* [PATCH 1/3] kvmtool/setup: Introduce extract_file() helper
2015-10-19 10:59 [PATCH 0/3] kvmtool: tiny init fox x86_64 Oleg Nesterov
@ 2015-10-19 10:59 ` Oleg Nesterov
2015-10-19 10:59 ` [PATCH 2/3] kvmtool/build: introduce GUEST_PRE_INIT target Oleg Nesterov
` (2 subsequent siblings)
3 siblings, 0 replies; 6+ messages in thread
From: Oleg Nesterov @ 2015-10-19 10:59 UTC (permalink / raw)
To: Andre Przywara, Dimitri Ledkov, Ingo Molnar, Pekka Enberg,
Will Deacon; +Cc: kvm
Turn kvm_setup_guest_init(guestfs_name) into a more generic helper,
extract_file(guestfs_name, filename, data, size) and reimplement
kvm_setup_guest_init() as a trivial wrapper.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
builtin-setup.c | 24 ++++++++++++++----------
1 file changed, 14 insertions(+), 10 deletions(-)
diff --git a/builtin-setup.c b/builtin-setup.c
index 40fef15..bb7c71c 100644
--- a/builtin-setup.c
+++ b/builtin-setup.c
@@ -122,30 +122,34 @@ static const char *guestfs_symlinks[] = {
};
#ifdef CONFIG_GUEST_INIT
-extern char _binary_guest_init_start;
-extern char _binary_guest_init_size;
-
-int kvm_setup_guest_init(const char *guestfs_name)
+static int extract_file(const char *guestfs_name, const char *filename,
+ const void *data, const void *_size)
{
char path[PATH_MAX];
- size_t size;
int fd, ret;
- char *data;
- size = (size_t)&_binary_guest_init_size;
- data = (char *)&_binary_guest_init_start;
- snprintf(path, PATH_MAX, "%s%s/virt/init", kvm__get_dir(), guestfs_name);
+ snprintf(path, PATH_MAX, "%s%s/%s", kvm__get_dir(),
+ guestfs_name, filename);
remove(path);
fd = open(path, O_CREAT | O_WRONLY, 0755);
if (fd < 0)
die("Fail to setup %s", path);
- ret = xwrite(fd, data, size);
+ ret = xwrite(fd, data, (size_t)_size);
if (ret < 0)
die("Fail to setup %s", path);
close(fd);
return 0;
+}
+extern char _binary_guest_init_start;
+extern char _binary_guest_init_size;
+
+int kvm_setup_guest_init(const char *guestfs_name)
+{
+ return extract_file(guestfs_name, "virt/init",
+ &_binary_guest_init_start,
+ &_binary_guest_init_size);
}
#else
int kvm_setup_guest_init(const char *guestfs_name)
--
2.4.3
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH 2/3] kvmtool/build: introduce GUEST_PRE_INIT target
2015-10-19 10:59 [PATCH 0/3] kvmtool: tiny init fox x86_64 Oleg Nesterov
2015-10-19 10:59 ` [PATCH 1/3] kvmtool/setup: Introduce extract_file() helper Oleg Nesterov
@ 2015-10-19 10:59 ` Oleg Nesterov
2015-10-19 10:59 ` [PATCH 3/3] kvmtool/x86: implement guest_pre_init Oleg Nesterov
2015-10-22 7:59 ` [PATCH 0/3] kvmtool: tiny init fox x86_64 Pekka Enberg
3 siblings, 0 replies; 6+ messages in thread
From: Oleg Nesterov @ 2015-10-19 10:59 UTC (permalink / raw)
To: Andre Przywara, Dimitri Ledkov, Ingo Molnar, Pekka Enberg,
Will Deacon; +Cc: kvm
This comes as a separate patch because I do not really understand
/usr/bin/make, probably it should be updated.
Change the main Makefile so that if an arch defines ARCH_PRE_INIT
then we
- build $GUEST_INIT without "-static"
- add -DCONFIG_GUEST_PRE_INIT to $CFLAGS
- build $ARCH_PRE_INIT as guest/guest_pre_init.o and embed it
into lkvm the same as we do with guest/guest_init.o
This also means that ARCH_PRE_INIT case doesn't depend on glibc-static,
we can relax the SOURCE_STATIC check later.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
.gitignore | 1 +
Makefile | 25 ++++++++++++++++++++-----
2 files changed, 21 insertions(+), 5 deletions(-)
diff --git a/.gitignore b/.gitignore
index f10d3c5..697a63f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -9,6 +9,7 @@ include/common-cmds.h
tests/boot/boot_test.iso
tests/boot/rootfs/
guest/init
+guest/pre_init
guest/init_stage2
KVMTOOLS-VERSION-FILE
/x86/bios/bios.bin
diff --git a/Makefile b/Makefile
index f1701aa..0f8e003 100644
--- a/Makefile
+++ b/Makefile
@@ -281,6 +281,14 @@ ifeq ($(call try-build,$(SOURCE_STATIC),,-static),y)
CFLAGS += -DCONFIG_GUEST_INIT
GUEST_INIT := guest/init
GUEST_OBJS = guest/guest_init.o
+ ifeq ($(ARCH_PRE_INIT),)
+ GUEST_INIT_FLAGS += -static
+ else
+ CFLAGS += -DCONFIG_GUEST_PRE_INIT
+ GUEST_INIT_FLAGS += -DCONFIG_GUEST_PRE_INIT
+ GUEST_PRE_INIT := guest/pre_init
+ GUEST_OBJS += guest/guest_pre_init.o
+ endif
else
$(warning No static libc found. Skipping guest init)
NOTFOUND += static-libc
@@ -346,7 +354,7 @@ ifneq ($(WERROR),0)
CFLAGS += -Werror
endif
-all: $(PROGRAM) $(PROGRAM_ALIAS) $(GUEST_INIT)
+all: $(PROGRAM) $(PROGRAM_ALIAS) $(GUEST_INIT) $(GUEST_PRE_INIT)
# CFLAGS used when building objects
# This is intentionally not assigned using :=
@@ -360,11 +368,11 @@ c_flags = -Wp,-MD,$(depfile) $(CFLAGS)
#
STATIC_OBJS = $(patsubst %.o,%.static.o,$(OBJS) $(OBJS_STATOPT))
-$(PROGRAM)-static: $(STATIC_OBJS) $(OTHEROBJS) $(GUEST_INIT)
+$(PROGRAM)-static: $(STATIC_OBJS) $(OTHEROBJS) $(GUEST_INIT) $(GUEST_PRE_INIT)
$(E) " LINK " $@
$(Q) $(CC) -static $(CFLAGS) $(STATIC_OBJS) $(OTHEROBJS) $(GUEST_OBJS) $(LIBS) $(LIBS_STATOPT) -o $@
-$(PROGRAM): $(OBJS) $(OBJS_DYNOPT) $(OTHEROBJS) $(GUEST_INIT)
+$(PROGRAM): $(OBJS) $(OBJS_DYNOPT) $(OTHEROBJS) $(GUEST_INIT) $(GUEST_PRE_INIT)
$(E) " LINK " $@
$(Q) $(CC) $(CFLAGS) $(OBJS) $(OBJS_DYNOPT) $(OTHEROBJS) $(GUEST_OBJS) $(LIBS) $(LIBS_DYNOPT) -o $@
@@ -372,9 +380,16 @@ $(PROGRAM_ALIAS): $(PROGRAM)
$(E) " LN " $@
$(Q) ln -f $(PROGRAM) $@
+ifneq ($(ARCH_PRE_INIT),)
+$(GUEST_PRE_INIT): $(ARCH_PRE_INIT)
+ $(E) " LINK " $@
+ $(Q) $(CC) -s -nostdlib $(ARCH_PRE_INIT) -o $@
+ $(Q) $(LD) $(LDFLAGS) -r -b binary -o guest/guest_pre_init.o $(GUEST_PRE_INIT)
+endif
+
$(GUEST_INIT): guest/init.c
$(E) " LINK " $@
- $(Q) $(CC) -static guest/init.c -o $@
+ $(Q) $(CC) $(GUEST_INIT_FLAGS) guest/init.c -o $@
$(Q) $(LD) $(LDFLAGS) -r -b binary -o guest/guest_init.o $(GUEST_INIT)
%.s: %.c
@@ -473,7 +488,7 @@ clean:
$(Q) rm -f x86/bios/bios-rom.h
$(Q) rm -f tests/boot/boot_test.iso
$(Q) rm -rf tests/boot/rootfs/
- $(Q) rm -f $(DEPS) $(OBJS) $(OTHEROBJS) $(OBJS_DYNOPT) $(STATIC_OBJS) $(PROGRAM) $(PROGRAM_ALIAS) $(PROGRAM)-static $(GUEST_INIT) $(GUEST_OBJS)
+ $(Q) rm -f $(DEPS) $(OBJS) $(OTHEROBJS) $(OBJS_DYNOPT) $(STATIC_OBJS) $(PROGRAM) $(PROGRAM_ALIAS) $(PROGRAM)-static $(GUEST_INIT) $(GUEST_PRE_INIT) $(GUEST_OBJS)
$(Q) rm -f cscope.*
$(Q) rm -f tags
$(Q) rm -f TAGS
--
2.4.3
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH 3/3] kvmtool/x86: implement guest_pre_init
2015-10-19 10:59 [PATCH 0/3] kvmtool: tiny init fox x86_64 Oleg Nesterov
2015-10-19 10:59 ` [PATCH 1/3] kvmtool/setup: Introduce extract_file() helper Oleg Nesterov
2015-10-19 10:59 ` [PATCH 2/3] kvmtool/build: introduce GUEST_PRE_INIT target Oleg Nesterov
@ 2015-10-19 10:59 ` Oleg Nesterov
2015-10-22 7:59 ` [PATCH 0/3] kvmtool: tiny init fox x86_64 Pekka Enberg
3 siblings, 0 replies; 6+ messages in thread
From: Oleg Nesterov @ 2015-10-19 10:59 UTC (permalink / raw)
To: Andre Przywara, Dimitri Ledkov, Ingo Molnar, Pekka Enberg,
Will Deacon; +Cc: kvm
Add the tiny x86/init.S which just mounts /host and execs
/virt/init.
NOTE: of course, the usage of CONFIG_GUEST_PRE_INIT is ugly, we
need to cleanup this code. But I'd prefer to do this on top of
this minimal/simple change. And I think this needs cleanups in
any case, for example I think lkvm shouldn't abuse the "init="
kernel parameter at all.
TODO: x86/init.S doesn't handle i386, should be simple to add.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
Makefile | 1 +
builtin-run.c | 4 ++++
builtin-setup.c | 14 +++++++++++++-
guest/init.c | 2 ++
x86/init.S | 38 ++++++++++++++++++++++++++++++++++++++
5 files changed, 58 insertions(+), 1 deletion(-)
create mode 100644 x86/init.S
diff --git a/Makefile b/Makefile
index 0f8e003..f8f7cc4 100644
--- a/Makefile
+++ b/Makefile
@@ -110,6 +110,7 @@ endif
ifeq ($(ARCH),x86_64)
ARCH := x86
DEFINES += -DCONFIG_X86_64
+ ARCH_PRE_INIT = x86/init.S
endif
### Arch-specific stuff
diff --git a/builtin-run.c b/builtin-run.c
index e0c8732..3da00da 100644
--- a/builtin-run.c
+++ b/builtin-run.c
@@ -600,7 +600,11 @@ static struct kvm *kvm_cmd_run_init(int argc, const char **argv)
if (kvm->cfg.custom_rootfs) {
kvm_run_set_sandbox(kvm);
+#ifdef CONFIG_GUEST_PRE_INIT
+ strcat(real_cmdline, " init=/virt/pre_init");
+#else
strcat(real_cmdline, " init=/virt/init");
+#endif
if (!kvm->cfg.no_dhcp)
strcat(real_cmdline, " ip=dhcp");
diff --git a/builtin-setup.c b/builtin-setup.c
index bb7c71c..1e5b1e4 100644
--- a/builtin-setup.c
+++ b/builtin-setup.c
@@ -144,12 +144,24 @@ static int extract_file(const char *guestfs_name, const char *filename,
extern char _binary_guest_init_start;
extern char _binary_guest_init_size;
+extern char _binary_guest_pre_init_start;
+extern char _binary_guest_pre_init_size;
int kvm_setup_guest_init(const char *guestfs_name)
{
- return extract_file(guestfs_name, "virt/init",
+ int err;
+
+#ifdef CONFIG_GUEST_PRE_INIT
+ err = extract_file(guestfs_name, "virt/pre_init",
+ &_binary_guest_pre_init_start,
+ &_binary_guest_pre_init_size);
+ if (err)
+ return err;
+#endif
+ err = extract_file(guestfs_name, "virt/init",
&_binary_guest_init_start,
&_binary_guest_init_size);
+ return err;
}
#else
int kvm_setup_guest_init(const char *guestfs_name)
diff --git a/guest/init.c b/guest/init.c
index 7277a07..46e3fa4 100644
--- a/guest/init.c
+++ b/guest/init.c
@@ -30,7 +30,9 @@ static int run_process_sandbox(char *filename)
static void do_mounts(void)
{
+#ifndef CONFIG_GUEST_PRE_INIT
mount("hostfs", "/host", "9p", MS_RDONLY, "trans=virtio,version=9p2000.L");
+#endif
mount("", "/sys", "sysfs", 0, NULL);
mount("proc", "/proc", "proc", 0, NULL);
mount("devtmpfs", "/dev", "devtmpfs", 0, NULL);
diff --git a/x86/init.S b/x86/init.S
new file mode 100644
index 0000000..488a93f
--- /dev/null
+++ b/x86/init.S
@@ -0,0 +1,38 @@
+.data
+
+.m_dev:
+.string "hostfs"
+.m_dir:
+.string "/host"
+.m_typ:
+.string "9p"
+.m_opt:
+.string "trans=virtio,version=9p2000.L"
+
+.e_nam:
+.string "/virt/init"
+
+.text
+.globl _start
+_start:
+
+ mov $165, %rax # __NR_mount
+ mov $.m_dev, %rdi
+ mov $.m_dir, %rsi
+ mov $.m_typ, %rdx
+ mov $1, %r10 # MS_RDONLY
+ mov $.m_opt, %r8
+ syscall
+
+ mov $59, %rax # __NR_execve
+ mov $.e_nam, %rdi
+ lea 8(%rsp), %rsi # argv[]
+ mov %rdi, (%rsi) # change argv[0]
+ pop %rcx # argc
+ inc %rcx
+ lea (%rsi,%rcx,8), %rdx # envp[]
+ syscall
+
+ mov $60, %rax # __NR_exit
+ mov $1, %rdi
+ syscall # panic
--
2.4.3
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH 0/3] kvmtool: tiny init fox x86_64
2015-10-19 10:59 [PATCH 0/3] kvmtool: tiny init fox x86_64 Oleg Nesterov
` (2 preceding siblings ...)
2015-10-19 10:59 ` [PATCH 3/3] kvmtool/x86: implement guest_pre_init Oleg Nesterov
@ 2015-10-22 7:59 ` Pekka Enberg
2015-10-22 15:58 ` Oleg Nesterov
3 siblings, 1 reply; 6+ messages in thread
From: Pekka Enberg @ 2015-10-22 7:59 UTC (permalink / raw)
To: Oleg Nesterov, Andre Przywara, Dimitri Ledkov, Ingo Molnar,
Pekka Enberg, Will Deacon
Cc: kvm
Hi Oleg,
On 10/19/2015 01:59 PM, Oleg Nesterov wrote:
> Yesterday I discovered kvmtool and it looks really cool! Thanks!
> Looks like, it does exactly what I need.
>
> But the static /virt/init doesn't look good. This series lessens
> the size of lkvm binary from 1045952 to 196200 bytes on x86_64,
> but this is minor. I want to write my /virt/init in shell or perl
> and this change can help.
>
> I don't really know who should be cc'ed, I've picked some names
> from git-log guest/init.c.
Will maintains the standalone kvmtool.git tree.
The series looks good to me:
Acked-by: Pekka Enberg <penberg@kernel.org>
- Pekka
^ permalink raw reply [flat|nested] 6+ messages in thread