* [kvm-unit-tests PATCH v3 0/3] Add additional testing for routing L2 exceptions
@ 2022-01-19 16:45 Aaron Lewis
2022-01-19 16:45 ` [kvm-unit-tests PATCH v3 1/3] x86: Make exception_mnemonic() visible to the tests Aaron Lewis
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Aaron Lewis @ 2022-01-19 16:45 UTC (permalink / raw)
To: kvm; +Cc: pbonzini, jmattson, seanjc, Aaron Lewis
In a previous series testing was added to verify that when a #PF occured
in L2 the exception was routed to the correct place. In this series
other exceptions are tested (ie: #GP, #UD, #DE, #DB, #BP, #AC).
v2 -> v3:
- Commits 1 and 2 from v2 were accepted upstream (bug fixes).
- Moved exception_mnemonic() into a separate commit.
- Moved support for running a nested guest multiple times in
one test into a separate commit.
- Moved the test framework into the same commit as the test itself.
- Simplified the test framework and test code based on Sean's
recommendations.
v1 -> v2:
- Add guest_stack_top and guest_syscall_stack_top for aligning L2's
stacks.
- Refactor test to make it more extensible (ie: Added
vmx_exception_tests array and framework around it).
- Split test into 2 commits:
1. Test infrustructure.
2. Test cases.
Aaron Lewis (3):
x86: Make exception_mnemonic() visible to the tests
x86: Add support for running a nested guest multiple times in one test
x86: Add test coverage for nested_vmx_reflect_vmexit() testing
lib/x86/desc.c | 2 +-
lib/x86/desc.h | 1 +
x86/unittests.cfg | 7 +++
x86/vmx.c | 24 ++++++++-
x86/vmx.h | 2 +
x86/vmx_tests.c | 129 ++++++++++++++++++++++++++++++++++++++++++++++
6 files changed, 162 insertions(+), 3 deletions(-)
--
2.34.1.703.g22d0c6ccf7-goog
^ permalink raw reply [flat|nested] 4+ messages in thread
* [kvm-unit-tests PATCH v3 1/3] x86: Make exception_mnemonic() visible to the tests
2022-01-19 16:45 [kvm-unit-tests PATCH v3 0/3] Add additional testing for routing L2 exceptions Aaron Lewis
@ 2022-01-19 16:45 ` Aaron Lewis
2022-01-19 16:45 ` [kvm-unit-tests PATCH v3 2/3] x86: Add support for running a nested guest multiple times in one test Aaron Lewis
2022-01-19 16:45 ` [kvm-unit-tests PATCH v3 3/3] x86: Add test coverage for nested_vmx_reflect_vmexit() testing Aaron Lewis
2 siblings, 0 replies; 4+ messages in thread
From: Aaron Lewis @ 2022-01-19 16:45 UTC (permalink / raw)
To: kvm; +Cc: pbonzini, jmattson, seanjc, Aaron Lewis
exception_mnemonic() is a useful function for more than just desc.c.
Make it global, so it can be used in other KUT tests.
Signed-off-by: Aaron Lewis <aaronlewis@google.com>
---
lib/x86/desc.c | 2 +-
lib/x86/desc.h | 1 +
2 files changed, 2 insertions(+), 1 deletion(-)
diff --git a/lib/x86/desc.c b/lib/x86/desc.c
index 16b7256..c2eb16e 100644
--- a/lib/x86/desc.c
+++ b/lib/x86/desc.c
@@ -91,7 +91,7 @@ struct ex_record {
extern struct ex_record exception_table_start, exception_table_end;
-static const char* exception_mnemonic(int vector)
+const char* exception_mnemonic(int vector)
{
switch(vector) {
case 0: return "#DE";
diff --git a/lib/x86/desc.h b/lib/x86/desc.h
index 9b81da0..ad6277b 100644
--- a/lib/x86/desc.h
+++ b/lib/x86/desc.h
@@ -224,6 +224,7 @@ void set_intr_alt_stack(int e, void *fn);
void print_current_tss_info(void);
handler handle_exception(u8 v, handler fn);
void unhandled_exception(struct ex_regs *regs, bool cpu);
+const char* exception_mnemonic(int vector);
bool test_for_exception(unsigned int ex, void (*trigger_func)(void *data),
void *data);
--
2.34.1.703.g22d0c6ccf7-goog
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [kvm-unit-tests PATCH v3 2/3] x86: Add support for running a nested guest multiple times in one test
2022-01-19 16:45 [kvm-unit-tests PATCH v3 0/3] Add additional testing for routing L2 exceptions Aaron Lewis
2022-01-19 16:45 ` [kvm-unit-tests PATCH v3 1/3] x86: Make exception_mnemonic() visible to the tests Aaron Lewis
@ 2022-01-19 16:45 ` Aaron Lewis
2022-01-19 16:45 ` [kvm-unit-tests PATCH v3 3/3] x86: Add test coverage for nested_vmx_reflect_vmexit() testing Aaron Lewis
2 siblings, 0 replies; 4+ messages in thread
From: Aaron Lewis @ 2022-01-19 16:45 UTC (permalink / raw)
To: kvm; +Cc: pbonzini, jmattson, seanjc, Aaron Lewis
KUT has a limit of only being able to run one nested guest per vmx test.
This is limiting and not necessary. Add support for allowing a test to
run guest code multiple times.
Signed-off-by: Aaron Lewis <aaronlewis@google.com>
---
x86/vmx.c | 24 ++++++++++++++++++++++--
x86/vmx.h | 2 ++
2 files changed, 24 insertions(+), 2 deletions(-)
diff --git a/x86/vmx.c b/x86/vmx.c
index f4fbb94..51eed8c 100644
--- a/x86/vmx.c
+++ b/x86/vmx.c
@@ -1884,15 +1884,35 @@ void test_add_teardown(test_teardown_func func, void *data)
step->data = data;
}
+static void __test_set_guest(test_guest_func func)
+{
+ assert(current->v2);
+ v2_guest_main = func;
+}
+
/*
* Set the target of the first enter_guest call. Can only be called once per
* test. Must be called before first enter_guest call.
*/
void test_set_guest(test_guest_func func)
{
- assert(current->v2);
TEST_ASSERT_MSG(!v2_guest_main, "Already set guest func.");
- v2_guest_main = func;
+ __test_set_guest(func);
+}
+
+/*
+ * Set the target of the enter_guest call and reset the RIP so 'func' will
+ * start from the beginning. This can be called multiple times per test.
+ */
+void test_override_guest(test_guest_func func)
+{
+ __test_set_guest(func);
+ init_vmcs_guest();
+}
+
+void test_set_guest_finished(void)
+{
+ guest_finished = 1;
}
static void check_for_guest_termination(union exit_reason exit_reason)
diff --git a/x86/vmx.h b/x86/vmx.h
index 4423986..11cb665 100644
--- a/x86/vmx.h
+++ b/x86/vmx.h
@@ -1055,7 +1055,9 @@ void hypercall(u32 hypercall_no);
typedef void (*test_guest_func)(void);
typedef void (*test_teardown_func)(void *data);
void test_set_guest(test_guest_func func);
+void test_override_guest(test_guest_func func);
void test_add_teardown(test_teardown_func func, void *data);
void test_skip(const char *msg);
+void test_set_guest_finished(void);
#endif
--
2.34.1.703.g22d0c6ccf7-goog
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [kvm-unit-tests PATCH v3 3/3] x86: Add test coverage for nested_vmx_reflect_vmexit() testing
2022-01-19 16:45 [kvm-unit-tests PATCH v3 0/3] Add additional testing for routing L2 exceptions Aaron Lewis
2022-01-19 16:45 ` [kvm-unit-tests PATCH v3 1/3] x86: Make exception_mnemonic() visible to the tests Aaron Lewis
2022-01-19 16:45 ` [kvm-unit-tests PATCH v3 2/3] x86: Add support for running a nested guest multiple times in one test Aaron Lewis
@ 2022-01-19 16:45 ` Aaron Lewis
2 siblings, 0 replies; 4+ messages in thread
From: Aaron Lewis @ 2022-01-19 16:45 UTC (permalink / raw)
To: kvm; +Cc: pbonzini, jmattson, seanjc, Aaron Lewis
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@google.com>
---
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
^ permalink raw reply related [flat|nested] 4+ messages in thread
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2022-01-19 16:45 ` [kvm-unit-tests PATCH v3 1/3] x86: Make exception_mnemonic() visible to the tests Aaron Lewis
2022-01-19 16:45 ` [kvm-unit-tests PATCH v3 2/3] x86: Add support for running a nested guest multiple times in one test Aaron Lewis
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