From: Nicușor Cîțu <nicu.c...@icloud.com>
The next commit that adds the KVMI_VCPU_EVENT_SINGLESTEP event will make
this command more useful.
Signed-off-by: Nicușor Cîțu <nicu.c...@icloud.com>
Co-developed-by: Adalbert Lazăr <ala...@bitdefender.com>
Signed-off-by: Adalbert Lazăr <ala...@bitdefender.com>
---
Documentation/virt/kvm/kvmi.rst | 33 +++++++++++
arch/x86/kvm/kvmi.c | 14 ++++-
arch/x86/kvm/kvmi_msg.c | 56 +++++++++++++++----
arch/x86/kvm/x86.c | 18 ++++--
include/linux/kvmi_host.h | 7 +++
include/uapi/linux/kvmi.h | 30 ++++++----
.../testing/selftests/kvm/x86_64/kvmi_test.c | 39 +++++++++++++
virt/kvm/introspection/kvmi.c | 22 ++++++++
virt/kvm/introspection/kvmi_int.h | 2 +
9 files changed, 190 insertions(+), 31 deletions(-)
diff --git a/Documentation/virt/kvm/kvmi.rst b/Documentation/virt/kvm/kvmi.rst
index 54cb3fbe184e..7f70345ebaac 100644
--- a/Documentation/virt/kvm/kvmi.rst
+++ b/Documentation/virt/kvm/kvmi.rst
@@ -791,6 +791,7 @@ exception.
* -KVM_EINVAL - the selected vCPU is invalid
* -KVM_EINVAL - the padding is not zero
* -KVM_EAGAIN - the selected vCPU can't be introspected yet
+* -KVM_EBUSY - the vCPU is switched in singlestep mode
(*KVMI_VCPU_CONTROL_SINGLESTEP*)
* -KVM_EBUSY - another *KVMI_VCPU_INJECT_EXCEPTION*-*KVMI_VCPU_EVENT_TRAP*
pair is in progress
@@ -1017,6 +1018,38 @@ In order to 'forget' an address, all three bits ('rwx')
must be set.
* -KVM_EAGAIN - the selected vCPU can't be introspected yet
* -KVM_ENOMEM - there is not enough memory to add the page tracking structures
+23. KVMI_VCPU_CONTROL_SINGLESTEP
+--------------------------------
+
+:Architectures: x86 (vmx)
+:Versions: >= 1
+:Parameters:
+
+::
+
+ struct kvmi_vcpu_hdr;
+ struct kvmi_vcpu_control_singlestep {
+ __u8 enable;
+ __u8 padding[7];
+ };
+
+:Returns:
+
+::
+
+ struct kvmi_error_code;
+
+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**).
+
+:Errors:
+
+* -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
+
Events
======
diff --git a/arch/x86/kvm/kvmi.c b/arch/x86/kvm/kvmi.c
index eee874890e29..e26a0eee1592 100644
--- a/arch/x86/kvm/kvmi.c
+++ b/arch/x86/kvm/kvmi.c
@@ -779,7 +779,9 @@ void kvmi_enter_guest(struct kvm_vcpu *vcpu)
if (kvmi) {
vcpui = VCPUI(vcpu);
- if (vcpui->arch.exception.pending)
+ if (vcpui->singlestep.loop)
+ kvmi_arch_start_singlestep(vcpu);
+ else if (vcpui->arch.exception.pending)
kvmi_inject_pending_exception(vcpu);
kvmi_put(vcpu->kvm);
@@ -1089,3 +1091,13 @@ void kvmi_arch_features(struct kvmi_features *feat)
{
feat->singlestep = !!kvm_x86_ops.control_singlestep;
}
+
+void kvmi_arch_start_singlestep(struct kvm_vcpu *vcpu)
+{
+ static_call(kvm_x86_control_singlestep)(vcpu, true);
+}
+
+void kvmi_arch_stop_singlestep(struct kvm_vcpu *vcpu)
+{
+ static_call(kvm_x86_control_singlestep)(vcpu, false);
+}
diff --git a/arch/x86/kvm/kvmi_msg.c b/arch/x86/kvm/kvmi_msg.c
index 98e29e1d3961..6d3980e18281 100644
--- a/arch/x86/kvm/kvmi_msg.c
+++ b/arch/x86/kvm/kvmi_msg.c
@@ -166,7 +166,8 @@ static int handle_vcpu_inject_exception(const struct
kvmi_vcpu_msg_job *job,
else if (req->padding1 || req->padding2)
ec = -KVM_EINVAL;
else if (VCPUI(vcpu)->arch.exception.pending ||
- VCPUI(vcpu)->arch.exception.send_event)
+ VCPUI(vcpu)->arch.exception.send_event ||
+ VCPUI(vcpu)->singlestep.loop)
ec = -KVM_EBUSY;
else
ec = kvmi_arch_cmd_vcpu_inject_exception(vcpu, req);
@@ -275,18 +276,49 @@ static int handle_vcpu_control_msr(const struct
kvmi_vcpu_msg_job *job,
return kvmi_msg_vcpu_reply(job, msg, ec, NULL, 0);
}
+static int handle_vcpu_control_singlestep(const struct kvmi_vcpu_msg_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 = 0;
+
+ if (non_zero_padding(req->padding, ARRAY_SIZE(req->padding)) ||
+ req->enable > 1) {
+ ec = -KVM_EINVAL;
+ goto reply;
+ }
+
+ if (!kvm_x86_ops.control_singlestep) {
+ ec = -KVM_EOPNOTSUPP;
+ goto reply;
+ }
+
+ if (req->enable)
+ kvmi_arch_start_singlestep(vcpu);
+ else
+ kvmi_arch_stop_singlestep(vcpu);
+
+ VCPUI(vcpu)->singlestep.loop = !!req->enable;
+
+reply:
+ return kvmi_msg_vcpu_reply(job, msg, ec, NULL, 0);
+}
+
static const kvmi_vcpu_msg_job_fct msg_vcpu[] = {
- [KVMI_VCPU_CONTROL_CR] = handle_vcpu_control_cr,
- [KVMI_VCPU_CONTROL_MSR] = handle_vcpu_control_msr,
- [KVMI_VCPU_GET_CPUID] = handle_vcpu_get_cpuid,
- [KVMI_VCPU_GET_INFO] = handle_vcpu_get_info,
- [KVMI_VCPU_GET_MTRR_TYPE] = handle_vcpu_get_mtrr_type,
- [KVMI_VCPU_GET_REGISTERS] = handle_vcpu_get_registers,
- [KVMI_VCPU_GET_XCR] = handle_vcpu_get_xcr,
- [KVMI_VCPU_GET_XSAVE] = handle_vcpu_get_xsave,
- [KVMI_VCPU_INJECT_EXCEPTION] = handle_vcpu_inject_exception,
- [KVMI_VCPU_SET_REGISTERS] = handle_vcpu_set_registers,
- [KVMI_VCPU_SET_XSAVE] = handle_vcpu_set_xsave,
+ [KVMI_VCPU_CONTROL_CR] = handle_vcpu_control_cr,
+ [KVMI_VCPU_CONTROL_MSR] = handle_vcpu_control_msr,
+ [KVMI_VCPU_CONTROL_SINGLESTEP] = handle_vcpu_control_singlestep,
+ [KVMI_VCPU_GET_CPUID] = handle_vcpu_get_cpuid,
+ [KVMI_VCPU_GET_INFO] = handle_vcpu_get_info,
+ [KVMI_VCPU_GET_MTRR_TYPE] = handle_vcpu_get_mtrr_type,
+ [KVMI_VCPU_GET_REGISTERS] = handle_vcpu_get_registers,
+ [KVMI_VCPU_GET_XCR] = handle_vcpu_get_xcr,
+ [KVMI_VCPU_GET_XSAVE] = handle_vcpu_get_xsave,
+ [KVMI_VCPU_INJECT_EXCEPTION] = handle_vcpu_inject_exception,
+ [KVMI_VCPU_SET_REGISTERS] = handle_vcpu_set_registers,
+ [KVMI_VCPU_SET_XSAVE] = handle_vcpu_set_xsave,
};
kvmi_vcpu_msg_job_fct kvmi_arch_vcpu_msg_handler(u16 id)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 238f3de10894..9a3fac9b30ba 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -9613,13 +9613,19 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
goto out;
}
- r = inject_pending_event(vcpu, &req_immediate_exit);
- if (r < 0) {
- r = 0;
- goto out;
+ if (!kvmi_vcpu_running_singlestep(vcpu)) {
+ /*
+ * We cannot inject events during single-stepping.
+ * Try again later.
+ */
+ r = inject_pending_event(vcpu, &req_immediate_exit);
+ if (r < 0) {
+ r = 0;
+ goto out;
+ }
+ if (req_int_win)
+ static_call(kvm_x86_enable_irq_window)(vcpu);
}
- if (req_int_win)
- static_call(kvm_x86_enable_irq_window)(vcpu);
if (kvm_lapic_enabled(vcpu)) {
update_cr8_intercept(vcpu);
diff --git a/include/linux/kvmi_host.h b/include/linux/kvmi_host.h
index 14ac075a3ea9..e2103ab9d0d5 100644
--- a/include/linux/kvmi_host.h
+++ b/include/linux/kvmi_host.h
@@ -33,6 +33,10 @@ struct kvm_vcpu_introspection {
bool waiting_for_reply;
unsigned long *ev_enable_mask;
+
+ struct {
+ bool loop;
+ } singlestep;
};
struct kvm_introspection {
@@ -76,6 +80,7 @@ int kvmi_ioctl_preunhook(struct kvm *kvm);
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_vcpu_running_singlestep(struct kvm_vcpu *vcpu);
#else
@@ -90,6 +95,8 @@ static inline void kvmi_handle_requests(struct kvm_vcpu
*vcpu) { }
static inline bool kvmi_hypercall_event(struct kvm_vcpu *vcpu) { return false;
}
static inline bool kvmi_breakpoint_event(struct kvm_vcpu *vcpu, u64 gva,
u8 insn_len) { 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 b594463795c6..31bf2b6f3779 100644
--- a/include/uapi/linux/kvmi.h
+++ b/include/uapi/linux/kvmi.h
@@ -37,18 +37,19 @@ enum {
enum {
KVMI_VCPU_EVENT = KVMI_VCPU_MESSAGE_ID(0),
- KVMI_VCPU_GET_INFO = KVMI_VCPU_MESSAGE_ID(1),
- KVMI_VCPU_CONTROL_EVENTS = KVMI_VCPU_MESSAGE_ID(2),
- KVMI_VCPU_GET_REGISTERS = KVMI_VCPU_MESSAGE_ID(3),
- KVMI_VCPU_SET_REGISTERS = KVMI_VCPU_MESSAGE_ID(4),
- KVMI_VCPU_GET_CPUID = KVMI_VCPU_MESSAGE_ID(5),
- KVMI_VCPU_CONTROL_CR = KVMI_VCPU_MESSAGE_ID(6),
- KVMI_VCPU_INJECT_EXCEPTION = KVMI_VCPU_MESSAGE_ID(7),
- KVMI_VCPU_GET_XCR = KVMI_VCPU_MESSAGE_ID(8),
- KVMI_VCPU_GET_XSAVE = KVMI_VCPU_MESSAGE_ID(9),
- KVMI_VCPU_SET_XSAVE = KVMI_VCPU_MESSAGE_ID(10),
- KVMI_VCPU_GET_MTRR_TYPE = KVMI_VCPU_MESSAGE_ID(11),
- KVMI_VCPU_CONTROL_MSR = KVMI_VCPU_MESSAGE_ID(12),
+ KVMI_VCPU_GET_INFO = KVMI_VCPU_MESSAGE_ID(1),
+ KVMI_VCPU_CONTROL_EVENTS = KVMI_VCPU_MESSAGE_ID(2),
+ KVMI_VCPU_GET_REGISTERS = KVMI_VCPU_MESSAGE_ID(3),
+ KVMI_VCPU_SET_REGISTERS = KVMI_VCPU_MESSAGE_ID(4),
+ KVMI_VCPU_GET_CPUID = KVMI_VCPU_MESSAGE_ID(5),
+ KVMI_VCPU_CONTROL_CR = KVMI_VCPU_MESSAGE_ID(6),
+ KVMI_VCPU_INJECT_EXCEPTION = KVMI_VCPU_MESSAGE_ID(7),
+ KVMI_VCPU_GET_XCR = KVMI_VCPU_MESSAGE_ID(8),
+ KVMI_VCPU_GET_XSAVE = KVMI_VCPU_MESSAGE_ID(9),
+ KVMI_VCPU_SET_XSAVE = KVMI_VCPU_MESSAGE_ID(10),
+ KVMI_VCPU_GET_MTRR_TYPE = KVMI_VCPU_MESSAGE_ID(11),
+ KVMI_VCPU_CONTROL_MSR = KVMI_VCPU_MESSAGE_ID(12),
+ KVMI_VCPU_CONTROL_SINGLESTEP = KVMI_VCPU_MESSAGE_ID(13),
KVMI_NEXT_VCPU_MESSAGE
};
@@ -216,4 +217,9 @@ struct kvmi_vcpu_event_pf {
__u32 padding3;
};
+struct kvmi_vcpu_control_singlestep {
+ __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 f7735e3ea9e8..1bd01115be31 100644
--- a/tools/testing/selftests/kvm/x86_64/kvmi_test.c
+++ b/tools/testing/selftests/kvm/x86_64/kvmi_test.c
@@ -1808,6 +1808,44 @@ static void test_event_pf(struct kvm_vm *vm)
test_pf(vm, cbk_test_event_pf);
}
+static void cmd_vcpu_singlestep(struct kvm_vm *vm, __u8 enable,
+ int expected_err)
+{
+ struct {
+ struct kvmi_msg_hdr hdr;
+ struct kvmi_vcpu_hdr vcpu_hdr;
+ struct kvmi_vcpu_control_singlestep cmd;
+ } req = {};
+
+ req.cmd.enable = enable;
+
+ test_vcpu0_command(vm, KVMI_VCPU_CONTROL_SINGLESTEP,
+ &req.hdr, sizeof(req), NULL, 0, expected_err);
+}
+
+static void test_supported_singlestep(struct kvm_vm *vm)
+{
+ __u8 disable = 0, enable = 1, enable_inval = 2;
+
+ cmd_vcpu_singlestep(vm, enable, 0);
+ cmd_vcpu_singlestep(vm, disable, 0);
+
+ cmd_vcpu_singlestep(vm, enable_inval, -KVM_EINVAL);
+}
+
+static void test_unsupported_singlestep(struct kvm_vm *vm)
+{
+ cmd_vcpu_singlestep(vm, 1, -KVM_EOPNOTSUPP);
+}
+
+static void test_cmd_vcpu_control_singlestep(struct kvm_vm *vm)
+{
+ if (features.singlestep)
+ test_supported_singlestep(vm);
+ else
+ test_unsupported_singlestep(vm);
+}
+
static void test_introspection(struct kvm_vm *vm)
{
srandom(time(0));
@@ -1841,6 +1879,7 @@ 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 4bc29382ba5a..c20c70547065 100644
--- a/virt/kvm/introspection/kvmi.c
+++ b/virt/kvm/introspection/kvmi.c
@@ -437,6 +437,11 @@ 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);
+ vcpui->singlestep.loop = false;
+ }
}
static void kvmi_release_vcpus(struct kvm *kvm)
@@ -1172,3 +1177,20 @@ void kvmi_remove_memslot(struct kvm *kvm, struct
kvm_memory_slot *slot)
KVM_MMU_UNLOCK(kvm);
srcu_read_unlock(&kvm->srcu, idx);
}
+
+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 a51e7e4ed511..4815fa61b136 100644
--- a/virt/kvm/introspection/kvmi_int.h
+++ b/virt/kvm/introspection/kvmi_int.h
@@ -122,5 +122,7 @@ void kvmi_arch_update_page_tracking(struct kvm *kvm,
void kvmi_arch_hook(struct kvm *kvm);
void kvmi_arch_unhook(struct kvm *kvm);
void kvmi_arch_features(struct kvmi_features *feat);
+void kvmi_arch_start_singlestep(struct kvm_vcpu *vcpu);
+void kvmi_arch_stop_singlestep(struct kvm_vcpu *vcpu);
#endif
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