On Fri, Oct 15, 2021 at 07:55:53PM -0700, Krish Sadhukhan wrote:
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@amd.com
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 ?
It seems like a good sanity check that KVM is setting the expected bits (via KVM_GET_SUPPORTED_CPUID) for SEV guests. This is also a fairly common example of the sort of things a guest would do during boot to detect/initialize SEV-related functionality.
It becomes a little more useful for the SEV-ES/SEV-SNP tests, where cpuid instructions cause a #VC exception, which in turn leads to a VMGExit and exercises the host KVM's handling of host-guest communiction via GHCB MSR/GHCB page.
- 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().
That makes sense. I'll try to rework this according to your suggestions.
- /* 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
Will do.
collapse them and place their code in test_sev() only if you separate the out the setup code as I suggested above.
Hmm, I did it that way because in the guest_{sev,sev_es,sev_snp}_code routines there are some type-specific checks that happen before guest_test_done(), so it made sense to have that in a separate routine, and seemed more readable to then also have check_test_done() separate to pair with it. But I'll see if I can rework that a bit.
- 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;
+}