[PATCH] kvm tools: Add 'kvm nmi' command

[PATCH] kvm tools: Add 'kvm nmi' command

[Sasha Levin]

This patch adds a 'kvm nmi' command which can be used to trigger NMIs in
guests.

Mostly useful for debugging purposes.

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
---
 tools/kvm/Documentation/kvm-nmi.txt |   16 +++++++
 tools/kvm/Makefile                  |    3 +-
 tools/kvm/builtin-nmi.c             |   80 +++++++++++++++++++++++++++++++++++
 tools/kvm/builtin-run.c             |    9 ++++
 tools/kvm/command-list.txt          |    1 +
 tools/kvm/include/kvm/builtin-nmi.h |   15 +++++++
 tools/kvm/include/kvm/kvm-ipc.h     |    1 +
 tools/kvm/kvm-cmd.c                 |    2 +
 8 files changed, 126 insertions(+), 1 deletions(-)
 create mode 100644 tools/kvm/Documentation/kvm-nmi.txt
 create mode 100644 tools/kvm/builtin-nmi.c
 create mode 100644 tools/kvm/include/kvm/builtin-nmi.h

diff --git a/tools/kvm/Documentation/kvm-nmi.txt b/tools/kvm/Documentation/kvm-nmi.txt
new file mode 100644
index 0000000..d562abc
--- /dev/null
+++ b/tools/kvm/Documentation/kvm-nmi.txt
@@ -0,0 +1,16 @@
+kvm-nmi(1)
+================
+
+NAME
+----
+kvm-nmi - Trigger an NMI on a specific cpu in the guest
+
+SYNOPSIS
+--------
+[verse]
+'kvm nmi [instance] -c [cpu]'
+
+DESCRIPTION
+-----------
+The command triggers a NMI on cpu 'cpu' in the guest.
+For a list of running instances see 'kvm list'.
diff --git a/tools/kvm/Makefile b/tools/kvm/Makefile
index 243886e..b5a76e2 100644
--- a/tools/kvm/Makefile
+++ b/tools/kvm/Makefile
@@ -80,6 +80,7 @@ OBJS	+= hw/vesa.o
 OBJS	+= hw/i8042.o
 OBJS	+= hw/pci-shmem.o
 OBJS	+= kvm-ipc.o
+OBJS	+= builtin-nmi.o
 
 FLAGS_BFD := $(CFLAGS) -lbfd
 has_bfd := $(call try-cc,$(SOURCE_BFD),$(FLAGS_BFD))
@@ -176,7 +177,7 @@ DEFINES	+= -DKVMTOOLS_VERSION='"$(KVMTOOLS_VERSION)"'
 DEFINES	+= -DBUILD_ARCH='"$(ARCH)"'
 
 KVM_INCLUDE := include
-CFLAGS	+= $(CPPFLAGS) $(DEFINES) -I$(KVM_INCLUDE) -I$(ARCH_INCLUDE) -I../../include -I../../arch/$(ARCH)/include/ -Os -g
+CFLAGS	+= $(CPPFLAGS) $(DEFINES) -I$(KVM_INCLUDE) -I$(ARCH_INCLUDE) -I../../include -I../../arch/$(ARCH)/include/ -O0 -g
 
 ifneq ($(WERROR),0)
 	WARNINGS += -Werror
diff --git a/tools/kvm/builtin-nmi.c b/tools/kvm/builtin-nmi.c
new file mode 100644
index 0000000..ad60ac2
--- /dev/null
+++ b/tools/kvm/builtin-nmi.c
@@ -0,0 +1,80 @@
+#include <kvm/builtin-nmi.h>
+#include <kvm/kvm.h>
+#include <kvm/parse-options.h>
+#include <kvm/kvm-ipc.h>
+#include <kvm/read-write.h>
+#include <kvm/util.h>
+
+#include <stdio.h>
+#include <string.h>
+#include <signal.h>
+
+static bool all;
+static int instance;
+static int cpu = -1;
+static const char *instance_name;
+
+static const char * const nmi_usage[] = {
+	"kvm nmi [--all] [-n name] -c cpu",
+	NULL
+};
+
+static const struct option nmi_options[] = {
+	OPT_GROUP("General options:"),
+	OPT_BOOLEAN('a', "all", &all, "Send NMI to all instances"),
+	OPT_STRING('n', "name", &instance_name, "name", "Instance name"),
+	OPT_INTEGER('c', "cpu", &cpu, "CPU which will receive NMI"),
+	OPT_END()
+};
+
+static void parse_nmi_options(int argc, const char **argv)
+{
+	while (argc != 0) {
+		argc = parse_options(argc, argv, nmi_options, nmi_usage,
+				PARSE_OPT_STOP_AT_NON_OPTION);
+		if (argc != 0)
+			kvm_nmi_help();
+	}
+}
+
+void kvm_nmi_help(void)
+{
+	usage_with_options(nmi_usage, nmi_options);
+}
+
+static int do_nmi(const char *name, int sock)
+{
+	struct nmi_cmd cmd = {KVM_IPC_NMI, sizeof(u32)};
+	int r;
+
+	r = xwrite(sock, &cmd, sizeof(cmd));
+	if (r < 0)
+		return r;
+
+	pr_info("NMI sent to %s!\n", name);
+
+	return 0;
+}
+
+int kvm_cmd_nmi(int argc, const char **argv, const char *prefix)
+{
+	parse_nmi_options(argc, argv);
+
+	if (all)
+		return kvm__enumerate_instances(do_nmi);
+
+	if (instance_name == NULL &&
+	    instance == 0)
+		kvm_nmi_help();
+
+	if (cpu == -1)
+		kvm_nmi_help();
+
+	if (instance_name)
+		instance = kvm__get_sock_by_instance(instance_name);
+
+	if (instance <= 0)
+		die("Failed locating instance");
+
+	return do_nmi(instance_name, instance);
+}
diff --git a/tools/kvm/builtin-run.c b/tools/kvm/builtin-run.c
index 9148d83..b8743cd 100644
--- a/tools/kvm/builtin-run.c
+++ b/tools/kvm/builtin-run.c
@@ -31,6 +31,7 @@
 #include "kvm/guest_compat.h"
 #include "kvm/pci-shmem.h"
 #include "kvm/kvm-ipc.h"
+#include "kvm/builtin-nmi.h"
 
 #include <linux/types.h>
 
@@ -529,6 +530,13 @@ static void handle_stop(int fd, u32 type, u32 len, u8 *msg)
 	kvm_cpu__reboot();
 }
 
+static void handle_nmi(int fd, u32 type, u32 len, u8 *msg)
+{
+	u32 vcpu = *(u32 *)msg;
+
+	ioctl(kvm_cpus[vcpu]->vcpu_fd, KVM_NMI);
+}
+
 static void *kvm_cpu_thread(void *arg)
 {
 	current_kvm_cpu		= arg;
@@ -718,6 +726,7 @@ int kvm_cmd_run(int argc, const char **argv, const char *prefix)
 	kvm_ipc__register_handler(KVM_IPC_PAUSE, handle_pause);
 	kvm_ipc__register_handler(KVM_IPC_RESUME, handle_pause);
 	kvm_ipc__register_handler(KVM_IPC_STOP, handle_stop);
+	kvm_ipc__register_handler(KVM_IPC_NMI, handle_nmi);
 
 	nr_online_cpus = sysconf(_SC_NPROCESSORS_ONLN);
 
diff --git a/tools/kvm/command-list.txt b/tools/kvm/command-list.txt
index 0d16c62..e9ab8e4 100644
--- a/tools/kvm/command-list.txt
+++ b/tools/kvm/command-list.txt
@@ -12,3 +12,4 @@ kvm-debug			common
 kvm-balloon			common
 kvm-stop			common
 kvm-stat			common
+kvm-nmi				common
diff --git a/tools/kvm/include/kvm/builtin-nmi.h b/tools/kvm/include/kvm/builtin-nmi.h
new file mode 100644
index 0000000..ffdc288
--- /dev/null
+++ b/tools/kvm/include/kvm/builtin-nmi.h
@@ -0,0 +1,15 @@
+#ifndef KVM__NMI_H
+#define KVM__NMI_H
+
+#include <linux/types.h>
+
+struct nmi_cmd {
+	u32 type;
+	u32 len;
+	u32 cpu;
+};
+
+int kvm_cmd_nmi(int argc, const char **argv, const char *prefix);
+void kvm_nmi_help(void);
+
+#endif
diff --git a/tools/kvm/include/kvm/kvm-ipc.h b/tools/kvm/include/kvm/kvm-ipc.h
index 731767f..366f54e 100644
--- a/tools/kvm/include/kvm/kvm-ipc.h
+++ b/tools/kvm/include/kvm/kvm-ipc.h
@@ -17,6 +17,7 @@ enum {
 	KVM_IPC_RESUME	= 5,
 	KVM_IPC_STOP	= 6,
 	KVM_IPC_PID	= 7,
+	KVM_IPC_NMI	= 8,
 };
 
 int kvm_ipc__register_handler(u32 type, void (*cb)(int fd, u32 type, u32 len, u8 *msg));
diff --git a/tools/kvm/kvm-cmd.c b/tools/kvm/kvm-cmd.c
index 96108a8..6ab9897 100644
--- a/tools/kvm/kvm-cmd.c
+++ b/tools/kvm/kvm-cmd.c
@@ -15,6 +15,7 @@
 #include "kvm/builtin-stop.h"
 #include "kvm/builtin-stat.h"
 #include "kvm/builtin-help.h"
+#include "kvm/builtin-nmi.h"
 #include "kvm/kvm-cmd.h"
 #include "kvm/builtin-run.h"
 #include "kvm/util.h"
@@ -31,6 +32,7 @@ struct cmd_struct kvm_commands[] = {
 	{ "stat",	kvm_cmd_stat,		kvm_stat_help,		0 },
 	{ "help",	kvm_cmd_help,		NULL,			0 },
 	{ "setup",	kvm_cmd_setup,		kvm_setup_help,		0 },
+	{ "nmi",	kvm_cmd_nmi,		kvm_nmi_help,		0 },
 	{ "run",	kvm_cmd_run,		kvm_run_help,		0 },
 	{ NULL,		NULL,			NULL,			0 },
 };
-- 
1.7.8

Re: [PATCH] kvm tools: Add 'kvm nmi' command

[Ingo Molnar]

* Sasha Levin <levinsasha928@gmail.com> wrote:

> This patch adds a 'kvm nmi' command which can be used to trigger NMIs in
> guests.
> 
> Mostly useful for debugging purposes.

Could we make this something like 'kvm debug nmi'?

We already have some debug functionality, right? Those should be 
consolidated under 'kvm debug'.

Thanks,

	Ingo

Re: [PATCH] kvm tools: Add 'kvm nmi' command

[Gleb Natapov]

On Tue, Dec 06, 2011 at 10:42:55PM +0200, Sasha Levin wrote:
> +static void handle_nmi(int fd, u32 type, u32 len, u8 *msg)
> +{
> +	u32 vcpu = *(u32 *)msg;
> +
> +	ioctl(kvm_cpus[vcpu]->vcpu_fd, KVM_NMI);
You need to check that vcpu apic's LINT1 is configured to receive
NMI (and not masked obviously) before injecting NMI. 

--
			Gleb.

Re: [PATCH] kvm tools: Add 'kvm nmi' command

[Cyrill Gorcunov]

On Wed, Dec 07, 2011 at 12:21:52PM +0200, Gleb Natapov wrote:
> On Tue, Dec 06, 2011 at 10:42:55PM +0200, Sasha Levin wrote:
> > +static void handle_nmi(int fd, u32 type, u32 len, u8 *msg)
> > +{
> > +	u32 vcpu = *(u32 *)msg;
> > +
> > +	ioctl(kvm_cpus[vcpu]->vcpu_fd, KVM_NMI);
>
> You need to check that vcpu apic's LINT1 is configured to receive
> NMI (and not masked obviously) before injecting NMI. 
> 

I've been configuring mptable to have lint1 as nmi receiver,
so it should remain so I suppose (if only we've not masked it
somewhere else ;)

	Cyrill

Re: [PATCH] kvm tools: Add 'kvm nmi' command

[Gleb Natapov]

On Wed, Dec 07, 2011 at 02:31:11PM +0400, Cyrill Gorcunov wrote:
> On Wed, Dec 07, 2011 at 12:21:52PM +0200, Gleb Natapov wrote:
> > On Tue, Dec 06, 2011 at 10:42:55PM +0200, Sasha Levin wrote:
> > > +static void handle_nmi(int fd, u32 type, u32 len, u8 *msg)
> > > +{
> > > +	u32 vcpu = *(u32 *)msg;
> > > +
> > > +	ioctl(kvm_cpus[vcpu]->vcpu_fd, KVM_NMI);
> >
> > You need to check that vcpu apic's LINT1 is configured to receive
> > NMI (and not masked obviously) before injecting NMI. 
> > 
> 
> I've been configuring mptable to have lint1 as nmi receiver,
> so it should remain so I suppose (if only we've not masked it
> somewhere else ;)
> 
That's up to the guest. mptable is just a hint to an OS on how things is
wired in HW.

--
			Gleb.

Re: [PATCH] kvm tools: Add 'kvm nmi' command

[Cyrill Gorcunov]

On Wed, Dec 07, 2011 at 12:33:05PM +0200, Gleb Natapov wrote:
> On Wed, Dec 07, 2011 at 02:31:11PM +0400, Cyrill Gorcunov wrote:
> > On Wed, Dec 07, 2011 at 12:21:52PM +0200, Gleb Natapov wrote:
> > > On Tue, Dec 06, 2011 at 10:42:55PM +0200, Sasha Levin wrote:
> > > > +static void handle_nmi(int fd, u32 type, u32 len, u8 *msg)
> > > > +{
> > > > +	u32 vcpu = *(u32 *)msg;
> > > > +
> > > > +	ioctl(kvm_cpus[vcpu]->vcpu_fd, KVM_NMI);
> > >
> > > You need to check that vcpu apic's LINT1 is configured to receive
> > > NMI (and not masked obviously) before injecting NMI. 
> > > 
> > 
> > I've been configuring mptable to have lint1 as nmi receiver,
> > so it should remain so I suppose (if only we've not masked it
> > somewhere else ;)
> > 
>
> That's up to the guest. mptable is just a hint to an OS on how things is
> wired in HW.
> 

Yup, but while we support linux kernels only it should be fine. Still
of course on long term we need a check.

	Cyrill

Re: [PATCH] kvm tools: Add 'kvm nmi' command

[Gleb Natapov]

On Wed, Dec 07, 2011 at 02:37:25PM +0400, Cyrill Gorcunov wrote:
> On Wed, Dec 07, 2011 at 12:33:05PM +0200, Gleb Natapov wrote:
> > On Wed, Dec 07, 2011 at 02:31:11PM +0400, Cyrill Gorcunov wrote:
> > > On Wed, Dec 07, 2011 at 12:21:52PM +0200, Gleb Natapov wrote:
> > > > On Tue, Dec 06, 2011 at 10:42:55PM +0200, Sasha Levin wrote:
> > > > > +static void handle_nmi(int fd, u32 type, u32 len, u8 *msg)
> > > > > +{
> > > > > +	u32 vcpu = *(u32 *)msg;
> > > > > +
> > > > > +	ioctl(kvm_cpus[vcpu]->vcpu_fd, KVM_NMI);
> > > >
> > > > You need to check that vcpu apic's LINT1 is configured to receive
> > > > NMI (and not masked obviously) before injecting NMI. 
> > > > 
> > > 
> > > I've been configuring mptable to have lint1 as nmi receiver,
> > > so it should remain so I suppose (if only we've not masked it
> > > somewhere else ;)
> > > 
> >
> > That's up to the guest. mptable is just a hint to an OS on how things is
> > wired in HW.
> > 
> 
> Yup, but while we support linux kernels only it should be fine. Still
> of course on long term we need a check.
> 
Tomorrow someone will send a patch to change how Linux behaves and
slightly older kvmtool will not be able to run newer kernels :) No need
to wait for long term, a couple of lines of code will fix the issue in the
patch. Look here for reference:

http://article.gmane.org/gmane.comp.emulators.kvm.devel/80339

--
			Gleb.

Re: [PATCH] kvm tools: Add 'kvm nmi' command

[Cyrill Gorcunov]

On Wed, Dec 07, 2011 at 12:41:50PM +0200, Gleb Natapov wrote:
> > 
> > Yup, but while we support linux kernels only it should be fine. Still
> > of course on long term we need a check.
> > 
> Tomorrow someone will send a patch to change how Linux behaves and
> slightly older kvmtool will not be able to run newer kernels :) No need
> to wait for long term, a couple of lines of code will fix the issue in the
> patch. Look here for reference:
> 
> http://article.gmane.org/gmane.comp.emulators.kvm.devel/80339
> 

Sure. Thanks Gleb!

	Cyrill

Re: [PATCH] kvm tools: Add 'kvm nmi' command

[Pekka Enberg]

On Wed, 2011-12-07 at 09:16 +0100, Ingo Molnar wrote:
> * Sasha Levin <levinsasha928@gmail.com> wrote:
> 
> > This patch adds a 'kvm nmi' command which can be used to trigger NMIs in
> > guests.
> > 
> > Mostly useful for debugging purposes.
> 
> Could we make this something like 'kvm debug nmi'?
> 
> We already have some debug functionality, right? Those should be 
> consolidated under 'kvm debug'.

Agreed. It's probably best to implement this as a option to 'kvm debug'.
For example,

  kvm debug [-n|--nmi]

or something.

			Pekka

Re: [PATCH] kvm tools: Add 'kvm nmi' command

[Sasha Levin]

On Wed, 2011-12-07 at 19:13 +0200, Pekka Enberg wrote:
> On Wed, 2011-12-07 at 09:16 +0100, Ingo Molnar wrote:
> > * Sasha Levin <levinsasha928@gmail.com> wrote:
> > 
> > > This patch adds a 'kvm nmi' command which can be used to trigger NMIs in
> > > guests.
> > > 
> > > Mostly useful for debugging purposes.
> > 
> > Could we make this something like 'kvm debug nmi'?
> > 
> > We already have some debug functionality, right? Those should be 
> > consolidated under 'kvm debug'.
> 
> Agreed. It's probably best to implement this as a option to 'kvm debug'.
> For example,
> 
>   kvm debug [-n|--nmi]
> 
> or something.

Okay, so changes required so far:

1. 'kvm nmi' -> 'kvm debug --nmi'
2. Use method described in api.txt
3. Use same thread as vcpu.

Will modify and resend.

-- 

Sasha.