[PATCH 5/5] selftests/kvm/x86_64: add tests for KVM_HC_HOST_SYSCALL

[Andrei Vagin <avagin@google.com>]

* check that syscall are executed.
* check that non-existing syscalls return ENOSYS.

Signed-off-by: Andrei Vagin <avagin@google.com>
---
 0000-kvm-host-syscall.patch                   |   7 +
 tools/testing/selftests/kvm/.gitignore        |   1 +
 tools/testing/selftests/kvm/Makefile          |   1 +
 .../selftests/kvm/include/x86_64/processor.h  |   4 +
 .../kvm/x86_64/kvm_pv_syscall_test.c          | 145 ++++++++++++++++++
 5 files changed, 158 insertions(+)
 create mode 100644 tools/testing/selftests/kvm/x86_64/kvm_pv_syscall_test.c

diff --git a/0000-kvm-host-syscall.patch b/0000-kvm-host-syscall.patch
index 364db7471abc..653430d57c62 100644
--- a/0000-kvm-host-syscall.patch
+++ b/0000-kvm-host-syscall.patch
@@ -57,6 +57,13 @@ In the Google kernel, we have a kvm-like subsystem designed especially
 for gVisor. This change is the first step of integrating it into the KVM
 code base and making it available to all Linux users.
 
+Cc: Paolo Bonzini <pbonzini@redhat.com>
+Cc: Sean Christopherson <seanjc@google.com>
+Cc: Wanpeng Li <wanpengli@tencent.com>
+Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
+Cc: Jianfeng Tan <henry.tjf@antfin.com>
+Cc: Adin Scannell <ascannell@google.com>
+
 Andrei Vagin (5):
   kernel: add a new helper to execute system calls from kernel code
   kvm: add controls to enable/disable paravirtualized system calls
diff --git a/tools/testing/selftests/kvm/.gitignore b/tools/testing/selftests/kvm/.gitignore
index 4509a3a7eeae..57d39fec6fdd 100644
--- a/tools/testing/selftests/kvm/.gitignore
+++ b/tools/testing/selftests/kvm/.gitignore
@@ -21,6 +21,7 @@
 /x86_64/get_msr_index_features
 /x86_64/kvm_clock_test
 /x86_64/kvm_pv_test
+/x86_64/kvm_pv_syscall_test
 /x86_64/hyperv_clock
 /x86_64/hyperv_cpuid
 /x86_64/hyperv_features
diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index 22423c871ed6..e6459f3e5318 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -82,6 +82,7 @@ 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
 TEST_GEN_PROGS_x86_64 += x86_64/kvm_pv_test
+TEST_GEN_PROGS_x86_64 += x86_64/kvm_pv_syscall_test
 TEST_GEN_PROGS_x86_64 += x86_64/mmio_warning_test
 TEST_GEN_PROGS_x86_64 += x86_64/mmu_role_test
 TEST_GEN_PROGS_x86_64 += x86_64/platform_info_test
diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h
index 6ce185449259..4503e9556279 100644
--- a/tools/testing/selftests/kvm/include/x86_64/processor.h
+++ b/tools/testing/selftests/kvm/include/x86_64/processor.h
@@ -17,6 +17,7 @@
 
 #include "../kvm_util.h"
 
+#ifndef X86_EFLAGS_FIXED
 #define X86_EFLAGS_FIXED	 (1u << 1)
 
 #define X86_CR4_VME		(1ul << 0)
@@ -40,6 +41,7 @@
 #define X86_CR4_SMEP		(1ul << 20)
 #define X86_CR4_SMAP		(1ul << 21)
 #define X86_CR4_PKE		(1ul << 22)
+#endif
 
 /* CPUID.1.ECX */
 #define CPUID_VMX		(1ul << 5)
@@ -503,6 +505,7 @@ void __virt_pg_map(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr, int level)
 /*
  * Basic CPU control in CR0
  */
+#ifndef X86_CR0_PE
 #define X86_CR0_PE          (1UL<<0) /* Protection Enable */
 #define X86_CR0_MP          (1UL<<1) /* Monitor Coprocessor */
 #define X86_CR0_EM          (1UL<<2) /* Emulation */
@@ -514,6 +517,7 @@ void __virt_pg_map(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr, int level)
 #define X86_CR0_NW          (1UL<<29) /* Not Write-through */
 #define X86_CR0_CD          (1UL<<30) /* Cache Disable */
 #define X86_CR0_PG          (1UL<<31) /* Paging */
+#endif
 
 #define XSTATE_XTILE_CFG_BIT		17
 #define XSTATE_XTILE_DATA_BIT		18
diff --git a/tools/testing/selftests/kvm/x86_64/kvm_pv_syscall_test.c b/tools/testing/selftests/kvm/x86_64/kvm_pv_syscall_test.c
new file mode 100644
index 000000000000..601f84b11711
--- /dev/null
+++ b/tools/testing/selftests/kvm/x86_64/kvm_pv_syscall_test.c
@@ -0,0 +1,145 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2020, Google LLC.
+ *
+ * Tests for KVM paravirtual feature disablement
+ */
+#include <asm/kvm_para.h>
+#include <asm/ptrace.h>
+#include <linux/kvm_para.h>
+#include <stdint.h>
+
+#include <linux/unistd.h>
+
+#include "test_util.h"
+#include "kvm_util.h"
+#include "processor.h"
+
+struct pt_regs regs_dup = {
+	.rax = __NR_dup,
+	.rdi = -1,
+};
+
+struct pt_regs regs_nosys = {
+	.rax = -1,
+};
+
+struct hcall_data {
+	const char *name;
+	struct pt_regs *regs;
+	long ret;
+};
+
+#define TEST_HCALL(hc) { .nr = hc, .name = #hc }
+#define UCALL_PR_HCALL 0xdeadc0de
+#define PR_HCALL(hc) ucall(UCALL_PR_HCALL, 1, hc)
+
+/*
+ * KVM hypercalls to test. Expect -KVM_ENOSYS when called, as the corresponding
+ * features have been cleared in KVM_CPUID_FEATURES.
+ */
+static struct hcall_data hcalls_to_test[] = {
+	{.name = "dup",    .regs = &regs_dup,   .ret = -EBADF},
+	{.name = "enosys", .regs = &regs_nosys, .ret = -ENOSYS},
+};
+
+static void test_hcall(struct hcall_data *hc)
+{
+	uint64_t r;
+
+	PR_HCALL(hc);
+	r = kvm_hypercall(KVM_HC_HOST_SYSCALL, (unsigned long)hc->regs, 0, 0, 0);
+	GUEST_ASSERT(r == 0);
+}
+
+static void guest_main(void)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(hcalls_to_test); i++)
+		test_hcall(&hcalls_to_test[i]);
+
+	GUEST_DONE();
+}
+
+static void pr_hcall(struct ucall *uc)
+{
+	struct hcall_data *hc = (struct hcall_data *)uc->args[0];
+
+	pr_info("testing hcall: %s\n", hc->name);
+}
+
+static void handle_abort(struct ucall *uc)
+{
+	TEST_FAIL("%s at %s:%ld", (const char *)uc->args[0],
+		  __FILE__, uc->args[1]);
+}
+
+#define VCPU_ID 0
+
+static void enter_guest(struct kvm_vm *vm)
+{
+	struct kvm_run *run;
+	struct ucall uc;
+	int r, i;
+
+	run = vcpu_state(vm, VCPU_ID);
+
+	while (true) {
+		r = _vcpu_run(vm, VCPU_ID);
+		TEST_ASSERT(!r, "vcpu_run failed: %d\n", r);
+		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(vm, VCPU_ID, &uc)) {
+		case UCALL_PR_HCALL:
+			pr_hcall(&uc);
+			break;
+		case UCALL_ABORT:
+			handle_abort(&uc);
+			return;
+		case UCALL_DONE:
+			goto out;
+		}
+	}
+
+out:
+	for (i = 0; i < ARRAY_SIZE(hcalls_to_test); i++) {
+		struct hcall_data *hc = &hcalls_to_test[i];
+
+		TEST_ASSERT(hc->ret == hc->regs->rax, "%s: ret %ld (expected %ld)",
+				hc->name, hc->ret, hc->regs->rax);
+	}
+}
+
+int main(void)
+{
+	struct kvm_enable_cap cap = {0};
+	struct kvm_cpuid2 *best;
+	struct kvm_vm *vm;
+
+	if (!kvm_check_cap(KVM_CAP_ENFORCE_PV_FEATURE_CPUID)) {
+		pr_info("will skip kvm paravirt restriction tests.\n");
+		return 0;
+	}
+
+	vm = vm_create_default(VCPU_ID, 0, guest_main);
+
+	cap.cap = KVM_CAP_ENFORCE_PV_FEATURE_CPUID;
+	cap.args[0] = 1;
+	vcpu_enable_cap(vm, VCPU_ID, &cap);
+
+	best = kvm_get_supported_cpuid();
+	vcpu_set_cpuid(vm, VCPU_ID, best);
+
+	cap.cap = KVM_CAP_PV_HOST_SYSCALL;
+	cap.args[0] = 1;
+	vcpu_enable_cap(vm, VCPU_ID, &cap);
+
+	vm_init_descriptor_tables(vm);
+	vcpu_init_descriptor_tables(vm, VCPU_ID);
+
+	enter_guest(vm);
+	kvm_vm_free(vm);
+}
-- 
2.37.1.359.gd136c6c3e2-goog