These commands are used to check what introspection commands and events
are supported (kernel) and allowed (device manager).
These are alternative methods to KVMI_GET_VERSION in checking if the
introspection supports a specific command/event.
As with the KVMI_GET_VERSION command, these two commands can never be
disallowed by the device manager.
Signed-off-by: Adalbert Lazăr <alazar@xxxxxxxxxxxxxxx>
---
Documentation/virt/kvm/kvmi.rst | 62 +++++++++++++++++++
include/uapi/linux/kvmi.h | 16 ++++-
.../testing/selftests/kvm/x86_64/kvmi_test.c | 59 ++++++++++++++++++
virt/kvm/introspection/kvmi.c | 14 +++++
virt/kvm/introspection/kvmi_int.h | 1 +
virt/kvm/introspection/kvmi_msg.c | 45 +++++++++++++-
6 files changed, 195 insertions(+), 2 deletions(-)
diff --git a/Documentation/virt/kvm/kvmi.rst b/Documentation/virt/kvm/kvmi.rst
index 41fd48222bcb..a2cda3268da0 100644
--- a/Documentation/virt/kvm/kvmi.rst
+++ b/Documentation/virt/kvm/kvmi.rst
@@ -261,3 +261,65 @@ larger/newer messages.
The introspection tool should use this command to identify the features
supported by the kernel side and what messages must be used for event
replies.
+
+2. KVMI_VM_CHECK_COMMAND
+------------------------
+
+:Architectures: all
+:Versions: >= 1
+:Parameters:
+
+::
+
+ struct kvmi_vm_check_command {
+ __u16 id;
+ __u16 padding1;
+ __u32 padding2;
+ };
+
+:Returns:
+
+::
+
+ struct kvmi_error_code;
+
+Checks if the command specified by ``id`` is supported and allowed.
+
+This command is always allowed.
+
+:Errors:
+
+* -KVM_ENOENT - the command specified by ``id`` is unsupported
+* -KVM_EPERM - the command specified by ``id`` is disallowed
+* -KVM_EINVAL - the padding is not zero
+
+3. KVMI_VM_CHECK_EVENT
+----------------------
+
+:Architectures: all
+:Versions: >= 1
+:Parameters:
+
+::
+
+ struct kvmi_vm_check_event {
+ __u16 id;
+ __u16 padding1;
+ __u32 padding2;
+ };
+
+:Returns:
+
+::
+
+ struct kvmi_error_code;
+
+Checks if the event specified by ``id`` is supported and allowed.
+
+This command is always allowed.
+
+:Errors:
+
+* -KVM_ENOENT - the event specified by ``id`` is unsupported
+* -KVM_EPERM - the event specified by ``id`` is disallowed
+* -KVM_EINVAL - the padding is not zero
diff --git a/include/uapi/linux/kvmi.h b/include/uapi/linux/kvmi.h
index 896fcb6abf2c..e55a0fa66ac5 100644
--- a/include/uapi/linux/kvmi.h
+++ b/include/uapi/linux/kvmi.h
@@ -14,7 +14,9 @@ enum {
};
enum {
- KVMI_GET_VERSION = 1,
+ KVMI_GET_VERSION = 1,
+ KVMI_VM_CHECK_COMMAND = 2,
+ KVMI_VM_CHECK_EVENT = 3,
KVMI_NUM_MESSAGES
};
@@ -49,4 +51,16 @@ struct kvmi_get_version_reply {
__u32 padding;
};
+struct kvmi_vm_check_command {
+ __u16 id;
+ __u16 padding1;
+ __u32 padding2;
+};
+
+struct kvmi_vm_check_event {
+ __u16 id;
+ __u16 padding1;
+ __u32 padding2;
+};
+
#endif /* _UAPI__LINUX_KVMI_H */
diff --git a/tools/testing/selftests/kvm/x86_64/kvmi_test.c b/tools/testing/selftests/kvm/x86_64/kvmi_test.c
index d15eccc330e5..28216c4e8b9d 100644
--- a/tools/testing/selftests/kvm/x86_64/kvmi_test.c
+++ b/tools/testing/selftests/kvm/x86_64/kvmi_test.c
@@ -99,6 +99,8 @@ static void hook_introspection(struct kvm_vm *vm)
do_hook_ioctl(vm, Kvm_socket, no_padding, EEXIST);
set_command_perm(vm, KVMI_GET_VERSION, disallow, EPERM);
+ set_command_perm(vm, KVMI_VM_CHECK_COMMAND, disallow, EPERM);
+ set_command_perm(vm, KVMI_VM_CHECK_EVENT, disallow, EPERM);
set_command_perm(vm, all_IDs, allow_inval, EINVAL);
set_command_perm(vm, all_IDs, disallow, 0);
set_command_perm(vm, all_IDs, allow, 0);
@@ -238,6 +240,61 @@ static void test_cmd_get_version(void)
pr_info("KVMI version: %u\n", rpl.version);
}
+static void cmd_vm_check_command(__u16 id, __u16 padding, int expected_err)
+{
+ struct {
+ struct kvmi_msg_hdr hdr;
+ struct kvmi_vm_check_command cmd;
+ } req = {};
+ int r;
+
+ req.cmd.id = id;
+ req.cmd.padding1 = padding;
+ req.cmd.padding2 = padding;
+
+ r = do_command(KVMI_VM_CHECK_COMMAND, &req.hdr, sizeof(req), NULL, 0);
+ TEST_ASSERT(r == expected_err,
+ "KVMI_VM_CHECK_COMMAND failed, error %d (%s), expected %d\n",
+ -r, kvm_strerror(-r), expected_err);
+}
+
+static void test_cmd_vm_check_command(void)
+{
+ __u16 valid_id = KVMI_GET_VERSION, invalid_id = 0xffff;
+ __u16 padding = 1, no_padding = 0;
+
+ cmd_vm_check_command(valid_id, no_padding, 0);
+ cmd_vm_check_command(valid_id, padding, -KVM_EINVAL);
+ cmd_vm_check_command(invalid_id, no_padding, -KVM_ENOENT);
+}
+
+static void cmd_vm_check_event(__u16 id, __u16 padding, int expected_err)
+{
+ struct {
+ struct kvmi_msg_hdr hdr;
+ struct kvmi_vm_check_event cmd;
+ } req = {};
+ int r;
+
+ req.cmd.id = id;
+ req.cmd.padding1 = padding;
+ req.cmd.padding2 = padding;
+
+ r = do_command(KVMI_VM_CHECK_EVENT, &req.hdr, sizeof(req), NULL, 0);
+ TEST_ASSERT(r == expected_err,
+ "KVMI_VM_CHECK_EVENT failed, error %d (%s), expected %d\n",
+ -r, kvm_strerror(-r), expected_err);
+}
+
+static void test_cmd_vm_check_event(void)
+{
+ __u16 invalid_id = 0xffff;
+ __u16 padding = 1, no_padding = 0;
+
+ cmd_vm_check_event(invalid_id, padding, -KVM_EINVAL);
+ cmd_vm_check_event(invalid_id, no_padding, -KVM_ENOENT);
+}
+
static void test_introspection(struct kvm_vm *vm)
{
setup_socket();
@@ -245,6 +302,8 @@ static void test_introspection(struct kvm_vm *vm)
test_cmd_invalid();
test_cmd_get_version();
+ test_cmd_vm_check_command();
+ test_cmd_vm_check_event();
unhook_introspection(vm);
}
diff --git a/virt/kvm/introspection/kvmi.c b/virt/kvm/introspection/kvmi.c
index c44aa49dc6b5..f5ca49167f70 100644
--- a/virt/kvm/introspection/kvmi.c
+++ b/virt/kvm/introspection/kvmi.c
@@ -12,6 +12,7 @@
#define KVMI_MSG_SIZE_ALLOC (sizeof(struct kvmi_msg_hdr) + KVMI_MSG_SIZE)
static DECLARE_BITMAP(Kvmi_always_allowed_commands, KVMI_NUM_COMMANDS);
+static DECLARE_BITMAP(Kvmi_known_events, KVMI_NUM_EVENTS);
static struct kmem_cache *msg_cache;
@@ -51,15 +52,28 @@ bool kvmi_is_command_allowed(struct kvm_introspection *kvmi, u16 id)
return id < KVMI_NUM_COMMANDS && test_bit(id, kvmi->cmd_allow_mask);
}
+bool kvmi_is_known_event(u8 id)
+{
+ return id < KVMI_NUM_EVENTS && test_bit(id, Kvmi_known_events);
+}
+
static void setup_always_allowed_commands(void)
{
bitmap_zero(Kvmi_always_allowed_commands, KVMI_NUM_COMMANDS);
set_bit(KVMI_GET_VERSION, Kvmi_always_allowed_commands);
+ set_bit(KVMI_VM_CHECK_COMMAND, Kvmi_always_allowed_commands);
+ set_bit(KVMI_VM_CHECK_EVENT, Kvmi_always_allowed_commands);
+}
+
+static void setup_known_events(void)
+{
+ bitmap_zero(Kvmi_known_events, KVMI_NUM_EVENTS);
}
int kvmi_init(void)
{
setup_always_allowed_commands();
+ setup_known_events();
return kvmi_cache_create();
}
diff --git a/virt/kvm/introspection/kvmi_int.h b/virt/kvm/introspection/kvmi_int.h
index 5e4eabeefc5b..0bca4bd0a415 100644
--- a/virt/kvm/introspection/kvmi_int.h
+++ b/virt/kvm/introspection/kvmi_int.h
@@ -30,5 +30,6 @@ bool kvmi_msg_process(struct kvm_introspection *kvmi);
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);
#endif
diff --git a/virt/kvm/introspection/kvmi_msg.c b/virt/kvm/introspection/kvmi_msg.c
index 386636aa9832..86c356afc154 100644
--- a/virt/kvm/introspection/kvmi_msg.c
+++ b/virt/kvm/introspection/kvmi_msg.c
@@ -8,6 +8,8 @@
#include <linux/net.h>
#include "kvmi_int.h"
+static bool is_vm_command(u16 id);
+
bool kvmi_sock_get(struct kvm_introspection *kvmi, int fd)
{
struct socket *sock;
@@ -109,12 +111,53 @@ static int handle_get_version(struct kvm_introspection *kvmi,
return kvmi_msg_vm_reply(kvmi, msg, 0, &rpl, sizeof(rpl));
}
+static int handle_vm_check_command(struct kvm_introspection *kvmi,
+ const struct kvmi_msg_hdr *msg,
+ const void *_req)
+{
+ const struct kvmi_vm_check_command *req = _req;
+ int ec = 0;
+
+ if (req->padding1 || req->padding2)
+ ec = -KVM_EINVAL;
+ else if (!is_vm_command(req->id))
+ ec = -KVM_ENOENT;
+ else if (!kvmi_is_command_allowed(kvmi, req->id))
+ ec = -KVM_EPERM;
+
+ return kvmi_msg_vm_reply(kvmi, msg, ec, NULL, 0);
+}
+
+static bool is_event_allowed(struct kvm_introspection *kvmi, u16 id)
+{
+ return id < KVMI_NUM_EVENTS && test_bit(id, kvmi->event_allow_mask);
+}
+
+static int handle_vm_check_event(struct kvm_introspection *kvmi,
+ const struct kvmi_msg_hdr *msg,
+ const void *_req)
+{
+ const struct kvmi_vm_check_event *req = _req;
+ int ec = 0;
+
+ if (req->padding1 || req->padding2)
+ ec = -KVM_EINVAL;
+ else if (!kvmi_is_known_event(req->id))
+ ec = -KVM_ENOENT;
+ else if (!is_event_allowed(kvmi, req->id))
+ ec = -KVM_EPERM;
+
+ 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_GET_VERSION] = handle_get_version,
+ [KVMI_VM_CHECK_COMMAND] = handle_vm_check_command,
+ [KVMI_VM_CHECK_EVENT] = handle_vm_check_event,
};
static bool is_vm_command(u16 id)
