[PATCH v3 6/6] KVM: selftests: test KVM_GUESTDBG_BLOCKIRQ

Maxim Levitsky
2021-08-11T12:31:09Z

Modify debug_regs test to create a pending interrupt
and see that it is blocked when single stepping is done
with KVM_GUESTDBG_BLOCKIRQ

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
---
.../testing/selftests/kvm/x86_64/debug_regs.c | 24 ++++++++++++++++---
1 file changed, 21 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/kvm/x86_64/debug_regs.c b/tools/testing/selftests/kvm/x86_64/debug_regs.c
index 6097a8283377..5f078db1bcba 100644
--- a/tools/testing/selftests/kvm/x86_64/debug_regs.c
+++ b/tools/testing/selftests/kvm/x86_64/debug_regs.c
@@ -8,12 +8,15 @@
#include <string.h>
#include "kvm_util.h"
#include "processor.h"
+#include "apic.h"

#define VCPU_ID 0

#define DR6_BD (1 << 13)
#define DR7_GD (1 << 13)

+#define IRQ_VECTOR 0xAA
+
/* For testing data access debug BP */
uint32_t guest_value;

@@ -21,6 +24,11 @@ extern unsigned char sw_bp, hw_bp, write_data, ss_start, bd_start;

static void guest_code(void)
{
+ /* Create a pending interrupt on current vCPU */
+ x2apic_enable();
+ x2apic_write_reg(APIC_ICR, APIC_DEST_SELF | APIC_INT_ASSERT |
+ APIC_DM_FIXED | IRQ_VECTOR);
+
/*
* Software BP tests.
*
@@ -38,12 +46,19 @@ static void guest_code(void)
"mov %%rax,%0;\n\t write_data:"
: "=m" (guest_value) : : "rax");

- /* Single step test, covers 2 basic instructions and 2 emulated */
+ /*
+ * Single step test, covers 2 basic instructions and 2 emulated
+ *
+ * Enable interrupts during the single stepping to see that
+ * pending interrupt we raised is not handled due to KVM_GUESTDBG_BLOCKIRQ
+ */
asm volatile("ss_start: "
+ "sti\n\t"
"xor %%eax,%%eax\n\t"
"cpuid\n\t"
"movl $0x1a0,%%ecx\n\t"
"rdmsr\n\t"
+ "cli\n\t"
: : : "eax", "ebx", "ecx", "edx");

/* DR6.BD test */
@@ -72,11 +87,13 @@ int main(void)
uint64_t cmd;
int i;
/* Instruction lengths starting at ss_start */
- int ss_size[4] = {
+ int ss_size[6] = {
+ 1, /* sti*/
2, /* xor */
2, /* cpuid */
5, /* mov */
2, /* rdmsr */
+ 1, /* cli */
};

if (!kvm_check_cap(KVM_CAP_SET_GUEST_DEBUG)) {
@@ -154,7 +171,8 @@ int main(void)
for (i = 0; i < (sizeof(ss_size) / sizeof(ss_size[0])); i++) {
target_rip += ss_size[i];
CLEAR_DEBUG();
- debug.control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_SINGLESTEP;
+ debug.control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_SINGLESTEP |
+ KVM_GUESTDBG_BLOCKIRQ;
debug.arch.debugreg[7] = 0x00000400;
APPLY_DEBUG();
vcpu_run(vm, VCPU_ID);
--
2.26.3