From: Nicușor Cîțu <ncitu@xxxxxxxxxxxxxxx>
This command is extremely useful for debuggers.
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 | 31 ++++++
arch/x86/kvm/kvmi.c | 18 ++++
arch/x86/kvm/x86.c | 7 ++
include/linux/kvmi_host.h | 7 ++
include/uapi/linux/kvmi.h | 7 ++
.../testing/selftests/kvm/x86_64/kvmi_test.c | 21 +++++
virt/kvm/introspection/kvmi.c | 23 +++++
virt/kvm/introspection/kvmi_int.h | 3 +
virt/kvm/introspection/kvmi_msg.c | 94 ++++++++++++-------
9 files changed, 179 insertions(+), 32 deletions(-)
diff --git a/Documentation/virt/kvm/kvmi.rst b/Documentation/virt/kvm/kvmi.rst
index 454d7ae75ae6..ffa183745722 100644
--- a/Documentation/virt/kvm/kvmi.rst
+++ b/Documentation/virt/kvm/kvmi.rst
@@ -930,6 +930,37 @@ In order to 'forget' an address, all the access bits ('rwx') must be set.
* -KVM_EINVAL - the message size is invalid
* -KVM_ENOMEM - not enough memory to add the page tracking structures
+20. KVMI_VCPU_CONTROL_SINGLESTEP
+--------------------------------
+
+:Architectures: x86 (vmx)
+:Versions: >= 1
+:Parameters:
+
+::
+
+ struct kvmi_vcpu_control_singlestep {
+ __u8 enable;
+ __u8 padding[7];
+ };
+
+:Returns:
+
+::
+
+ struct kvmi_error_code
+
+Enables/disables singlestep.
+
+The introspection tool can use *KVMI_GET_VERSION*, to check
+if the hardware supports singlestep (see **KVMI_GET_VERSION**).
+
+:Errors:
+
+* -KVM_EOPNOTSUPP - the hardware doesn't support it
+* -KVM_EINVAL - padding is not zero
+* -KVM_EAGAIN - the selected vCPU can't be introspected yet
+
Events
======
diff --git a/arch/x86/kvm/kvmi.c b/arch/x86/kvm/kvmi.c
index 5cf266d13375..feebb0327e27 100644
--- a/arch/x86/kvm/kvmi.c
+++ b/arch/x86/kvm/kvmi.c
@@ -1111,3 +1111,21 @@ bool kvmi_arch_pf_of_interest(struct kvm_vcpu *vcpu)
!kvm_x86_ops->gpt_translation_fault(vcpu);
}
+bool kvmi_arch_start_singlestep(struct kvm_vcpu *vcpu)
+{
+ if (!kvm_x86_ops->control_singlestep)
+ return false;
+
+ kvm_x86_ops->control_singlestep(vcpu, true);
+ return true;
+}
+
+bool kvmi_arch_stop_singlestep(struct kvm_vcpu *vcpu)
+{
+ if (!kvm_x86_ops->control_singlestep)
+ return false;
+
+ kvm_x86_ops->control_singlestep(vcpu, false);
+ return true;
+}
+
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 5d6ac6c99246..b87ff31ce486 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7625,6 +7625,13 @@ static int inject_pending_event(struct kvm_vcpu *vcpu, bool req_int_win)
{
int r;
+ if (kvmi_vcpu_running_singlestep(vcpu))
+ /*
+ * We cannot inject events during single-stepping.
+ * Try again later.
+ */
+ return -1;
+
/* try to reinject previous events if any */
if (vcpu->arch.exception.injected)
diff --git a/include/linux/kvmi_host.h b/include/linux/kvmi_host.h
index a9f572df1809..7c84ca681411 100644
--- a/include/linux/kvmi_host.h
+++ b/include/linux/kvmi_host.h
@@ -50,6 +50,10 @@ struct kvm_vcpu_introspection {
bool pending;
bool send_event;
} exception;
+
+ struct {
+ bool loop;
+ } singlestep;
};
struct kvm_introspection {
@@ -90,6 +94,7 @@ void kvmi_handle_requests(struct kvm_vcpu *vcpu);
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);
#else
@@ -106,6 +111,8 @@ static inline bool kvmi_breakpoint_event(struct kvm_vcpu *vcpu, u64 gva,
{ return true; }
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; }
#endif /* CONFIG_KVM_INTROSPECTION */
diff --git a/include/uapi/linux/kvmi.h b/include/uapi/linux/kvmi.h
index 7cd41a815967..c6c5019ccf85 100644
--- a/include/uapi/linux/kvmi.h
+++ b/include/uapi/linux/kvmi.h
@@ -43,6 +43,8 @@ enum {
KVMI_VM_SET_PAGE_ACCESS = 21,
+ KVMI_VCPU_CONTROL_SINGLESTEP = 22,
+
KVMI_NUM_MESSAGES
};
@@ -168,6 +170,11 @@ struct kvmi_vm_set_page_access {
struct kvmi_page_access_entry entries[0];
};
+struct kvmi_vcpu_control_singlestep {
+ __u8 enable;
+ __u8 padding[7];
+};
+
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 a27588c27eb8..090cb7acd2ed 100644
--- a/tools/testing/selftests/kvm/x86_64/kvmi_test.c
+++ b/tools/testing/selftests/kvm/x86_64/kvmi_test.c
@@ -1681,6 +1681,26 @@ 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)
+{
+ struct {
+ struct kvmi_msg_hdr hdr;
+ struct kvmi_vcpu_hdr vcpu_hdr;
+ struct kvmi_vcpu_control_singlestep cmd;
+ } req = {};
+
+ if (!features.singlestep)
+ return;
+
+ req.cmd.enable = true;
+ test_vcpu0_command(vm, KVMI_VCPU_CONTROL_SINGLESTEP,
+ &req.hdr, sizeof(req), NULL, 0);
+
+ req.cmd.enable = false;
+ test_vcpu0_command(vm, KVMI_VCPU_CONTROL_SINGLESTEP,
+ &req.hdr, sizeof(req), NULL, 0);
+}
+
static void test_introspection(struct kvm_vm *vm)
{
setup_socket();
@@ -1712,6 +1732,7 @@ static void test_introspection(struct kvm_vm *vm)
test_cmd_vcpu_control_msr(vm);
test_cmd_vm_set_page_access(vm);
test_event_pf(vm);
+ test_cmd_vcpu_control_singlestep(vm);
unhook_introspection(vm);
}
diff --git a/virt/kvm/introspection/kvmi.c b/virt/kvm/introspection/kvmi.c
index 10d59061fa82..b798eeab6618 100644
--- a/virt/kvm/introspection/kvmi.c
+++ b/virt/kvm/introspection/kvmi.c
@@ -361,6 +361,9 @@ static void kvmi_job_release_vcpu(struct kvm_vcpu *vcpu, void *ctx)
atomic_set(&vcpui->pause_requests, 0);
vcpui->waiting_for_reply = false;
+
+ if (vcpui->singlestep.loop)
+ kvmi_arch_stop_singlestep(vcpu);
}
static void kvmi_release_vcpus(struct kvm *kvm)
@@ -1003,6 +1006,9 @@ bool kvmi_enter_guest(struct kvm_vcpu *vcpu)
if (!kvmi)
return true;
+ if (VCPUI(vcpu)->singlestep.loop)
+ kvmi_arch_start_singlestep(vcpu);
+
if (kvmi_inject_pending_exception(vcpu))
r = false;
@@ -1296,3 +1302,20 @@ static void kvmi_track_flush_slot(struct kvm *kvm, struct kvm_memory_slot *slot,
kvmi_put(kvm);
}
+
+bool kvmi_vcpu_running_singlestep(struct kvm_vcpu *vcpu)
+{
+ struct kvm_introspection *kvmi;
+ bool ret;
+
+ kvmi = kvmi_get(vcpu->kvm);
+ if (!kvmi)
+ return false;
+
+ ret = VCPUI(vcpu)->singlestep.loop;
+
+ kvmi_put(vcpu->kvm);
+
+ return ret;
+}
+EXPORT_SYMBOL(kvmi_vcpu_running_singlestep);
diff --git a/virt/kvm/introspection/kvmi_int.h b/virt/kvm/introspection/kvmi_int.h
index 06b924277f37..64425ff16c7d 100644
--- a/virt/kvm/introspection/kvmi_int.h
+++ b/virt/kvm/introspection/kvmi_int.h
@@ -50,6 +50,7 @@
| BIT(KVMI_VCPU_CONTROL_CR) \
| BIT(KVMI_VCPU_CONTROL_EVENTS) \
| BIT(KVMI_VCPU_CONTROL_MSR) \
+ | BIT(KVMI_VCPU_CONTROL_SINGLESTEP) \
| BIT(KVMI_VCPU_GET_CPUID) \
| BIT(KVMI_VCPU_GET_MTRR_TYPE) \
| BIT(KVMI_VCPU_GET_REGISTERS) \
@@ -168,5 +169,7 @@ bool kvmi_arch_pf_event(struct kvm_vcpu *vcpu, gpa_t gpa, gva_t gva,
u8 access);
bool kvmi_arch_pf_of_interest(struct kvm_vcpu *vcpu);
void kvmi_arch_features(struct kvmi_features *feat);
+bool kvmi_arch_start_singlestep(struct kvm_vcpu *vcpu);
+bool kvmi_arch_stop_singlestep(struct kvm_vcpu *vcpu);
#endif
diff --git a/virt/kvm/introspection/kvmi_msg.c b/virt/kvm/introspection/kvmi_msg.c
index 8c7cdbd96faa..4c49033a6407 100644
--- a/virt/kvm/introspection/kvmi_msg.c
+++ b/virt/kvm/introspection/kvmi_msg.c
@@ -17,27 +17,28 @@ struct kvmi_vcpu_cmd_job {
};
static const char *const msg_IDs[] = {
- [KVMI_EVENT_REPLY] = "KVMI_EVENT_REPLY",
- [KVMI_GET_VERSION] = "KVMI_GET_VERSION",
- [KVMI_VM_CHECK_COMMAND] = "KVMI_VM_CHECK_COMMAND",
- [KVMI_VM_CHECK_EVENT] = "KVMI_VM_CHECK_EVENT",
- [KVMI_VM_CONTROL_EVENTS] = "KVMI_VM_CONTROL_EVENTS",
- [KVMI_VM_GET_INFO] = "KVMI_VM_GET_INFO",
- [KVMI_VM_GET_MAX_GFN] = "KVMI_VM_GET_MAX_GFN",
- [KVMI_VM_READ_PHYSICAL] = "KVMI_VM_READ_PHYSICAL",
- [KVMI_VM_SET_PAGE_ACCESS] = "KVMI_VM_SET_PAGE_ACCESS",
- [KVMI_VM_WRITE_PHYSICAL] = "KVMI_VM_WRITE_PHYSICAL",
- [KVMI_VCPU_CONTROL_CR] = "KVMI_VCPU_CONTROL_CR",
- [KVMI_VCPU_CONTROL_EVENTS] = "KVMI_VCPU_CONTROL_EVENTS",
- [KVMI_VCPU_CONTROL_MSR] = "KVMI_VCPU_CONTROL_MSR",
- [KVMI_VCPU_GET_CPUID] = "KVMI_VCPU_GET_CPUID",
- [KVMI_VCPU_GET_INFO] = "KVMI_VCPU_GET_INFO",
- [KVMI_VCPU_GET_MTRR_TYPE] = "KVMI_VCPU_GET_MTRR_TYPE",
- [KVMI_VCPU_GET_REGISTERS] = "KVMI_VCPU_GET_REGISTERS",
- [KVMI_VCPU_GET_XSAVE] = "KVMI_VCPU_GET_XSAVE",
- [KVMI_VCPU_INJECT_EXCEPTION] = "KVMI_VCPU_INJECT_EXCEPTION",
- [KVMI_VCPU_PAUSE] = "KVMI_VCPU_PAUSE",
- [KVMI_VCPU_SET_REGISTERS] = "KVMI_VCPU_SET_REGISTERS",
+ [KVMI_EVENT_REPLY] = "KVMI_EVENT_REPLY",
+ [KVMI_GET_VERSION] = "KVMI_GET_VERSION",
+ [KVMI_VM_CHECK_COMMAND] = "KVMI_VM_CHECK_COMMAND",
+ [KVMI_VM_CHECK_EVENT] = "KVMI_VM_CHECK_EVENT",
+ [KVMI_VM_CONTROL_EVENTS] = "KVMI_VM_CONTROL_EVENTS",
+ [KVMI_VM_GET_INFO] = "KVMI_VM_GET_INFO",
+ [KVMI_VM_GET_MAX_GFN] = "KVMI_VM_GET_MAX_GFN",
+ [KVMI_VM_READ_PHYSICAL] = "KVMI_VM_READ_PHYSICAL",
+ [KVMI_VM_SET_PAGE_ACCESS] = "KVMI_VM_SET_PAGE_ACCESS",
+ [KVMI_VM_WRITE_PHYSICAL] = "KVMI_VM_WRITE_PHYSICAL",
+ [KVMI_VCPU_CONTROL_CR] = "KVMI_VCPU_CONTROL_CR",
+ [KVMI_VCPU_CONTROL_EVENTS] = "KVMI_VCPU_CONTROL_EVENTS",
+ [KVMI_VCPU_CONTROL_MSR] = "KVMI_VCPU_CONTROL_MSR",
+ [KVMI_VCPU_CONTROL_SINGLESTEP] = "KVMI_VCPU_CONTROL_SINGLESTEP",
+ [KVMI_VCPU_GET_CPUID] = "KVMI_VCPU_GET_CPUID",
+ [KVMI_VCPU_GET_INFO] = "KVMI_VCPU_GET_INFO",
+ [KVMI_VCPU_GET_MTRR_TYPE] = "KVMI_VCPU_GET_MTRR_TYPE",
+ [KVMI_VCPU_GET_REGISTERS] = "KVMI_VCPU_GET_REGISTERS",
+ [KVMI_VCPU_GET_XSAVE] = "KVMI_VCPU_GET_XSAVE",
+ [KVMI_VCPU_INJECT_EXCEPTION] = "KVMI_VCPU_INJECT_EXCEPTION",
+ [KVMI_VCPU_PAUSE] = "KVMI_VCPU_PAUSE",
+ [KVMI_VCPU_SET_REGISTERS] = "KVMI_VCPU_SET_REGISTERS",
};
static bool is_known_message(u16 id)
@@ -585,6 +586,34 @@ static int handle_vcpu_control_msr(const struct kvmi_vcpu_cmd_job *job,
return kvmi_msg_vcpu_reply(job, msg, ec, NULL, 0);
}
+static int handle_vcpu_control_singlestep(const struct kvmi_vcpu_cmd_job *job,
+ const struct kvmi_msg_hdr *msg,
+ const void *_req)
+{
+ const struct kvmi_vcpu_control_singlestep *req = _req;
+ struct kvm_vcpu *vcpu = job->vcpu;
+ int ec = -KVM_EINVAL;
+ bool done;
+ int i;
+
+ for (i = 0; i < sizeof(req->padding); i++)
+ if (req->padding[i])
+ goto reply;
+
+ if (req->enable)
+ done = kvmi_arch_start_singlestep(vcpu);
+ else
+ done = kvmi_arch_stop_singlestep(vcpu);
+
+ if (done) {
+ ec = 0;
+ VCPUI(vcpu)->singlestep.loop = !!req->enable;
+ }
+
+reply:
+ return kvmi_msg_vcpu_reply(job, msg, ec, NULL, 0);
+}
+
/*
* These commands are executed on the vCPU thread. The receiving thread
* passes the messages using a newly allocated 'struct kvmi_vcpu_cmd_job'
@@ -593,17 +622,18 @@ static int handle_vcpu_control_msr(const struct kvmi_vcpu_cmd_job *job,
*/
static int(*const msg_vcpu[])(const struct kvmi_vcpu_cmd_job *,
const struct kvmi_msg_hdr *, const void *) = {
- [KVMI_EVENT_REPLY] = handle_event_reply,
- [KVMI_VCPU_CONTROL_CR] = handle_vcpu_control_cr,
- [KVMI_VCPU_CONTROL_EVENTS] = handle_vcpu_control_events,
- [KVMI_VCPU_CONTROL_MSR] = handle_vcpu_control_msr,
- [KVMI_VCPU_GET_CPUID] = handle_get_cpuid,
- [KVMI_VCPU_GET_INFO] = handle_get_vcpu_info,
- [KVMI_VCPU_GET_MTRR_TYPE] = handle_vcpu_get_mtrr_type,
- [KVMI_VCPU_GET_REGISTERS] = handle_get_registers,
- [KVMI_VCPU_GET_XSAVE] = handle_vcpu_get_xsave,
- [KVMI_VCPU_INJECT_EXCEPTION] = handle_vcpu_inject_exception,
- [KVMI_VCPU_SET_REGISTERS] = handle_set_registers,
+ [KVMI_EVENT_REPLY] = handle_event_reply,
+ [KVMI_VCPU_CONTROL_CR] = handle_vcpu_control_cr,
+ [KVMI_VCPU_CONTROL_EVENTS] = handle_vcpu_control_events,
+ [KVMI_VCPU_CONTROL_MSR] = handle_vcpu_control_msr,
+ [KVMI_VCPU_CONTROL_SINGLESTEP] = handle_vcpu_control_singlestep,
+ [KVMI_VCPU_GET_CPUID] = handle_get_cpuid,
+ [KVMI_VCPU_GET_INFO] = handle_get_vcpu_info,
+ [KVMI_VCPU_GET_MTRR_TYPE] = handle_vcpu_get_mtrr_type,
+ [KVMI_VCPU_GET_REGISTERS] = handle_get_registers,
+ [KVMI_VCPU_GET_XSAVE] = handle_vcpu_get_xsave,
+ [KVMI_VCPU_INJECT_EXCEPTION] = handle_vcpu_inject_exception,
+ [KVMI_VCPU_SET_REGISTERS] = handle_set_registers,
};
static void kvmi_job_vcpu_cmd(struct kvm_vcpu *vcpu, void *ctx)
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