diff mbox series

[kvm-unit-tests,v2] x86: vmx: Add test for SIPI signal processing

Message ID 20201013052845.249113-1-yadong.qi@intel.com (mailing list archive)
State New, archived
Headers show
Series [kvm-unit-tests,v2] x86: vmx: Add test for SIPI signal processing | expand

Commit Message

Qi, Yadong Oct. 13, 2020, 5:28 a.m. UTC
From: Yadong Qi <yadong.qi@intel.com>

The test verifies the following functionality:
A SIPI signal received when CPU is in VMX non-root mode:
    if ACTIVITY_STATE == WAIT_SIPI
        VMExit with (reason == 4)
    else
        SIPI signal is ignored

The test cases depends on IA32_VMX_MISC:bit(8), if this bit is 1
then the test cases would be executed, otherwise the test cases
would be skiped.

Signed-off-by: Yadong Qi <yadong.qi@intel.com>
---
v1->v2:
 * update CR3 on AP

---
 lib/x86/msr.h       |   1 +
 lib/x86/processor.h |   5 ++
 x86/apic.c          |   5 --
 x86/ioapic.c        |   5 --
 x86/unittests.cfg   |   8 +++
 x86/vmx.c           |   2 +-
 x86/vmx.h           |   3 +
 x86/vmx_tests.c     | 138 ++++++++++++++++++++++++++++++++++++++++++++
 8 files changed, 156 insertions(+), 11 deletions(-)

Comments

Paolo Bonzini Oct. 31, 2020, 2:37 p.m. UTC | #1
On 13/10/20 07:28, yadong.qi@intel.com wrote:
> From: Yadong Qi <yadong.qi@intel.com>
> 
> The test verifies the following functionality:
> A SIPI signal received when CPU is in VMX non-root mode:
>     if ACTIVITY_STATE == WAIT_SIPI
>         VMExit with (reason == 4)
>     else
>         SIPI signal is ignored
> 
> The test cases depends on IA32_VMX_MISC:bit(8), if this bit is 1
> then the test cases would be executed, otherwise the test cases
> would be skiped.
> 
> Signed-off-by: Yadong Qi <yadong.qi@intel.com>
> ---
> v1->v2:
>  * update CR3 on AP
> 
> ---
>  lib/x86/msr.h       |   1 +
>  lib/x86/processor.h |   5 ++
>  x86/apic.c          |   5 --
>  x86/ioapic.c        |   5 --
>  x86/unittests.cfg   |   8 +++
>  x86/vmx.c           |   2 +-
>  x86/vmx.h           |   3 +
>  x86/vmx_tests.c     | 138 ++++++++++++++++++++++++++++++++++++++++++++
>  8 files changed, 156 insertions(+), 11 deletions(-)
> 
> diff --git a/lib/x86/msr.h b/lib/x86/msr.h
> index 6ef5502..29e3947 100644
> --- a/lib/x86/msr.h
> +++ b/lib/x86/msr.h
> @@ -421,6 +421,7 @@
>  #define MSR_IA32_VMX_TRUE_ENTRY		0x00000490
>  
>  /* MSR_IA32_VMX_MISC bits */
> +#define MSR_IA32_VMX_MISC_ACTIVITY_WAIT_SIPI		(1ULL << 8)
>  #define MSR_IA32_VMX_MISC_VMWRITE_SHADOW_RO_FIELDS	(1ULL << 29)
>  
>  #define MSR_IA32_TSCDEADLINE		0x000006e0
> diff --git a/lib/x86/processor.h b/lib/x86/processor.h
> index c2c487c..849554f 100644
> --- a/lib/x86/processor.h
> +++ b/lib/x86/processor.h
> @@ -359,6 +359,11 @@ static inline ulong read_cr3(void)
>      return val;
>  }
>  
> +static inline void update_cr3(void *cr3)
> +{
> +    write_cr3((ulong)cr3);
> +}
> +
>  static inline void write_cr4(ulong val)
>  {
>      asm volatile ("mov %0, %%cr4" : : "r"(val) : "memory");
> diff --git a/x86/apic.c b/x86/apic.c
> index a7681fe..b57345b 100644
> --- a/x86/apic.c
> +++ b/x86/apic.c
> @@ -318,11 +318,6 @@ static void nmi_handler(isr_regs_t *regs)
>      nmi_hlt_counter += regs->rip == (ulong)post_sti;
>  }
>  
> -static void update_cr3(void *cr3)
> -{
> -    write_cr3((ulong)cr3);
> -}
> -
>  static void test_sti_nmi(void)
>  {
>      unsigned old_counter;
> diff --git a/x86/ioapic.c b/x86/ioapic.c
> index b9f6dd2..7cbccd7 100644
> --- a/x86/ioapic.c
> +++ b/x86/ioapic.c
> @@ -463,11 +463,6 @@ static void test_ioapic_logical_destination_mode(void)
>  	report(g_isr_86 == nr_vcpus, "ioapic logical destination mode");
>  }
>  
> -static void update_cr3(void *cr3)
> -{
> -	write_cr3((ulong)cr3);
> -}
> -
>  int main(void)
>  {
>  	setup_vm();
> diff --git a/x86/unittests.cfg b/x86/unittests.cfg
> index 872d679..c035c79 100644
> --- a/x86/unittests.cfg
> +++ b/x86/unittests.cfg
> @@ -305,6 +305,14 @@ arch = x86_64
>  groups = vmx
>  timeout = 10
>  
> +[vmx_sipi_signal_test]
> +file = vmx.flat
> +smp = 2
> +extra_params = -cpu host,+vmx -m 2048 -append vmx_sipi_signal_test
> +arch = x86_64
> +groups = vmx
> +timeout = 10
> +
>  [vmx_apic_passthrough_tpr_threshold_test]
>  file = vmx.flat
>  extra_params = -cpu host,+vmx -m 2048 -append vmx_apic_passthrough_tpr_threshold_test
> diff --git a/x86/vmx.c b/x86/vmx.c
> index 1a84a74..f0b853a 100644
> --- a/x86/vmx.c
> +++ b/x86/vmx.c
> @@ -1369,7 +1369,7 @@ static void init_vmcs_guest(void)
>  	vmcs_write(GUEST_INTR_STATE, 0);
>  }
>  
> -static int init_vmcs(struct vmcs **vmcs)
> +int init_vmcs(struct vmcs **vmcs)
>  {
>  	*vmcs = alloc_page();
>  	(*vmcs)->hdr.revision_id = basic.revision;
> diff --git a/x86/vmx.h b/x86/vmx.h
> index e29301e..7e39b84 100644
> --- a/x86/vmx.h
> +++ b/x86/vmx.h
> @@ -697,6 +697,8 @@ enum vm_entry_failure_code {
>  
>  #define ACTV_ACTIVE		0
>  #define ACTV_HLT		1
> +#define ACTV_SHUTDOWN		2
> +#define ACTV_WAIT_SIPI		3
>  
>  /*
>   * VMCS field encoding:
> @@ -856,6 +858,7 @@ static inline bool invvpid(unsigned long type, u64 vpid, u64 gla)
>  
>  void enable_vmx(void);
>  void init_vmx(u64 *vmxon_region);
> +int init_vmcs(struct vmcs **vmcs);
>  
>  const char *exit_reason_description(u64 reason);
>  void print_vmexit_info(union exit_reason exit_reason);
> diff --git a/x86/vmx_tests.c b/x86/vmx_tests.c
> index d2084ae..4e8215e 100644
> --- a/x86/vmx_tests.c
> +++ b/x86/vmx_tests.c
> @@ -9855,6 +9855,143 @@ static void vmx_init_signal_test(void)
>  	 */
>  }
>  
> +#define SIPI_SIGNAL_TEST_DELAY	100000000ULL
> +
> +static void vmx_sipi_test_guest(void)
> +{
> +	if (apic_id() == 0) {
> +		/* wait AP enter guest with activity=WAIT_SIPI */
> +		while (vmx_get_test_stage() != 1)
> +			;
> +		delay(SIPI_SIGNAL_TEST_DELAY);
> +
> +		/* First SIPI signal */
> +		apic_icr_write(APIC_DEST_PHYSICAL | APIC_DM_STARTUP | APIC_INT_ASSERT, id_map[1]);
> +		report(1, "BSP(L2): Send first SIPI to cpu[%d]", id_map[1]);
> +
> +		/* wait AP enter guest */
> +		while (vmx_get_test_stage() != 2)
> +			;
> +		delay(SIPI_SIGNAL_TEST_DELAY);
> +
> +		/* Second SIPI signal should be ignored since AP is not in WAIT_SIPI state */
> +		apic_icr_write(APIC_DEST_PHYSICAL | APIC_DM_STARTUP | APIC_INT_ASSERT, id_map[1]);
> +		report(1, "BSP(L2): Send second SIPI to cpu[%d]", id_map[1]);
> +
> +		/* Delay a while to check whether second SIPI would cause VMExit */
> +		delay(SIPI_SIGNAL_TEST_DELAY);
> +
> +		/* Test is done, notify AP to exit test */
> +		vmx_set_test_stage(3);
> +
> +		/* wait AP exit non-root mode */
> +		while (vmx_get_test_stage() != 5)
> +			;
> +	} else {
> +		/* wait BSP notify test is done */
> +		while (vmx_get_test_stage() != 3)
> +			;
> +
> +		/* AP exit guest */
> +		vmx_set_test_stage(4);
> +	}
> +}
> +
> +static void sipi_test_ap_thread(void *data)
> +{
> +	struct vmcs *ap_vmcs;
> +	u64 *ap_vmxon_region;
> +	void *ap_stack, *ap_syscall_stack;
> +	u64 cpu_ctrl_0 = CPU_SECONDARY;
> +	u64 cpu_ctrl_1 = 0;
> +
> +	/* Enter VMX operation (i.e. exec VMXON) */
> +	ap_vmxon_region = alloc_page();
> +	enable_vmx();
> +	init_vmx(ap_vmxon_region);
> +	_vmx_on(ap_vmxon_region);
> +	init_vmcs(&ap_vmcs);
> +	make_vmcs_current(ap_vmcs);
> +
> +	/* Set stack for AP */
> +	ap_stack = alloc_page();
> +	ap_syscall_stack = alloc_page();
> +	vmcs_write(GUEST_RSP, (u64)(ap_stack + PAGE_SIZE - 1));
> +	vmcs_write(GUEST_SYSENTER_ESP, (u64)(ap_syscall_stack + PAGE_SIZE - 1));
> +
> +	/* passthrough lapic to L2 */
> +	disable_intercept_for_x2apic_msrs();
> +	vmcs_write(PIN_CONTROLS, vmcs_read(PIN_CONTROLS) & ~PIN_EXTINT);
> +	vmcs_write(CPU_EXEC_CTRL0, vmcs_read(CPU_EXEC_CTRL0) | cpu_ctrl_0);
> +	vmcs_write(CPU_EXEC_CTRL1, vmcs_read(CPU_EXEC_CTRL1) | cpu_ctrl_1);
> +
> +	/* Set guest activity state to wait-for-SIPI state */
> +	vmcs_write(GUEST_ACTV_STATE, ACTV_WAIT_SIPI);
> +
> +	vmx_set_test_stage(1);
> +
> +	/* AP enter guest */
> +	enter_guest();
> +
> +	if (vmcs_read(EXI_REASON) == VMX_SIPI) {
> +		report(1, "AP: Handle SIPI VMExit");
> +		vmcs_write(GUEST_ACTV_STATE, ACTV_ACTIVE);
> +		vmx_set_test_stage(2);
> +	} else {
> +		report(0, "AP: Unexpected VMExit, reason=%ld", vmcs_read(EXI_REASON));
> +		vmx_off();
> +		return;
> +	}
> +
> +	/* AP enter guest */
> +	enter_guest();
> +
> +	report(vmcs_read(EXI_REASON) != VMX_SIPI,
> +		"AP: should no SIPI VMExit since activity is not in WAIT_SIPI state");
> +
> +	/* notify BSP that AP is already exit from non-root mode */
> +	vmx_set_test_stage(5);
> +
> +	/* Leave VMX operation */
> +	vmx_off();
> +}
> +
> +static void vmx_sipi_signal_test(void)
> +{
> +	if (!(rdmsr(MSR_IA32_VMX_MISC) & MSR_IA32_VMX_MISC_ACTIVITY_WAIT_SIPI)) {
> +		printf("\tACTIVITY_WAIT_SIPI state is not supported.\n");
> +		return;
> +	}
> +
> +	if (cpu_count() < 2) {
> +		report_skip(__func__);
> +		return;
> +	}
> +
> +	u64 cpu_ctrl_0 = CPU_SECONDARY;
> +	u64 cpu_ctrl_1 = 0;
> +
> +	/* passthrough lapic to L2 */
> +	disable_intercept_for_x2apic_msrs();
> +	vmcs_write(PIN_CONTROLS, vmcs_read(PIN_CONTROLS) & ~PIN_EXTINT);
> +	vmcs_write(CPU_EXEC_CTRL0, vmcs_read(CPU_EXEC_CTRL0) | cpu_ctrl_0);
> +	vmcs_write(CPU_EXEC_CTRL1, vmcs_read(CPU_EXEC_CTRL1) | cpu_ctrl_1);
> +
> +	test_set_guest(vmx_sipi_test_guest);
> +
> +	/* update CR3 on AP */
> +	on_cpu(1, update_cr3, (void *)read_cr3());
> +
> +	/* start AP */
> +	on_cpu_async(1, sipi_test_ap_thread, NULL);
> +
> +	vmx_set_test_stage(0);
> +
> +	/* BSP enter guest */
> +	enter_guest();
> +}
> +
> +
>  enum vmcs_access {
>  	ACCESS_VMREAD,
>  	ACCESS_VMWRITE,
> @@ -10492,6 +10629,7 @@ struct vmx_test vmx_tests[] = {
>  	TEST(vmx_apic_passthrough_thread_test),
>  	TEST(vmx_apic_passthrough_tpr_threshold_test),
>  	TEST(vmx_init_signal_test),
> +	TEST(vmx_sipi_signal_test),
>  	/* VMCS Shadowing tests */
>  	TEST(vmx_vmcs_shadow_test),
>  	/* Regression tests */
> 

Queued, thanks.

Paolo
diff mbox series

Patch

diff --git a/lib/x86/msr.h b/lib/x86/msr.h
index 6ef5502..29e3947 100644
--- a/lib/x86/msr.h
+++ b/lib/x86/msr.h
@@ -421,6 +421,7 @@ 
 #define MSR_IA32_VMX_TRUE_ENTRY		0x00000490
 
 /* MSR_IA32_VMX_MISC bits */
+#define MSR_IA32_VMX_MISC_ACTIVITY_WAIT_SIPI		(1ULL << 8)
 #define MSR_IA32_VMX_MISC_VMWRITE_SHADOW_RO_FIELDS	(1ULL << 29)
 
 #define MSR_IA32_TSCDEADLINE		0x000006e0
diff --git a/lib/x86/processor.h b/lib/x86/processor.h
index c2c487c..849554f 100644
--- a/lib/x86/processor.h
+++ b/lib/x86/processor.h
@@ -359,6 +359,11 @@  static inline ulong read_cr3(void)
     return val;
 }
 
+static inline void update_cr3(void *cr3)
+{
+    write_cr3((ulong)cr3);
+}
+
 static inline void write_cr4(ulong val)
 {
     asm volatile ("mov %0, %%cr4" : : "r"(val) : "memory");
diff --git a/x86/apic.c b/x86/apic.c
index a7681fe..b57345b 100644
--- a/x86/apic.c
+++ b/x86/apic.c
@@ -318,11 +318,6 @@  static void nmi_handler(isr_regs_t *regs)
     nmi_hlt_counter += regs->rip == (ulong)post_sti;
 }
 
-static void update_cr3(void *cr3)
-{
-    write_cr3((ulong)cr3);
-}
-
 static void test_sti_nmi(void)
 {
     unsigned old_counter;
diff --git a/x86/ioapic.c b/x86/ioapic.c
index b9f6dd2..7cbccd7 100644
--- a/x86/ioapic.c
+++ b/x86/ioapic.c
@@ -463,11 +463,6 @@  static void test_ioapic_logical_destination_mode(void)
 	report(g_isr_86 == nr_vcpus, "ioapic logical destination mode");
 }
 
-static void update_cr3(void *cr3)
-{
-	write_cr3((ulong)cr3);
-}
-
 int main(void)
 {
 	setup_vm();
diff --git a/x86/unittests.cfg b/x86/unittests.cfg
index 872d679..c035c79 100644
--- a/x86/unittests.cfg
+++ b/x86/unittests.cfg
@@ -305,6 +305,14 @@  arch = x86_64
 groups = vmx
 timeout = 10
 
+[vmx_sipi_signal_test]
+file = vmx.flat
+smp = 2
+extra_params = -cpu host,+vmx -m 2048 -append vmx_sipi_signal_test
+arch = x86_64
+groups = vmx
+timeout = 10
+
 [vmx_apic_passthrough_tpr_threshold_test]
 file = vmx.flat
 extra_params = -cpu host,+vmx -m 2048 -append vmx_apic_passthrough_tpr_threshold_test
diff --git a/x86/vmx.c b/x86/vmx.c
index 1a84a74..f0b853a 100644
--- a/x86/vmx.c
+++ b/x86/vmx.c
@@ -1369,7 +1369,7 @@  static void init_vmcs_guest(void)
 	vmcs_write(GUEST_INTR_STATE, 0);
 }
 
-static int init_vmcs(struct vmcs **vmcs)
+int init_vmcs(struct vmcs **vmcs)
 {
 	*vmcs = alloc_page();
 	(*vmcs)->hdr.revision_id = basic.revision;
diff --git a/x86/vmx.h b/x86/vmx.h
index e29301e..7e39b84 100644
--- a/x86/vmx.h
+++ b/x86/vmx.h
@@ -697,6 +697,8 @@  enum vm_entry_failure_code {
 
 #define ACTV_ACTIVE		0
 #define ACTV_HLT		1
+#define ACTV_SHUTDOWN		2
+#define ACTV_WAIT_SIPI		3
 
 /*
  * VMCS field encoding:
@@ -856,6 +858,7 @@  static inline bool invvpid(unsigned long type, u64 vpid, u64 gla)
 
 void enable_vmx(void);
 void init_vmx(u64 *vmxon_region);
+int init_vmcs(struct vmcs **vmcs);
 
 const char *exit_reason_description(u64 reason);
 void print_vmexit_info(union exit_reason exit_reason);
diff --git a/x86/vmx_tests.c b/x86/vmx_tests.c
index d2084ae..4e8215e 100644
--- a/x86/vmx_tests.c
+++ b/x86/vmx_tests.c
@@ -9855,6 +9855,143 @@  static void vmx_init_signal_test(void)
 	 */
 }
 
+#define SIPI_SIGNAL_TEST_DELAY	100000000ULL
+
+static void vmx_sipi_test_guest(void)
+{
+	if (apic_id() == 0) {
+		/* wait AP enter guest with activity=WAIT_SIPI */
+		while (vmx_get_test_stage() != 1)
+			;
+		delay(SIPI_SIGNAL_TEST_DELAY);
+
+		/* First SIPI signal */
+		apic_icr_write(APIC_DEST_PHYSICAL | APIC_DM_STARTUP | APIC_INT_ASSERT, id_map[1]);
+		report(1, "BSP(L2): Send first SIPI to cpu[%d]", id_map[1]);
+
+		/* wait AP enter guest */
+		while (vmx_get_test_stage() != 2)
+			;
+		delay(SIPI_SIGNAL_TEST_DELAY);
+
+		/* Second SIPI signal should be ignored since AP is not in WAIT_SIPI state */
+		apic_icr_write(APIC_DEST_PHYSICAL | APIC_DM_STARTUP | APIC_INT_ASSERT, id_map[1]);
+		report(1, "BSP(L2): Send second SIPI to cpu[%d]", id_map[1]);
+
+		/* Delay a while to check whether second SIPI would cause VMExit */
+		delay(SIPI_SIGNAL_TEST_DELAY);
+
+		/* Test is done, notify AP to exit test */
+		vmx_set_test_stage(3);
+
+		/* wait AP exit non-root mode */
+		while (vmx_get_test_stage() != 5)
+			;
+	} else {
+		/* wait BSP notify test is done */
+		while (vmx_get_test_stage() != 3)
+			;
+
+		/* AP exit guest */
+		vmx_set_test_stage(4);
+	}
+}
+
+static void sipi_test_ap_thread(void *data)
+{
+	struct vmcs *ap_vmcs;
+	u64 *ap_vmxon_region;
+	void *ap_stack, *ap_syscall_stack;
+	u64 cpu_ctrl_0 = CPU_SECONDARY;
+	u64 cpu_ctrl_1 = 0;
+
+	/* Enter VMX operation (i.e. exec VMXON) */
+	ap_vmxon_region = alloc_page();
+	enable_vmx();
+	init_vmx(ap_vmxon_region);
+	_vmx_on(ap_vmxon_region);
+	init_vmcs(&ap_vmcs);
+	make_vmcs_current(ap_vmcs);
+
+	/* Set stack for AP */
+	ap_stack = alloc_page();
+	ap_syscall_stack = alloc_page();
+	vmcs_write(GUEST_RSP, (u64)(ap_stack + PAGE_SIZE - 1));
+	vmcs_write(GUEST_SYSENTER_ESP, (u64)(ap_syscall_stack + PAGE_SIZE - 1));
+
+	/* passthrough lapic to L2 */
+	disable_intercept_for_x2apic_msrs();
+	vmcs_write(PIN_CONTROLS, vmcs_read(PIN_CONTROLS) & ~PIN_EXTINT);
+	vmcs_write(CPU_EXEC_CTRL0, vmcs_read(CPU_EXEC_CTRL0) | cpu_ctrl_0);
+	vmcs_write(CPU_EXEC_CTRL1, vmcs_read(CPU_EXEC_CTRL1) | cpu_ctrl_1);
+
+	/* Set guest activity state to wait-for-SIPI state */
+	vmcs_write(GUEST_ACTV_STATE, ACTV_WAIT_SIPI);
+
+	vmx_set_test_stage(1);
+
+	/* AP enter guest */
+	enter_guest();
+
+	if (vmcs_read(EXI_REASON) == VMX_SIPI) {
+		report(1, "AP: Handle SIPI VMExit");
+		vmcs_write(GUEST_ACTV_STATE, ACTV_ACTIVE);
+		vmx_set_test_stage(2);
+	} else {
+		report(0, "AP: Unexpected VMExit, reason=%ld", vmcs_read(EXI_REASON));
+		vmx_off();
+		return;
+	}
+
+	/* AP enter guest */
+	enter_guest();
+
+	report(vmcs_read(EXI_REASON) != VMX_SIPI,
+		"AP: should no SIPI VMExit since activity is not in WAIT_SIPI state");
+
+	/* notify BSP that AP is already exit from non-root mode */
+	vmx_set_test_stage(5);
+
+	/* Leave VMX operation */
+	vmx_off();
+}
+
+static void vmx_sipi_signal_test(void)
+{
+	if (!(rdmsr(MSR_IA32_VMX_MISC) & MSR_IA32_VMX_MISC_ACTIVITY_WAIT_SIPI)) {
+		printf("\tACTIVITY_WAIT_SIPI state is not supported.\n");
+		return;
+	}
+
+	if (cpu_count() < 2) {
+		report_skip(__func__);
+		return;
+	}
+
+	u64 cpu_ctrl_0 = CPU_SECONDARY;
+	u64 cpu_ctrl_1 = 0;
+
+	/* passthrough lapic to L2 */
+	disable_intercept_for_x2apic_msrs();
+	vmcs_write(PIN_CONTROLS, vmcs_read(PIN_CONTROLS) & ~PIN_EXTINT);
+	vmcs_write(CPU_EXEC_CTRL0, vmcs_read(CPU_EXEC_CTRL0) | cpu_ctrl_0);
+	vmcs_write(CPU_EXEC_CTRL1, vmcs_read(CPU_EXEC_CTRL1) | cpu_ctrl_1);
+
+	test_set_guest(vmx_sipi_test_guest);
+
+	/* update CR3 on AP */
+	on_cpu(1, update_cr3, (void *)read_cr3());
+
+	/* start AP */
+	on_cpu_async(1, sipi_test_ap_thread, NULL);
+
+	vmx_set_test_stage(0);
+
+	/* BSP enter guest */
+	enter_guest();
+}
+
+
 enum vmcs_access {
 	ACCESS_VMREAD,
 	ACCESS_VMWRITE,
@@ -10492,6 +10629,7 @@  struct vmx_test vmx_tests[] = {
 	TEST(vmx_apic_passthrough_thread_test),
 	TEST(vmx_apic_passthrough_tpr_threshold_test),
 	TEST(vmx_init_signal_test),
+	TEST(vmx_sipi_signal_test),
 	/* VMCS Shadowing tests */
 	TEST(vmx_vmcs_shadow_test),
 	/* Regression tests */