From faf06a238254cec0c8c9bc0876caede63fcfeb24 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Fri, 19 Jul 2024 16:51:04 -0700 Subject: [PATCH] KVM: selftests: Skip ICR.BUSY test in xapic_state_test if x2APIC is enabled Don't test the ICR BUSY bit when x2APIC is enabled as AMD and Intel have different behavior (AMD #GPs, Intel ignores), and the fact that the CPU performs the reserved bit checks when IPI virtualization is enabled makes it impossible for KVM to precisely emulate one or the other. Link: https://lore.kernel.org/r/20240719235107.3023592-8-seanjc@google.com Signed-off-by: Sean Christopherson --- .../selftests/kvm/x86_64/xapic_state_test.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) diff --git a/tools/testing/selftests/kvm/x86_64/xapic_state_test.c b/tools/testing/selftests/kvm/x86_64/xapic_state_test.c index 618cd2442390..d5a7adaa9502 100644 --- a/tools/testing/selftests/kvm/x86_64/xapic_state_test.c +++ b/tools/testing/selftests/kvm/x86_64/xapic_state_test.c @@ -70,12 +70,10 @@ static void ____test_icr(struct xapic_vcpu *x, uint64_t val) vcpu_ioctl(vcpu, KVM_GET_LAPIC, &xapic); icr = (u64)(*((u32 *)&xapic.regs[APIC_ICR])) | (u64)(*((u32 *)&xapic.regs[APIC_ICR2])) << 32; - if (!x->is_x2apic) { + if (!x->is_x2apic) val &= (-1u | (0xffull << (32 + 24))); - TEST_ASSERT_EQ(icr, val & ~APIC_ICR_BUSY); - } else { - TEST_ASSERT_EQ(icr & ~APIC_ICR_BUSY, val & ~APIC_ICR_BUSY); - } + + TEST_ASSERT_EQ(icr, val & ~APIC_ICR_BUSY); } #define X2APIC_RSVED_BITS_MASK (GENMASK_ULL(31,20) | \ @@ -91,7 +89,15 @@ static void __test_icr(struct xapic_vcpu *x, uint64_t val) */ val &= ~X2APIC_RSVED_BITS_MASK; } - ____test_icr(x, val | APIC_ICR_BUSY); + + /* + * The BUSY bit is reserved on both AMD and Intel, but only AMD treats + * it is as _must_ be zero. Intel simply ignores the bit. Don't test + * the BUSY bit for x2APIC, as there is no single correct behavior. + */ + if (!x->is_x2apic) + ____test_icr(x, val | APIC_ICR_BUSY); + ____test_icr(x, val & ~(u64)APIC_ICR_BUSY); } -- 2.50.1