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On Thu, Dec 16, 2021 at 10:18 AM Michael Roth michael.roth@amd.com wrote:
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
Similar logic is already in open_sev_dev_path_or_exit() should we move that function here?
+#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);
If the helper vm_get_fd() exists why not add another which takes a struct sev_vm. So you can do __vm_get_fd(sev) here?
TEST_ASSERT(ret == 0,"SEV KVM ioctl %d failed, rc: %i errno: %i (%s), fw_error: %d",cmd, ret, errno, strerror(errno), arg.error);+}
Can you dedup this from sev_ioctl() in sev_migrate_tests.c? That function already correctly asserts the fw_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))) {
For readability could we save have a new variable:
const uint64_t page_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);
As noted above please use open_sev_dev_path_or_exit()
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);
Technically we are returning NULL not skipping the test.
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;
Can we get macros for these magics?
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);
In this file we've done this a lot. Thoughts about a helper like this?
+ void assert_guest_state(uint32_t expected_state, struct sev_vm *sev) + { + struct kvm_sev_guest_status ksev_status = {0}; + + 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;
Can we document that this measure pointer must be backed by at least a given amount of memory?
Also should this be 48 as the length required (256bits for MEASURE and 128 for MNONCE?
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);
We don't pre check the state in any other calls, should we? Or why are we here?
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);+}
2.25.1