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Re: [Qemu-devel] [RFC PATCH v2 2/7] Add plugin support
From: |
Pavel Dovgalyuk |
Subject: |
Re: [Qemu-devel] [RFC PATCH v2 2/7] Add plugin support |
Date: |
Thu, 13 Sep 2018 09:40:34 +0300 |
> From: Alex Bennée [mailto:address@hidden
> Pavel Dovgalyuk <address@hidden> writes:
>
> > This patch adds support for dynamically loaded plugins.
> > Every plugin is a dynamic library with a set of optional exported
> > functions that will be called from QEMU.
> >
> > Signed-off-by: Pavel Dovgalyuk <address@hidden>
> > ---
> <snip>
> > qemu-options.hx | 10 +++++
> > vl.c | 8 ++++
>
> There are a couple of trivial conflicts vs master here, simple to fix.
>
> > 7 files changed, 143 insertions(+), 1 deletion(-)
> > create mode 100644 include/qemu/plugins.h
> > create mode 100644 plugins/include/plugins.h
> > create mode 100644 plugins/plugins.c
> >
> > diff --git a/Makefile.target b/Makefile.target
> > index dad2cf8..4cffd96 100644
> > --- a/Makefile.target
> > +++ b/Makefile.target
> > @@ -93,6 +93,7 @@ all: $(PROGS) stap
> > # cpu emulator library
> > obj-y += exec.o
> > obj-y += accel/
> > +obj-$(CONFIG_PLUGINS) += plugins/plugins.o
> > obj-$(CONFIG_TCG) += tcg/tcg.o tcg/tcg-op.o tcg/tcg-op-vec.o
> > tcg/tcg-op-gvec.o
> > obj-$(CONFIG_TCG) += tcg/tcg-common.o tcg/optimize.o
> > obj-$(CONFIG_TCG_INTERPRETER) += tcg/tci.o
> > diff --git a/configure b/configure
> > index a71bf9b..34e6f00 100755
> > --- a/configure
> > +++ b/configure
> > @@ -373,6 +373,7 @@ EXESUF=""
> > DSOSUF=".so"
> > LDFLAGS_SHARED="-shared"
> > modules="no"
> > +plugins="no"
> > prefix="/usr/local"
> > mandir="\${prefix}/share/man"
> > datadir="\${prefix}/share"
> > @@ -922,6 +923,12 @@ for opt do
> > --disable-modules)
> > modules="no"
> > ;;
> > + --enable-plugins)
> > + plugins="yes"
> > + ;;
> > + --disable-plugins)
> > + plugins="no"
> > + ;;
> > --cpu=*)
> > ;;
> > --target-list=*) target_list="$optarg"
> > @@ -1567,6 +1574,7 @@ disabled with --disable-FEATURE, default is enabled
> > if available:
> > guest-agent-msi build guest agent Windows MSI installation package
> > pie Position Independent Executables
> > modules modules support
> > + plugins plugins support
> > debug-tcg TCG debugging (default is disabled)
> > debug-info debugging information
> > sparse sparse checker
> > @@ -3392,7 +3400,7 @@ else
> > glib_req_ver=2.22
> > fi
> > glib_modules=gthread-2.0
> > -if test "$modules" = yes; then
> > +if test "$modules" = yes || test "$plugins" = yes; then
> > glib_modules="$glib_modules gmodule-export-2.0"
> > fi
> >
> > @@ -5777,6 +5785,7 @@ if test "$slirp" = "yes" ; then
> > echo "smbd $smbd"
> > fi
> > echo "module support $modules"
> > +echo "plugin support $plugins"
> > echo "host CPU $cpu"
> > echo "host big endian $bigendian"
> > echo "target list $target_list"
> > @@ -6111,6 +6120,9 @@ if test "$modules" = "yes"; then
> > echo "CONFIG_STAMP=_$( (echo $qemu_version; echo $pkgversion; cat $0) |
> > $shacmd - | cut -
> f1 -d\ )" >> $config_host_mak
> > echo "CONFIG_MODULES=y" >> $config_host_mak
> > fi
> > +if test "$plugins" = "yes"; then
> > + echo "CONFIG_PLUGINS=y" >> $config_host_mak
> > +fi
> > if test "$have_x11" = "yes" -a "$need_x11" = "yes"; then
> > echo "CONFIG_X11=y" >> $config_host_mak
> > echo "X11_CFLAGS=$x11_cflags" >> $config_host_mak
> > diff --git a/include/qemu/plugins.h b/include/qemu/plugins.h
> > new file mode 100644
> > index 0000000..4464822
> > --- /dev/null
> > +++ b/include/qemu/plugins.h
> > @@ -0,0 +1,8 @@
> > +#ifndef PLUGINS_H
> > +#define PLUGINS_H
> > +
> > +void qemu_plugin_parse_cmd_args(const char *optarg);
> > +void qemu_plugin_load(const char *filename, const char *args);
> > +void qemu_plugins_init(void);
> > +
> > +#endif /* PLUGINS_H */
> > diff --git a/plugins/include/plugins.h b/plugins/include/plugins.h
> > new file mode 100644
> > index 0000000..100a786
> > --- /dev/null
> > +++ b/plugins/include/plugins.h
> > @@ -0,0 +1,12 @@
> > +#ifndef PLUGINS_INTERFACE_H
> > +#define PLUGINS_INTERFACE_H
> > +
> > +#include <stdbool.h>
> > +
> > +/* Plugin interface */
> > +
> > +bool plugin_init(const char *args);
> > +bool plugin_needs_before_insn(uint64_t pc, void *cpu);
> > +void plugin_before_insn(uint64_t pc, void *cpu);
> > +
> > +#endif /* PLUGINS_INTERFACE_H */
> > diff --git a/plugins/plugins.c b/plugins/plugins.c
> > new file mode 100644
> > index 0000000..eabc931
> > --- /dev/null
> > +++ b/plugins/plugins.c
> > @@ -0,0 +1,91 @@
> > +#include "qemu/osdep.h"
> > +#include "qemu-common.h"
> > +#include "qemu/error-report.h"
> > +#include "qemu/plugins.h"
> > +#include "qemu/queue.h"
> > +#include <gmodule.h>
> > +
> > +typedef bool (*PluginInitFunc)(const char *);
> > +typedef bool (*PluginNeedsBeforeInsnFunc)(uint64_t, void *);
> > +typedef void (*PluginBeforeInsnFunc)(uint64_t, void *);
> > +
> > +typedef struct QemuPluginInfo {
> > + const char *filename;
> > + const char *args;
> > + GModule *g_module;
> > +
> > + PluginInitFunc init;
> > + PluginNeedsBeforeInsnFunc needs_before_insn;
>
> It seems a bit heavyweight to have a query function here. Is this
> dynamic state the plugin might change during execution? If not could we
> not better report plugin requirements during initialisation?
Yes, it is dynamic.
For example, we created a plugin, which detects dynamic module loading
in the guest. Then it can add tracepoints to the entry addresses of the loaded
functions. These addresses are not known in advance.
Pavel Dovgalyuk