Add a framework and test cases to ensure exceptions that occur in L2 are
forwarded to the correct place by nested_vmx_reflect_vmexit().
Add testing for exceptions: #GP, #UD, #DE, #DB, #BP, and #AC.
Signed-off-by: Aaron Lewis <aaronlewis@xxxxxxxxxx>
---
x86/unittests.cfg | 7 +++
x86/vmx_tests.c | 129 ++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 136 insertions(+)
diff --git a/x86/unittests.cfg b/x86/unittests.cfg
index 9a70ba3..8399b05 100644
--- a/x86/unittests.cfg
+++ b/x86/unittests.cfg
@@ -390,6 +390,13 @@ arch = x86_64
groups = vmx nested_exception
check = /sys/module/kvm_intel/parameters/allow_smaller_maxphyaddr=Y
+[vmx_exception_test]
+file = vmx.flat
+extra_params = -cpu max,+vmx -append vmx_exception_test
+arch = x86_64
+groups = vmx nested_exception
+timeout = 10
+
[debug]
file = debug.flat
arch = x86_64
diff --git a/x86/vmx_tests.c b/x86/vmx_tests.c
index 3d57ed6..af6f33b 100644
--- a/x86/vmx_tests.c
+++ b/x86/vmx_tests.c
@@ -21,6 +21,7 @@
#include "smp.h"
#include "delay.h"
#include "access.h"
+#include "x86/usermode.h"
#define VPID_CAP_INVVPID_TYPES_SHIFT 40
@@ -10701,6 +10702,133 @@ static void vmx_pf_vpid_test(void)
__vmx_pf_vpid_test(invalidate_tlb_new_vpid, 1);
}
+static void vmx_l2_gp_test(void)
+{
+ *(volatile u64 *)NONCANONICAL = 0;
+}
+
+static void vmx_l2_ud_test(void)
+{
+ asm volatile ("ud2");
+}
+
+static void vmx_l2_de_test(void)
+{
+ asm volatile (
+ "xor %%eax, %%eax\n\t"
+ "xor %%ebx, %%ebx\n\t"
+ "xor %%edx, %%edx\n\t"
+ "idiv %%ebx\n\t"
+ ::: "eax", "ebx", "edx");
+}
+
+static void vmx_l2_bp_test(void)
+{
+ asm volatile ("int3");
+}
+
+static void vmx_l2_db_test(void)
+{
+ write_rflags(read_rflags() | X86_EFLAGS_TF);
+}
+
+static uint64_t usermode_callback(void)
+{
+ /* Trigger an #AC by writing 8 bytes to a 4-byte aligned address. */
+ asm volatile(
+ "sub $0x10, %rsp\n\t"
+ "movq $0, 0x4(%rsp)\n\t"
+ "add $0x10, %rsp\n\t");
+
+ return 0;
+}
+
+static void vmx_l2_ac_test(void)
+{
+ bool raised_vector = false;
+
+ write_cr0(read_cr0() | X86_CR0_AM);
+ write_rflags(read_rflags() | X86_EFLAGS_AC);
+
+ run_in_user(usermode_callback, AC_VECTOR, 0, 0, 0, 0, &raised_vector);
+ report(raised_vector, "#AC vector raised from usermode in L2");
+ vmcall();
+}
+
+struct vmx_exception_test {
+ u8 vector;
+ void (*guest_code)(void);
+};
+
+struct vmx_exception_test vmx_exception_tests[] = {
+ { GP_VECTOR, vmx_l2_gp_test },
+ { UD_VECTOR, vmx_l2_ud_test },
+ { DE_VECTOR, vmx_l2_de_test },
+ { DB_VECTOR, vmx_l2_db_test },
+ { BP_VECTOR, vmx_l2_bp_test },
+ { AC_VECTOR, vmx_l2_ac_test },
+};
+
+static u8 vmx_exception_test_vector;
+
+static void vmx_exception_handler(struct ex_regs *regs)
+{
+ report(regs->vector == vmx_exception_test_vector,
+ "Handling %s in L2's exception handler",
+ exception_mnemonic(vmx_exception_test_vector));
+ vmcall();
+}
+
+static void handle_exception_in_l2(u8 vector)
+{
+ handler old_handler = handle_exception(vector, vmx_exception_handler);
+
+ vmx_exception_test_vector = vector;
+
+ enter_guest();
+ report(vmcs_read(EXI_REASON) == VMX_VMCALL,
+ "%s handled by L2", exception_mnemonic(vector));
+
+ handle_exception(vector, old_handler);
+}
+
+static void handle_exception_in_l1(u32 vector)
+{
+ u32 old_eb = vmcs_read(EXC_BITMAP);
+
+ vmcs_write(EXC_BITMAP, old_eb | (1u << vector));
+
+ enter_guest();
+
+ report((vmcs_read(EXI_REASON) == VMX_EXC_NMI) &&
+ ((vmcs_read(EXI_INTR_INFO) & 0xff) == vector),
+ "%s handled by L1", exception_mnemonic(vector));
+
+ vmcs_write(EXC_BITMAP, old_eb);
+}
+
+static void vmx_exception_test(void)
+{
+ struct vmx_exception_test *t;
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(vmx_exception_tests); i++) {
+ t = &vmx_exception_tests[i];
+
+ /*
+ * Override the guest code before each run even though it's the
+ * same code, the VMCS guest state needs to be reinitialized.
+ */
+ test_override_guest(t->guest_code);
+ handle_exception_in_l2(t->vector);
+
+ test_override_guest(t->guest_code);
+ handle_exception_in_l1(t->vector);
+ }
+
+ test_set_guest_finished();
+}
+
#define TEST(name) { #name, .v2 = name }
/* name/init/guest_main/exit_handler/syscall_handler/guest_regs */
@@ -10810,5 +10938,6 @@ struct vmx_test vmx_tests[] = {
TEST(vmx_pf_no_vpid_test),
TEST(vmx_pf_invvpid_test),
TEST(vmx_pf_vpid_test),
+ TEST(vmx_exception_test),
{ NULL, NULL, NULL, NULL, NULL, {0} },
};
--
2.34.1.703.g22d0c6ccf7-goog
