On 10/6/21 1:37 PM, Michael Roth wrote:
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);
+
Is there any need to do the cpuid and MSR tests every time the guest
code is executed ?
+ 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);
Since the above section of this function is actually setup code and is
not running the test yet, it is best placed in a setup function. My
suggestion is that you place the above section into a function called
setup_test_common() and within that function you further separate out
the SEV-related setup into a function called setup_test_sev() or
something similar. Then call the top-level setup function from within
main().
+
+ /* 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);
These function names can be better. These functions are not just
checking the result, they are actually running the guest code. So, may
be, calling them 'test_start, test_common and test_done are better. I
would just collapse them and place their code in test_sev() only if you
separate the out the setup code as I suggested above.
+
+ 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;
+}
