From: Mihai Donțu <mdontu@xxxxxxxxxxxxxxx>
This event is sent when the extended control register XCR0 is going to
be changed.
Signed-off-by: Mihai Donțu <mdontu@xxxxxxxxxxxxxxx>
Co-developed-by: Nicușor Cîțu <ncitu@xxxxxxxxxxxxxxx>
Signed-off-by: Nicușor Cîțu <ncitu@xxxxxxxxxxxxxxx>
Signed-off-by: Adalbert Lazăr <alazar@xxxxxxxxxxxxxxx>
---
Documentation/virt/kvm/kvmi.rst | 26 ++++++
arch/x86/include/asm/kvmi_host.h | 2 +
arch/x86/kvm/x86.c | 6 ++
include/uapi/linux/kvmi.h | 1 +
.../testing/selftests/kvm/x86_64/kvmi_test.c | 83 +++++++++++++++++++
virt/kvm/introspection/kvmi_int.h | 1 +
virt/kvm/introspection/kvmi_msg.c | 39 +++++++++
7 files changed, 158 insertions(+)
diff --git a/Documentation/virt/kvm/kvmi.rst b/Documentation/virt/kvm/kvmi.rst
index c1badcde1662..8b43e0f80f77 100644
--- a/Documentation/virt/kvm/kvmi.rst
+++ b/Documentation/virt/kvm/kvmi.rst
@@ -534,6 +534,7 @@ the following events::
KVMI_EVENT_CR
KVMI_EVENT_HYPERCALL
KVMI_EVENT_TRAP
+ KVMI_EVENT_XSETBV
When an event is enabled, the introspection tool is notified and it
must reply with: continue, retry, crash, etc. (see **Events** below).
@@ -999,3 +1000,28 @@ took place and the introspection has been enabled for this event
``kvmi_event``, exception/interrupt number (vector), exception code
(``error_code``) and CR2 are sent to the introspection tool,
which should check if its exception has been injected or overridden.
+
+7. KVMI_EVENT_XSETBV
+--------------------
+
+:Architectures: x86
+:Versions: >= 1
+:Actions: CONTINUE, CRASH
+:Parameters:
+
+::
+
+ struct kvmi_event;
+
+:Returns:
+
+::
+
+ struct kvmi_vcpu_hdr;
+ struct kvmi_event_reply;
+
+This event is sent when the extended control register XCR0 is going
+to be changed and the introspection has been enabled for this event
+(see *KVMI_VCPU_CONTROL_EVENTS*).
+
+``kvmi_event`` is sent to the introspection tool.
diff --git a/arch/x86/include/asm/kvmi_host.h b/arch/x86/include/asm/kvmi_host.h
index 24f3f8fdee62..b3fa950362db 100644
--- a/arch/x86/include/asm/kvmi_host.h
+++ b/arch/x86/include/asm/kvmi_host.h
@@ -30,6 +30,7 @@ bool kvmi_cr_event(struct kvm_vcpu *vcpu, unsigned int cr,
unsigned long old_value, unsigned long *new_value);
bool kvmi_cr3_intercepted(struct kvm_vcpu *vcpu);
bool kvmi_monitor_cr3w_intercept(struct kvm_vcpu *vcpu, bool enable);
+void kvmi_xsetbv_event(struct kvm_vcpu *vcpu);
#else /* CONFIG_KVM_INTROSPECTION */
@@ -41,6 +42,7 @@ static inline bool kvmi_cr_event(struct kvm_vcpu *vcpu, unsigned int cr,
static inline bool kvmi_cr3_intercepted(struct kvm_vcpu *vcpu) { return false; }
static inline bool kvmi_monitor_cr3w_intercept(struct kvm_vcpu *vcpu,
bool enable) { return false; }
+static inline void kvmi_xsetbv_event(struct kvm_vcpu *vcpu) { }
#endif /* CONFIG_KVM_INTROSPECTION */
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index ff61123ce4bd..fa583f82298e 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -866,6 +866,12 @@ static int __kvm_set_xcr(struct kvm_vcpu *vcpu, u32 index, u64 xcr)
}
vcpu->arch.xcr0 = xcr0;
+#ifdef CONFIG_KVM_INTROSPECTION
+ if (index == 0 && xcr0 != old_xcr0)
+ kvmi_xsetbv_event(vcpu);
+#endif /* CONFIG_KVM_INTROSPECTION */
+
+
if ((xcr0 ^ old_xcr0) & XFEATURE_MASK_EXTEND)
kvm_update_cpuid(vcpu);
return 0;
diff --git a/include/uapi/linux/kvmi.h b/include/uapi/linux/kvmi.h
index 70d5a67badef..3ea4882ac469 100644
--- a/include/uapi/linux/kvmi.h
+++ b/include/uapi/linux/kvmi.h
@@ -47,6 +47,7 @@ enum {
KVMI_EVENT_BREAKPOINT = 3,
KVMI_EVENT_CR = 4,
KVMI_EVENT_TRAP = 5,
+ KVMI_EVENT_XSETBV = 6,
KVMI_NUM_EVENTS
};
diff --git a/tools/testing/selftests/kvm/x86_64/kvmi_test.c b/tools/testing/selftests/kvm/x86_64/kvmi_test.c
index 2852e6894e81..299f4d29d0d6 100644
--- a/tools/testing/selftests/kvm/x86_64/kvmi_test.c
+++ b/tools/testing/selftests/kvm/x86_64/kvmi_test.c
@@ -21,6 +21,8 @@
#define VCPU_ID 5
+#define X86_FEATURE_XSAVE (1<<26)
+
static int socket_pair[2];
#define Kvm_socket socket_pair[0]
#define Userspace_socket socket_pair[1]
@@ -53,6 +55,7 @@ enum {
GUEST_TEST_BP,
GUEST_TEST_CR,
GUEST_TEST_HYPERCALL,
+ GUEST_TEST_XSETBV,
};
#define GUEST_REQUEST_TEST() GUEST_SYNC(0)
@@ -84,6 +87,45 @@ static void guest_hypercall_test(void)
asm volatile(".byte 0x0f,0x01,0xc1");
}
+/* from fpu/internal.h */
+static u64 xgetbv(u32 index)
+{
+ u32 eax, edx;
+
+ asm volatile(".byte 0x0f,0x01,0xd0" /* xgetbv */
+ : "=a" (eax), "=d" (edx)
+ : "c" (index));
+ return eax + ((u64)edx << 32);
+}
+
+/* from fpu/internal.h */
+static void xsetbv(u32 index, u64 value)
+{
+ u32 eax = value;
+ u32 edx = value >> 32;
+
+ asm volatile(".byte 0x0f,0x01,0xd1" /* xsetbv */
+ : : "a" (eax), "d" (edx), "c" (index));
+}
+
+static void guest_xsetbv_test(void)
+{
+ const int SSE_BIT = 1 << 1;
+ const int AVX_BIT = 1 << 2;
+ u64 xcr0;
+
+ /* avoid #UD */
+ set_cr4(get_cr4() | X86_CR4_OSXSAVE);
+
+ xcr0 = xgetbv(0);
+ if (xcr0 & AVX_BIT)
+ xcr0 &= ~AVX_BIT;
+ else
+ xcr0 |= (AVX_BIT | SSE_BIT);
+
+ xsetbv(0, xcr0);
+}
+
static void guest_code(void)
{
while (true) {
@@ -99,6 +141,9 @@ static void guest_code(void)
case GUEST_TEST_HYPERCALL:
guest_hypercall_test();
break;
+ case GUEST_TEST_XSETBV:
+ guest_xsetbv_test();
+ break;
}
GUEST_SIGNAL_TEST_DONE();
}
@@ -1240,6 +1285,43 @@ static void test_cmd_vm_get_max_gfn(void)
DEBUG("max_gfn: 0x%llx\n", rpl.gfn);
}
+static void test_event_xsetbv(struct kvm_vm *vm)
+{
+ struct vcpu_worker_data data = {
+ .vm = vm,
+ .vcpu_id = VCPU_ID,
+ .test_id = GUEST_TEST_XSETBV,
+ };
+ __u16 event_id = KVMI_EVENT_XSETBV;
+ struct kvm_cpuid_entry2 *entry;
+ struct vcpu_reply rpl = {};
+ struct kvmi_msg_hdr hdr;
+ pthread_t vcpu_thread;
+ struct kvmi_event ev;
+
+ entry = kvm_get_supported_cpuid_entry(1);
+ if (!(entry->ecx & X86_FEATURE_XSAVE)) {
+ DEBUG("XSAVE is not supported, ecx 0x%x, skipping xsetbv test\n",
+ entry->ecx);
+ return;
+ }
+
+ enable_vcpu_event(vm, event_id);
+
+ vcpu_thread = start_vcpu_worker(&data);
+
+ receive_event(&hdr, &ev, sizeof(ev), event_id);
+
+ DEBUG("XSETBV event, rip 0x%llx\n", ev.arch.regs.rip);
+
+ reply_to_event(&hdr, &ev, KVMI_EVENT_ACTION_CONTINUE,
+ &rpl, sizeof(rpl));
+
+ stop_vcpu_worker(vcpu_thread, &data);
+
+ disable_vcpu_event(vm, event_id);
+}
+
static void test_introspection(struct kvm_vm *vm)
{
setup_socket();
@@ -1264,6 +1346,7 @@ static void test_introspection(struct kvm_vm *vm)
test_cmd_vcpu_control_cr(vm);
test_cmd_vcpu_inject_exception(vm);
test_cmd_vm_get_max_gfn();
+ test_event_xsetbv(vm);
unhook_introspection(vm);
}
diff --git a/virt/kvm/introspection/kvmi_int.h b/virt/kvm/introspection/kvmi_int.h
index 65a5801f143c..5a00e38c88cc 100644
--- a/virt/kvm/introspection/kvmi_int.h
+++ b/virt/kvm/introspection/kvmi_int.h
@@ -27,6 +27,7 @@
| BIT(KVMI_EVENT_HYPERCALL) \
| BIT(KVMI_EVENT_TRAP) \
| BIT(KVMI_EVENT_PAUSE_VCPU) \
+ | BIT(KVMI_EVENT_XSETBV) \
)
#define KVMI_KNOWN_EVENTS (KVMI_KNOWN_VM_EVENTS | KVMI_KNOWN_VCPU_EVENTS)
diff --git a/virt/kvm/introspection/kvmi_msg.c b/virt/kvm/introspection/kvmi_msg.c
index 94fab70b56fa..ba2d7c6acb22 100644
--- a/virt/kvm/introspection/kvmi_msg.c
+++ b/virt/kvm/introspection/kvmi_msg.c
@@ -956,3 +956,42 @@ u32 kvmi_msg_send_bp(struct kvm_vcpu *vcpu, u64 gpa, u8 insn_len)
return action;
}
+
+static u32 kvmi_send_xsetbv(struct kvm_vcpu *vcpu)
+{
+ int err, action;
+
+ err = kvmi_send_event(vcpu, KVMI_EVENT_XSETBV, NULL, 0,
+ NULL, 0, &action);
+ if (err)
+ return KVMI_EVENT_ACTION_CONTINUE;
+
+ return action;
+}
+
+static void __kvmi_xsetbv_event(struct kvm_vcpu *vcpu)
+{
+ u32 action;
+
+ action = kvmi_send_xsetbv(vcpu);
+ switch (action) {
+ case KVMI_EVENT_ACTION_CONTINUE:
+ break;
+ default:
+ kvmi_handle_common_event_actions(vcpu->kvm, action, "XSETBV");
+ }
+}
+
+void kvmi_xsetbv_event(struct kvm_vcpu *vcpu)
+{
+ struct kvm_introspection *kvmi;
+
+ kvmi = kvmi_get(vcpu->kvm);
+ if (!kvmi)
+ return;
+
+ if (is_event_enabled(vcpu, KVMI_EVENT_XSETBV))
+ __kvmi_xsetbv_event(vcpu);
+
+ kvmi_put(vcpu->kvm);
+}
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