From: Ștefan Șicleru <ssicl...@bitdefender.com>
This will be used by the introspection tool to control the EPT views to
which the guest is allowed to switch.
Signed-off-by: Ștefan Șicleru <ssicl...@bitdefender.com>
Signed-off-by: Adalbert Lazăr <ala...@bitdefender.com>
---
Documentation/virt/kvm/kvmi.rst | 37 ++++++
arch/x86/include/uapi/asm/kvmi.h | 7 ++
arch/x86/kvm/kvmi.c | 9 ++
include/uapi/linux/kvmi.h | 1 +
.../testing/selftests/kvm/x86_64/kvmi_test.c | 118 ++++++++++++++++++
virt/kvm/introspection/kvmi_int.h | 2 +
virt/kvm/introspection/kvmi_msg.c | 19 +++
7 files changed, 193 insertions(+)
diff --git a/Documentation/virt/kvm/kvmi.rst b/Documentation/virt/kvm/kvmi.rst
index 02f03c62adef..f4c60aba9b53 100644
--- a/Documentation/virt/kvm/kvmi.rst
+++ b/Documentation/virt/kvm/kvmi.rst
@@ -1190,6 +1190,43 @@ EPTP switching mechanism (see **KVMI_GET_VERSION**).
* -KVM_EAGAIN - the selected vCPU can't be introspected yet
* -KVM_EOPNOTSUPP - an EPT view was selected but the hardware doesn't support
it
+28. KVMI_VCPU_CONTROL_EPT_VIEW
+------------------------------
+
+:Architecture: x86
+:Versions: >= 1
+:Parameters:
+
+::
+
+ struct kvmi_vcpu_hdr;
+ struct kvmi_vcpu_control_ept_view {
+ __u16 view;
+ __u8 visible;
+ __u8 padding1;
+ __u32 padding2;
+ };
+
+:Returns:
+
+::
+
+ struct kvmi_error_code;
+
+Controls the capability of the guest to successfully change EPT views
+through VMFUNC instruction without triggering a vm-exit. If ``visible``
+is true, the guest will be capable to change EPT views through VMFUNC(0,
+``view``). If ``visible`` is false, VMFUNC(0, ``view``) triggers a
+vm-exit, a #UD exception is injected to guest and the guest application
+is terminated.
+
+:Errors:
+
+* -KVM_EINVAL - the selected vCPU is invalid
+* -KVM_EAGAIN - the selected vCPU can't be introspected yet
+* -KVM_EINVAL - padding is not zero
+* -KVM_EINVAL - the selected EPT view is not valid
+
Events
======
diff --git a/arch/x86/include/uapi/asm/kvmi.h b/arch/x86/include/uapi/asm/kvmi.h
index f7a080d5e227..fc35da900778 100644
--- a/arch/x86/include/uapi/asm/kvmi.h
+++ b/arch/x86/include/uapi/asm/kvmi.h
@@ -166,4 +166,11 @@ struct kvmi_vcpu_set_ept_view {
__u32 padding2;
};
+struct kvmi_vcpu_control_ept_view {
+ __u16 view;
+ __u8 visible;
+ __u8 padding1;
+ __u32 padding2;
+};
+
#endif /* _UAPI_ASM_X86_KVMI_H */
diff --git a/arch/x86/kvm/kvmi.c b/arch/x86/kvm/kvmi.c
index 99ea8ef70be2..06357b8ab54a 100644
--- a/arch/x86/kvm/kvmi.c
+++ b/arch/x86/kvm/kvmi.c
@@ -1432,3 +1432,12 @@ int kvmi_arch_cmd_set_ept_view(struct kvm_vcpu *vcpu,
u16 view)
return kvm_x86_ops.set_ept_view(vcpu, view);
}
+
+int kvmi_arch_cmd_control_ept_view(struct kvm_vcpu *vcpu, u16 view,
+ bool visible)
+{
+ if (!kvm_x86_ops.control_ept_view)
+ return -KVM_EINVAL;
+
+ return kvm_x86_ops.control_ept_view(vcpu, view, visible);
+}
diff --git a/include/uapi/linux/kvmi.h b/include/uapi/linux/kvmi.h
index 8204661d944d..a72c536a2c80 100644
--- a/include/uapi/linux/kvmi.h
+++ b/include/uapi/linux/kvmi.h
@@ -51,6 +51,7 @@ enum {
KVMI_VCPU_TRANSLATE_GVA = 25,
KVMI_VCPU_GET_EPT_VIEW = 26,
KVMI_VCPU_SET_EPT_VIEW = 27,
+ KVMI_VCPU_CONTROL_EPT_VIEW = 28,
KVMI_NUM_MESSAGES
};
diff --git a/tools/testing/selftests/kvm/x86_64/kvmi_test.c
b/tools/testing/selftests/kvm/x86_64/kvmi_test.c
index c6f7d10563db..d808cb61463d 100644
--- a/tools/testing/selftests/kvm/x86_64/kvmi_test.c
+++ b/tools/testing/selftests/kvm/x86_64/kvmi_test.c
@@ -56,6 +56,7 @@ struct vcpu_worker_data {
bool stop;
bool shutdown;
bool restart_on_shutdown;
+ bool run_guest_once;
};
static struct kvmi_features features;
@@ -72,6 +73,7 @@ enum {
GUEST_TEST_HYPERCALL,
GUEST_TEST_MSR,
GUEST_TEST_PF,
+ GUEST_TEST_VMFUNC,
GUEST_TEST_XSETBV,
};
@@ -130,6 +132,13 @@ static void guest_pf_test(void)
*((uint8_t *)test_gva) = READ_ONCE(test_write_pattern);
}
+static void guest_vmfunc_test(void)
+{
+ asm volatile("mov $0, %rax");
+ asm volatile("mov $1, %rcx");
+ asm volatile(".byte 0x0f,0x01,0xd4");
+}
+
/* from fpu/internal.h */
static u64 xgetbv(u32 index)
{
@@ -193,6 +202,9 @@ static void guest_code(void)
case GUEST_TEST_PF:
guest_pf_test();
break;
+ case GUEST_TEST_VMFUNC:
+ guest_vmfunc_test();
+ break;
case GUEST_TEST_XSETBV:
guest_xsetbv_test();
break;
@@ -777,6 +789,7 @@ static void test_memory_access(struct kvm_vm *vm)
static void *vcpu_worker(void *data)
{
struct vcpu_worker_data *ctx = data;
+ bool first_run = false;
struct kvm_run *run;
run = vcpu_state(ctx->vm, ctx->vcpu_id);
@@ -805,6 +818,13 @@ static void *vcpu_worker(void *data)
if (HOST_SEND_TEST(uc)) {
test_id = READ_ONCE(ctx->test_id);
sync_global_to_guest(ctx->vm, test_id);
+ if (run->exit_reason == KVM_EXIT_IO &&
+ ctx->run_guest_once) {
+ if (!first_run)
+ first_run = true;
+ else
+ break;
+ }
}
}
@@ -2140,6 +2160,103 @@ static void test_cmd_vcpu_set_ept_view(struct kvm_vm
*vm)
set_ept_view(vm, old_view);
}
+static void check_expected_view(struct kvm_vm *vm,
+ __u16 check_view)
+{
+ __u16 found_view = get_ept_view(vm);
+
+ TEST_ASSERT(check_view == found_view,
+ "Unexpected EPT view, found ept view (%u), expected
view (%u)\n",
+ found_view, check_view);
+}
+
+static void test_guest_switch_to_invisible_view(struct kvm_vm *vm)
+{
+ struct vcpu_worker_data data = {
+ .vm = vm,
+ .vcpu_id = VCPU_ID,
+ .shutdown = true,
+ .test_id = GUEST_TEST_VMFUNC,
+ };
+ pthread_t vcpu_thread;
+ struct kvm_regs regs;
+ __u16 view = 0;
+
+ check_expected_view(vm, view);
+
+ vcpu_thread = start_vcpu_worker(&data);
+ wait_vcpu_worker(vcpu_thread);
+
+ /*
+ * Move to the next instruction, so the guest would not
+ * re-execute VMFUNC again when vcpu_run() is called.
+ */
+ vcpu_regs_get(vm, VCPU_ID, ®s);
+ regs.rip += 3;
+ vcpu_regs_set(vm, VCPU_ID, ®s);
+
+ check_expected_view(vm, view);
+}
+
+static void test_control_ept_view(struct kvm_vm *vm, __u16 view, bool visible)
+{
+ struct {
+ struct kvmi_msg_hdr hdr;
+ struct kvmi_vcpu_hdr vcpu_hdr;
+ struct kvmi_vcpu_control_ept_view cmd;
+ } req = {};
+
+ req.cmd.view = view;
+ req.cmd.visible = visible;
+
+ test_vcpu0_command(vm, KVMI_VCPU_CONTROL_EPT_VIEW,
+ &req.hdr, sizeof(req), NULL, 0);
+}
+
+static void enable_ept_view_visibility(struct kvm_vm *vm, __u16 view)
+{
+ test_control_ept_view(vm, view, true);
+}
+
+static void disable_ept_view_visibility(struct kvm_vm *vm, __u16 view)
+{
+ test_control_ept_view(vm, view, false);
+}
+
+static void test_guest_switch_to_visible_view(struct kvm_vm *vm)
+{
+ struct vcpu_worker_data data = {
+ .vm = vm,
+ .vcpu_id = VCPU_ID,
+ .run_guest_once = true,
+ .test_id = GUEST_TEST_VMFUNC,
+ };
+ pthread_t vcpu_thread;
+ __u16 old_view = 0, new_view = 1;
+
+ enable_ept_view_visibility(vm, new_view);
+
+ vcpu_thread = start_vcpu_worker(&data);
+ wait_vcpu_worker(vcpu_thread);
+
+ check_expected_view(vm, new_view);
+
+ disable_ept_view_visibility(vm, new_view);
+
+ set_ept_view(vm, old_view);
+}
+
+static void test_cmd_vcpu_vmfunc(struct kvm_vm *vm)
+{
+ if (!features.vmfunc) {
+ print_skip("EPT views not supported");
+ return;
+ }
+
+ test_guest_switch_to_invisible_view(vm);
+ test_guest_switch_to_visible_view(vm);
+}
+
static void test_introspection(struct kvm_vm *vm)
{
srandom(time(0));
@@ -2178,6 +2295,7 @@ static void test_introspection(struct kvm_vm *vm)
test_cmd_translate_gva(vm);
test_cmd_vcpu_get_ept_view(vm);
test_cmd_vcpu_set_ept_view(vm);
+ test_cmd_vcpu_vmfunc(vm);
unhook_introspection(vm);
}
diff --git a/virt/kvm/introspection/kvmi_int.h
b/virt/kvm/introspection/kvmi_int.h
index f093aad2f804..d78116442ddd 100644
--- a/virt/kvm/introspection/kvmi_int.h
+++ b/virt/kvm/introspection/kvmi_int.h
@@ -149,5 +149,7 @@ bool kvmi_arch_stop_singlestep(struct kvm_vcpu *vcpu);
gpa_t kvmi_arch_cmd_translate_gva(struct kvm_vcpu *vcpu, gva_t gva);
u16 kvmi_arch_cmd_get_ept_view(struct kvm_vcpu *vcpu);
int kvmi_arch_cmd_set_ept_view(struct kvm_vcpu *vcpu, u16 view);
+int kvmi_arch_cmd_control_ept_view(struct kvm_vcpu *vcpu, u16 view,
+ bool visible);
#endif
diff --git a/virt/kvm/introspection/kvmi_msg.c
b/virt/kvm/introspection/kvmi_msg.c
index 73a7179f7031..696857f6d008 100644
--- a/virt/kvm/introspection/kvmi_msg.c
+++ b/virt/kvm/introspection/kvmi_msg.c
@@ -693,6 +693,24 @@ static int handle_vcpu_set_ept_view(const struct
kvmi_vcpu_msg_job *job,
return kvmi_msg_vcpu_reply(job, msg, ec, NULL, 0);
}
+static int handle_vcpu_control_ept_view(const struct kvmi_vcpu_msg_job *job,
+ const struct kvmi_msg_hdr *msg,
+ const void *_req)
+{
+ const struct kvmi_vcpu_control_ept_view *req = _req;
+ int ec;
+
+ if (req->padding1 || req->padding2)
+ ec = -KVM_EINVAL;
+ else if (!is_valid_view(req->view))
+ ec = -KVM_EINVAL;
+ else
+ ec = kvmi_arch_cmd_control_ept_view(job->vcpu, req->view,
+ req->visible);
+
+ return kvmi_msg_vcpu_reply(job, msg, ec, NULL, 0);
+}
+
/*
* These functions are executed from the vCPU thread. The receiving thread
* passes the messages using a newly allocated 'struct kvmi_vcpu_msg_job'
@@ -703,6 +721,7 @@ static int(*const msg_vcpu[])(const struct
kvmi_vcpu_msg_job *,
const struct kvmi_msg_hdr *, const void *) = {
[KVMI_EVENT] = handle_vcpu_event_reply,
[KVMI_VCPU_CONTROL_CR] = handle_vcpu_control_cr,
+ [KVMI_VCPU_CONTROL_EPT_VIEW] = handle_vcpu_control_ept_view,
[KVMI_VCPU_CONTROL_EVENTS] = handle_vcpu_control_events,
[KVMI_VCPU_CONTROL_MSR] = handle_vcpu_control_msr,
[KVMI_VCPU_CONTROL_SINGLESTEP] = handle_vcpu_control_singlestep,
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