[Patch v3 13/13] KVM: selftests: Test Hyper-V extended hypercall exit to userspace

Vipin Sharma
2022-12-05T19:16:36Z

Hyper-V extended hypercalls by default exit to userspace. Verify
userspace gets the call, update the result and then verify in guest
correct result is received.

Signed-off-by: Vipin Sharma <vipinsh@google.com>
---
tools/testing/selftests/kvm/.gitignore | 1 +
tools/testing/selftests/kvm/Makefile | 1 +
.../kvm/x86_64/hyperv_extended_hypercalls.c | 93 +++++++++++++++++++
3 files changed, 95 insertions(+)
create mode 100644 tools/testing/selftests/kvm/x86_64/hyperv_extended_hypercalls.c

diff --git a/tools/testing/selftests/kvm/.gitignore b/tools/testing/selftests/kvm/.gitignore
index 082855d94c72..b17874697d74 100644
--- a/tools/testing/selftests/kvm/.gitignore
+++ b/tools/testing/selftests/kvm/.gitignore
@@ -24,6 +24,7 @@
/x86_64/hyperv_clock
/x86_64/hyperv_cpuid
/x86_64/hyperv_evmcs
+/x86_64/hyperv_extended_hypercalls
/x86_64/hyperv_features
/x86_64/hyperv_ipi
/x86_64/hyperv_svm_test
diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index 2275ba861e0e..a0e12f5d9835 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -87,6 +87,7 @@ 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_evmcs
+TEST_GEN_PROGS_x86_64 += x86_64/hyperv_extended_hypercalls
TEST_GEN_PROGS_x86_64 += x86_64/hyperv_features
TEST_GEN_PROGS_x86_64 += x86_64/hyperv_ipi
TEST_GEN_PROGS_x86_64 += x86_64/hyperv_svm_test
diff --git a/tools/testing/selftests/kvm/x86_64/hyperv_extended_hypercalls.c b/tools/testing/selftests/kvm/x86_64/hyperv_extended_hypercalls.c
new file mode 100644
index 000000000000..6635f5988d8d
--- /dev/null
+++ b/tools/testing/selftests/kvm/x86_64/hyperv_extended_hypercalls.c
@@ -0,0 +1,93 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Test Hyper-V extended hypercall, HV_EXT_CALL_QUERY_CAPABILITIES (0x8001),
+ * exit to userspace and receive result in guest.
+ *
+ * Negative tests are present in hyperv_features.c
+ *
+ * Copyright 2022 Google LLC
+ * Author: Vipin Sharma <vipinsh@google.com>
+ */
+
+#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 in_pg_gpa, vm_vaddr_t out_pg_gpa,
+ vm_vaddr_t out_pg_gva)
+{
+ uint64_t *output_gva;
+
+ wrmsr(HV_X64_MSR_GUEST_OS_ID, HYPERV_LINUX_OS_ID);
+ wrmsr(HV_X64_MSR_HYPERCALL, in_pg_gpa);
+
+ output_gva = (uint64_t *)out_pg_gva;
+
+ hyperv_hypercall(HV_EXT_CALL_QUERY_CAPABILITIES, in_pg_gpa, out_pg_gpa);
+
+ /* TLFS states output will be a uint64_t value */
+ GUEST_ASSERT_EQ(*output_gva, EXT_CAPABILITIES);
+
+ GUEST_DONE();
+}
+
+int main(void)
+{
+ vm_vaddr_t hcall_out_page;
+ vm_vaddr_t hcall_in_page;
+ struct kvm_vcpu *vcpu;
+ struct kvm_run *run;
+ struct kvm_vm *vm;
+ uint64_t *outval;
+ struct ucall uc;
+
+ /* Verify if extended hypercalls are supported */
+ if (!kvm_cpuid_has(kvm_get_supported_hv_cpuid(),
+ HV_ENABLE_EXTENDED_HYPERCALLS)) {
+ print_skip("Extended calls not supported by the kernel");
+ exit(KSFT_SKIP);
+ }
+
+ vm = vm_create_with_one_vcpu(&vcpu, guest_code);
+ run = vcpu->run;
+ vcpu_set_hv_cpuid(vcpu);
+
+ /* Hypercall input */
+ hcall_in_page = vm_vaddr_alloc_pages(vm, 1);
+ memset(addr_gva2hva(vm, hcall_in_page), 0x0, vm->page_size);
+
+ /* Hypercall output */
+ hcall_out_page = vm_vaddr_alloc_pages(vm, 1);
+ memset(addr_gva2hva(vm, hcall_out_page), 0x0, vm->page_size);
+
+ vcpu_args_set(vcpu, 3, addr_gva2gpa(vm, hcall_in_page),
+ addr_gva2gpa(vm, hcall_out_page), hcall_out_page);
+
+ vcpu_run(vcpu);
+
+ ASSERT_EXIT_REASON(vcpu, KVM_EXIT_HYPERV);
+
+ outval = addr_gpa2hva(vm, run->hyperv.u.hcall.params[1]);
+ *outval = EXT_CAPABILITIES;
+ run->hyperv.u.hcall.result = HV_STATUS_SUCCESS;
+
+ vcpu_run(vcpu);
+
+ ASSERT_EXIT_REASON(vcpu, KVM_EXIT_IO);
+
+ 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);
+ return 0;
+}