Messages in this thread |  | | Subject | Re: [RFC 07/16] KVM: selftests: add SEV boot tests | From | Krish Sadhukhan <> | Date | Fri, 15 Oct 2021 19:55:53 -0700 |
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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 ? > + 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; > +}
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