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qemu-e2k/target/i386/sev.c
Tom Lendacky 8168fed9f8 i386/sev: Update checks and information related to reduced-phys-bits 
The value of the reduced-phys-bits parameter is propogated to the CPUID
information exposed to the guest. Update the current validation check to
account for the size of the CPUID field (6-bits), ensuring the value is
in the range of 1 to 63.

Maintain backward compatibility, to an extent, by allowing a value greater
than 1 (so that the previously documented value of 5 still works), but not
allowing anything over 63.

Fixes: d8575c6c02 ("sev/i386: add command to initialize the memory encryption context")
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <cca5341a95ac73f904e6300f10b04f9c62e4e8ff.1664550870.git.thomas.lendacky@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-04-28 12:50:34 +02:00

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/*
* QEMU SEV support
*
* Copyright Advanced Micro Devices 2016-2018
*
* Author:
* Brijesh Singh <brijesh.singh@amd.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*
*/
#include "qemu/osdep.h"
#include <linux/kvm.h>
#include <linux/psp-sev.h>
#include <sys/ioctl.h>
#include "qapi/error.h"
#include "qom/object_interfaces.h"
#include "qemu/base64.h"
#include "qemu/module.h"
#include "qemu/uuid.h"
#include "qemu/error-report.h"
#include "crypto/hash.h"
#include "sysemu/kvm.h"
#include "sev.h"
#include "sysemu/sysemu.h"
#include "sysemu/runstate.h"
#include "trace.h"
#include "migration/blocker.h"
#include "qom/object.h"
#include "monitor/monitor.h"
#include "monitor/hmp-target.h"
#include "qapi/qapi-commands-misc-target.h"
#include "exec/confidential-guest-support.h"
#include "hw/i386/pc.h"
#include "exec/address-spaces.h"
#define TYPE_SEV_GUEST "sev-guest"
OBJECT_DECLARE_SIMPLE_TYPE(SevGuestState, SEV_GUEST)
/**
* SevGuestState:
*
* The SevGuestState object is used for creating and managing a SEV
* guest.
*
* # $QEMU \
* -object sev-guest,id=sev0 \
* -machine ...,memory-encryption=sev0
*/
struct SevGuestState {
ConfidentialGuestSupport parent_obj;
/* configuration parameters */
char *sev_device;
uint32_t policy;
char *dh_cert_file;
char *session_file;
uint32_t cbitpos;
uint32_t reduced_phys_bits;
bool kernel_hashes;
/* runtime state */
uint32_t handle;
uint8_t api_major;
uint8_t api_minor;
uint8_t build_id;
int sev_fd;
SevState state;
gchar *measurement;
uint32_t reset_cs;
uint32_t reset_ip;
bool reset_data_valid;
};
#define DEFAULT_GUEST_POLICY 0x1 /* disable debug */
#define DEFAULT_SEV_DEVICE "/dev/sev"
#define SEV_INFO_BLOCK_GUID "00f771de-1a7e-4fcb-890e-68c77e2fb44e"
typedef struct __attribute__((__packed__)) SevInfoBlock {
/* SEV-ES Reset Vector Address */
uint32_t reset_addr;
} SevInfoBlock;
#define SEV_HASH_TABLE_RV_GUID "7255371f-3a3b-4b04-927b-1da6efa8d454"
typedef struct QEMU_PACKED SevHashTableDescriptor {
/* SEV hash table area guest address */
uint32_t base;
/* SEV hash table area size (in bytes) */
uint32_t size;
} SevHashTableDescriptor;
/* hard code sha256 digest size */
#define HASH_SIZE 32
typedef struct QEMU_PACKED SevHashTableEntry {
QemuUUID guid;
uint16_t len;
uint8_t hash[HASH_SIZE];
} SevHashTableEntry;
typedef struct QEMU_PACKED SevHashTable {
QemuUUID guid;
uint16_t len;
SevHashTableEntry cmdline;
SevHashTableEntry initrd;
SevHashTableEntry kernel;
} SevHashTable;
/*
* Data encrypted by sev_encrypt_flash() must be padded to a multiple of
* 16 bytes.
*/
typedef struct QEMU_PACKED PaddedSevHashTable {
SevHashTable ht;
uint8_t padding[ROUND_UP(sizeof(SevHashTable), 16) - sizeof(SevHashTable)];
} PaddedSevHashTable;
QEMU_BUILD_BUG_ON(sizeof(PaddedSevHashTable) % 16 != 0);
static SevGuestState *sev_guest;
static Error *sev_mig_blocker;
static const char *const sev_fw_errlist[] = {
[SEV_RET_SUCCESS] = "",
[SEV_RET_INVALID_PLATFORM_STATE] = "Platform state is invalid",
[SEV_RET_INVALID_GUEST_STATE] = "Guest state is invalid",
[SEV_RET_INAVLID_CONFIG] = "Platform configuration is invalid",
[SEV_RET_INVALID_LEN] = "Buffer too small",
[SEV_RET_ALREADY_OWNED] = "Platform is already owned",
[SEV_RET_INVALID_CERTIFICATE] = "Certificate is invalid",
[SEV_RET_POLICY_FAILURE] = "Policy is not allowed",
[SEV_RET_INACTIVE] = "Guest is not active",
[SEV_RET_INVALID_ADDRESS] = "Invalid address",
[SEV_RET_BAD_SIGNATURE] = "Bad signature",
[SEV_RET_BAD_MEASUREMENT] = "Bad measurement",
[SEV_RET_ASID_OWNED] = "ASID is already owned",
[SEV_RET_INVALID_ASID] = "Invalid ASID",
[SEV_RET_WBINVD_REQUIRED] = "WBINVD is required",
[SEV_RET_DFFLUSH_REQUIRED] = "DF_FLUSH is required",
[SEV_RET_INVALID_GUEST] = "Guest handle is invalid",
[SEV_RET_INVALID_COMMAND] = "Invalid command",
[SEV_RET_ACTIVE] = "Guest is active",
[SEV_RET_HWSEV_RET_PLATFORM] = "Hardware error",
[SEV_RET_HWSEV_RET_UNSAFE] = "Hardware unsafe",
[SEV_RET_UNSUPPORTED] = "Feature not supported",
[SEV_RET_INVALID_PARAM] = "Invalid parameter",
[SEV_RET_RESOURCE_LIMIT] = "Required firmware resource depleted",
[SEV_RET_SECURE_DATA_INVALID] = "Part-specific integrity check failure",
};
#define SEV_FW_MAX_ERROR ARRAY_SIZE(sev_fw_errlist)
static int
sev_ioctl(int fd, int cmd, void *data, int *error)
{
int r;
struct kvm_sev_cmd input;
memset(&input, 0x0, sizeof(input));
input.id = cmd;
input.sev_fd = fd;
input.data = (__u64)(unsigned long)data;
r = kvm_vm_ioctl(kvm_state, KVM_MEMORY_ENCRYPT_OP, &input);
if (error) {
*error = input.error;
}
return r;
}
static int
sev_platform_ioctl(int fd, int cmd, void *data, int *error)
{
int r;
struct sev_issue_cmd arg;
arg.cmd = cmd;
arg.data = (unsigned long)data;
r = ioctl(fd, SEV_ISSUE_CMD, &arg);
if (error) {
*error = arg.error;
}
return r;
}
static const char *
fw_error_to_str(int code)
{
if (code < 0 || code >= SEV_FW_MAX_ERROR) {
return "unknown error";
}
return sev_fw_errlist[code];
}
static bool
sev_check_state(const SevGuestState *sev, SevState state)
{
assert(sev);
return sev->state == state ? true : false;
}
static void
sev_set_guest_state(SevGuestState *sev, SevState new_state)
{
assert(new_state < SEV_STATE__MAX);
assert(sev);
trace_kvm_sev_change_state(SevState_str(sev->state),
SevState_str(new_state));
sev->state = new_state;
}
static void
sev_ram_block_added(RAMBlockNotifier *n, void *host, size_t size,
size_t max_size)
{
int r;
struct kvm_enc_region range;
ram_addr_t offset;
MemoryRegion *mr;
/*
* The RAM device presents a memory region that should be treated
* as IO region and should not be pinned.
*/
mr = memory_region_from_host(host, &offset);
if (mr && memory_region_is_ram_device(mr)) {
return;
}
range.addr = (__u64)(unsigned long)host;
range.size = max_size;
trace_kvm_memcrypt_register_region(host, max_size);
r = kvm_vm_ioctl(kvm_state, KVM_MEMORY_ENCRYPT_REG_REGION, &range);
if (r) {
error_report("%s: failed to register region (%p+%#zx) error '%s'",
__func__, host, max_size, strerror(errno));
exit(1);
}
}
static void
sev_ram_block_removed(RAMBlockNotifier *n, void *host, size_t size,
size_t max_size)
{
int r;
struct kvm_enc_region range;
ram_addr_t offset;
MemoryRegion *mr;
/*
* The RAM device presents a memory region that should be treated
* as IO region and should not have been pinned.
*/
mr = memory_region_from_host(host, &offset);
if (mr && memory_region_is_ram_device(mr)) {
return;
}
range.addr = (__u64)(unsigned long)host;
range.size = max_size;
trace_kvm_memcrypt_unregister_region(host, max_size);
r = kvm_vm_ioctl(kvm_state, KVM_MEMORY_ENCRYPT_UNREG_REGION, &range);
if (r) {
error_report("%s: failed to unregister region (%p+%#zx)",
__func__, host, max_size);
}
}
static struct RAMBlockNotifier sev_ram_notifier = {
.ram_block_added = sev_ram_block_added,
.ram_block_removed = sev_ram_block_removed,
};
static void
sev_guest_finalize(Object *obj)
{
}
static char *
sev_guest_get_session_file(Object *obj, Error **errp)
{
SevGuestState *s = SEV_GUEST(obj);
return s->session_file ? g_strdup(s->session_file) : NULL;
}
static void
sev_guest_set_session_file(Object *obj, const char *value, Error **errp)
{
SevGuestState *s = SEV_GUEST(obj);
s->session_file = g_strdup(value);
}
static char *
sev_guest_get_dh_cert_file(Object *obj, Error **errp)
{
SevGuestState *s = SEV_GUEST(obj);
return g_strdup(s->dh_cert_file);
}
static void
sev_guest_set_dh_cert_file(Object *obj, const char *value, Error **errp)
{
SevGuestState *s = SEV_GUEST(obj);
s->dh_cert_file = g_strdup(value);
}
static char *
sev_guest_get_sev_device(Object *obj, Error **errp)
{
SevGuestState *sev = SEV_GUEST(obj);
return g_strdup(sev->sev_device);
}
static void
sev_guest_set_sev_device(Object *obj, const char *value, Error **errp)
{
SevGuestState *sev = SEV_GUEST(obj);
sev->sev_device = g_strdup(value);
}
static bool sev_guest_get_kernel_hashes(Object *obj, Error **errp)
{
SevGuestState *sev = SEV_GUEST(obj);
return sev->kernel_hashes;
}
static void sev_guest_set_kernel_hashes(Object *obj, bool value, Error **errp)
{
SevGuestState *sev = SEV_GUEST(obj);
sev->kernel_hashes = value;
}
static void
sev_guest_class_init(ObjectClass *oc, void *data)
{
object_class_property_add_str(oc, "sev-device",
sev_guest_get_sev_device,
sev_guest_set_sev_device);
object_class_property_set_description(oc, "sev-device",
"SEV device to use");
object_class_property_add_str(oc, "dh-cert-file",
sev_guest_get_dh_cert_file,
sev_guest_set_dh_cert_file);
object_class_property_set_description(oc, "dh-cert-file",
"guest owners DH certificate (encoded with base64)");
object_class_property_add_str(oc, "session-file",
sev_guest_get_session_file,
sev_guest_set_session_file);
object_class_property_set_description(oc, "session-file",
"guest owners session parameters (encoded with base64)");
object_class_property_add_bool(oc, "kernel-hashes",
sev_guest_get_kernel_hashes,
sev_guest_set_kernel_hashes);
object_class_property_set_description(oc, "kernel-hashes",
"add kernel hashes to guest firmware for measured Linux boot");
}
static void
sev_guest_instance_init(Object *obj)
{
SevGuestState *sev = SEV_GUEST(obj);
sev->sev_device = g_strdup(DEFAULT_SEV_DEVICE);
sev->policy = DEFAULT_GUEST_POLICY;
object_property_add_uint32_ptr(obj, "policy", &sev->policy,
OBJ_PROP_FLAG_READWRITE);
object_property_add_uint32_ptr(obj, "handle", &sev->handle,
OBJ_PROP_FLAG_READWRITE);
object_property_add_uint32_ptr(obj, "cbitpos", &sev->cbitpos,
OBJ_PROP_FLAG_READWRITE);
object_property_add_uint32_ptr(obj, "reduced-phys-bits",
&sev->reduced_phys_bits,
OBJ_PROP_FLAG_READWRITE);
}
/* sev guest info */
static const TypeInfo sev_guest_info = {
.parent = TYPE_CONFIDENTIAL_GUEST_SUPPORT,
.name = TYPE_SEV_GUEST,
.instance_size = sizeof(SevGuestState),
.instance_finalize = sev_guest_finalize,
.class_init = sev_guest_class_init,
.instance_init = sev_guest_instance_init,
.interfaces = (InterfaceInfo[]) {
{ TYPE_USER_CREATABLE },
{ }
}
};
bool
sev_enabled(void)
{
return !!sev_guest;
}
bool
sev_es_enabled(void)
{
return sev_enabled() && (sev_guest->policy & SEV_POLICY_ES);
}
uint32_t
sev_get_cbit_position(void)
{
return sev_guest ? sev_guest->cbitpos : 0;
}
uint32_t
sev_get_reduced_phys_bits(void)
{
return sev_guest ? sev_guest->reduced_phys_bits : 0;
}
static SevInfo *sev_get_info(void)
{
SevInfo *info;
info = g_new0(SevInfo, 1);
info->enabled = sev_enabled();
if (info->enabled) {
info->api_major = sev_guest->api_major;
info->api_minor = sev_guest->api_minor;
info->build_id = sev_guest->build_id;
info->policy = sev_guest->policy;
info->state = sev_guest->state;
info->handle = sev_guest->handle;
}
return info;
}
SevInfo *qmp_query_sev(Error **errp)
{
SevInfo *info;
info = sev_get_info();
if (!info) {
error_setg(errp, "SEV feature is not available");
return NULL;
}
return info;
}
void hmp_info_sev(Monitor *mon, const QDict *qdict)
{
SevInfo *info = sev_get_info();
if (info && info->enabled) {
monitor_printf(mon, "handle: %d\n", info->handle);
monitor_printf(mon, "state: %s\n", SevState_str(info->state));
monitor_printf(mon, "build: %d\n", info->build_id);
monitor_printf(mon, "api version: %d.%d\n",
info->api_major, info->api_minor);
monitor_printf(mon, "debug: %s\n",
info->policy & SEV_POLICY_NODBG ? "off" : "on");
monitor_printf(mon, "key-sharing: %s\n",
info->policy & SEV_POLICY_NOKS ? "off" : "on");
} else {
monitor_printf(mon, "SEV is not enabled\n");
}
qapi_free_SevInfo(info);
}
static int
sev_get_pdh_info(int fd, guchar **pdh, size_t *pdh_len, guchar **cert_chain,
size_t *cert_chain_len, Error **errp)
{
guchar *pdh_data = NULL;
guchar *cert_chain_data = NULL;
struct sev_user_data_pdh_cert_export export = {};
int err, r;
/* query the certificate length */
r = sev_platform_ioctl(fd, SEV_PDH_CERT_EXPORT, &export, &err);
if (r < 0) {
if (err != SEV_RET_INVALID_LEN) {
error_setg(errp, "SEV: Failed to export PDH cert"
" ret=%d fw_err=%d (%s)",
r, err, fw_error_to_str(err));
return 1;
}
}
pdh_data = g_new(guchar, export.pdh_cert_len);
cert_chain_data = g_new(guchar, export.cert_chain_len);
export.pdh_cert_address = (unsigned long)pdh_data;
export.cert_chain_address = (unsigned long)cert_chain_data;
r = sev_platform_ioctl(fd, SEV_PDH_CERT_EXPORT, &export, &err);
if (r < 0) {
error_setg(errp, "SEV: Failed to export PDH cert ret=%d fw_err=%d (%s)",
r, err, fw_error_to_str(err));
goto e_free;
}
*pdh = pdh_data;
*pdh_len = export.pdh_cert_len;
*cert_chain = cert_chain_data;
*cert_chain_len = export.cert_chain_len;
return 0;
e_free:
g_free(pdh_data);
g_free(cert_chain_data);
return 1;
}
static int sev_get_cpu0_id(int fd, guchar **id, size_t *id_len, Error **errp)
{
guchar *id_data;
struct sev_user_data_get_id2 get_id2 = {};
int err, r;
/* query the ID length */
r = sev_platform_ioctl(fd, SEV_GET_ID2, &get_id2, &err);
if (r < 0 && err != SEV_RET_INVALID_LEN) {
error_setg(errp, "SEV: Failed to get ID ret=%d fw_err=%d (%s)",
r, err, fw_error_to_str(err));
return 1;
}
id_data = g_new(guchar, get_id2.length);
get_id2.address = (unsigned long)id_data;
r = sev_platform_ioctl(fd, SEV_GET_ID2, &get_id2, &err);
if (r < 0) {
error_setg(errp, "SEV: Failed to get ID ret=%d fw_err=%d (%s)",
r, err, fw_error_to_str(err));
goto err;
}
*id = id_data;
*id_len = get_id2.length;
return 0;
err:
g_free(id_data);
return 1;
}
static SevCapability *sev_get_capabilities(Error **errp)
{
SevCapability *cap = NULL;
guchar *pdh_data = NULL;
guchar *cert_chain_data = NULL;
guchar *cpu0_id_data = NULL;
size_t pdh_len = 0, cert_chain_len = 0, cpu0_id_len = 0;
uint32_t ebx;
int fd;
if (!kvm_enabled()) {
error_setg(errp, "KVM not enabled");
return NULL;
}
if (kvm_vm_ioctl(kvm_state, KVM_MEMORY_ENCRYPT_OP, NULL) < 0) {
error_setg(errp, "SEV is not enabled in KVM");
return NULL;
}
fd = open(DEFAULT_SEV_DEVICE, O_RDWR);
if (fd < 0) {
error_setg_errno(errp, errno, "SEV: Failed to open %s",
DEFAULT_SEV_DEVICE);
return NULL;
}
if (sev_get_pdh_info(fd, &pdh_data, &pdh_len,
&cert_chain_data, &cert_chain_len, errp)) {
goto out;
}
if (sev_get_cpu0_id(fd, &cpu0_id_data, &cpu0_id_len, errp)) {
goto out;
}
cap = g_new0(SevCapability, 1);
cap->pdh = g_base64_encode(pdh_data, pdh_len);
cap->cert_chain = g_base64_encode(cert_chain_data, cert_chain_len);
cap->cpu0_id = g_base64_encode(cpu0_id_data, cpu0_id_len);
host_cpuid(0x8000001F, 0, NULL, &ebx, NULL, NULL);
cap->cbitpos = ebx & 0x3f;
/*
* When SEV feature is enabled, we loose one bit in guest physical
* addressing.
*/
cap->reduced_phys_bits = 1;
out:
g_free(cpu0_id_data);
g_free(pdh_data);
g_free(cert_chain_data);
close(fd);
return cap;
}
SevCapability *qmp_query_sev_capabilities(Error **errp)
{
return sev_get_capabilities(errp);
}
static SevAttestationReport *sev_get_attestation_report(const char *mnonce,
Error **errp)
{
struct kvm_sev_attestation_report input = {};
SevAttestationReport *report = NULL;
SevGuestState *sev = sev_guest;
g_autofree guchar *data = NULL;
g_autofree guchar *buf = NULL;
gsize len;
int err = 0, ret;
if (!sev_enabled()) {
error_setg(errp, "SEV is not enabled");
return NULL;
}
/* lets decode the mnonce string */
buf = g_base64_decode(mnonce, &len);
if (!buf) {
error_setg(errp, "SEV: failed to decode mnonce input");
return NULL;
}
/* verify the input mnonce length */
if (len != sizeof(input.mnonce)) {
error_setg(errp, "SEV: mnonce must be %zu bytes (got %" G_GSIZE_FORMAT ")",
sizeof(input.mnonce), len);
return NULL;
}
/* Query the report length */
ret = sev_ioctl(sev->sev_fd, KVM_SEV_GET_ATTESTATION_REPORT,
&input, &err);
if (ret < 0) {
if (err != SEV_RET_INVALID_LEN) {
error_setg(errp, "SEV: Failed to query the attestation report"
" length ret=%d fw_err=%d (%s)",
ret, err, fw_error_to_str(err));
return NULL;
}
}
data = g_malloc(input.len);
input.uaddr = (unsigned long)data;
memcpy(input.mnonce, buf, sizeof(input.mnonce));
/* Query the report */
ret = sev_ioctl(sev->sev_fd, KVM_SEV_GET_ATTESTATION_REPORT,
&input, &err);
if (ret) {
error_setg_errno(errp, errno, "SEV: Failed to get attestation report"
" ret=%d fw_err=%d (%s)", ret, err, fw_error_to_str(err));
return NULL;
}
report = g_new0(SevAttestationReport, 1);
report->data = g_base64_encode(data, input.len);
trace_kvm_sev_attestation_report(mnonce, report->data);
return report;
}
SevAttestationReport *qmp_query_sev_attestation_report(const char *mnonce,
Error **errp)
{
return sev_get_attestation_report(mnonce, errp);
}
static int
sev_read_file_base64(const char *filename, guchar **data, gsize *len)
{
gsize sz;
g_autofree gchar *base64 = NULL;
GError *error = NULL;
if (!g_file_get_contents(filename, &base64, &sz, &error)) {
error_report("SEV: Failed to read '%s' (%s)", filename, error->message);
g_error_free(error);
return -1;
}
*data = g_base64_decode(base64, len);
return 0;
}
static int
sev_launch_start(SevGuestState *sev)
{
gsize sz;
int ret = 1;
int fw_error, rc;
struct kvm_sev_launch_start start = {
.handle = sev->handle, .policy = sev->policy
};
guchar *session = NULL, *dh_cert = NULL;
if (sev->session_file) {
if (sev_read_file_base64(sev->session_file, &session, &sz) < 0) {
goto out;
}
start.session_uaddr = (unsigned long)session;
start.session_len = sz;
}
if (sev->dh_cert_file) {
if (sev_read_file_base64(sev->dh_cert_file, &dh_cert, &sz) < 0) {
goto out;
}
start.dh_uaddr = (unsigned long)dh_cert;
start.dh_len = sz;
}
trace_kvm_sev_launch_start(start.policy, session, dh_cert);
rc = sev_ioctl(sev->sev_fd, KVM_SEV_LAUNCH_START, &start, &fw_error);
if (rc < 0) {
error_report("%s: LAUNCH_START ret=%d fw_error=%d '%s'",
__func__, ret, fw_error, fw_error_to_str(fw_error));
goto out;
}
sev_set_guest_state(sev, SEV_STATE_LAUNCH_UPDATE);
sev->handle = start.handle;
ret = 0;
out:
g_free(session);
g_free(dh_cert);
return ret;
}
static int
sev_launch_update_data(SevGuestState *sev, uint8_t *addr, uint64_t len)
{
int ret, fw_error;
struct kvm_sev_launch_update_data update;
if (!addr || !len) {
return 1;
}
update.uaddr = (__u64)(unsigned long)addr;
update.len = len;
trace_kvm_sev_launch_update_data(addr, len);
ret = sev_ioctl(sev->sev_fd, KVM_SEV_LAUNCH_UPDATE_DATA,
&update, &fw_error);
if (ret) {
error_report("%s: LAUNCH_UPDATE ret=%d fw_error=%d '%s'",
__func__, ret, fw_error, fw_error_to_str(fw_error));
}
return ret;
}
static int
sev_launch_update_vmsa(SevGuestState *sev)
{
int ret, fw_error;
ret = sev_ioctl(sev->sev_fd, KVM_SEV_LAUNCH_UPDATE_VMSA, NULL, &fw_error);
if (ret) {
error_report("%s: LAUNCH_UPDATE_VMSA ret=%d fw_error=%d '%s'",
__func__, ret, fw_error, fw_error_to_str(fw_error));
}
return ret;
}
static void
sev_launch_get_measure(Notifier *notifier, void *unused)
{
SevGuestState *sev = sev_guest;
int ret, error;
g_autofree guchar *data = NULL;
struct kvm_sev_launch_measure measurement = {};
if (!sev_check_state(sev, SEV_STATE_LAUNCH_UPDATE)) {
return;
}
if (sev_es_enabled()) {
/* measure all the VM save areas before getting launch_measure */
ret = sev_launch_update_vmsa(sev);
if (ret) {
exit(1);
}
}
/* query the measurement blob length */
ret = sev_ioctl(sev->sev_fd, KVM_SEV_LAUNCH_MEASURE,
&measurement, &error);
if (!measurement.len) {
error_report("%s: LAUNCH_MEASURE ret=%d fw_error=%d '%s'",
__func__, ret, error, fw_error_to_str(errno));
return;
}
data = g_new0(guchar, measurement.len);
measurement.uaddr = (unsigned long)data;
/* get the measurement blob */
ret = sev_ioctl(sev->sev_fd, KVM_SEV_LAUNCH_MEASURE,
&measurement, &error);
if (ret) {
error_report("%s: LAUNCH_MEASURE ret=%d fw_error=%d '%s'",
__func__, ret, error, fw_error_to_str(errno));
return;
}
sev_set_guest_state(sev, SEV_STATE_LAUNCH_SECRET);
/* encode the measurement value and emit the event */
sev->measurement = g_base64_encode(data, measurement.len);
trace_kvm_sev_launch_measurement(sev->measurement);
}
static char *sev_get_launch_measurement(void)
{
if (sev_guest &&
sev_guest->state >= SEV_STATE_LAUNCH_SECRET) {
return g_strdup(sev_guest->measurement);
}
return NULL;
}
SevLaunchMeasureInfo *qmp_query_sev_launch_measure(Error **errp)
{
char *data;
SevLaunchMeasureInfo *info;
data = sev_get_launch_measurement();
if (!data) {
error_setg(errp, "SEV launch measurement is not available");
return NULL;
}
info = g_malloc0(sizeof(*info));
info->data = data;
return info;
}
static Notifier sev_machine_done_notify = {
.notify = sev_launch_get_measure,
};
static void
sev_launch_finish(SevGuestState *sev)
{
int ret, error;
trace_kvm_sev_launch_finish();
ret = sev_ioctl(sev->sev_fd, KVM_SEV_LAUNCH_FINISH, 0, &error);
if (ret) {
error_report("%s: LAUNCH_FINISH ret=%d fw_error=%d '%s'",
__func__, ret, error, fw_error_to_str(error));
exit(1);
}
sev_set_guest_state(sev, SEV_STATE_RUNNING);
/* add migration blocker */
error_setg(&sev_mig_blocker,
"SEV: Migration is not implemented");
migrate_add_blocker(sev_mig_blocker, &error_fatal);
}
static void
sev_vm_state_change(void *opaque, bool running, RunState state)
{
SevGuestState *sev = opaque;
if (running) {
if (!sev_check_state(sev, SEV_STATE_RUNNING)) {
sev_launch_finish(sev);
}
}
}
int sev_kvm_init(ConfidentialGuestSupport *cgs, Error **errp)
{
SevGuestState *sev
= (SevGuestState *)object_dynamic_cast(OBJECT(cgs), TYPE_SEV_GUEST);
char *devname;
int ret, fw_error, cmd;
uint32_t ebx;
uint32_t host_cbitpos;
struct sev_user_data_status status = {};
if (!sev) {
return 0;
}
ret = ram_block_discard_disable(true);
if (ret) {
error_report("%s: cannot disable RAM discard", __func__);
return -1;
}
sev_guest = sev;
sev->state = SEV_STATE_UNINIT;
host_cpuid(0x8000001F, 0, NULL, &ebx, NULL, NULL);
host_cbitpos = ebx & 0x3f;
/*
* The cbitpos value will be placed in bit positions 5:0 of the EBX
* register of CPUID 0x8000001F. No need to verify the range as the
* comparison against the host value accomplishes that.
*/
if (host_cbitpos != sev->cbitpos) {
error_setg(errp, "%s: cbitpos check failed, host '%d' requested '%d'",
__func__, host_cbitpos, sev->cbitpos);
goto err;
}
/*
* The reduced-phys-bits value will be placed in bit positions 11:6 of
* the EBX register of CPUID 0x8000001F, so verify the supplied value
* is in the range of 1 to 63.
*/
if (sev->reduced_phys_bits < 1 || sev->reduced_phys_bits > 63) {
error_setg(errp, "%s: reduced_phys_bits check failed,"
" it should be in the range of 1 to 63, requested '%d'",
__func__, sev->reduced_phys_bits);
goto err;
}
devname = object_property_get_str(OBJECT(sev), "sev-device", NULL);
sev->sev_fd = open(devname, O_RDWR);
if (sev->sev_fd < 0) {
error_setg(errp, "%s: Failed to open %s '%s'", __func__,
devname, strerror(errno));
g_free(devname);
goto err;
}
g_free(devname);
ret = sev_platform_ioctl(sev->sev_fd, SEV_PLATFORM_STATUS, &status,
&fw_error);
if (ret) {
error_setg(errp, "%s: failed to get platform status ret=%d "
"fw_error='%d: %s'", __func__, ret, fw_error,
fw_error_to_str(fw_error));
goto err;
}
sev->build_id = status.build;
sev->api_major = status.api_major;
sev->api_minor = status.api_minor;
if (sev_es_enabled()) {
if (!kvm_kernel_irqchip_allowed()) {
error_report("%s: SEV-ES guests require in-kernel irqchip support",
__func__);
goto err;
}
if (!(status.flags & SEV_STATUS_FLAGS_CONFIG_ES)) {
error_report("%s: guest policy requires SEV-ES, but "
"host SEV-ES support unavailable",
__func__);
goto err;
}
cmd = KVM_SEV_ES_INIT;
} else {
cmd = KVM_SEV_INIT;
}
trace_kvm_sev_init();
ret = sev_ioctl(sev->sev_fd, cmd, NULL, &fw_error);
if (ret) {
error_setg(errp, "%s: failed to initialize ret=%d fw_error=%d '%s'",
__func__, ret, fw_error, fw_error_to_str(fw_error));
goto err;
}
ret = sev_launch_start(sev);
if (ret) {
error_setg(errp, "%s: failed to create encryption context", __func__);
goto err;
}
ram_block_notifier_add(&sev_ram_notifier);
qemu_add_machine_init_done_notifier(&sev_machine_done_notify);
qemu_add_vm_change_state_handler(sev_vm_state_change, sev);
cgs->ready = true;
return 0;
err:
sev_guest = NULL;
ram_block_discard_disable(false);
return -1;
}
int
sev_encrypt_flash(uint8_t *ptr, uint64_t len, Error **errp)
{
if (!sev_guest) {
return 0;
}
/* if SEV is in update state then encrypt the data else do nothing */
if (sev_check_state(sev_guest, SEV_STATE_LAUNCH_UPDATE)) {
int ret = sev_launch_update_data(sev_guest, ptr, len);
if (ret < 0) {
error_setg(errp, "SEV: Failed to encrypt pflash rom");
return ret;
}
}
return 0;
}
int sev_inject_launch_secret(const char *packet_hdr, const char *secret,
uint64_t gpa, Error **errp)
{
struct kvm_sev_launch_secret input;
g_autofree guchar *data = NULL, *hdr = NULL;
int error, ret = 1;
void *hva;
gsize hdr_sz = 0, data_sz = 0;
MemoryRegion *mr = NULL;
if (!sev_guest) {
error_setg(errp, "SEV not enabled for guest");
return 1;
}
/* secret can be injected only in this state */
if (!sev_check_state(sev_guest, SEV_STATE_LAUNCH_SECRET)) {
error_setg(errp, "SEV: Not in correct state. (LSECRET) %x",
sev_guest->state);
return 1;
}
hdr = g_base64_decode(packet_hdr, &hdr_sz);
if (!hdr || !hdr_sz) {
error_setg(errp, "SEV: Failed to decode sequence header");
return 1;
}
data = g_base64_decode(secret, &data_sz);
if (!data || !data_sz) {
error_setg(errp, "SEV: Failed to decode data");
return 1;
}
hva = gpa2hva(&mr, gpa, data_sz, errp);
if (!hva) {
error_prepend(errp, "SEV: Failed to calculate guest address: ");
return 1;
}
input.hdr_uaddr = (uint64_t)(unsigned long)hdr;
input.hdr_len = hdr_sz;
input.trans_uaddr = (uint64_t)(unsigned long)data;
input.trans_len = data_sz;
input.guest_uaddr = (uint64_t)(unsigned long)hva;
input.guest_len = data_sz;
trace_kvm_sev_launch_secret(gpa, input.guest_uaddr,
input.trans_uaddr, input.trans_len);
ret = sev_ioctl(sev_guest->sev_fd, KVM_SEV_LAUNCH_SECRET,
&input, &error);
if (ret) {
error_setg(errp, "SEV: failed to inject secret ret=%d fw_error=%d '%s'",
ret, error, fw_error_to_str(error));
return ret;
}
return 0;
}
#define SEV_SECRET_GUID "4c2eb361-7d9b-4cc3-8081-127c90d3d294"
struct sev_secret_area {
uint32_t base;
uint32_t size;
};
void qmp_sev_inject_launch_secret(const char *packet_hdr,
const char *secret,
bool has_gpa, uint64_t gpa,
Error **errp)
{
if (!sev_enabled()) {
error_setg(errp, "SEV not enabled for guest");
return;
}
if (!has_gpa) {
uint8_t *data;
struct sev_secret_area *area;
if (!pc_system_ovmf_table_find(SEV_SECRET_GUID, &data, NULL)) {
error_setg(errp, "SEV: no secret area found in OVMF,"
" gpa must be specified.");
return;
}
area = (struct sev_secret_area *)data;
gpa = area->base;
}
sev_inject_launch_secret(packet_hdr, secret, gpa, errp);
}
static int
sev_es_parse_reset_block(SevInfoBlock *info, uint32_t *addr)
{
if (!info->reset_addr) {
error_report("SEV-ES reset address is zero");
return 1;
}
*addr = info->reset_addr;
return 0;
}
static int
sev_es_find_reset_vector(void *flash_ptr, uint64_t flash_size,
uint32_t *addr)
{
QemuUUID info_guid, *guid;
SevInfoBlock *info;
uint8_t *data;
uint16_t *len;
/*
* Initialize the address to zero. An address of zero with a successful
* return code indicates that SEV-ES is not active.
*/
*addr = 0;
/*
* Extract the AP reset vector for SEV-ES guests by locating the SEV GUID.
* The SEV GUID is located on its own (original implementation) or within
* the Firmware GUID Table (new implementation), either of which are
* located 32 bytes from the end of the flash.
*
* Check the Firmware GUID Table first.
*/
if (pc_system_ovmf_table_find(SEV_INFO_BLOCK_GUID, &data, NULL)) {
return sev_es_parse_reset_block((SevInfoBlock *)data, addr);
}
/*
* SEV info block not found in the Firmware GUID Table (or there isn't
* a Firmware GUID Table), fall back to the original implementation.
*/
data = flash_ptr + flash_size - 0x20;
qemu_uuid_parse(SEV_INFO_BLOCK_GUID, &info_guid);
info_guid = qemu_uuid_bswap(info_guid); /* GUIDs are LE */
guid = (QemuUUID *)(data - sizeof(info_guid));
if (!qemu_uuid_is_equal(guid, &info_guid)) {
error_report("SEV information block/Firmware GUID Table block not found in pflash rom");
return 1;
}
len = (uint16_t *)((uint8_t *)guid - sizeof(*len));
info = (SevInfoBlock *)(data - le16_to_cpu(*len));
return sev_es_parse_reset_block(info, addr);
}
void sev_es_set_reset_vector(CPUState *cpu)
{
X86CPU *x86;
CPUX86State *env;
/* Only update if we have valid reset information */
if (!sev_guest || !sev_guest->reset_data_valid) {
return;
}
/* Do not update the BSP reset state */
if (cpu->cpu_index == 0) {
return;
}
x86 = X86_CPU(cpu);
env = &x86->env;
cpu_x86_load_seg_cache(env, R_CS, 0xf000, sev_guest->reset_cs, 0xffff,
DESC_P_MASK | DESC_S_MASK | DESC_CS_MASK |
DESC_R_MASK | DESC_A_MASK);
env->eip = sev_guest->reset_ip;
}
int sev_es_save_reset_vector(void *flash_ptr, uint64_t flash_size)
{
CPUState *cpu;
uint32_t addr;
int ret;
if (!sev_es_enabled()) {
return 0;
}
addr = 0;
ret = sev_es_find_reset_vector(flash_ptr, flash_size,
&addr);
if (ret) {
return ret;
}
if (addr) {
sev_guest->reset_cs = addr & 0xffff0000;
sev_guest->reset_ip = addr & 0x0000ffff;
sev_guest->reset_data_valid = true;
CPU_FOREACH(cpu) {
sev_es_set_reset_vector(cpu);
}
}
return 0;
}
static const QemuUUID sev_hash_table_header_guid = {
.data = UUID_LE(0x9438d606, 0x4f22, 0x4cc9, 0xb4, 0x79, 0xa7, 0x93,
0xd4, 0x11, 0xfd, 0x21)
};
static const QemuUUID sev_kernel_entry_guid = {
.data = UUID_LE(0x4de79437, 0xabd2, 0x427f, 0xb8, 0x35, 0xd5, 0xb1,
0x72, 0xd2, 0x04, 0x5b)
};
static const QemuUUID sev_initrd_entry_guid = {
.data = UUID_LE(0x44baf731, 0x3a2f, 0x4bd7, 0x9a, 0xf1, 0x41, 0xe2,
0x91, 0x69, 0x78, 0x1d)
};
static const QemuUUID sev_cmdline_entry_guid = {
.data = UUID_LE(0x97d02dd8, 0xbd20, 0x4c94, 0xaa, 0x78, 0xe7, 0x71,
0x4d, 0x36, 0xab, 0x2a)
};
/*
* Add the hashes of the linux kernel/initrd/cmdline to an encrypted guest page
* which is included in SEV's initial memory measurement.
*/
bool sev_add_kernel_loader_hashes(SevKernelLoaderContext *ctx, Error **errp)
{
uint8_t *data;
SevHashTableDescriptor *area;
SevHashTable *ht;
PaddedSevHashTable *padded_ht;
uint8_t cmdline_hash[HASH_SIZE];
uint8_t initrd_hash[HASH_SIZE];
uint8_t kernel_hash[HASH_SIZE];
uint8_t *hashp;
size_t hash_len = HASH_SIZE;
hwaddr mapped_len = sizeof(*padded_ht);
MemTxAttrs attrs = { 0 };
bool ret = true;
/*
* Only add the kernel hashes if the sev-guest configuration explicitly
* stated kernel-hashes=on.
*/
if (!sev_guest->kernel_hashes) {
return false;
}
if (!pc_system_ovmf_table_find(SEV_HASH_TABLE_RV_GUID, &data, NULL)) {
error_setg(errp, "SEV: kernel specified but guest firmware "
"has no hashes table GUID");
return false;
}
area = (SevHashTableDescriptor *)data;
if (!area->base || area->size < sizeof(PaddedSevHashTable)) {
error_setg(errp, "SEV: guest firmware hashes table area is invalid "
"(base=0x%x size=0x%x)", area->base, area->size);
return false;
}
/*
* Calculate hash of kernel command-line with the terminating null byte. If
* the user doesn't supply a command-line via -append, the 1-byte "\0" will
* be used.
*/
hashp = cmdline_hash;
if (qcrypto_hash_bytes(QCRYPTO_HASH_ALG_SHA256, ctx->cmdline_data,
ctx->cmdline_size, &hashp, &hash_len, errp) < 0) {
return false;
}
assert(hash_len == HASH_SIZE);
/*
* Calculate hash of initrd. If the user doesn't supply an initrd via
* -initrd, an empty buffer will be used (ctx->initrd_size == 0).
*/
hashp = initrd_hash;
if (qcrypto_hash_bytes(QCRYPTO_HASH_ALG_SHA256, ctx->initrd_data,
ctx->initrd_size, &hashp, &hash_len, errp) < 0) {
return false;
}
assert(hash_len == HASH_SIZE);
/* Calculate hash of the kernel */
hashp = kernel_hash;
struct iovec iov[2] = {
{ .iov_base = ctx->setup_data, .iov_len = ctx->setup_size },
{ .iov_base = ctx->kernel_data, .iov_len = ctx->kernel_size }
};
if (qcrypto_hash_bytesv(QCRYPTO_HASH_ALG_SHA256, iov, ARRAY_SIZE(iov),
&hashp, &hash_len, errp) < 0) {
return false;
}
assert(hash_len == HASH_SIZE);
/*
* Populate the hashes table in the guest's memory at the OVMF-designated
* area for the SEV hashes table
*/
padded_ht = address_space_map(&address_space_memory, area->base,
&mapped_len, true, attrs);
if (!padded_ht || mapped_len != sizeof(*padded_ht)) {
error_setg(errp, "SEV: cannot map hashes table guest memory area");
return false;
}
ht = &padded_ht->ht;
ht->guid = sev_hash_table_header_guid;
ht->len = sizeof(*ht);
ht->cmdline.guid = sev_cmdline_entry_guid;
ht->cmdline.len = sizeof(ht->cmdline);
memcpy(ht->cmdline.hash, cmdline_hash, sizeof(ht->cmdline.hash));
ht->initrd.guid = sev_initrd_entry_guid;
ht->initrd.len = sizeof(ht->initrd);
memcpy(ht->initrd.hash, initrd_hash, sizeof(ht->initrd.hash));
ht->kernel.guid = sev_kernel_entry_guid;
ht->kernel.len = sizeof(ht->kernel);
memcpy(ht->kernel.hash, kernel_hash, sizeof(ht->kernel.hash));
/* zero the excess data so the measurement can be reliably calculated */
memset(padded_ht->padding, 0, sizeof(padded_ht->padding));
if (sev_encrypt_flash((uint8_t *)padded_ht, sizeof(*padded_ht), errp) < 0) {
ret = false;
}
address_space_unmap(&address_space_memory, padded_ht,
mapped_len, true, mapped_len);
return ret;
}
static void
sev_register_types(void)
{
type_register_static(&sev_guest_info);
}
type_init(sev_register_types);
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