If a guest blocks interrupts for the entirety of running in root mode
(RFLAGS.IF=0), a pending interrupt corresponding to the posted-interrupt
vector set in the VMCS should result in an interrupt posting to the vIRR
at VM-entry. However, on KVM this is not the case. The pending interrupt
is not recognized as the posted-interrupt vector and instead results in
an external interrupt VM-exit.
Add a regression test to exercise this issue.
Signed-off-by: Oliver Upton <oupton@xxxxxxxxxx>
---
lib/x86/asm/bitops.h | 8 +++++
x86/vmx_tests.c | 76 ++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 84 insertions(+)
diff --git a/lib/x86/asm/bitops.h b/lib/x86/asm/bitops.h
index 13a25ec9853d..ce5743538f65 100644
--- a/lib/x86/asm/bitops.h
+++ b/lib/x86/asm/bitops.h
@@ -13,4 +13,12 @@
#define HAVE_BUILTIN_FLS 1
+static inline void test_and_set_bit(long nr, unsigned long *addr)
+{
+ asm volatile("lock; bts %1, %0"
+ : "+m" (*addr)
+ : "Ir" (nr)
+ : "memory");
+}
+
#endif
diff --git a/x86/vmx_tests.c b/x86/vmx_tests.c
index d2084ae9e8ce..9ba9a5d452a2 100644
--- a/x86/vmx_tests.c
+++ b/x86/vmx_tests.c
@@ -10430,6 +10430,81 @@ static void atomic_switch_overflow_msrs_test(void)
test_skip("Test is only supported on KVM");
}
+#define PI_VECTOR 0xe0
+#define PI_TEST_VECTOR 0x21
+
+static void enable_posted_interrupts(void)
+{
+ void *pi_desc = alloc_page();
+
+ vmcs_set_bits(PIN_CONTROLS, PIN_POST_INTR);
+ vmcs_set_bits(EXI_CONTROLS, EXI_INTA);
+ vmcs_write(PINV, PI_VECTOR);
+ vmcs_write(POSTED_INTR_DESC_ADDR, (u64)pi_desc);
+}
+
+static unsigned long *get_pi_desc(void)
+{
+ return (unsigned long *)vmcs_read(POSTED_INTR_DESC_ADDR);
+}
+
+static void post_interrupt(u8 vector, u32 dest)
+{
+ unsigned long *pi_desc = get_pi_desc();
+
+ test_and_set_bit(vector, pi_desc);
+ test_and_set_bit(256, pi_desc);
+ apic_icr_write(PI_VECTOR, dest);
+}
+
+static struct vmx_posted_interrupt_test_args {
+ bool isr_fired;
+} vmx_posted_interrupt_test_args;
+
+static void vmx_posted_interrupt_test_isr(isr_regs_t *regs)
+{
+ volatile struct vmx_posted_interrupt_test_args *args
+ = &vmx_posted_interrupt_test_args;
+
+ args->isr_fired = true;
+ eoi();
+}
+
+static void vmx_posted_interrupt_test_guest(void)
+{
+ handle_irq(PI_TEST_VECTOR, vmx_posted_interrupt_test_isr);
+ irq_enable();
+ vmcall();
+ asm volatile("nop");
+ vmcall();
+}
+
+static void vmx_posted_interrupt_test(void)
+{
+ volatile struct vmx_posted_interrupt_test_args *args
+ = &vmx_posted_interrupt_test_args;
+
+ if (!cpu_has_apicv()) {
+ report_skip(__func__);
+ return;
+ }
+
+ enable_vid();
+ enable_posted_interrupts();
+ test_set_guest(vmx_posted_interrupt_test_guest);
+
+ enter_guest();
+ skip_exit_vmcall();
+
+ irq_disable();
+ post_interrupt(PI_TEST_VECTOR, apic_id());
+ enter_guest();
+
+ skip_exit_vmcall();
+ TEST_ASSERT(args->isr_fired);
+ enter_guest();
+}
+
#define TEST(name) { #name, .v2 = name }
/* name/init/guest_main/exit_handler/syscall_handler/guest_regs */
@@ -10533,5 +10608,6 @@ struct vmx_test vmx_tests[] = {
TEST(rdtsc_vmexit_diff_test),
TEST(vmx_mtf_test),
TEST(vmx_mtf_pdpte_test),
+ TEST(vmx_posted_interrupt_test),
{ NULL, NULL, NULL, NULL, NULL, {0} },
};
--
2.28.0.806.g8561365e88-goog
