[PATCH v2 2/5] KVM: selftests: Introduce UCALL_UNHANDLED for unhandled vector reporting

[Ricardo Koller <ricarkol@google.com>]

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>
---
 tools/testing/selftests/kvm/include/kvm_util.h    |  1 +
 .../selftests/kvm/include/x86_64/processor.h      |  2 --
 .../testing/selftests/kvm/lib/x86_64/processor.c  | 15 ++++++---------
 3 files changed, 7 insertions(+), 11 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
index bea4644d645d..7880929ea548 100644
--- a/tools/testing/selftests/kvm/include/kvm_util.h
+++ b/tools/testing/selftests/kvm/include/kvm_util.h
@@ -347,6 +347,7 @@ 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 12889d3e8948..ff4da2f95b13 100644
--- 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 e156061263a6..96e2bd9d66eb 100644
--- a/tools/testing/selftests/kvm/lib/x86_64/processor.c
+++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c
@@ -1207,7 +1207,7 @@ 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)
@@ -1260,16 +1260,13 @@ void vm_install_vector_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;
+	struct ucall uc;
 
+	if (get_ucall(vm, vcpuid, &uc) == UCALL_UNHANDLED) {
+		uint64_t vector = uc.args[0];
 		TEST_ASSERT(false,
-			    "Unexpected vectored event in guest (vector:0x%x)",
-			    *data);
+			    "Unexpected vectored event in guest (vector:0x%lx)",
+			    vector);
 	}
 }
 
-- 
2.31.1.527.g47e6f16901-goog