Add interfaces to allow tests to create/manage SEV guests. The additional state associated with these guests is encapsulated in a new struct sev_vm, which is a light wrapper around struct kvm_vm. These VMs will use vm_set_memory_encryption() and vm_get_encrypted_phy_pages() under the covers to configure and sync up with the core kvm_util library on what should/shouldn't be treated as encrypted memory.
Signed-off-by: Michael Roth michael.roth@amd.com --- tools/testing/selftests/kvm/Makefile | 9 +- .../selftests/kvm/include/x86_64/sev.h | 44 ++++ tools/testing/selftests/kvm/lib/x86_64/sev.c | 245 ++++++++++++++++++ 3 files changed, 297 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/kvm/include/x86_64/sev.h create mode 100644 tools/testing/selftests/kvm/lib/x86_64/sev.c
diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile index 412de8093e6c..ccc382a827f1 100644 --- a/tools/testing/selftests/kvm/Makefile +++ b/tools/testing/selftests/kvm/Makefile @@ -33,8 +33,14 @@ ifeq ($(ARCH),s390) UNAME_M := s390x endif
+# On some systems the SEV device path may not be present in the standard +# location, so allow it to be configured via, e.g.: +# make TARGETS=kvm SEV_PATH=/path/to/sev_device ... +SEV_PATH=/dev/sev + LIBKVM = lib/assert.c lib/elf.c lib/io.c lib/kvm_util.c lib/rbtree.c lib/sparsebit.c lib/test_util.c lib/guest_modes.c lib/perf_test_util.c lib/ucall_common.c LIBKVM_x86_64 = lib/x86_64/apic.c lib/x86_64/processor.c lib/x86_64/vmx.c lib/x86_64/svm.c lib/x86_64/ucall.c lib/x86_64/handlers.S +LIBKVM_x86_64 += lib/x86_64/sev.c LIBKVM_aarch64 = lib/aarch64/processor.c lib/aarch64/ucall.c lib/aarch64/handlers.S lib/aarch64/spinlock.c lib/aarch64/gic.c lib/aarch64/gic_v3.c lib/aarch64/vgic.c LIBKVM_s390x = lib/s390x/processor.c lib/s390x/ucall.c lib/s390x/diag318_test_handler.c
@@ -134,7 +140,8 @@ endif CFLAGS += -Wall -Wstrict-prototypes -Wuninitialized -O2 -g -std=gnu99 \ -fno-stack-protector -fno-PIE -I$(LINUX_TOOL_INCLUDE) \ -I$(LINUX_TOOL_ARCH_INCLUDE) -I$(LINUX_HDR_PATH) -Iinclude \ - -I$(<D) -Iinclude/$(UNAME_M) -I.. + -I$(<D) -Iinclude/$(UNAME_M) -I.. \ + -DSEV_DEV_PATH="$(SEV_PATH)"
no-pie-option := $(call try-run, echo 'int main() { return 0; }' | \ $(CC) -Werror -no-pie -x c - -o "$$TMP", -no-pie) diff --git a/tools/testing/selftests/kvm/include/x86_64/sev.h b/tools/testing/selftests/kvm/include/x86_64/sev.h new file mode 100644 index 000000000000..2f7f7c741b12 --- /dev/null +++ b/tools/testing/selftests/kvm/include/x86_64/sev.h @@ -0,0 +1,44 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Helpers used for SEV guests + * + * Copyright (C) 2021 Advanced Micro Devices + */ +#ifndef SELFTEST_KVM_SEV_H +#define SELFTEST_KVM_SEV_H + +#include <stdint.h> +#include <stdbool.h> +#include "kvm_util.h" + +/* Makefile might set this separately for user-overrides */ +#ifndef SEV_DEV_PATH +#define SEV_DEV_PATH "/dev/sev" +#endif + +#define SEV_FW_REQ_VER_MAJOR 0 +#define SEV_FW_REQ_VER_MINOR 17 + +#define SEV_POLICY_NO_DBG (1UL << 0) +#define SEV_POLICY_ES (1UL << 2) + +enum { + SEV_GSTATE_UNINIT = 0, + SEV_GSTATE_LUPDATE, + SEV_GSTATE_LSECRET, + SEV_GSTATE_RUNNING, +}; + +struct sev_vm; + +void kvm_sev_ioctl(struct sev_vm *sev, int cmd, void *data); +struct kvm_vm *sev_get_vm(struct sev_vm *sev); +uint8_t sev_get_enc_bit(struct sev_vm *sev); + +struct sev_vm *sev_vm_create(uint32_t policy, uint64_t npages); +void sev_vm_free(struct sev_vm *sev); +void sev_vm_launch(struct sev_vm *sev); +void sev_vm_launch_measure(struct sev_vm *sev, uint8_t *measurement); +void sev_vm_launch_finish(struct sev_vm *sev); + +#endif /* SELFTEST_KVM_SEV_H */ diff --git a/tools/testing/selftests/kvm/lib/x86_64/sev.c b/tools/testing/selftests/kvm/lib/x86_64/sev.c new file mode 100644 index 000000000000..4a99862d62e6 --- /dev/null +++ b/tools/testing/selftests/kvm/lib/x86_64/sev.c @@ -0,0 +1,245 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Helpers used for SEV guests + * + * Copyright (C) 2021 Advanced Micro Devices + */ + +#include <stdint.h> +#include <stdbool.h> +#include "kvm_util.h" +#include "linux/psp-sev.h" +#include "processor.h" +#include "sev.h" + +#define PAGE_SHIFT 12 +#define PAGE_SIZE (1UL << PAGE_SHIFT) + +struct sev_vm { + struct kvm_vm *vm; + int fd; + int enc_bit; + uint32_t sev_policy; +}; + +/* Common SEV helpers/accessors. */ + +struct kvm_vm *sev_get_vm(struct sev_vm *sev) +{ + return sev->vm; +} + +uint8_t sev_get_enc_bit(struct sev_vm *sev) +{ + return sev->enc_bit; +} + +void sev_ioctl(int sev_fd, int cmd, void *data) +{ + int ret; + struct sev_issue_cmd arg; + + arg.cmd = cmd; + arg.data = (unsigned long)data; + ret = ioctl(sev_fd, SEV_ISSUE_CMD, &arg); + TEST_ASSERT(ret == 0, + "SEV ioctl %d failed, error: %d, fw_error: %d", + cmd, ret, arg.error); +} + +void kvm_sev_ioctl(struct sev_vm *sev, int cmd, void *data) +{ + struct kvm_sev_cmd arg = {0}; + int ret; + + arg.id = cmd; + arg.sev_fd = sev->fd; + arg.data = (__u64)data; + + ret = ioctl(vm_get_fd(sev->vm), KVM_MEMORY_ENCRYPT_OP, &arg); + TEST_ASSERT(ret == 0, + "SEV KVM ioctl %d failed, rc: %i errno: %i (%s), fw_error: %d", + cmd, ret, errno, strerror(errno), arg.error); +} + +/* Local helpers. */ + +static void +sev_register_user_region(struct sev_vm *sev, void *hva, uint64_t size) +{ + struct kvm_enc_region range = {0}; + int ret; + + pr_debug("%s: hva: %p, size: %lu\n", __func__, hva, size); + + range.addr = (__u64)hva; + range.size = size; + + ret = ioctl(vm_get_fd(sev->vm), KVM_MEMORY_ENCRYPT_REG_REGION, &range); + TEST_ASSERT(ret == 0, "failed to register user range, errno: %i\n", errno); +} + +static void +sev_encrypt_phy_range(struct sev_vm *sev, vm_paddr_t gpa, uint64_t size) +{ + struct kvm_sev_launch_update_data ksev_update_data = {0}; + + pr_debug("%s: addr: 0x%lx, size: %lu\n", __func__, gpa, size); + + ksev_update_data.uaddr = (__u64)addr_gpa2hva(sev->vm, gpa); + ksev_update_data.len = size; + + kvm_sev_ioctl(sev, KVM_SEV_LAUNCH_UPDATE_DATA, &ksev_update_data); +} + +static void sev_encrypt(struct sev_vm *sev) +{ + const struct sparsebit *enc_phy_pages; + struct kvm_vm *vm = sev->vm; + sparsebit_idx_t pg = 0; + vm_paddr_t gpa_start; + uint64_t memory_size; + + /* Only memslot 0 supported for now. */ + enc_phy_pages = vm_get_encrypted_phy_pages(sev->vm, 0, &gpa_start, &memory_size); + TEST_ASSERT(enc_phy_pages, "Unable to retrieve encrypted pages bitmap"); + while (pg < (memory_size / vm_get_page_size(vm))) { + sparsebit_idx_t pg_cnt; + + if (sparsebit_is_clear(enc_phy_pages, pg)) { + pg = sparsebit_next_set(enc_phy_pages, pg); + if (!pg) + break; + } + + pg_cnt = sparsebit_next_clear(enc_phy_pages, pg) - pg; + if (pg_cnt <= 0) + pg_cnt = 1; + + sev_encrypt_phy_range(sev, + gpa_start + pg * vm_get_page_size(vm), + pg_cnt * vm_get_page_size(vm)); + pg += pg_cnt; + } +} + +/* SEV VM implementation. */ + +static struct sev_vm *sev_vm_alloc(struct kvm_vm *vm) +{ + struct sev_user_data_status sev_status = {0}; + uint32_t eax, ebx, ecx, edx; + struct sev_vm *sev; + int sev_fd; + + sev_fd = open(SEV_DEV_PATH, O_RDWR); + if (sev_fd < 0) { + pr_info("Failed to open SEV device, path: %s, error: %d, skipping test.\n", + SEV_DEV_PATH, sev_fd); + return NULL; + } + + sev_ioctl(sev_fd, SEV_PLATFORM_STATUS, &sev_status); + + if (!(sev_status.api_major > SEV_FW_REQ_VER_MAJOR || + (sev_status.api_major == SEV_FW_REQ_VER_MAJOR && + sev_status.api_minor >= SEV_FW_REQ_VER_MINOR))) { + pr_info("SEV FW version too old. Have API %d.%d (build: %d), need %d.%d, skipping test.\n", + sev_status.api_major, sev_status.api_minor, sev_status.build, + SEV_FW_REQ_VER_MAJOR, SEV_FW_REQ_VER_MINOR); + return NULL; + } + + sev = calloc(1, sizeof(*sev)); + sev->fd = sev_fd; + sev->vm = vm; + + /* Get encryption bit via CPUID. */ + eax = 0x8000001f; + ecx = 0; + cpuid(&eax, &ebx, &ecx, &edx); + sev->enc_bit = ebx & 0x3F; + + return sev; +} + +void sev_vm_free(struct sev_vm *sev) +{ + kvm_vm_free(sev->vm); + close(sev->fd); + free(sev); +} + +struct sev_vm *sev_vm_create(uint32_t policy, uint64_t npages) +{ + struct sev_vm *sev; + struct kvm_vm *vm; + + /* Need to handle memslots after init, and after setting memcrypt. */ + vm = vm_create(VM_MODE_DEFAULT, 0, O_RDWR); + sev = sev_vm_alloc(vm); + if (!sev) + return NULL; + sev->sev_policy = policy; + + kvm_sev_ioctl(sev, KVM_SEV_INIT, NULL); + + vm_set_memory_encryption(vm, true, true, sev->enc_bit); + vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS, 0, 0, npages, 0); + sev_register_user_region(sev, addr_gpa2hva(vm, 0), + npages * vm_get_page_size(vm)); + + pr_info("SEV guest created, policy: 0x%x, size: %lu KB\n", + sev->sev_policy, npages * vm_get_page_size(vm) / 1024); + + return sev; +} + +void sev_vm_launch(struct sev_vm *sev) +{ + struct kvm_sev_launch_start ksev_launch_start = {0}; + struct kvm_sev_guest_status ksev_status = {0}; + + /* Need to use ucall_shared for synchronization. */ + ucall_init_ops(sev_get_vm(sev), NULL, &ucall_ops_halt); + + ksev_launch_start.policy = sev->sev_policy; + kvm_sev_ioctl(sev, KVM_SEV_LAUNCH_START, &ksev_launch_start); + kvm_sev_ioctl(sev, KVM_SEV_GUEST_STATUS, &ksev_status); + TEST_ASSERT(ksev_status.policy == sev->sev_policy, "Incorrect guest policy."); + TEST_ASSERT(ksev_status.state == SEV_GSTATE_LUPDATE, + "Unexpected guest state: %d", ksev_status.state); + + sev_encrypt(sev); +} + +void sev_vm_launch_measure(struct sev_vm *sev, uint8_t *measurement) +{ + struct kvm_sev_launch_measure ksev_launch_measure = {0}; + struct kvm_sev_guest_status ksev_guest_status = {0}; + + ksev_launch_measure.len = 256; + ksev_launch_measure.uaddr = (__u64)measurement; + kvm_sev_ioctl(sev, KVM_SEV_LAUNCH_MEASURE, &ksev_launch_measure); + + /* Measurement causes a state transition, check that. */ + kvm_sev_ioctl(sev, KVM_SEV_GUEST_STATUS, &ksev_guest_status); + TEST_ASSERT(ksev_guest_status.state == SEV_GSTATE_LSECRET, + "Unexpected guest state: %d", ksev_guest_status.state); +} + +void sev_vm_launch_finish(struct sev_vm *sev) +{ + struct kvm_sev_guest_status ksev_status = {0}; + + kvm_sev_ioctl(sev, KVM_SEV_GUEST_STATUS, &ksev_status); + TEST_ASSERT(ksev_status.state == SEV_GSTATE_LUPDATE || + ksev_status.state == SEV_GSTATE_LSECRET, + "Unexpected guest state: %d", ksev_status.state); + + kvm_sev_ioctl(sev, KVM_SEV_LAUNCH_FINISH, NULL); + + kvm_sev_ioctl(sev, KVM_SEV_GUEST_STATUS, &ksev_status); + TEST_ASSERT(ksev_status.state == SEV_GSTATE_RUNNING, + "Unexpected guest state: %d", ksev_status.state); +}