This command increments a pause requests counter for a vCPU and kicks
it out of guest.
The introspection tool can pause a VM by sending this command for all
vCPUs. If it sets 'wait=1', it can consider that the VM is paused when
it receives the reply for the last KVMI_VM_PAUSE_VCPU command.
Signed-off-by: Adalbert Lazăr <alazar@xxxxxxxxxxxxxxx>
---
Documentation/virt/kvm/kvmi.rst | 39 +++++++++++++++
include/linux/kvmi_host.h | 2 +
include/uapi/linux/kvmi.h | 8 ++++
.../testing/selftests/kvm/x86_64/kvmi_test.c | 30 ++++++++++++
virt/kvm/introspection/kvmi.c | 47 +++++++++++++++++--
virt/kvm/introspection/kvmi_int.h | 1 +
virt/kvm/introspection/kvmi_msg.c | 24 ++++++++++
7 files changed, 147 insertions(+), 4 deletions(-)
diff --git a/Documentation/virt/kvm/kvmi.rst b/Documentation/virt/kvm/kvmi.rst
index 902ced4dd0c4..a71fb78d546e 100644
--- a/Documentation/virt/kvm/kvmi.rst
+++ b/Documentation/virt/kvm/kvmi.rst
@@ -470,6 +470,45 @@ Returns the TSC frequency (in HZ) for the specified vCPU if available
* -KVM_EINVAL - the selected vCPU is invalid
* -KVM_EAGAIN - the selected vCPU can't be introspected yet
+9. KVMI_VM_PAUSE_VCPU
+---------------------
+
+:Architectures: all
+:Versions: >= 1
+:Parameters:
+
+::
+
+ struct kvmi_vm_pause_vcpu {
+ __u16 vcpu;
+ __u8 wait;
+ __u8 padding1;
+ __u32 padding2;
+ };
+
+:Returns:
+
+::
+
+ struct kvmi_error_code;
+
+Kicks the vCPU out of guest.
+
+If `wait` is 1, the command will wait for vCPU to acknowledge the IPI.
+
+The vCPU will handle the pending commands/events and send the
+*KVMI_VCPU_EVENT_PAUSE* event (one for every successful *KVMI_VM_PAUSE_VCPU*
+command) before returning to guest.
+
+:Errors:
+
+* -KVM_EINVAL - the padding is not zero
+* -KVM_EINVAL - the selected vCPU is invalid
+* -KVM_EAGAIN - the selected vCPU can't be introspected yet
+* -KVM_EBUSY - the selected vCPU has too many queued
+ *KVMI_VCPU_EVENT_PAUSE* events
+* -KVM_EPERM - the *KVMI_VCPU_EVENT_PAUSE* event is disallowed
+
Events
======
diff --git a/include/linux/kvmi_host.h b/include/linux/kvmi_host.h
index 736edb400c05..59e645d9ea34 100644
--- a/include/linux/kvmi_host.h
+++ b/include/linux/kvmi_host.h
@@ -18,6 +18,8 @@ struct kvm_vcpu_introspection {
struct list_head job_list;
spinlock_t job_lock;
+
+ atomic_t pause_requests;
};
struct kvm_introspection {
diff --git a/include/uapi/linux/kvmi.h b/include/uapi/linux/kvmi.h
index da766427231e..bb90d03f059b 100644
--- a/include/uapi/linux/kvmi.h
+++ b/include/uapi/linux/kvmi.h
@@ -26,6 +26,7 @@ enum {
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_NEXT_VM_MESSAGE
};
@@ -115,4 +116,11 @@ struct kvmi_vcpu_hdr {
__u32 padding2;
};
+struct kvmi_vm_pause_vcpu {
+ __u16 vcpu;
+ __u8 wait;
+ __u8 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 9350ba8b7f9b..52765ca3f9c8 100644
--- a/tools/testing/selftests/kvm/x86_64/kvmi_test.c
+++ b/tools/testing/selftests/kvm/x86_64/kvmi_test.c
@@ -671,6 +671,35 @@ static void test_cmd_vcpu_get_info(struct kvm_vm *vm)
&rpl, sizeof(rpl), -KVM_EINVAL);
}
+static void cmd_vcpu_pause(__u8 wait, int expected_err)
+{
+ struct {
+ struct kvmi_msg_hdr hdr;
+ struct kvmi_vm_pause_vcpu cmd;
+ } req = {};
+ __u16 vcpu_idx = 0;
+
+ req.cmd.wait = wait;
+ req.cmd.vcpu = vcpu_idx;
+
+ test_vm_command(KVMI_VM_PAUSE_VCPU, &req.hdr, sizeof(req), NULL, 0, expected_err);
+}
+
+static void pause_vcpu(void)
+{
+ cmd_vcpu_pause(1, 0);
+}
+
+static void test_pause(struct kvm_vm *vm)
+{
+ __u8 wait = 1, wait_inval = 2;
+
+ pause_vcpu();
+
+ cmd_vcpu_pause(wait, 0);
+ cmd_vcpu_pause(wait_inval, -KVM_EINVAL);
+}
+
static void test_introspection(struct kvm_vm *vm)
{
srandom(time(0));
@@ -686,6 +715,7 @@ static void test_introspection(struct kvm_vm *vm)
test_cmd_vm_control_events(vm);
test_memory_access(vm);
test_cmd_vcpu_get_info(vm);
+ test_pause(vm);
unhook_introspection(vm);
}
diff --git a/virt/kvm/introspection/kvmi.c b/virt/kvm/introspection/kvmi.c
index b608751780fc..4999132a65bc 100644
--- a/virt/kvm/introspection/kvmi.c
+++ b/virt/kvm/introspection/kvmi.c
@@ -17,6 +17,8 @@
#define KVMI_MSG_SIZE_ALLOC (sizeof(struct kvmi_msg_hdr) + KVMI_MAX_MSG_SIZE)
+#define MAX_PAUSE_REQUESTS 1001
+
static DECLARE_BITMAP(Kvmi_always_allowed_commands, KVMI_NUM_COMMANDS);
static DECLARE_BITMAP(Kvmi_known_events, KVMI_NUM_EVENTS);
static DECLARE_BITMAP(Kvmi_known_vm_events, KVMI_NUM_EVENTS);
@@ -124,10 +126,14 @@ void kvmi_uninit(void)
kvmi_cache_destroy();
}
-static void kvmi_make_request(struct kvm_vcpu *vcpu)
+static void kvmi_make_request(struct kvm_vcpu *vcpu, bool wait)
{
kvm_make_request(KVM_REQ_INTROSPECTION, vcpu);
- kvm_vcpu_kick(vcpu);
+
+ if (wait)
+ kvm_vcpu_kick_and_wait(vcpu);
+ else
+ kvm_vcpu_kick(vcpu);
}
static int __kvmi_add_job(struct kvm_vcpu *vcpu,
@@ -162,7 +168,7 @@ int kvmi_add_job(struct kvm_vcpu *vcpu,
err = __kvmi_add_job(vcpu, fct, ctx, free_fct);
if (!err)
- kvmi_make_request(vcpu);
+ kvmi_make_request(vcpu, false);
return err;
}
@@ -359,6 +365,9 @@ static int __kvmi_hook(struct kvm *kvm,
static void kvmi_job_release_vcpu(struct kvm_vcpu *vcpu, void *ctx)
{
+ struct kvm_vcpu_introspection *vcpui = VCPUI(vcpu);
+
+ atomic_set(&vcpui->pause_requests, 0);
}
static void kvmi_release_vcpus(struct kvm *kvm)
@@ -730,15 +739,45 @@ void kvmi_run_jobs(struct kvm_vcpu *vcpu)
}
}
+static void kvmi_vcpu_pause_event(struct kvm_vcpu *vcpu)
+{
+ struct kvm_vcpu_introspection *vcpui = VCPUI(vcpu);
+
+ atomic_dec(&vcpui->pause_requests);
+ /* to be implemented */
+}
+
void kvmi_handle_requests(struct kvm_vcpu *vcpu)
{
+ struct kvm_vcpu_introspection *vcpui = VCPUI(vcpu);
struct kvm_introspection *kvmi;
kvmi = kvmi_get(vcpu->kvm);
if (!kvmi)
return;
- kvmi_run_jobs(vcpu);
+ for (;;) {
+ kvmi_run_jobs(vcpu);
+
+ if (atomic_read(&vcpui->pause_requests))
+ kvmi_vcpu_pause_event(vcpu);
+ else
+ break;
+ }
kvmi_put(vcpu->kvm);
}
+
+int kvmi_cmd_vcpu_pause(struct kvm_vcpu *vcpu, bool wait)
+{
+ struct kvm_vcpu_introspection *vcpui = VCPUI(vcpu);
+
+ if (atomic_read(&vcpui->pause_requests) > MAX_PAUSE_REQUESTS)
+ return -KVM_EBUSY;
+
+ atomic_inc(&vcpui->pause_requests);
+
+ kvmi_make_request(vcpu, wait);
+
+ return 0;
+}
diff --git a/virt/kvm/introspection/kvmi_int.h b/virt/kvm/introspection/kvmi_int.h
index 126e72201518..f1caa67dbdc3 100644
--- a/virt/kvm/introspection/kvmi_int.h
+++ b/virt/kvm/introspection/kvmi_int.h
@@ -55,6 +55,7 @@ int kvmi_cmd_read_physical(struct kvm *kvm, u64 gpa, size_t size,
const struct kvmi_msg_hdr *ctx);
int kvmi_cmd_write_physical(struct kvm *kvm, u64 gpa, size_t size,
const void *buf);
+int kvmi_cmd_vcpu_pause(struct kvm_vcpu *vcpu, bool wait);
/* arch */
void kvmi_arch_init_vcpu_events_mask(unsigned long *supported);
diff --git a/virt/kvm/introspection/kvmi_msg.c b/virt/kvm/introspection/kvmi_msg.c
index efd04b4aa4ff..02bdec5bfbe7 100644
--- a/virt/kvm/introspection/kvmi_msg.c
+++ b/virt/kvm/introspection/kvmi_msg.c
@@ -245,6 +245,29 @@ static int handle_vm_write_physical(struct kvm_introspection *kvmi,
return kvmi_msg_vm_reply(kvmi, msg, ec, NULL, 0);
}
+static int handle_vm_pause_vcpu(struct kvm_introspection *kvmi,
+ const struct kvmi_msg_hdr *msg,
+ const void *_req)
+{
+ const struct kvmi_vm_pause_vcpu *req = _req;
+ struct kvm_vcpu *vcpu;
+ int err;
+
+ if (req->wait > 1 || req->padding1 || req->padding2) {
+ err = -KVM_EINVAL;
+ goto reply;
+ }
+
+ vcpu = kvmi_get_vcpu(kvmi, req->vcpu);
+ if (!vcpu)
+ err = -KVM_EINVAL;
+ else
+ err = kvmi_cmd_vcpu_pause(vcpu, req->wait == 1);
+
+reply:
+ return kvmi_msg_vm_reply(kvmi, msg, err, NULL, 0);
+}
+
/*
* These commands are executed by the receiving thread.
*/
@@ -254,6 +277,7 @@ static kvmi_vm_msg_fct const msg_vm[] = {
[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,
};
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