtest tests/qemu-iotests tests/vm tests/fp tests/qgraph"
 DIRS="$DIRS docs docs/interop fsdev scsi"
 DIRS="$DIRS pc-bios/optionrom pc-bios/s390-ccw"
 DIRS="$DIRS roms/seabios"
+DIRS="$DIRS contrib/plugins/"
 LINKS="Makefile"
 LINKS="$LINKS tests/tcg/lm32/Makefile"
 LINKS="$LINKS tests/tcg/Makefile.target"
@@ -8084,6 +8085,7 @@ LINKS="$LINKS .gdbinit scripts" # scripts needed by relative path in .gdbinit
 LINKS="$LINKS tests/acceptance tests/data"
 LINKS="$LINKS tests/qemu-iotests/check"
 LINKS="$LINKS python"
+LINKS="$LINKS contrib/plugins/Makefile "
 UNLINK="pc-bios/keymaps"
 for bios_file in \
     $source_path/pc-bios/*.bin \
diff --git a/Makefile b/Makefile
index ed354c43b0b..2f1b18327dc 100644
--- a/Makefile
+++ b/Makefile
@@ -98,6 +98,12 @@ config-host.mak: $(SRC_PATH)/configure $(SRC_PATH)/pc-bios $(SRC_PATH)/VERSION
 # Force configure to re-run if the API symbols are updated
 ifeq ($(CONFIG_PLUGIN),y)
 config-host.mak: $(SRC_PATH)/plugins/qemu-plugins.symbols
+
+.PHONY: plugins
+plugins:
+	$(call quiet-command,\
+		$(MAKE) $(SUBDIR_MAKEFLAGS) -C contrib/plugins V="$(V)", \
+		"BUILD", "example plugins")
 endif
 
 else
@@ -276,6 +282,11 @@ help:
 	$(call print-help,cscope,Generate cscope index)
 	$(call print-help,sparse,Run sparse on the QEMU source)
 	@echo  ''
+ifeq ($(CONFIG_PLUGIN),y)
+	@echo  'Plugin targets:'
+	$(call print-help,plugins,Build the example TCG plugins)
+	@echo  ''
+endif
 	@echo  'Cleaning targets:'
 	$(call print-help,clean,Remove most generated files but keep the config)
 	$(call print-help,distclean,Remove all generated files)
diff --git a/tests/plugin/hotblocks.c b/contrib/plugins/hotblocks.c
similarity index 100%
rename from tests/plugin/hotblocks.c
rename to contrib/plugins/hotblocks.c
diff --git a/tests/plugin/hotpages.c b/contrib/plugins/hotpages.c
similarity index 100%
rename from tests/plugin/hotpages.c
rename to contrib/plugins/hotpages.c
diff --git a/tests/plugin/howvec.c b/contrib/plugins/howvec.c
similarity index 100%
rename from tests/plugin/howvec.c
rename to contrib/plugins/howvec.c
diff --git a/tests/plugin/lockstep.c b/contrib/plugins/lockstep.c
similarity index 100%
rename from tests/plugin/lockstep.c
rename to contrib/plugins/lockstep.c
diff --git a/MAINTAINERS b/MAINTAINERS
index b233da2a737..8d8eeac61f5 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2746,6 +2746,7 @@ S: Maintained
 F: docs/devel/tcg-plugins.rst
 F: plugins/
 F: tests/plugin
+F: contrib/plugins
 
 AArch64 TCG target
 M: Richard Henderson <richard.henderson@linaro.org>
diff --git a/contrib/plugins/Makefile b/contrib/plugins/Makefile
new file mode 100644
index 00000000000..7801b08b0d6
--- /dev/null
+++ b/contrib/plugins/Makefile
@@ -0,0 +1,42 @@
+# -*- Mode: makefile -*-
+#
+# This Makefile example is fairly independent from the main makefile
+# so users can take and adapt it for their build. We only really
+# include config-host.mak so we don't have to repeat probing for
+# cflags that the main configure has already done for us.
+#
+
+BUILD_DIR := $(CURDIR)/../..
+
+include $(BUILD_DIR)/config-host.mak
+
+VPATH += $(SRC_PATH)/contrib/plugins
+
+NAMES :=
+NAMES += hotblocks
+NAMES += hotpages
+NAMES += howvec
+NAMES += lockstep
+
+SONAMES := $(addsuffix .so,$(addprefix lib,$(NAMES)))
+
+# The main QEMU uses Glib extensively so it's perfectly fine to use it
+# in plugins (which many example do).
+CFLAGS = $(GLIB_CFLAGS)
+CFLAGS += -fPIC
+CFLAGS += $(if $(findstring no-psabi,$(QEMU_CFLAGS)),-Wpsabi)
+CFLAGS += -I$(SRC_PATH)/include/qemu
+
+all: $(SONAMES)
+
+%.o: %.c
+	$(CC) $(CFLAGS) -c -o $@ $<
+
+lib%.so: %.o
+	$(CC) -shared -Wl,-soname,$@ -o $@ $^ $(LDLIBS)
+
+clean:
+	rm -f *.o *.so *.d
+	rm -Rf .libs
+
+.PHONY: all clean
diff --git a/tests/Makefile.include b/tests/Makefile.include
index 9ac8f5b86a6..5a961d366e5 100644
--- a/tests/Makefile.include
+++ b/tests/Makefile.include
@@ -439,7 +439,7 @@ RUN_TCG_TARGET_RULES=$(patsubst %,run-tcg-tests-%, $(TARGET_DIRS))
 $(foreach PROBE_TARGET,$(TARGET_DIRS), 				\
 	$(eval -include $(SRC_PATH)/tests/tcg/Makefile.prereqs))
 
-build-tcg-tests-%: $(if $(CONFIG_PLUGIN),plugins)
+build-tcg-tests-%: $(if $(CONFIG_PLUGIN),test-plugins)
 	$(call quiet-command,$(MAKE) $(SUBDIR_MAKEFLAGS) \
 		-f $(SRC_PATH)/tests/tcg/Makefile.qemu \
 		SRC_PATH=$(SRC_PATH) \
diff --git a/tests/plugin/meson.build b/tests/plugin/meson.build
index dbbdcbaa670..1eacfa6e355 100644
--- a/tests/plugin/meson.build
+++ b/tests/plugin/meson.build
@@ -1,7 +1,7 @@
 t = []
-foreach i : ['bb', 'empty', 'insn', 'mem', 'hotblocks', 'howvec', 'hotpages', 'lockstep']
+foreach i : ['bb', 'empty', 'insn', 'mem']
   t += shared_module(i, files(i + '.c'),
                      include_directories: '../../include/qemu',
                      dependencies: glib)
 endforeach
-alias_target('plugins', t)
+alias_target('test-plugins', t)
diff --git a/tests/tcg/Makefile.target b/tests/tcg/Makefile.target
index 4b2b696fcee..2ae86776cdc 100644
--- a/tests/tcg/Makefile.target
+++ b/tests/tcg/Makefile.target
@@ -129,8 +129,7 @@ ifeq ($(CONFIG_PLUGIN),y)
 PLUGIN_SRC=$(SRC_PATH)/tests/plugin
 PLUGIN_LIB=../../plugin
 VPATH+=$(PLUGIN_LIB)
-PLUGINS=$(filter-out liblockstep.so,\
-		$(patsubst %.c, lib%.so, $(notdir $(wildcard $(PLUGIN_SRC)/*.c))))
+PLUGINS=$(patsubst %.c, lib%.so, $(notdir $(wildcard $(PLUGIN_SRC)/*.c)))
 
 # We need to ensure expand the run-plugin-TEST-with-PLUGIN
 # pre-requistes manually here as we can't use stems to handle it. We
-- 
2.20.1

[PATCH v1 4/4] plugins: new hwprofile plugin

[Alex Bennée]

This is a plugin intended to help with profiling access to various
bits of system hardware. It only really makes sense for system
emulation.

It takes advantage of the recently exposed helper API that allows us
to see the device name (memory region name) associated with a device.

You can specify arg=read or arg=write to limit the tracking to just
reads or writes (by default it does both).

The pattern option:

  -plugin ./tests/plugin/libhwprofile.so,arg=pattern

will allow you to see the access pattern to devices, eg:

  gic_cpu @ 0xffffffc010040000
    off:00000000, 8, 1, 8, 1
    off:00000000, 4, 1, 4, 1
    off:00000000, 2, 1, 2, 1
    off:00000000, 1, 1, 1, 1

The source option:

  -plugin ./tests/plugin/libhwprofile.so,arg=source

will track the virtual source address of the instruction making the
access:

  pl011 @ 0xffffffc010031000
    pc:ffffffc0104c785c, 1, 4, 0, 0
    pc:ffffffc0104c7898, 1, 4, 0, 0
    pc:ffffffc010512bcc, 2, 1867, 0, 0

You cannot mix source and pattern.

Finally the match option allow you to limit the tracking to just the
devices you care about.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Robert Foley <robert.foley@linaro.org>
Tested-by: Robert Foley <robert.foley@linaro.org>
Message-Id: <20200713200415.26214-12-alex.bennee@linaro.org>

---
vN
  - add some notes to tcg-plugins.rst
---
 docs/devel/tcg-plugins.rst  |  34 ++++
 contrib/plugins/hwprofile.c | 305 ++++++++++++++++++++++++++++++++++++
 contrib/plugins/Makefile    |   1 +
 3 files changed, 340 insertions(+)
 create mode 100644 contrib/plugins/hwprofile.c

diff --git a/docs/devel/tcg-plugins.rst b/docs/devel/tcg-plugins.rst
index e079695caf9..4af6d609c98 100644
--- a/docs/devel/tcg-plugins.rst
+++ b/docs/devel/tcg-plugins.rst
@@ -276,3 +276,37 @@ which will eventually report::
     previously @ 0x000000ffd08098/5 (809900593 insns)
     previously @ 0x000000ffd080c0/1 (809900588 insns)
 
+- contrib/plugins/hwprofile
+
+The hwprofile tool can only be used with system emulation and allows
+the user to see what hardware is accessed how often. It has a number of options:
+
+ * arg=read or arg=write
+
+ By default the plugin tracks both reads and writes. You can use one
+ of these options to limit the tracking to just one class of accesses.
+
+ * arg=source
+
+ Will include a detailed break down of what the guest PC that made the
+ access was. Not compatible with arg=pattern. Example output::
+
+   cirrus-low-memory @ 0xfffffd00000a0000
+    pc:fffffc0000005cdc, 1, 256
+    pc:fffffc0000005ce8, 1, 256
+    pc:fffffc0000005cec, 1, 256
+
+ * arg=pattern
+
+ Instead break down the accesses based on the offset into the HW
+ region. This can be useful for seeing the most used registers of a
+ device. Example output::
+
+    pci0-conf @ 0xfffffd01fe000000
+      off:00000004, 1, 1
+      off:00000010, 1, 3
+      off:00000014, 1, 3
+      off:00000018, 1, 2
+      off:0000001c, 1, 2
+      off:00000020, 1, 2
+      ...
diff --git a/contrib/plugins/hwprofile.c b/contrib/plugins/hwprofile.c
new file mode 100644
index 00000000000..6dac1d5f854
--- /dev/null
+++ b/contrib/plugins/hwprofile.c
@@ -0,0 +1,305 @@
+/*
+ * Copyright (C) 2020, Alex Bennée <alex.bennee@linaro.org>
+ *
+ * HW Profile - breakdown access patterns for IO to devices
+ *
+ * License: GNU GPL, version 2 or later.
+ *   See the COPYING file in the top-level directory.
+ */
+
+#include <inttypes.h>
+#include <assert.h>
+#include <stdlib.h>
+#include <inttypes.h>
+#include <string.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <glib.h>
+
+#include <qemu-plugin.h>
+
+QEMU_PLUGIN_EXPORT int qemu_plugin_version = QEMU_PLUGIN_VERSION;
+
+#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
+
+typedef struct {
+    uint64_t cpu_read;
+    uint64_t cpu_write;
+    uint64_t reads;
+    uint64_t writes;
+} IOCounts;
+
+typedef struct {
+    uint64_t off_or_pc;
+    IOCounts counts;
+} IOLocationCounts;
+
+typedef struct {
+    const char *name;
+    uint64_t   base;
+    IOCounts   totals;
+    GHashTable *detail;
+} DeviceCounts;
+
+static GMutex lock;
+static GHashTable *devices;
+
+/* track the access pattern to a piece of HW */
+static bool pattern;
+/* track the source address of access to HW */
+static bool source;
+/* track only matched regions of HW */
+static bool check_match;
+static gchar **matches;
+
+static enum qemu_plugin_mem_rw rw = QEMU_PLUGIN_MEM_RW;
+
+static inline bool track_reads(void)
+{
+    return rw == QEMU_PLUGIN_MEM_RW || rw == QEMU_PLUGIN_MEM_R;
+}
+
+static inline bool track_writes(void)
+{
+    return rw == QEMU_PLUGIN_MEM_RW || rw == QEMU_PLUGIN_MEM_W;
+}
+
+static void plugin_init(void)
+{
+    devices = g_hash_table_new(NULL, NULL);
+}
+
+static gint sort_cmp(gconstpointer a, gconstpointer b)
+{
+    DeviceCounts *ea = (DeviceCounts *) a;
+    DeviceCounts *eb = (DeviceCounts *) b;
+    return ea->totals.reads + ea->totals.writes >
+           eb->totals.reads + eb->totals.writes ? -1 : 1;
+}
+
+static gint sort_loc(gconstpointer a, gconstpointer b)
+{
+    IOLocationCounts *ea = (IOLocationCounts *) a;
+    IOLocationCounts *eb = (IOLocationCounts *) b;
+    return ea->off_or_pc > eb->off_or_pc;
+}
+
+static void fmt_iocount_record(GString *s, IOCounts *rec)
+{
+    if (track_reads()) {
+        g_string_append_printf(s, ", %"PRIx64", %"PRId64,
+                               rec->cpu_read, rec->reads);
+    }
+    if (track_writes()) {
+        g_string_append_printf(s, ", %"PRIx64", %"PRId64,
+                               rec->cpu_write, rec->writes);
+    }
+}
+
+static void fmt_dev_record(GString *s, DeviceCounts *rec)
+{
+    g_string_append_printf(s, "%s, 0x%"PRIx64,
+                           rec->name, rec->base);
+    fmt_iocount_record(s, &rec->totals);
+    g_string_append_c(s, '\n');
+}
+
+static void plugin_exit(qemu_plugin_id_t id, void *p)
+{
+    g_autoptr(GString) report = g_string_new("");
+    GList *counts;
+
+    if (!(pattern || source)) {
+        g_string_printf(report, "Device, Address");
+        if (track_reads()) {
+            g_string_append_printf(report, ", RCPUs, Reads");
+        }
+        if (track_writes()) {
+            g_string_append_printf(report, ",  WCPUs, Writes");
+        }
+        g_string_append_c(report, '\n');
+    }
+
+    counts = g_hash_table_get_values(devices);
+    if (counts && g_list_next(counts)) {
+        GList *it;
+
+        it = g_list_sort(counts, sort_cmp);
+
+        while (it) {
+            DeviceCounts *rec = (DeviceCounts *) it->data;
+            if (rec->detail) {
+                GList *accesses = g_hash_table_get_values(rec->detail);
+                GList *io_it = g_list_sort(accesses, sort_loc);
+                const char *prefix = pattern ? "off" : "pc";
+                g_string_append_printf(report, "%s @ 0x%"PRIx64"\n",
+                                       rec->name, rec->base);
+                while (io_it) {
+                    IOLocationCounts *loc = (IOLocationCounts *) io_it->data;
+                    g_string_append_printf(report, "  %s:%08"PRIx64,
+                                           prefix, loc->off_or_pc);
+                    fmt_iocount_record(report, &loc->counts);
+                    g_string_append_c(report, '\n');
+                    io_it = io_it->next;
+                }
+            } else {
+                fmt_dev_record(report, rec);
+            }
+            it = it->next;
+        };
+        g_list_free(it);
+    }
+
+    qemu_plugin_outs(report->str);
+}
+
+static DeviceCounts *new_count(const char *name, uint64_t base)
+{
+    DeviceCounts *count = g_new0(DeviceCounts, 1);
+    count->name = name;
+    count->base = base;
+    if (pattern || source) {
+        count->detail = g_hash_table_new(NULL, NULL);
+    }
+    g_hash_table_insert(devices, (gpointer) name, count);
+    return count;
+}
+
+static IOLocationCounts *new_location(GHashTable *table, uint64_t off_or_pc)
+{
+    IOLocationCounts *loc = g_new0(IOLocationCounts, 1);
+    loc->off_or_pc = off_or_pc;
+    g_hash_table_insert(table, (gpointer) off_or_pc, loc);
+    return loc;
+}
+
+static void hwprofile_match_hit(DeviceCounts *rec, uint64_t off)
+{
+    g_autoptr(GString) report = g_string_new("hwprofile: match @ offset");
+    g_string_append_printf(report, "%"PRIx64", previous hits\n", off);
+    fmt_dev_record(report, rec);
+    qemu_plugin_outs(report->str);
+}
+
+static void inc_count(IOCounts *count, bool is_write, unsigned int cpu_index)
+{
+    if (is_write) {
+        count->writes++;
+        count->cpu_write |= (1 << cpu_index);
+    } else {
+        count->reads++;
+        count->cpu_read |= (1 << cpu_index);
+    }
+}
+
+static void vcpu_haddr(unsigned int cpu_index, qemu_plugin_meminfo_t meminfo,
+                       uint64_t vaddr, void *udata)
+{
+    struct qemu_plugin_hwaddr *hwaddr = qemu_plugin_get_hwaddr(meminfo, vaddr);
+
+    if (!hwaddr || !qemu_plugin_hwaddr_is_io(hwaddr)) {
+        return;
+    } else {
+        const char *name = qemu_plugin_hwaddr_device_name(hwaddr);
+        uint64_t off = qemu_plugin_hwaddr_device_offset(hwaddr);
+        bool is_write = qemu_plugin_mem_is_store(meminfo);
+        DeviceCounts *counts;
+
+        g_mutex_lock(&lock);
+        counts = (DeviceCounts *) g_hash_table_lookup(devices, name);
+
+        if (!counts) {
+            uint64_t base = vaddr - off;
+            counts = new_count(name, base);
+        }
+
+        if (check_match) {
+            if (g_strv_contains((const char * const *)matches, counts->name)) {
+                hwprofile_match_hit(counts, off);
+                inc_count(&counts->totals, is_write, cpu_index);
+            }
+        } else {
+            inc_count(&counts->totals, is_write, cpu_index);
+        }
+
+        /* either track offsets or source of access */
+        if (source) {
+            off = (uint64_t) udata;
+        }
+
+        if (pattern || source) {
+            IOLocationCounts *io_count = g_hash_table_lookup(counts->detail,
+                                                             (gpointer) off);
+            if (!io_count) {
+                io_count = new_location(counts->detail, off);
+            }
+            inc_count(&io_count->counts, is_write, cpu_index);
+        }
+
+        g_mutex_unlock(&lock);
+    }
+}
+
+static void vcpu_tb_trans(qemu_plugin_id_t id, struct qemu_plugin_tb *tb)
+{
+    size_t n = qemu_plugin_tb_n_insns(tb);
+    size_t i;
+
+    for (i = 0; i < n; i++) {
+        struct qemu_plugin_insn *insn = qemu_plugin_tb_get_insn(tb, i);
+        gpointer udata = (gpointer) (source ? qemu_plugin_insn_vaddr(insn) : 0);
+        qemu_plugin_register_vcpu_mem_cb(insn, vcpu_haddr,
+                                         QEMU_PLUGIN_CB_NO_REGS,
+                                         rw, udata);
+    }
+}
+
+QEMU_PLUGIN_EXPORT
+int qemu_plugin_install(qemu_plugin_id_t id, const qemu_info_t *info,
+                        int argc, char **argv)
+{
+    int i;
+
+    for (i = 0; i < argc; i++) {
+        char *opt = argv[i];
+        if (g_strcmp0(opt, "read") == 0) {
+            rw = QEMU_PLUGIN_MEM_R;
+        } else if (g_strcmp0(opt, "write") == 0) {
+            rw = QEMU_PLUGIN_MEM_W;
+        } else if (g_strcmp0(opt, "pattern") == 0) {
+            pattern = true;
+        } else if (g_strcmp0(opt, "source") == 0) {
+            source = true;
+        } else if (g_str_has_prefix(opt, "match")) {
+            gchar **parts = g_strsplit(opt, "=", 2);
+            check_match = true;
+            matches = g_strsplit(parts[1], ",", -1);
+            g_strfreev(parts);
+        } else {
+            fprintf(stderr, "option parsing failed: %s\n", opt);
+            return -1;
+        }
+    }
+
+    if (source && pattern) {
+        fprintf(stderr, "can only currently track either source or pattern.\n");
+        return -1;
+    }
+
+    if (!info->system_emulation) {
+        fprintf(stderr, "hwprofile: plugin only useful for system emulation\n");
+        return -1;
+    }
+
+    /* Just warn about overflow */
+    if (info->system.smp_vcpus > 64 ||
+        info->system.max_vcpus > 64) {
+        fprintf(stderr, "hwprofile: can only track up to 64 CPUs\n");
+    }
+
+    plugin_init();
+
+    qemu_plugin_register_vcpu_tb_trans_cb(id, vcpu_tb_trans);
+    qemu_plugin_register_atexit_cb(id, plugin_exit, NULL);
+    return 0;
+}
diff --git a/contrib/plugins/Makefile b/contrib/plugins/Makefile
index 7801b08b0d6..b9d7935e5ef 100644
--- a/contrib/plugins/Makefile
+++ b/contrib/plugins/Makefile
@@ -17,6 +17,7 @@ NAMES += hotblocks
 NAMES += hotpages
 NAMES += howvec
 NAMES += lockstep
+NAMES += hwprofile
 
 SONAMES := $(addsuffix .so,$(addprefix lib,$(NAMES)))
 
-- 
2.20.1

Re: [PATCH v1 2/4] plugins: add API to return a name for a IO device

[Richard Henderson]

On 9/4/20 6:40 AM, Alex Bennée wrote:
> +        return g_intern_string("RAM");
> +    }
> +#else
> +    return g_intern_string("Invalid");

g_intern_static_string.


r~

Re: [PATCH v1 2/4] plugins: add API to return a name for a IO device

[Alex Bennée]

Richard Henderson <richard.henderson@linaro.org> writes:

> On 9/4/20 6:40 AM, Alex Bennée wrote:
>> +        return g_intern_string("RAM");
>> +    }
>> +#else
>> +    return g_intern_string("Invalid");
>
> g_intern_static_string.

doh - I'm sure I missed that from last time. Sorry.

>
>
> r~


-- 
Alex Bennée