[PATCH 6/6] KVM: selftests: Test Hyper-V extended hypercall exit to userspace

[Vipin Sharma]

Hyper-V extended hypercalls by default exit to userspace. Verify
userspace gets the call, update the result and then guest verifies
result it received.

Signed-off-by: Vipin Sharma <vipinsh@xxxxxxxxxx>
---
 tools/testing/selftests/kvm/.gitignore        |  1 +
 tools/testing/selftests/kvm/Makefile          |  1 +
 .../kvm/x86_64/hyperv_extended_hcalls.c       | 90 +++++++++++++++++++
 3 files changed, 92 insertions(+)
 create mode 100644 tools/testing/selftests/kvm/x86_64/hyperv_extended_hcalls.c

diff --git a/tools/testing/selftests/kvm/.gitignore b/tools/testing/selftests/kvm/.gitignore
index 2f0d705db9db..ffe06dd1cc6e 100644
--- a/tools/testing/selftests/kvm/.gitignore
+++ b/tools/testing/selftests/kvm/.gitignore
@@ -24,6 +24,7 @@
 /x86_64/kvm_pv_test
 /x86_64/hyperv_clock
 /x86_64/hyperv_cpuid
+/x86_64/hyperv_extended_hcalls
 /x86_64/hyperv_features
 /x86_64/hyperv_svm_test
 /x86_64/max_vcpuid_cap_test
diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index 0172eb6cb6ee..366345099363 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -85,6 +85,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/emulator_error_test
 TEST_GEN_PROGS_x86_64 += x86_64/fix_hypercall_test
 TEST_GEN_PROGS_x86_64 += x86_64/hyperv_clock
 TEST_GEN_PROGS_x86_64 += x86_64/hyperv_cpuid
+TEST_GEN_PROGS_x86_64 += x86_64/hyperv_extended_hcalls
 TEST_GEN_PROGS_x86_64 += x86_64/hyperv_features
 TEST_GEN_PROGS_x86_64 += x86_64/hyperv_svm_test
 TEST_GEN_PROGS_x86_64 += x86_64/kvm_clock_test
diff --git a/tools/testing/selftests/kvm/x86_64/hyperv_extended_hcalls.c b/tools/testing/selftests/kvm/x86_64/hyperv_extended_hcalls.c
new file mode 100644
index 000000000000..d378877235d4
--- /dev/null
+++ b/tools/testing/selftests/kvm/x86_64/hyperv_extended_hcalls.c
@@ -0,0 +1,90 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Test Hyper-V extended hypercalls
+ *
+ * Copyright 2020 Google LLC
+ * Author: Vipin Sharma <vipinsh@xxxxxxxxxx>
+ */
+
+#include "kvm_util.h"
+#include "processor.h"
+#include "hyperv.h"
+
+/* Any value is fine */
+#define EXT_CAPABILITIES 0xbull
+
+static void guest_code(vm_vaddr_t pgs_gpa, vm_vaddr_t output_pg_gva)
+{
+	uint64_t res, vector;
+	uint64_t *output_gva;
+
+	wrmsr(HV_X64_MSR_GUEST_OS_ID, hv_linux_guest_id());
+	wrmsr(HV_X64_MSR_HYPERCALL, pgs_gpa);
+
+	output_gva = (uint64_t *)output_pg_gva;
+
+	vector = hypercall(HV_EXT_CALL_QUERY_CAPABILITIES, pgs_gpa,
+			   pgs_gpa + 4096, &res);
+
+	GUEST_ASSERT_1(!vector, vector);
+	GUEST_ASSERT_2(res == HV_STATUS_SUCCESS, res, HV_STATUS_SUCCESS);
+
+	/* TLFS states output will be a uint64_t value */
+	GUEST_ASSERT_2(*output_gva == EXT_CAPABILITIES, *output_gva,
+		       EXT_CAPABILITIES);
+
+	GUEST_DONE();
+}
+
+static void guest_extended_hcall_test(void)
+{
+	struct kvm_vcpu *vcpu;
+	struct kvm_run *run;
+	struct kvm_vm *vm;
+	struct ucall uc;
+	vm_vaddr_t hcall_page;
+	uint64_t *outval;
+
+	vm = vm_create_with_one_vcpu(&vcpu, guest_code);
+	run = vcpu->run;
+	vcpu_enable_cap(vcpu, KVM_CAP_HYPERV_ENFORCE_CPUID, 1);
+	vcpu_set_hv_cpuid(vcpu);
+
+	/* Hypercall input/output */
+	hcall_page = vm_vaddr_alloc_pages(vm, 2);
+	memset(addr_gva2hva(vm, hcall_page), 0x0, 2 * getpagesize());
+	vcpu_args_set(vcpu, 2, addr_gva2gpa(vm, hcall_page), hcall_page + 4096);
+
+	vcpu_run(vcpu);
+
+	TEST_ASSERT((run->exit_reason == KVM_EXIT_HYPERV),
+		    "unexpected exit reason: %u (%s)", run->exit_reason,
+		    exit_reason_str(run->exit_reason));
+
+	outval = addr_gpa2hva(vm, run->hyperv.u.hcall.params[1]);
+	*outval = EXT_CAPABILITIES;
+	run->hyperv.u.hcall.result = HV_STATUS_SUCCESS;
+
+	vcpu_run(vcpu);
+
+	TEST_ASSERT((run->exit_reason == KVM_EXIT_IO),
+		    "unexpected exit reason: %u (%s)", run->exit_reason,
+		    exit_reason_str(run->exit_reason));
+
+	switch (get_ucall(vcpu, &uc)) {
+	case UCALL_ABORT:
+		REPORT_GUEST_ASSERT_2(uc, "arg1 = %ld, arg2 = %ld");
+		break;
+	case UCALL_DONE:
+		break;
+	default:
+		TEST_FAIL("Unhandled ucall: %ld", uc.cmd);
+	}
+
+	kvm_vm_free(vm);
+}
+
+int main(void)
+{
+	guest_extended_hcall_test();
+}
-- 
2.38.1.273.g43a17bfeac-goog