By default, all introspection VM events are disabled. The introspection
tool must explicitly enable the VM events it wants to receive. With
this command (KVMI_VM_CONTROL_EVENTS) it can enable/disable any VM event
(e.g. KVMI_EVENT_UNHOOK) if allowed by the device manager.
Signed-off-by: Adalbert Lazăr <alazar@xxxxxxxxxxxxxxx>
---
Documentation/virt/kvm/kvmi.rst | 44 +++++++++++++--
include/linux/kvmi_host.h | 2 +
include/uapi/linux/kvmi.h | 16 ++++--
.../testing/selftests/kvm/x86_64/kvmi_test.c | 54 +++++++++++++++++++
virt/kvm/introspection/kvmi.c | 30 ++++++++++-
virt/kvm/introspection/kvmi_int.h | 3 ++
virt/kvm/introspection/kvmi_msg.c | 29 ++++++++--
7 files changed, 165 insertions(+), 13 deletions(-)
diff --git a/Documentation/virt/kvm/kvmi.rst b/Documentation/virt/kvm/kvmi.rst
index 4174c969cb47..4ec0046b4138 100644
--- a/Documentation/virt/kvm/kvmi.rst
+++ b/Documentation/virt/kvm/kvmi.rst
@@ -342,11 +342,45 @@ This command is always allowed.
Returns the number of online vCPUs.
+5. KVMI_VM_CONTROL_EVENTS
+-------------------------
+
+:Architectures: all
+:Versions: >= 1
+:Parameters:
+
+::
+
+ struct kvmi_vm_control_events {
+ __u16 event_id;
+ __u8 enable;
+ __u8 padding1;
+ __u32 padding2;
+ };
+
+:Returns:
+
+::
+
+ struct kvmi_error_code
+
+Enables/disables VM introspection events. This command can be used with
+the following events::
+
+ KVMI_EVENT_UNHOOK
+
+:Errors:
+
+* -KVM_EINVAL - the padding is not zero
+* -KVM_EINVAL - the event ID is unknown (use *KVMI_VM_CHECK_EVENT* first)
+* -KVM_EPERM - the access is disallowed (use *KVMI_VM_CHECK_EVENT* first)
+
Events
======
All introspection events (VM or vCPU related) are sent
-using the *KVMI_EVENT* message id.
+using the *KVMI_EVENT* message id. No event will be sent unless
+it is explicitly enabled.
The *KVMI_EVENT_UNHOOK* event doesn't have a reply and share the kvmi_event
structure, for consistency with the vCPU events.
@@ -400,6 +434,8 @@ Specific event data can follow these common structures.
:Returns: none
-This event is sent when the device manager has to pause/stop/migrate the
-guest (see **Unhooking**). The introspection tool has a chance to unhook
-and close the KVMI channel (signaling that the operation can proceed).
+This event is sent when the device manager has to pause/stop/migrate
+the guest (see **Unhooking**) and the introspection has been enabled
+for this event (see **KVMI_VM_CONTROL_EVENTS**). The introspection tool
+has a chance to unhook and close the KVMI channel (signaling that the
+operation can proceed).
diff --git a/include/linux/kvmi_host.h b/include/linux/kvmi_host.h
index 8d21e031788e..8e142096ba47 100644
--- a/include/linux/kvmi_host.h
+++ b/include/linux/kvmi_host.h
@@ -18,6 +18,8 @@ struct kvm_introspection {
unsigned long *cmd_allow_mask;
unsigned long *event_allow_mask;
+ unsigned long *vm_event_enable_mask;
+
atomic_t ev_seq;
};
diff --git a/include/uapi/linux/kvmi.h b/include/uapi/linux/kvmi.h
index 9fbe52caf96c..f9e2cb8a2c5e 100644
--- a/include/uapi/linux/kvmi.h
+++ b/include/uapi/linux/kvmi.h
@@ -17,10 +17,11 @@ enum {
enum {
KVMI_EVENT = 0,
- KVMI_GET_VERSION = 1,
- KVMI_VM_CHECK_COMMAND = 2,
- KVMI_VM_CHECK_EVENT = 3,
- KVMI_VM_GET_INFO = 4,
+ KVMI_GET_VERSION = 1,
+ KVMI_VM_CHECK_COMMAND = 2,
+ KVMI_VM_CHECK_EVENT = 3,
+ KVMI_VM_GET_INFO = 4,
+ KVMI_VM_CONTROL_EVENTS = 5,
KVMI_NUM_MESSAGES
};
@@ -74,6 +75,13 @@ struct kvmi_vm_get_info_reply {
__u32 padding[3];
};
+struct kvmi_vm_control_events {
+ __u16 event_id;
+ __u8 enable;
+ __u8 padding1;
+ __u32 padding2;
+};
+
struct kvmi_event {
__u16 size;
__u16 vcpu;
diff --git a/tools/testing/selftests/kvm/x86_64/kvmi_test.c b/tools/testing/selftests/kvm/x86_64/kvmi_test.c
index 3d46d6e6b38c..bb2daaca0291 100644
--- a/tools/testing/selftests/kvm/x86_64/kvmi_test.c
+++ b/tools/testing/selftests/kvm/x86_64/kvmi_test.c
@@ -370,15 +370,68 @@ static void receive_event(struct kvmi_msg_hdr *hdr, struct kvmi_event *ev,
hdr->size, ev_size);
}
+static void cmd_vm_control_events(__u16 event_id, __u8 enable, __u16 padding,
+ int expected_err)
+{
+ struct {
+ struct kvmi_msg_hdr hdr;
+ struct kvmi_vm_control_events cmd;
+ } req = {};
+ int r;
+
+ req.cmd.event_id = event_id;
+ req.cmd.enable = enable;
+ req.cmd.padding1 = padding;
+ req.cmd.padding2 = padding;
+
+ r = do_command(KVMI_VM_CONTROL_EVENTS, &req.hdr, sizeof(req),
+ NULL, 0);
+ TEST_ASSERT(r == expected_err,
+ "KVMI_VM_CONTROL_EVENTS failed to enable VM event %d, error %d (%s), expected error %d\n",
+ event_id, -r, kvm_strerror(-r), expected_err);
+}
+
+static void enable_vm_event(__u16 event_id)
+{
+ cmd_vm_control_events(event_id, 1, 0, 0);
+}
+
+static void disable_vm_event(__u16 event_id)
+{
+ cmd_vm_control_events(event_id, 0, 0, 0);
+}
+
static void test_event_unhook(struct kvm_vm *vm)
{
__u16 id = KVMI_EVENT_UNHOOK;
struct kvmi_msg_hdr hdr;
struct kvmi_event ev;
+ enable_vm_event(id);
+
trigger_event_unhook_notification(vm);
receive_event(&hdr, &ev, sizeof(ev), id);
+
+ disable_vm_event(id);
+}
+
+static void test_cmd_vm_control_events(struct kvm_vm *vm)
+{
+ __u16 id = KVMI_EVENT_UNHOOK, invalid_id = 0xffff;
+ __u16 padding = 1, no_padding = 0;
+ __u8 enable = 1, enable_inval = 2;
+
+ enable_vm_event(id);
+ disable_vm_event(id);
+
+ cmd_vm_control_events(id, enable, padding, -KVM_EINVAL);
+ cmd_vm_control_events(id, enable_inval, no_padding, -KVM_EINVAL);
+ cmd_vm_control_events(invalid_id, enable, no_padding, -KVM_EINVAL);
+
+ disallow_event(vm, id);
+ cmd_vm_control_events(id, enable, no_padding, -KVM_EPERM);
+ allow_event(vm, id);
}
static void test_introspection(struct kvm_vm *vm)
@@ -392,6 +445,7 @@ static void test_introspection(struct kvm_vm *vm)
test_cmd_vm_check_event(vm);
test_cmd_vm_get_info();
test_event_unhook(vm);
+ test_cmd_vm_control_events(vm);
unhook_introspection(vm);
}
diff --git a/virt/kvm/introspection/kvmi.c b/virt/kvm/introspection/kvmi.c
index f128b1407c84..5af6ea041035 100644
--- a/virt/kvm/introspection/kvmi.c
+++ b/virt/kvm/introspection/kvmi.c
@@ -59,6 +59,16 @@ bool kvmi_is_known_event(u8 id)
return id < KVMI_NUM_EVENTS && test_bit(id, Kvmi_known_events);
}
+bool kvmi_is_known_vm_event(u8 id)
+{
+ return id < KVMI_NUM_EVENTS && test_bit(id, Kvmi_known_vm_events);
+}
+
+static bool is_vm_event_enabled(struct kvm_introspection *kvmi, int event)
+{
+ return test_bit(event, kvmi->vm_event_enable_mask);
+}
+
static void setup_always_allowed_commands(void)
{
bitmap_zero(Kvmi_always_allowed_commands, KVMI_NUM_COMMANDS);
@@ -100,6 +110,7 @@ static void free_kvmi(struct kvm *kvm)
{
bitmap_free(kvm->kvmi->cmd_allow_mask);
bitmap_free(kvm->kvmi->event_allow_mask);
+ bitmap_free(kvm->kvmi->vm_event_enable_mask);
kfree(kvm->kvmi);
kvm->kvmi = NULL;
@@ -116,9 +127,12 @@ alloc_kvmi(struct kvm *kvm, const struct kvm_introspection_hook *hook)
kvmi->cmd_allow_mask = bitmap_zalloc(KVMI_NUM_COMMANDS, GFP_KERNEL);
kvmi->event_allow_mask = bitmap_zalloc(KVMI_NUM_EVENTS, GFP_KERNEL);
- if (!kvmi->cmd_allow_mask || !kvmi->event_allow_mask) {
+ kvmi->vm_event_enable_mask = bitmap_zalloc(KVMI_NUM_EVENTS, GFP_KERNEL);
+ if (!kvmi->cmd_allow_mask || !kvmi->event_allow_mask ||
+ !kvmi->vm_event_enable_mask) {
bitmap_free(kvmi->cmd_allow_mask);
bitmap_free(kvmi->event_allow_mask);
+ bitmap_free(kvmi->vm_event_enable_mask);
kfree(kvmi);
return NULL;
}
@@ -392,6 +406,9 @@ static bool kvmi_unhook_event(struct kvm_introspection *kvmi)
{
int err;
+ if (!is_vm_event_enabled(kvmi, KVMI_EVENT_UNHOOK))
+ return false;
+
err = kvmi_msg_send_unhook(kvmi);
return !err;
@@ -417,3 +434,14 @@ int kvmi_ioctl_preunhook(struct kvm *kvm)
mutex_unlock(&kvm->kvmi_lock);
return err;
}
+
+int kvmi_cmd_vm_control_events(struct kvm_introspection *kvmi,
+ unsigned int event_id, bool enable)
+{
+ if (enable)
+ set_bit(event_id, kvmi->vm_event_enable_mask);
+ else
+ clear_bit(event_id, kvmi->vm_event_enable_mask);
+
+ return 0;
+}
diff --git a/virt/kvm/introspection/kvmi_int.h b/virt/kvm/introspection/kvmi_int.h
index c385dc0eb708..7c503b8ca043 100644
--- a/virt/kvm/introspection/kvmi_int.h
+++ b/virt/kvm/introspection/kvmi_int.h
@@ -32,5 +32,8 @@ void *kvmi_msg_alloc(void);
void kvmi_msg_free(void *addr);
bool kvmi_is_command_allowed(struct kvm_introspection *kvmi, u16 id);
bool kvmi_is_known_event(u8 id);
+bool kvmi_is_known_vm_event(u8 id);
+int kvmi_cmd_vm_control_events(struct kvm_introspection *kvmi,
+ unsigned int event_id, bool enable);
#endif
diff --git a/virt/kvm/introspection/kvmi_msg.c b/virt/kvm/introspection/kvmi_msg.c
index 596f5c02bb8c..a148ed1e767c 100644
--- a/virt/kvm/introspection/kvmi_msg.c
+++ b/virt/kvm/introspection/kvmi_msg.c
@@ -162,15 +162,36 @@ static int handle_vm_get_info(struct kvm_introspection *kvmi,
return kvmi_msg_vm_reply(kvmi, msg, 0, &rpl, sizeof(rpl));
}
+static int handle_vm_control_events(struct kvm_introspection *kvmi,
+ const struct kvmi_msg_hdr *msg,
+ const void *_req)
+{
+ const struct kvmi_vm_control_events *req = _req;
+ int ec;
+
+ if (req->padding1 || req->padding2 || req->enable > 1)
+ ec = -KVM_EINVAL;
+ else if (!kvmi_is_known_vm_event(req->event_id))
+ ec = -KVM_EINVAL;
+ else if (!is_event_allowed(kvmi, req->event_id))
+ ec = -KVM_EPERM;
+ else
+ ec = kvmi_cmd_vm_control_events(kvmi, req->event_id,
+ req->enable == 1);
+
+ return kvmi_msg_vm_reply(kvmi, msg, ec, NULL, 0);
+}
+
/*
* These commands are executed by the receiving thread.
*/
static int(*const msg_vm[])(struct kvm_introspection *,
const struct kvmi_msg_hdr *, const void *) = {
- [KVMI_GET_VERSION] = handle_get_version,
- [KVMI_VM_CHECK_COMMAND] = handle_vm_check_command,
- [KVMI_VM_CHECK_EVENT] = handle_vm_check_event,
- [KVMI_VM_GET_INFO] = handle_vm_get_info,
+ [KVMI_GET_VERSION] = handle_get_version,
+ [KVMI_VM_CHECK_COMMAND] = handle_vm_check_command,
+ [KVMI_VM_CHECK_EVENT] = handle_vm_check_event,
+ [KVMI_VM_CONTROL_EVENTS] = handle_vm_control_events,
+ [KVMI_VM_GET_INFO] = handle_vm_get_info,
};
static bool is_vm_command(u16 id)
