This command will allow more control over the guest state on
unhook. However, the memory restrictions (e.g. those set with
KVMI_VM_SET_PAGE_ACCESS) will be removed on unhook.
Signed-off-by: Adalbert Lazăr <alazar@xxxxxxxxxxxxxxx>
---
Documentation/virt/kvm/kvmi.rst | 28 +++++++++++++++
arch/x86/include/asm/kvmi_host.h | 1 +
arch/x86/kvm/kvmi.c | 17 +++++-----
include/linux/kvmi_host.h | 2 ++
include/uapi/linux/kvmi.h | 22 +++++++-----
.../testing/selftests/kvm/x86_64/kvmi_test.c | 24 +++++++++++++
virt/kvm/introspection/kvmi.c | 18 +++++++---
virt/kvm/introspection/kvmi_int.h | 12 ++++++-
virt/kvm/introspection/kvmi_msg.c | 34 ++++++++++++++-----
9 files changed, 129 insertions(+), 29 deletions(-)
diff --git a/Documentation/virt/kvm/kvmi.rst b/Documentation/virt/kvm/kvmi.rst
index c89f383e48f9..f9c10d27ce14 100644
--- a/Documentation/virt/kvm/kvmi.rst
+++ b/Documentation/virt/kvm/kvmi.rst
@@ -673,6 +673,34 @@ Returns a CPUID leaf (as seen by the guest OS).
* -KVM_EAGAIN - the selected vCPU can't be introspected yet
* -KVM_ENOENT - the selected leaf is not present or is invalid
+14. KVMI_VM_CONTROL_CLEANUP
+---------------------------
+:Architectures: all
+:Versions: >= 1
+:Parameters:
+
+::
+
+ struct kvmi_vm_control_cleanup {
+ __u8 enable;
+ __u8 padding[7];
+ };
+
+:Returns:
+
+::
+
+ struct kvmi_error_code
+
+Enables/disables the automatic cleanup of the changes made by
+the introspection tool at the hypervisor level (e.g. CR/MSR/BP
+interceptions). By default it is enabled.
+
+:Errors:
+
+* -KVM_EINVAL - the padding is not zero
+* -KVM_EINVAL - ``enable`` is not 1 or 0
+
Events
======
diff --git a/arch/x86/include/asm/kvmi_host.h b/arch/x86/include/asm/kvmi_host.h
index e008662f91a5..161d1ae5a7cf 100644
--- a/arch/x86/include/asm/kvmi_host.h
+++ b/arch/x86/include/asm/kvmi_host.h
@@ -11,6 +11,7 @@ struct kvmi_monitor_interception {
};
struct kvmi_interception {
+ bool cleanup;
bool restore_interception;
struct kvmi_monitor_interception breakpoint;
};
diff --git a/arch/x86/kvm/kvmi.c b/arch/x86/kvm/kvmi.c
index 3fd73087276e..e7a4ef48ed61 100644
--- a/arch/x86/kvm/kvmi.c
+++ b/arch/x86/kvm/kvmi.c
@@ -273,13 +273,11 @@ bool kvmi_arch_clean_up_interception(struct kvm_vcpu *vcpu)
{
struct kvmi_interception *arch_vcpui = vcpu->arch.kvmi;
- if (!arch_vcpui)
+ if (!arch_vcpui || !arch_vcpui->cleanup)
return false;
- if (!arch_vcpui->restore_interception)
- return false;
-
- kvmi_arch_restore_interception(vcpu);
+ if (arch_vcpui->restore_interception)
+ kvmi_arch_restore_interception(vcpu);
return true;
}
@@ -312,10 +310,13 @@ bool kvmi_arch_vcpu_introspected(struct kvm_vcpu *vcpu)
return !!READ_ONCE(vcpu->arch.kvmi);
}
-void kvmi_arch_request_interception_cleanup(struct kvm_vcpu *vcpu)
+void kvmi_arch_request_interception_cleanup(struct kvm_vcpu *vcpu,
+ bool restore_interception)
{
struct kvmi_interception *arch_vcpui = READ_ONCE(vcpu->arch.kvmi);
- if (arch_vcpui)
- arch_vcpui->restore_interception = true;
+ if (arch_vcpui) {
+ arch_vcpui->restore_interception = restore_interception;
+ arch_vcpui->cleanup = true;
+ }
}
diff --git a/include/linux/kvmi_host.h b/include/linux/kvmi_host.h
index 30b7269468dd..7a7360306812 100644
--- a/include/linux/kvmi_host.h
+++ b/include/linux/kvmi_host.h
@@ -50,6 +50,8 @@ struct kvm_introspection {
unsigned long *vm_event_enable_mask;
atomic_t ev_seq;
+
+ bool restore_on_unhook;
};
int kvmi_version(void);
diff --git a/include/uapi/linux/kvmi.h b/include/uapi/linux/kvmi.h
index ea66f3f803e7..9e28961a8387 100644
--- a/include/uapi/linux/kvmi.h
+++ b/include/uapi/linux/kvmi.h
@@ -20,14 +20,15 @@ enum {
enum {
KVMI_VM_EVENT = KVMI_VM_MESSAGE_ID(0),
- KVMI_GET_VERSION = KVMI_VM_MESSAGE_ID(1),
- KVMI_VM_CHECK_COMMAND = KVMI_VM_MESSAGE_ID(2),
- KVMI_VM_CHECK_EVENT = KVMI_VM_MESSAGE_ID(3),
- KVMI_VM_GET_INFO = KVMI_VM_MESSAGE_ID(4),
- KVMI_VM_CONTROL_EVENTS = KVMI_VM_MESSAGE_ID(5),
- KVMI_VM_READ_PHYSICAL = KVMI_VM_MESSAGE_ID(6),
- KVMI_VM_WRITE_PHYSICAL = KVMI_VM_MESSAGE_ID(7),
- KVMI_VM_PAUSE_VCPU = KVMI_VM_MESSAGE_ID(8),
+ KVMI_GET_VERSION = KVMI_VM_MESSAGE_ID(1),
+ KVMI_VM_CHECK_COMMAND = KVMI_VM_MESSAGE_ID(2),
+ KVMI_VM_CHECK_EVENT = KVMI_VM_MESSAGE_ID(3),
+ KVMI_VM_GET_INFO = KVMI_VM_MESSAGE_ID(4),
+ KVMI_VM_CONTROL_EVENTS = KVMI_VM_MESSAGE_ID(5),
+ KVMI_VM_READ_PHYSICAL = KVMI_VM_MESSAGE_ID(6),
+ KVMI_VM_WRITE_PHYSICAL = KVMI_VM_MESSAGE_ID(7),
+ KVMI_VM_PAUSE_VCPU = KVMI_VM_MESSAGE_ID(8),
+ KVMI_VM_CONTROL_CLEANUP = KVMI_VM_MESSAGE_ID(9),
KVMI_NEXT_VM_MESSAGE
};
@@ -167,4 +168,9 @@ struct kvmi_vcpu_event_breakpoint {
__u8 padding[7];
};
+struct kvmi_vm_control_cleanup {
+ __u8 enable;
+ __u8 padding[7];
+};
+
#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 143ee1a8f618..f95f2771a123 100644
--- a/tools/testing/selftests/kvm/x86_64/kvmi_test.c
+++ b/tools/testing/selftests/kvm/x86_64/kvmi_test.c
@@ -1077,6 +1077,29 @@ static void test_event_breakpoint(struct kvm_vm *vm)
disable_vcpu_event(vm, event_id);
}
+static void cmd_vm_control_cleanup(__u8 enable, int expected_err)
+{
+ struct {
+ struct kvmi_msg_hdr hdr;
+ struct kvmi_vm_control_cleanup cmd;
+ } req = {};
+
+ req.cmd.enable = enable;
+
+ test_vm_command(KVMI_VM_CONTROL_CLEANUP, &req.hdr, sizeof(req),
+ NULL, 0, expected_err);
+}
+
+static void test_cmd_vm_control_cleanup(struct kvm_vm *vm)
+{
+ __u8 disable = 0, enable = 1, enable_inval = 2;
+
+ cmd_vm_control_cleanup(enable_inval, -KVM_EINVAL);
+
+ cmd_vm_control_cleanup(enable, 0);
+ cmd_vm_control_cleanup(disable, 0);
+}
+
static void test_introspection(struct kvm_vm *vm)
{
srandom(time(0));
@@ -1099,6 +1122,7 @@ static void test_introspection(struct kvm_vm *vm)
test_cmd_vcpu_get_cpuid(vm);
test_event_hypercall(vm);
test_event_breakpoint(vm);
+ test_cmd_vm_control_cleanup(vm);
unhook_introspection(vm);
}
diff --git a/virt/kvm/introspection/kvmi.c b/virt/kvm/introspection/kvmi.c
index a0cd98839944..e6333708c584 100644
--- a/virt/kvm/introspection/kvmi.c
+++ b/virt/kvm/introspection/kvmi.c
@@ -227,7 +227,7 @@ static void kvmi_free_vcpu_jobs(struct kvm_vcpu_introspection *vcpui)
}
}
-static void kvmi_free_vcpui(struct kvm_vcpu *vcpu)
+static void kvmi_free_vcpui(struct kvm_vcpu *vcpu, bool restore_interception)
{
struct kvm_vcpu_introspection *vcpui = VCPUI(vcpu);
@@ -241,17 +241,18 @@ static void kvmi_free_vcpui(struct kvm_vcpu *vcpu)
kfree(vcpui);
vcpu->kvmi = NULL;
- kvmi_arch_request_interception_cleanup(vcpu);
+ kvmi_arch_request_interception_cleanup(vcpu, restore_interception);
kvmi_make_request(vcpu, false);
}
static void kvmi_free(struct kvm *kvm)
{
+ bool restore_interception = KVMI(kvm)->restore_on_unhook;
struct kvm_vcpu *vcpu;
int i;
kvm_for_each_vcpu(i, vcpu, kvm)
- kvmi_free_vcpui(vcpu);
+ kvmi_free_vcpui(vcpu, restore_interception);
bitmap_free(kvm->kvmi->cmd_allow_mask);
bitmap_free(kvm->kvmi->event_allow_mask);
@@ -263,8 +264,10 @@ static void kvmi_free(struct kvm *kvm)
void kvmi_vcpu_uninit(struct kvm_vcpu *vcpu)
{
+ bool restore_interception = false;
+
mutex_lock(&vcpu->kvm->kvmi_lock);
- kvmi_free_vcpui(vcpu);
+ kvmi_free_vcpui(vcpu, restore_interception);
kvmi_arch_vcpu_free_interception(vcpu);
mutex_unlock(&vcpu->kvm->kvmi_lock);
}
@@ -295,6 +298,8 @@ kvmi_alloc(struct kvm *kvm, const struct kvm_introspection_hook *hook)
BUILD_BUG_ON(sizeof(hook->uuid) != sizeof(kvmi->uuid));
memcpy(&kvmi->uuid, &hook->uuid, sizeof(kvmi->uuid));
+ kvmi->restore_on_unhook = true;
+
bitmap_copy(kvmi->cmd_allow_mask, Kvmi_always_allowed_commands,
KVMI_NUM_COMMANDS);
@@ -671,6 +676,11 @@ int kvmi_cmd_vcpu_control_events(struct kvm_vcpu *vcpu,
return 0;
}
+void kvmi_cmd_vm_control_cleanup(struct kvm_introspection *kvmi, bool enable)
+{
+ kvmi->restore_on_unhook = enable;
+}
+
static long
get_user_pages_remote_unlocked(struct mm_struct *mm, unsigned long start,
unsigned long nr_pages, unsigned int gup_flags,
diff --git a/virt/kvm/introspection/kvmi_int.h b/virt/kvm/introspection/kvmi_int.h
index 94de54d7ebb9..8a266b058155 100644
--- a/virt/kvm/introspection/kvmi_int.h
+++ b/virt/kvm/introspection/kvmi_int.h
@@ -31,6 +31,14 @@ static inline bool is_vcpu_event_enabled(struct kvm_vcpu *vcpu, u16 event_id)
return test_bit(event_id, VCPUI(vcpu)->ev_enable_mask);
}
+static inline bool non_zero_padding(const u8 *addr, size_t len)
+{
+ while (len--)
+ if (*addr++)
+ return true;
+ return false;
+}
+
/* kvmi_msg.c */
bool kvmi_sock_get(struct kvm_introspection *kvmi, int fd);
void kvmi_sock_shutdown(struct kvm_introspection *kvmi);
@@ -60,6 +68,7 @@ int kvmi_add_job(struct kvm_vcpu *vcpu,
void *ctx, void (*free_fct)(void *ctx));
void kvmi_run_jobs(struct kvm_vcpu *vcpu);
void kvmi_handle_common_event_actions(struct kvm_vcpu *vcpu, u32 action);
+void kvmi_cmd_vm_control_cleanup(struct kvm_introspection *kvmi, bool enable);
int kvmi_cmd_vm_control_events(struct kvm_introspection *kvmi,
u16 event_id, bool enable);
int kvmi_cmd_vcpu_control_events(struct kvm_vcpu *vcpu,
@@ -81,7 +90,8 @@ void kvmi_arch_setup_vcpu_event(struct kvm_vcpu *vcpu,
bool kvmi_arch_vcpu_alloc_interception(struct kvm_vcpu *vcpu);
void kvmi_arch_vcpu_free_interception(struct kvm_vcpu *vcpu);
bool kvmi_arch_vcpu_introspected(struct kvm_vcpu *vcpu);
-void kvmi_arch_request_interception_cleanup(struct kvm_vcpu *vcpu);
+void kvmi_arch_request_interception_cleanup(struct kvm_vcpu *vcpu,
+ bool restore_interception);
bool kvmi_arch_clean_up_interception(struct kvm_vcpu *vcpu);
void kvmi_arch_post_reply(struct kvm_vcpu *vcpu);
bool kvmi_arch_is_agent_hypercall(struct kvm_vcpu *vcpu);
diff --git a/virt/kvm/introspection/kvmi_msg.c b/virt/kvm/introspection/kvmi_msg.c
index 5c5f14bbcb40..9c1d69caaf11 100644
--- a/virt/kvm/introspection/kvmi_msg.c
+++ b/virt/kvm/introspection/kvmi_msg.c
@@ -273,18 +273,36 @@ static int handle_vm_pause_vcpu(struct kvm_introspection *kvmi,
return kvmi_msg_vm_reply(kvmi, msg, err, NULL, 0);
}
+static int handle_vm_control_cleanup(struct kvm_introspection *kvmi,
+ const struct kvmi_msg_hdr *msg,
+ const void *_req)
+{
+ const struct kvmi_vm_control_cleanup *req = _req;
+ int ec = 0;
+
+ if (non_zero_padding(req->padding, ARRAY_SIZE(req->padding)))
+ ec = -KVM_EINVAL;
+ else if (req->enable > 1)
+ ec = -KVM_EINVAL;
+ else
+ kvmi_cmd_vm_control_cleanup(kvmi, req->enable == 1);
+
+ return kvmi_msg_vm_reply(kvmi, msg, ec, NULL, 0);
+}
+
/*
* These commands are executed by the receiving thread.
*/
static kvmi_vm_msg_fct const msg_vm[] = {
- [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,
- [KVMI_VM_PAUSE_VCPU] = handle_vm_pause_vcpu,
- [KVMI_VM_READ_PHYSICAL] = handle_vm_read_physical,
- [KVMI_VM_WRITE_PHYSICAL] = handle_vm_write_physical,
+ [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_CLEANUP] = handle_vm_control_cleanup,
+ [KVMI_VM_CONTROL_EVENTS] = handle_vm_control_events,
+ [KVMI_VM_GET_INFO] = handle_vm_get_info,
+ [KVMI_VM_PAUSE_VCPU] = handle_vm_pause_vcpu,
+ [KVMI_VM_READ_PHYSICAL] = handle_vm_read_physical,
+ [KVMI_VM_WRITE_PHYSICAL] = handle_vm_write_physical,
};
static kvmi_vm_msg_fct get_vm_msg_handler(u16 id)
