[RFC 07/16] KVM: selftests: add SEV boot tests

[Michael Roth]

A common aspect of booting SEV guests is checking related CPUID/MSR
bits and accessing shared/private memory. Add a basic test to cover
this.

This test will be expanded to cover basic boot of SEV-ES and SEV-SNP in
subsequent patches.

Signed-off-by: Michael Roth <michael.roth@xxxxxxx>
---
 tools/testing/selftests/kvm/.gitignore        |   1 +
 tools/testing/selftests/kvm/Makefile          |   1 +
 .../selftests/kvm/x86_64/sev_all_boot_test.c  | 252 ++++++++++++++++++
 3 files changed, 254 insertions(+)
 create mode 100644 tools/testing/selftests/kvm/x86_64/sev_all_boot_test.c

diff --git a/tools/testing/selftests/kvm/.gitignore b/tools/testing/selftests/kvm/.gitignore
index 0709af0144c8..824f100bec2a 100644
--- a/tools/testing/selftests/kvm/.gitignore
+++ b/tools/testing/selftests/kvm/.gitignore
@@ -38,6 +38,7 @@
 /x86_64/xen_vmcall_test
 /x86_64/xss_msr_test
 /x86_64/vmx_pmu_msrs_test
+/x86_64/sev_all_boot_test
 /access_tracking_perf_test
 /demand_paging_test
 /dirty_log_test
diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index c7a5e1c69e0c..aa8901bdbd22 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -72,6 +72,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/tsc_msrs_test
 TEST_GEN_PROGS_x86_64 += x86_64/vmx_pmu_msrs_test
 TEST_GEN_PROGS_x86_64 += x86_64/xen_shinfo_test
 TEST_GEN_PROGS_x86_64 += x86_64/xen_vmcall_test
+TEST_GEN_PROGS_x86_64 += x86_64/sev_all_boot_test
 TEST_GEN_PROGS_x86_64 += access_tracking_perf_test
 TEST_GEN_PROGS_x86_64 += demand_paging_test
 TEST_GEN_PROGS_x86_64 += dirty_log_test
diff --git a/tools/testing/selftests/kvm/x86_64/sev_all_boot_test.c b/tools/testing/selftests/kvm/x86_64/sev_all_boot_test.c
new file mode 100644
index 000000000000..8df7143ac17d
--- /dev/null
+++ b/tools/testing/selftests/kvm/x86_64/sev_all_boot_test.c
@@ -0,0 +1,252 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Basic SEV boot tests.
+ *
+ * Copyright (C) 2021 Advanced Micro Devices
+ */
+#define _GNU_SOURCE /* for program_invocation_short_name */
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+
+#include "test_util.h"
+
+#include "kvm_util.h"
+#include "processor.h"
+#include "svm_util.h"
+#include "linux/psp-sev.h"
+#include "sev.h"
+
+#define VCPU_ID			2
+#define PAGE_SIZE		4096
+#define PAGE_STRIDE		32
+
+#define SHARED_PAGES		8192
+#define SHARED_VADDR_MIN	0x1000000
+
+#define PRIVATE_PAGES		2048
+#define PRIVATE_VADDR_MIN	(SHARED_VADDR_MIN + SHARED_PAGES * PAGE_SIZE)
+
+#define TOTAL_PAGES		(512 + SHARED_PAGES + PRIVATE_PAGES)
+
+static void fill_buf(uint8_t *buf, size_t pages, size_t stride, uint8_t val)
+{
+	int i, j;
+
+	for (i = 0; i < pages; i++)
+		for (j = 0; j < PAGE_SIZE; j += stride)
+			buf[i * PAGE_SIZE + j] = val;
+}
+
+static bool check_buf(uint8_t *buf, size_t pages, size_t stride, uint8_t val)
+{
+	int i, j;
+
+	for (i = 0; i < pages; i++)
+		for (j = 0; j < PAGE_SIZE; j += stride)
+			if (buf[i * PAGE_SIZE + j] != val)
+				return false;
+
+	return true;
+}
+
+static void guest_test_start(struct sev_sync_data *sync)
+{
+	/* Initial guest check-in. */
+	sev_guest_sync(sync, 1, 0);
+}
+
+static void check_test_start(struct kvm_vm *vm, struct sev_sync_data *sync)
+{
+	struct kvm_run *run;
+
+	run = vcpu_state(vm, VCPU_ID);
+	vcpu_run(vm, VCPU_ID);
+
+	/* Initial guest check-in. */
+	sev_check_guest_sync(run, sync, 1);
+}
+
+static void
+guest_test_common(struct sev_sync_data *sync, uint8_t *shared_buf, uint8_t *private_buf)
+{
+	bool success;
+
+	/* Initial check-in for common. */
+	sev_guest_sync(sync, 100, 0);
+
+	/* Ensure initial shared pages are intact. */
+	success = check_buf(shared_buf, SHARED_PAGES, PAGE_STRIDE, 0x41);
+	SEV_GUEST_ASSERT(sync, 103, success);
+
+	/* Ensure initial private pages are intact/encrypted. */
+	success = check_buf(private_buf, PRIVATE_PAGES, PAGE_STRIDE, 0x42);
+	SEV_GUEST_ASSERT(sync, 104, success);
+
+	/* Ensure host userspace can't read newly-written encrypted data. */
+	fill_buf(private_buf, PRIVATE_PAGES, PAGE_STRIDE, 0x43);
+
+	sev_guest_sync(sync, 200, 0);
+
+	/* Ensure guest can read newly-written shared data from host. */
+	success = check_buf(shared_buf, SHARED_PAGES, PAGE_STRIDE, 0x44);
+	SEV_GUEST_ASSERT(sync, 201, success);
+
+	/* Ensure host can read newly-written shared data from guest. */
+	fill_buf(shared_buf, SHARED_PAGES, PAGE_STRIDE, 0x45);
+
+	sev_guest_sync(sync, 300, 0);
+}
+
+static void
+check_test_common(struct kvm_vm *vm, struct sev_sync_data *sync,
+		  uint8_t *shared_buf, uint8_t *private_buf)
+{
+	struct kvm_run *run = vcpu_state(vm, VCPU_ID);
+	bool success;
+
+	/* Initial guest check-in. */
+	vcpu_run(vm, VCPU_ID);
+	sev_check_guest_sync(run, sync, 100);
+
+	/* Ensure initial private pages are intact/encrypted. */
+	success = check_buf(private_buf, PRIVATE_PAGES, PAGE_STRIDE, 0x42);
+	TEST_ASSERT(!success, "Initial guest memory not encrypted!");
+
+	vcpu_run(vm, VCPU_ID);
+	sev_check_guest_sync(run, sync, 200);
+
+	/* Ensure host userspace can't read newly-written encrypted data. */
+	success = check_buf(private_buf, PRIVATE_PAGES, PAGE_STRIDE, 0x43);
+	TEST_ASSERT(!success, "Modified guest memory not encrypted!");
+
+	/* Ensure guest can read newly-written shared data from host. */
+	fill_buf(shared_buf, SHARED_PAGES, PAGE_STRIDE, 0x44);
+
+	vcpu_run(vm, VCPU_ID);
+	sev_check_guest_sync(run, sync, 300);
+
+	/* Ensure host can read newly-written shared data from guest. */
+	success = check_buf(shared_buf, SHARED_PAGES, PAGE_STRIDE, 0x45);
+	TEST_ASSERT(success, "Host can't read shared guest memory!");
+}
+
+static void
+guest_test_done(struct sev_sync_data *sync)
+{
+	sev_guest_done(sync, 10000, 0);
+}
+
+static void
+check_test_done(struct kvm_vm *vm, struct sev_sync_data *sync)
+{
+	struct kvm_run *run = vcpu_state(vm, VCPU_ID);
+
+	vcpu_run(vm, VCPU_ID);
+	sev_check_guest_done(run, sync, 10000);
+}
+
+static void __attribute__((__flatten__))
+guest_sev_code(struct sev_sync_data *sync, uint8_t *shared_buf, uint8_t *private_buf)
+{
+	uint32_t eax, ebx, ecx, edx;
+	uint64_t sev_status;
+
+	guest_test_start(sync);
+
+	/* Check SEV CPUID bit. */
+	eax = 0x8000001f;
+	ecx = 0;
+	cpuid(&eax, &ebx, &ecx, &edx);
+	SEV_GUEST_ASSERT(sync, 2, eax & (1 << 1));
+
+	/* Check SEV MSR bit. */
+	sev_status = rdmsr(MSR_AMD64_SEV);
+	SEV_GUEST_ASSERT(sync, 3, (sev_status & 0x1) == 1);
+
+	guest_test_common(sync, shared_buf, private_buf);
+
+	guest_test_done(sync);
+}
+
+static void
+setup_test_common(struct sev_vm *sev, void *guest_code, vm_vaddr_t *sync_vaddr,
+		  vm_vaddr_t *shared_vaddr, vm_vaddr_t *private_vaddr)
+{
+	struct kvm_vm *vm = sev_get_vm(sev);
+	uint8_t *shared_buf, *private_buf;
+
+	/* Set up VCPU and initial guest kernel. */
+	vm_vcpu_add_default(vm, VCPU_ID, guest_code);
+	kvm_vm_elf_load(vm, program_invocation_name);
+
+	/* Set up shared sync buffer. */
+	*sync_vaddr = vm_vaddr_alloc_shared(vm, PAGE_SIZE, 0);
+
+	/* Set up buffer for reserved shared memory. */
+	*shared_vaddr = vm_vaddr_alloc_shared(vm, SHARED_PAGES * PAGE_SIZE,
+					      SHARED_VADDR_MIN);
+	shared_buf = addr_gva2hva(vm, *shared_vaddr);
+	fill_buf(shared_buf, SHARED_PAGES, PAGE_STRIDE, 0x41);
+
+	/* Set up buffer for reserved private memory. */
+	*private_vaddr = vm_vaddr_alloc(vm, PRIVATE_PAGES * PAGE_SIZE,
+					PRIVATE_VADDR_MIN);
+	private_buf = addr_gva2hva(vm, *private_vaddr);
+	fill_buf(private_buf, PRIVATE_PAGES, PAGE_STRIDE, 0x42);
+}
+
+static void test_sev(void *guest_code, uint64_t policy)
+{
+	vm_vaddr_t sync_vaddr, shared_vaddr, private_vaddr;
+	uint8_t *shared_buf, *private_buf;
+	struct sev_sync_data *sync;
+	uint8_t measurement[512];
+	struct sev_vm *sev;
+	struct kvm_vm *vm;
+	int i;
+
+	sev = sev_vm_create(policy, TOTAL_PAGES);
+	if (!sev)
+		return;
+	vm = sev_get_vm(sev);
+
+	setup_test_common(sev, guest_code, &sync_vaddr, &shared_vaddr, &private_vaddr);
+
+	/* Set up guest params. */
+	vcpu_args_set(vm, VCPU_ID, 4, sync_vaddr, shared_vaddr, private_vaddr);
+
+	sync = addr_gva2hva(vm, sync_vaddr);
+	shared_buf = addr_gva2hva(vm, shared_vaddr);
+	private_buf = addr_gva2hva(vm, private_vaddr);
+
+	/* Allocations/setup done. Encrypt initial guest payload. */
+	sev_vm_launch(sev);
+
+	/* Dump the initial measurement. A test to actually verify it would be nice. */
+	sev_vm_measure(sev, measurement);
+	pr_info("guest measurement: ");
+	for (i = 0; i < 32; ++i)
+		pr_info("%02x", measurement[i]);
+	pr_info("\n");
+
+	sev_vm_launch_finish(sev);
+
+	/* Guest is ready to run. Do the tests. */
+	check_test_start(vm, sync);
+	check_test_common(vm, sync, shared_buf, private_buf);
+	check_test_done(vm, sync);
+
+	sev_vm_free(sev);
+}
+
+int main(int argc, char *argv[])
+{
+	/* SEV tests */
+	test_sev(guest_sev_code, SEV_POLICY_NO_DBG);
+	test_sev(guest_sev_code, 0);
+
+	return 0;
+}
-- 
2.25.1