KVM: selftests: Introduce UCALL_UNHANDLED for unhandled vector reporting

x86, the only arch implementing exception handling, reports unhandled
vectors using port IO at a specific port number. This replicates what
ucall already does.

Introduce a new ucall type, UCALL_UNHANDLED, for guests to report
unhandled exceptions. Then replace the x86 unhandled vector exception
reporting to use it instead of port IO.  This new ucall type will be
used in the next commits by arm64 to report unhandled vectors as well.

Tested: Forcing a page fault in the ./x86_64/xapic_ipi_test
	halter_guest_code() shows this:

	$ ./x86_64/xapic_ipi_test
	...
	  Unexpected vectored event in guest (vector:0xe)

Signed-off-by: Ricardo Koller <ricarkol@google.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210611011020.3420067-4-ricarkol@google.com

diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
index fcd8e3855111c1e56e57de389dc5ef32ccb6a786..beb76d6deaa9548e5c175b2c3eb81a78fc365254 100644 (file)
--- a/tools/testing/selftests/kvm/include/kvm_util.h
+++ b/tools/testing/selftests/kvm/include/kvm_util.h
@@ -349,6 +349,7 @@ enum {
        UCALL_SYNC,
        UCALL_ABORT,
        UCALL_DONE,
+       UCALL_UNHANDLED,
 };
 
 #define UCALL_MAX_ARGS 6

diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h
index e9f58499133234d76c4c733f61315ea68a82e653..92a62c6999bc4684fc676d0b71e9baeb4318fa1d 100644 (file)
--- a/tools/testing/selftests/kvm/include/x86_64/processor.h
+++ b/tools/testing/selftests/kvm/include/x86_64/processor.h
@@ -53,8 +53,6 @@
 #define CPUID_PKU              (1ul << 3)
 #define CPUID_LA57             (1ul << 16)
 
-#define UNEXPECTED_VECTOR_PORT 0xfff0u
-
 /* General Registers in 64-Bit Mode */
 struct gpr64_regs {
        u64 rax;

diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c
index 257c5c33d04e795a2a6c533a47b9a760ce004ac0..a217515a9bc23e663e7cbe63bb33a5b231da6b8d 100644 (file)
--- a/tools/testing/selftests/kvm/lib/x86_64/processor.c
+++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c
@@ -1201,7 +1201,7 @@ static void set_idt_entry(struct kvm_vm *vm, int vector, unsigned long addr,
 
 void kvm_exit_unexpected_vector(uint32_t value)
 {
-       outl(UNEXPECTED_VECTOR_PORT, value);
+       ucall(UCALL_UNHANDLED, 1, value);
 }
 
 void route_exception(struct ex_regs *regs)
@@ -1254,16 +1254,13 @@ void vm_install_exception_handler(struct kvm_vm *vm, int vector,
 
 void assert_on_unhandled_exception(struct kvm_vm *vm, uint32_t vcpuid)
 {
-       if (vcpu_state(vm, vcpuid)->exit_reason == KVM_EXIT_IO
-               && vcpu_state(vm, vcpuid)->io.port == UNEXPECTED_VECTOR_PORT
-               && vcpu_state(vm, vcpuid)->io.size == 4) {
-               /* Grab pointer to io data */
-               uint32_t *data = (void *)vcpu_state(vm, vcpuid)
-                       + vcpu_state(vm, vcpuid)->io.data_offset;
-
-               TEST_ASSERT(false,
-                           "Unexpected vectored event in guest (vector:0x%x)",
-                           *data);
+       struct ucall uc;
+
+       if (get_ucall(vm, vcpuid, &uc) == UCALL_UNHANDLED) {
+               uint64_t vector = uc.args[0];
+
+               TEST_FAIL("Unexpected vectored event in guest (vector:0x%lx)",
+                         vector);
        }
 }