From: Nicușor Cîțu <ncitu@xxxxxxxxxxxxxxx>
This event is sent when the current instruction has been single stepped
with or without success.
Signed-off-by: Nicușor Cîțu <ncitu@xxxxxxxxxxxxxxx>
Co-developed-by: Adalbert Lazăr <alazar@xxxxxxxxxxxxxxx>
Signed-off-by: Adalbert Lazăr <alazar@xxxxxxxxxxxxxxx>
---
Documentation/virt/kvm/kvmi.rst | 32 ++++++++
arch/x86/kvm/vmx/vmx.c | 6 ++
include/linux/kvmi_host.h | 4 +
include/uapi/linux/kvmi.h | 6 ++
.../testing/selftests/kvm/x86_64/kvmi_test.c | 80 ++++++++++++++++---
virt/kvm/introspection/kvmi.c | 61 ++++++++++++++
virt/kvm/introspection/kvmi_msg.c | 5 ++
7 files changed, 185 insertions(+), 9 deletions(-)
diff --git a/Documentation/virt/kvm/kvmi.rst b/Documentation/virt/kvm/kvmi.rst
index 5e013ee4a79b..c761438801dd 100644
--- a/Documentation/virt/kvm/kvmi.rst
+++ b/Documentation/virt/kvm/kvmi.rst
@@ -572,6 +572,7 @@ The following vCPU events do not need to be enabled or disabled,
because these are sent as a result of certain commands::
KVMI_EVENT_PAUSE_VCPU
+ KVMI_EVENT_SINGLESTEP
KVMI_EVENT_TRAP
However, the events mentioned above can be disallowed.
@@ -980,8 +981,12 @@ Enables/disables singlestep for the selected vCPU.
The introspection tool should use *KVMI_GET_VERSION*, to check
if the hardware supports singlestep (see **KVMI_GET_VERSION**).
+After every instruction, a *KVMI_EVENT_SINGLESTEP* event is sent
+to the introspection tool.
+
:Errors:
+* -KVM_EPERM - the *KVMI_EVENT_SINGLESTEP* event is disallowed
* -KVM_EOPNOTSUPP - the hardware doesn't support singlestep
* -KVM_EINVAL - the padding is not zero
* -KVM_EAGAIN - the selected vCPU can't be introspected yet
@@ -1375,3 +1380,30 @@ The *CONTINUE* action will continue the page fault handling via emulation.
The *RETRY* action is used by the introspection tool to retry the
execution of the current instruction, usually because it changed the
instruction pointer or the page restrictions.
+
+11. KVMI_EVENT_SINGLESTEP
+-------------------------
+
+:Architectures: x86
+:Versions: >= 1
+:Actions: CONTINUE, CRASH
+:Parameters:
+
+::
+
+ struct kvmi_event;
+
+:Returns:
+
+::
+
+ struct kvmi_vcpu_hdr;
+ struct kvmi_event_reply;
+ struct kvmi_event_singlestep {
+ __u8 failed;
+ __u8 padding[7];
+ };
+
+This event is sent when the current instruction has been executed or
+failed and the singlestep has been enabled for the selected vCPU
+(see **KVMI_VCPU_CONTROL_SINGLESTEP**).
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index fd748c165e78..baae118f1cdc 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -5464,6 +5464,7 @@ static int handle_invalid_op(struct kvm_vcpu *vcpu)
static int handle_monitor_trap(struct kvm_vcpu *vcpu)
{
+ kvmi_singlestep_done(vcpu);
return 1;
}
@@ -6025,6 +6026,11 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu,
return 1;
}
+ if (kvmi_vcpu_running_singlestep(vcpu) &&
+ exit_reason != EXIT_REASON_EPT_VIOLATION &&
+ exit_reason != EXIT_REASON_MONITOR_TRAP_FLAG)
+ kvmi_singlestep_failed(vcpu);
+
if (exit_reason >= kvm_vmx_max_exit_handlers)
goto unexpected_vmexit;
#ifdef CONFIG_RETPOLINE
diff --git a/include/linux/kvmi_host.h b/include/linux/kvmi_host.h
index 23784611996e..58a30c087d63 100644
--- a/include/linux/kvmi_host.h
+++ b/include/linux/kvmi_host.h
@@ -95,6 +95,8 @@ bool kvmi_hypercall_event(struct kvm_vcpu *vcpu);
bool kvmi_breakpoint_event(struct kvm_vcpu *vcpu, u64 gva, u8 insn_len);
bool kvmi_enter_guest(struct kvm_vcpu *vcpu);
bool kvmi_vcpu_running_singlestep(struct kvm_vcpu *vcpu);
+void kvmi_singlestep_done(struct kvm_vcpu *vcpu);
+void kvmi_singlestep_failed(struct kvm_vcpu *vcpu);
#else
@@ -113,6 +115,8 @@ static inline bool kvmi_enter_guest(struct kvm_vcpu *vcpu)
{ return true; }
static inline bool kvmi_vcpu_running_singlestep(struct kvm_vcpu *vcpu)
{ return false; }
+static inline void kvmi_singlestep_done(struct kvm_vcpu *vcpu) { }
+static inline void kvmi_singlestep_failed(struct kvm_vcpu *vcpu) { }
#endif /* CONFIG_KVM_INTROSPECTION */
diff --git a/include/uapi/linux/kvmi.h b/include/uapi/linux/kvmi.h
index 97c4ef67bfe4..d69735918fd6 100644
--- a/include/uapi/linux/kvmi.h
+++ b/include/uapi/linux/kvmi.h
@@ -58,6 +58,7 @@ enum {
KVMI_EVENT_DESCRIPTOR = 7,
KVMI_EVENT_MSR = 8,
KVMI_EVENT_PF = 9,
+ KVMI_EVENT_SINGLESTEP = 10,
KVMI_NUM_EVENTS
};
@@ -209,4 +210,9 @@ struct kvmi_event_pf {
__u32 padding3;
};
+struct kvmi_event_singlestep {
+ __u8 failed;
+ __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 27642000c4e4..24dfcba113cd 100644
--- a/tools/testing/selftests/kvm/x86_64/kvmi_test.c
+++ b/tools/testing/selftests/kvm/x86_64/kvmi_test.c
@@ -745,6 +745,14 @@ static void stop_vcpu_worker(pthread_t vcpu_thread,
wait_vcpu_worker(vcpu_thread);
}
+static int __do_vcpu_command(struct kvm_vm *vm, int cmd_id,
+ struct kvmi_msg_hdr *req, size_t req_size,
+ void *rpl, size_t rpl_size)
+{
+ send_message(cmd_id, req, req_size);
+ return receive_cmd_reply(req, rpl, rpl_size);
+}
+
static int do_vcpu_command(struct kvm_vm *vm, int cmd_id,
struct kvmi_msg_hdr *req, size_t req_size,
void *rpl, size_t rpl_size)
@@ -755,13 +763,24 @@ static int do_vcpu_command(struct kvm_vm *vm, int cmd_id,
vcpu_thread = start_vcpu_worker(&data);
- send_message(cmd_id, req, req_size);
- r = receive_cmd_reply(req, rpl, rpl_size);
+ r = __do_vcpu_command(vm, cmd_id, req, req_size, rpl, rpl_size);
stop_vcpu_worker(vcpu_thread, &data);
return r;
}
+static int __do_vcpu0_command(struct kvm_vm *vm, int cmd_id,
+ struct kvmi_msg_hdr *req, size_t req_size,
+ void *rpl, size_t rpl_size)
+{
+ struct kvmi_vcpu_hdr *vcpu_hdr = (struct kvmi_vcpu_hdr *)req;
+
+ vcpu_hdr->vcpu = 0;
+
+ send_message(cmd_id, req, req_size);
+ return receive_cmd_reply(req, rpl, rpl_size);
+}
+
static int do_vcpu0_command(struct kvm_vm *vm, int cmd_id,
struct kvmi_msg_hdr *req, size_t req_size,
void *rpl, size_t rpl_size)
@@ -1668,26 +1687,69 @@ static void test_event_pf(struct kvm_vm *vm)
test_pf(vm, cbk_test_event_pf);
}
-static void test_cmd_vcpu_control_singlestep(struct kvm_vm *vm)
+static void control_singlestep(struct kvm_vm *vm, bool enable)
{
struct {
struct kvmi_msg_hdr hdr;
struct kvmi_vcpu_hdr vcpu_hdr;
struct kvmi_vcpu_control_singlestep cmd;
} req = {};
+ int r;
+
+ req.cmd.enable = enable;
+ r = __do_vcpu0_command(vm, KVMI_VCPU_CONTROL_SINGLESTEP,
+ &req.hdr, sizeof(req), NULL, 0);
+ TEST_ASSERT(r == 0,
+ "KVMI_VCPU_CONTROL_SINGLESTEP failed, error %d (%s)\n",
+ -r, kvm_strerror(-r));
+}
+
+static void enable_singlestep(struct kvm_vm *vm)
+{
+ control_singlestep(vm, true);
+}
+
+static void disable_singlestep(struct kvm_vm *vm)
+{
+ control_singlestep(vm, false);
+}
+
+static void test_cmd_vcpu_control_singlestep(struct kvm_vm *vm)
+{
+ struct vcpu_worker_data data = { .vm = vm, .vcpu_id = VCPU_ID };
+ struct {
+ struct kvmi_event common;
+ struct kvmi_event_singlestep singlestep;
+ } ev;
+ __u16 event_id = KVMI_EVENT_SINGLESTEP;
+ struct vcpu_reply rpl = {};
+ struct kvmi_msg_hdr hdr;
+ pthread_t vcpu_thread;
if (!features.singlestep) {
DEBUG("Skip %s()\n", __func__);
return;
}
- req.cmd.enable = true;
- test_vcpu0_command(vm, KVMI_VCPU_CONTROL_SINGLESTEP,
- &req.hdr, sizeof(req), NULL, 0);
+ enable_vcpu_event(vm, event_id);
- req.cmd.enable = false;
- test_vcpu0_command(vm, KVMI_VCPU_CONTROL_SINGLESTEP,
- &req.hdr, sizeof(req), NULL, 0);
+ vcpu_thread = start_vcpu_worker(&data);
+
+ enable_singlestep(vm);
+
+ receive_event(&hdr, &ev.common, sizeof(ev), event_id);
+
+ DEBUG("SINGLESTEP event, rip 0x%llx success %d\n",
+ ev.common.arch.regs.rip, !ev.singlestep.failed);
+
+ disable_singlestep(vm);
+
+ reply_to_event(&hdr, &ev.common, KVMI_EVENT_ACTION_CONTINUE,
+ &rpl, sizeof(rpl));
+
+ stop_vcpu_worker(vcpu_thread, &data);
+
+ disable_vcpu_event(vm, KVMI_EVENT_SINGLESTEP);
}
static void test_introspection(struct kvm_vm *vm)
diff --git a/virt/kvm/introspection/kvmi.c b/virt/kvm/introspection/kvmi.c
index 90e6c2d3dd4f..8a73fac287b4 100644
--- a/virt/kvm/introspection/kvmi.c
+++ b/virt/kvm/introspection/kvmi.c
@@ -110,6 +110,7 @@ static void setup_known_events(void)
set_bit(KVMI_EVENT_MSR, Kvmi_known_vcpu_events);
set_bit(KVMI_EVENT_PAUSE_VCPU, Kvmi_known_vcpu_events);
set_bit(KVMI_EVENT_PF, Kvmi_known_vcpu_events);
+ set_bit(KVMI_EVENT_SINGLESTEP, Kvmi_known_vcpu_events);
set_bit(KVMI_EVENT_TRAP, Kvmi_known_vcpu_events);
set_bit(KVMI_EVENT_XSETBV, Kvmi_known_vcpu_events);
@@ -1320,3 +1321,63 @@ bool kvmi_vcpu_running_singlestep(struct kvm_vcpu *vcpu)
return ret;
}
EXPORT_SYMBOL(kvmi_vcpu_running_singlestep);
+
+static u32 kvmi_send_singlestep(struct kvm_vcpu *vcpu, bool success)
+{
+ struct kvmi_event_singlestep e;
+ int err, action;
+
+ memset(&e, 0, sizeof(e));
+ e.failed = success ? 0 : 1;
+
+ err = kvmi_send_event(vcpu, KVMI_EVENT_SINGLESTEP, &e, sizeof(e),
+ NULL, 0, &action);
+ if (err)
+ return KVMI_EVENT_ACTION_CONTINUE;
+
+ return action;
+}
+
+static void kvmi_singlestep_event(struct kvm_vcpu *vcpu, bool success)
+{
+ u32 action;
+
+ action = kvmi_send_singlestep(vcpu, success);
+ switch (action) {
+ case KVMI_EVENT_ACTION_CONTINUE:
+ break;
+ default:
+ kvmi_handle_common_event_actions(vcpu->kvm, action,
+ "SINGLESTEP");
+ }
+}
+
+static void kvmi_handle_singlestep_exit(struct kvm_vcpu *vcpu, bool success)
+{
+ struct kvm_vcpu_introspection *vcpui;
+ struct kvm_introspection *kvmi;
+ struct kvm *kvm = vcpu->kvm;
+
+ kvmi = kvmi_get(kvm);
+ if (!kvmi)
+ return;
+
+ vcpui = VCPUI(vcpu);
+
+ if (vcpui->singlestep.loop)
+ kvmi_singlestep_event(vcpu, success);
+
+ kvmi_put(kvm);
+}
+
+void kvmi_singlestep_done(struct kvm_vcpu *vcpu)
+{
+ kvmi_handle_singlestep_exit(vcpu, true);
+}
+EXPORT_SYMBOL(kvmi_singlestep_done);
+
+void kvmi_singlestep_failed(struct kvm_vcpu *vcpu)
+{
+ kvmi_handle_singlestep_exit(vcpu, false);
+}
+EXPORT_SYMBOL(kvmi_singlestep_failed);
diff --git a/virt/kvm/introspection/kvmi_msg.c b/virt/kvm/introspection/kvmi_msg.c
index 14c063869c29..43762e4b7c5c 100644
--- a/virt/kvm/introspection/kvmi_msg.c
+++ b/virt/kvm/introspection/kvmi_msg.c
@@ -630,6 +630,11 @@ static int handle_vcpu_control_singlestep(const struct kvmi_vcpu_cmd_job *job,
bool done;
int i;
+ if (!is_event_allowed(KVMI(vcpu->kvm), KVMI_EVENT_SINGLESTEP)) {
+ ec = -KVM_EPERM;
+ goto reply;
+ }
+
for (i = 0; i < sizeof(req->padding); i++)
if (req->padding[i])
goto reply;
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