hyperv: Add support to process syndbg commands

SynDbg commands can come from two different flows:
1. Hypercalls, in this mode the data being sent is fully
   encapsulated network packets.
2. SynDbg specific MSRs, in this mode only the data that needs to be
   transfered is passed.

Signed-off-by: Jon Doron <arilou@gmail.com>
Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Message-Id: <20220216102500.692781-4-arilou@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Jon Doron 2022-02-16 12:24:59 +02:00 committed by Paolo Bonzini
parent ccbdf5e81b
commit 73d2407407
8 changed files with 451 additions and 8 deletions

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@ -225,6 +225,21 @@ default (WS2016).
Note: hv-version-id-* are not enlightenments and thus don't enable Hyper-V
identification when specified without any other enlightenments.
3.21. hv-syndbg
===============
Enables Hyper-V synthetic debugger interface, this is a special interface used
by Windows Kernel debugger to send the packets through, rather than sending
them via serial/network .
When enabled, this enlightenment provides additional communication facilities
to the guest: SynDbg messages.
This new communication is used by Windows Kernel debugger rather than sending
packets via serial/network, adding significant performance boost over the other
comm channels.
This enlightenment requires a VMBus device (-device vmbus-bridge,irq=15)
and the follow enlightenments to work:
hv-relaxed,hv_time,hv-vapic,hv-vpindex,hv-synic,hv-runtime,hv-stimer
4. Supplementary features
=========================

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@ -704,3 +704,246 @@ uint16_t hyperv_hcall_signal_event(uint64_t param, bool fast)
}
return HV_STATUS_INVALID_CONNECTION_ID;
}
static HvSynDbgHandler hv_syndbg_handler;
static void *hv_syndbg_context;
void hyperv_set_syndbg_handler(HvSynDbgHandler handler, void *context)
{
assert(!hv_syndbg_handler);
hv_syndbg_handler = handler;
hv_syndbg_context = context;
}
uint16_t hyperv_hcall_reset_dbg_session(uint64_t outgpa)
{
uint16_t ret;
HvSynDbgMsg msg;
struct hyperv_reset_debug_session_output *reset_dbg_session = NULL;
hwaddr len;
if (!hv_syndbg_handler) {
ret = HV_STATUS_INVALID_HYPERCALL_CODE;
goto cleanup;
}
len = sizeof(*reset_dbg_session);
reset_dbg_session = cpu_physical_memory_map(outgpa, &len, 1);
if (!reset_dbg_session || len < sizeof(*reset_dbg_session)) {
ret = HV_STATUS_INSUFFICIENT_MEMORY;
goto cleanup;
}
msg.type = HV_SYNDBG_MSG_CONNECTION_INFO;
ret = hv_syndbg_handler(hv_syndbg_context, &msg);
if (ret) {
goto cleanup;
}
reset_dbg_session->host_ip = msg.u.connection_info.host_ip;
reset_dbg_session->host_port = msg.u.connection_info.host_port;
/* The following fields are only used as validation for KDVM */
memset(&reset_dbg_session->host_mac, 0,
sizeof(reset_dbg_session->host_mac));
reset_dbg_session->target_ip = msg.u.connection_info.host_ip;
reset_dbg_session->target_port = msg.u.connection_info.host_port;
memset(&reset_dbg_session->target_mac, 0,
sizeof(reset_dbg_session->target_mac));
cleanup:
if (reset_dbg_session) {
cpu_physical_memory_unmap(reset_dbg_session,
sizeof(*reset_dbg_session), 1, len);
}
return ret;
}
uint16_t hyperv_hcall_retreive_dbg_data(uint64_t ingpa, uint64_t outgpa,
bool fast)
{
uint16_t ret;
struct hyperv_retrieve_debug_data_input *debug_data_in = NULL;
struct hyperv_retrieve_debug_data_output *debug_data_out = NULL;
hwaddr in_len, out_len;
HvSynDbgMsg msg;
if (fast || !hv_syndbg_handler) {
ret = HV_STATUS_INVALID_HYPERCALL_CODE;
goto cleanup;
}
in_len = sizeof(*debug_data_in);
debug_data_in = cpu_physical_memory_map(ingpa, &in_len, 0);
if (!debug_data_in || in_len < sizeof(*debug_data_in)) {
ret = HV_STATUS_INSUFFICIENT_MEMORY;
goto cleanup;
}
out_len = sizeof(*debug_data_out);
debug_data_out = cpu_physical_memory_map(outgpa, &out_len, 1);
if (!debug_data_out || out_len < sizeof(*debug_data_out)) {
ret = HV_STATUS_INSUFFICIENT_MEMORY;
goto cleanup;
}
msg.type = HV_SYNDBG_MSG_RECV;
msg.u.recv.buf_gpa = outgpa + sizeof(*debug_data_out);
msg.u.recv.count = TARGET_PAGE_SIZE - sizeof(*debug_data_out);
msg.u.recv.options = debug_data_in->options;
msg.u.recv.timeout = debug_data_in->timeout;
msg.u.recv.is_raw = true;
ret = hv_syndbg_handler(hv_syndbg_context, &msg);
if (ret == HV_STATUS_NO_DATA) {
debug_data_out->retrieved_count = 0;
debug_data_out->remaining_count = debug_data_in->count;
goto cleanup;
} else if (ret != HV_STATUS_SUCCESS) {
goto cleanup;
}
debug_data_out->retrieved_count = msg.u.recv.retrieved_count;
debug_data_out->remaining_count =
debug_data_in->count - msg.u.recv.retrieved_count;
cleanup:
if (debug_data_out) {
cpu_physical_memory_unmap(debug_data_out, sizeof(*debug_data_out), 1,
out_len);
}
if (debug_data_in) {
cpu_physical_memory_unmap(debug_data_in, sizeof(*debug_data_in), 0,
in_len);
}
return ret;
}
uint16_t hyperv_hcall_post_dbg_data(uint64_t ingpa, uint64_t outgpa, bool fast)
{
uint16_t ret;
struct hyperv_post_debug_data_input *post_data_in = NULL;
struct hyperv_post_debug_data_output *post_data_out = NULL;
hwaddr in_len, out_len;
HvSynDbgMsg msg;
if (fast || !hv_syndbg_handler) {
ret = HV_STATUS_INVALID_HYPERCALL_CODE;
goto cleanup;
}
in_len = sizeof(*post_data_in);
post_data_in = cpu_physical_memory_map(ingpa, &in_len, 0);
if (!post_data_in || in_len < sizeof(*post_data_in)) {
ret = HV_STATUS_INSUFFICIENT_MEMORY;
goto cleanup;
}
if (post_data_in->count > TARGET_PAGE_SIZE - sizeof(*post_data_in)) {
ret = HV_STATUS_INVALID_PARAMETER;
goto cleanup;
}
out_len = sizeof(*post_data_out);
post_data_out = cpu_physical_memory_map(outgpa, &out_len, 1);
if (!post_data_out || out_len < sizeof(*post_data_out)) {
ret = HV_STATUS_INSUFFICIENT_MEMORY;
goto cleanup;
}
msg.type = HV_SYNDBG_MSG_SEND;
msg.u.send.buf_gpa = ingpa + sizeof(*post_data_in);
msg.u.send.count = post_data_in->count;
msg.u.send.is_raw = true;
ret = hv_syndbg_handler(hv_syndbg_context, &msg);
if (ret != HV_STATUS_SUCCESS) {
goto cleanup;
}
post_data_out->pending_count = msg.u.send.pending_count;
ret = post_data_out->pending_count ? HV_STATUS_INSUFFICIENT_BUFFERS :
HV_STATUS_SUCCESS;
cleanup:
if (post_data_out) {
cpu_physical_memory_unmap(post_data_out,
sizeof(*post_data_out), 1, out_len);
}
if (post_data_in) {
cpu_physical_memory_unmap(post_data_in,
sizeof(*post_data_in), 0, in_len);
}
return ret;
}
uint32_t hyperv_syndbg_send(uint64_t ingpa, uint32_t count)
{
HvSynDbgMsg msg;
if (!hv_syndbg_handler) {
return HV_SYNDBG_STATUS_INVALID;
}
msg.type = HV_SYNDBG_MSG_SEND;
msg.u.send.buf_gpa = ingpa;
msg.u.send.count = count;
msg.u.send.is_raw = false;
if (hv_syndbg_handler(hv_syndbg_context, &msg)) {
return HV_SYNDBG_STATUS_INVALID;
}
return HV_SYNDBG_STATUS_SEND_SUCCESS;
}
uint32_t hyperv_syndbg_recv(uint64_t ingpa, uint32_t count)
{
uint16_t ret;
HvSynDbgMsg msg;
if (!hv_syndbg_handler) {
return HV_SYNDBG_STATUS_INVALID;
}
msg.type = HV_SYNDBG_MSG_RECV;
msg.u.recv.buf_gpa = ingpa;
msg.u.recv.count = count;
msg.u.recv.options = 0;
msg.u.recv.timeout = 0;
msg.u.recv.is_raw = false;
ret = hv_syndbg_handler(hv_syndbg_context, &msg);
if (ret != HV_STATUS_SUCCESS) {
return 0;
}
return HV_SYNDBG_STATUS_SET_SIZE(HV_SYNDBG_STATUS_RECV_SUCCESS,
msg.u.recv.retrieved_count);
}
void hyperv_syndbg_set_pending_page(uint64_t ingpa)
{
HvSynDbgMsg msg;
if (!hv_syndbg_handler) {
return;
}
msg.type = HV_SYNDBG_MSG_SET_PENDING_PAGE;
msg.u.pending_page.buf_gpa = ingpa;
hv_syndbg_handler(hv_syndbg_context, &msg);
}
uint64_t hyperv_syndbg_query_options(void)
{
HvSynDbgMsg msg;
if (!hv_syndbg_handler) {
return 0;
}
msg.type = HV_SYNDBG_MSG_QUERY_OPTIONS;
if (hv_syndbg_handler(hv_syndbg_context, &msg) != HV_STATUS_SUCCESS) {
return 0;
}
return msg.u.query_options.options;
}

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@ -81,4 +81,62 @@ void hyperv_synic_update(CPUState *cs, bool enable,
hwaddr msg_page_addr, hwaddr event_page_addr);
bool hyperv_is_synic_enabled(void);
/*
* Process HVCALL_RESET_DEBUG_SESSION hypercall.
*/
uint16_t hyperv_hcall_reset_dbg_session(uint64_t outgpa);
/*
* Process HVCALL_RETREIVE_DEBUG_DATA hypercall.
*/
uint16_t hyperv_hcall_retreive_dbg_data(uint64_t ingpa, uint64_t outgpa,
bool fast);
/*
* Process HVCALL_POST_DEBUG_DATA hypercall.
*/
uint16_t hyperv_hcall_post_dbg_data(uint64_t ingpa, uint64_t outgpa, bool fast);
uint32_t hyperv_syndbg_send(uint64_t ingpa, uint32_t count);
uint32_t hyperv_syndbg_recv(uint64_t ingpa, uint32_t count);
void hyperv_syndbg_set_pending_page(uint64_t ingpa);
uint64_t hyperv_syndbg_query_options(void);
typedef enum HvSynthDbgMsgType {
HV_SYNDBG_MSG_CONNECTION_INFO,
HV_SYNDBG_MSG_SEND,
HV_SYNDBG_MSG_RECV,
HV_SYNDBG_MSG_SET_PENDING_PAGE,
HV_SYNDBG_MSG_QUERY_OPTIONS
} HvDbgSynthMsgType;
typedef struct HvSynDbgMsg {
HvDbgSynthMsgType type;
union {
struct {
uint32_t host_ip;
uint16_t host_port;
} connection_info;
struct {
uint64_t buf_gpa;
uint32_t count;
uint32_t pending_count;
bool is_raw;
} send;
struct {
uint64_t buf_gpa;
uint32_t count;
uint32_t options;
uint64_t timeout;
uint32_t retrieved_count;
bool is_raw;
} recv;
struct {
uint64_t buf_gpa;
} pending_page;
struct {
uint64_t options;
} query_options;
} u;
} HvSynDbgMsg;
typedef uint16_t (*HvSynDbgHandler)(void *context, HvSynDbgMsg *msg);
void hyperv_set_syndbg_handler(HvSynDbgHandler handler, void *context);
#endif

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@ -6927,6 +6927,8 @@ static Property x86_cpu_properties[] = {
HYPERV_FEAT_AVIC, 0),
DEFINE_PROP_ON_OFF_AUTO("hv-no-nonarch-coresharing", X86CPU,
hyperv_no_nonarch_cs, ON_OFF_AUTO_OFF),
DEFINE_PROP_BIT64("hv-syndbg", X86CPU, hyperv_features,
HYPERV_FEAT_SYNDBG, 0),
DEFINE_PROP_BOOL("hv-passthrough", X86CPU, hyperv_passthrough, false),
DEFINE_PROP_BOOL("hv-enforce-cpuid", X86CPU, hyperv_enforce_cpuid, false),

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@ -1085,6 +1085,7 @@ uint64_t x86_cpu_get_supported_feature_word(FeatureWord w,
#define HYPERV_FEAT_IPI 13
#define HYPERV_FEAT_STIMER_DIRECT 14
#define HYPERV_FEAT_AVIC 15
#define HYPERV_FEAT_SYNDBG 16
#ifndef HYPERV_SPINLOCK_NEVER_NOTIFY
#define HYPERV_SPINLOCK_NEVER_NOTIFY 0xFFFFFFFF
@ -1601,6 +1602,12 @@ typedef struct CPUArchState {
uint64_t msr_hv_hypercall;
uint64_t msr_hv_guest_os_id;
uint64_t msr_hv_tsc;
uint64_t msr_hv_syndbg_control;
uint64_t msr_hv_syndbg_status;
uint64_t msr_hv_syndbg_send_page;
uint64_t msr_hv_syndbg_recv_page;
uint64_t msr_hv_syndbg_pending_page;
uint64_t msr_hv_syndbg_options;
/* Per-VCPU HV MSRs */
uint64_t msr_hv_vapic;

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@ -27,6 +27,12 @@ int kvm_hv_handle_exit(X86CPU *cpu, struct kvm_hyperv_exit *exit)
return 0;
case KVM_EXIT_HYPERV_HCALL:
exit->u.hcall.result = HV_STATUS_INVALID_HYPERCALL_CODE;
return 0;
case KVM_EXIT_HYPERV_SYNDBG:
if (!hyperv_feat_enabled(cpu, HYPERV_FEAT_SYNDBG)) {
return -1;
}
return 0;
default:
return -1;

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@ -81,20 +81,66 @@ int kvm_hv_handle_exit(X86CPU *cpu, struct kvm_hyperv_exit *exit)
case KVM_EXIT_HYPERV_HCALL: {
uint16_t code = exit->u.hcall.input & 0xffff;
bool fast = exit->u.hcall.input & HV_HYPERCALL_FAST;
uint64_t param = exit->u.hcall.params[0];
uint64_t in_param = exit->u.hcall.params[0];
uint64_t out_param = exit->u.hcall.params[1];
switch (code) {
case HV_POST_MESSAGE:
exit->u.hcall.result = hyperv_hcall_post_message(param, fast);
exit->u.hcall.result = hyperv_hcall_post_message(in_param, fast);
break;
case HV_SIGNAL_EVENT:
exit->u.hcall.result = hyperv_hcall_signal_event(param, fast);
exit->u.hcall.result = hyperv_hcall_signal_event(in_param, fast);
break;
case HV_POST_DEBUG_DATA:
exit->u.hcall.result =
hyperv_hcall_post_dbg_data(in_param, out_param, fast);
break;
case HV_RETRIEVE_DEBUG_DATA:
exit->u.hcall.result =
hyperv_hcall_retreive_dbg_data(in_param, out_param, fast);
break;
case HV_RESET_DEBUG_SESSION:
exit->u.hcall.result =
hyperv_hcall_reset_dbg_session(out_param);
break;
default:
exit->u.hcall.result = HV_STATUS_INVALID_HYPERCALL_CODE;
}
return 0;
}
case KVM_EXIT_HYPERV_SYNDBG:
if (!hyperv_feat_enabled(cpu, HYPERV_FEAT_SYNDBG)) {
return -1;
}
switch (exit->u.syndbg.msr) {
case HV_X64_MSR_SYNDBG_CONTROL: {
uint64_t control = exit->u.syndbg.control;
env->msr_hv_syndbg_control = control;
env->msr_hv_syndbg_send_page = exit->u.syndbg.send_page;
env->msr_hv_syndbg_recv_page = exit->u.syndbg.recv_page;
exit->u.syndbg.status = HV_STATUS_SUCCESS;
if (control & HV_SYNDBG_CONTROL_SEND) {
exit->u.syndbg.status =
hyperv_syndbg_send(env->msr_hv_syndbg_send_page,
HV_SYNDBG_CONTROL_SEND_SIZE(control));
} else if (control & HV_SYNDBG_CONTROL_RECV) {
exit->u.syndbg.status =
hyperv_syndbg_recv(env->msr_hv_syndbg_recv_page,
TARGET_PAGE_SIZE);
}
break;
}
case HV_X64_MSR_SYNDBG_PENDING_BUFFER:
env->msr_hv_syndbg_pending_page = exit->u.syndbg.pending_page;
hyperv_syndbg_set_pending_page(env->msr_hv_syndbg_pending_page);
break;
default:
return -1;
}
return 0;
default:
return -1;
}

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@ -104,6 +104,7 @@ static bool has_msr_hv_synic;
static bool has_msr_hv_stimer;
static bool has_msr_hv_frequencies;
static bool has_msr_hv_reenlightenment;
static bool has_msr_hv_syndbg_options;
static bool has_msr_xss;
static bool has_msr_umwait;
static bool has_msr_spec_ctrl;
@ -964,6 +965,14 @@ static struct {
.bits = HV_DEPRECATING_AEOI_RECOMMENDED}
}
},
[HYPERV_FEAT_SYNDBG] = {
.desc = "Enable synthetic kernel debugger channel (hv-syndbg)",
.flags = {
{.func = HV_CPUID_FEATURES, .reg = R_EDX,
.bits = HV_FEATURE_DEBUG_MSRS_AVAILABLE}
},
.dependencies = BIT(HYPERV_FEAT_SYNIC) | BIT(HYPERV_FEAT_RELAXED)
},
};
static struct kvm_cpuid2 *try_get_hv_cpuid(CPUState *cs, int max,
@ -1004,8 +1013,8 @@ static struct kvm_cpuid2 *try_get_hv_cpuid(CPUState *cs, int max,
static struct kvm_cpuid2 *get_supported_hv_cpuid(CPUState *cs)
{
struct kvm_cpuid2 *cpuid;
/* 0x40000000..0x40000005, 0x4000000A, 0x40000080..0x40000080 leaves */
int max = 10;
/* 0x40000000..0x40000005, 0x4000000A, 0x40000080..0x40000082 leaves */
int max = 11;
int i;
bool do_sys_ioctl;
@ -1118,6 +1127,12 @@ static struct kvm_cpuid2 *get_supported_hv_cpuid_legacy(CPUState *cs)
entry_feat->eax |= HV_SYNTIMERS_AVAILABLE;
}
if (has_msr_hv_syndbg_options) {
entry_feat->edx |= HV_GUEST_DEBUGGING_AVAILABLE;
entry_feat->edx |= HV_FEATURE_DEBUG_MSRS_AVAILABLE;
entry_feat->ebx |= HV_PARTITION_DEBUGGING_ALLOWED;
}
if (kvm_check_extension(cs->kvm_state,
KVM_CAP_HYPERV_TLBFLUSH) > 0) {
entry_recomm->eax |= HV_REMOTE_TLB_FLUSH_RECOMMENDED;
@ -1369,12 +1384,22 @@ static int hyperv_fill_cpuids(CPUState *cs,
{
X86CPU *cpu = X86_CPU(cs);
struct kvm_cpuid_entry2 *c;
uint32_t cpuid_i = 0;
uint32_t signature[3];
uint32_t cpuid_i = 0, max_cpuid_leaf = 0;
max_cpuid_leaf = HV_CPUID_IMPLEMENT_LIMITS;
if (hyperv_feat_enabled(cpu, HYPERV_FEAT_EVMCS)) {
max_cpuid_leaf = MAX(max_cpuid_leaf, HV_CPUID_NESTED_FEATURES);
}
if (hyperv_feat_enabled(cpu, HYPERV_FEAT_SYNDBG)) {
max_cpuid_leaf =
MAX(max_cpuid_leaf, HV_CPUID_SYNDBG_PLATFORM_CAPABILITIES);
}
c = &cpuid_ent[cpuid_i++];
c->function = HV_CPUID_VENDOR_AND_MAX_FUNCTIONS;
c->eax = hyperv_feat_enabled(cpu, HYPERV_FEAT_EVMCS) ?
HV_CPUID_NESTED_FEATURES : HV_CPUID_IMPLEMENT_LIMITS;
c->eax = max_cpuid_leaf;
c->ebx = cpu->hyperv_vendor_id[0];
c->ecx = cpu->hyperv_vendor_id[1];
c->edx = cpu->hyperv_vendor_id[2];
@ -1453,6 +1478,33 @@ static int hyperv_fill_cpuids(CPUState *cs,
c->eax = cpu->hyperv_nested[0];
}
if (hyperv_feat_enabled(cpu, HYPERV_FEAT_SYNDBG)) {
c = &cpuid_ent[cpuid_i++];
c->function = HV_CPUID_SYNDBG_VENDOR_AND_MAX_FUNCTIONS;
c->eax = hyperv_feat_enabled(cpu, HYPERV_FEAT_EVMCS) ?
HV_CPUID_NESTED_FEATURES : HV_CPUID_IMPLEMENT_LIMITS;
memcpy(signature, "Microsoft VS", 12);
c->eax = 0;
c->ebx = signature[0];
c->ecx = signature[1];
c->edx = signature[2];
c = &cpuid_ent[cpuid_i++];
c->function = HV_CPUID_SYNDBG_INTERFACE;
memcpy(signature, "VS#1\0\0\0\0\0\0\0\0", 12);
c->eax = signature[0];
c->ebx = 0;
c->ecx = 0;
c->edx = 0;
c = &cpuid_ent[cpuid_i++];
c->function = HV_CPUID_SYNDBG_PLATFORM_CAPABILITIES;
c->eax = HV_SYNDBG_CAP_ALLOW_KERNEL_DEBUGGING;
c->ebx = 0;
c->ecx = 0;
c->edx = 0;
}
return cpuid_i;
}
@ -2261,6 +2313,9 @@ static int kvm_get_supported_msrs(KVMState *s)
case HV_X64_MSR_REENLIGHTENMENT_CONTROL:
has_msr_hv_reenlightenment = true;
break;
case HV_X64_MSR_SYNDBG_OPTIONS:
has_msr_hv_syndbg_options = true;
break;
case MSR_IA32_SPEC_CTRL:
has_msr_spec_ctrl = true;
break;
@ -3178,6 +3233,11 @@ static int kvm_put_msrs(X86CPU *cpu, int level)
kvm_msr_entry_add(cpu, HV_X64_MSR_TSC_EMULATION_STATUS,
env->msr_hv_tsc_emulation_status);
}
if (hyperv_feat_enabled(cpu, HYPERV_FEAT_SYNDBG) &&
has_msr_hv_syndbg_options) {
kvm_msr_entry_add(cpu, HV_X64_MSR_SYNDBG_OPTIONS,
hyperv_syndbg_query_options());
}
}
if (hyperv_feat_enabled(cpu, HYPERV_FEAT_VAPIC)) {
kvm_msr_entry_add(cpu, HV_X64_MSR_APIC_ASSIST_PAGE,
@ -3619,6 +3679,9 @@ static int kvm_get_msrs(X86CPU *cpu)
kvm_msr_entry_add(cpu, HV_X64_MSR_TSC_EMULATION_CONTROL, 0);
kvm_msr_entry_add(cpu, HV_X64_MSR_TSC_EMULATION_STATUS, 0);
}
if (has_msr_hv_syndbg_options) {
kvm_msr_entry_add(cpu, HV_X64_MSR_SYNDBG_OPTIONS, 0);
}
if (has_msr_hv_crash) {
int j;
@ -3910,6 +3973,9 @@ static int kvm_get_msrs(X86CPU *cpu)
case HV_X64_MSR_TSC_EMULATION_STATUS:
env->msr_hv_tsc_emulation_status = msrs[i].data;
break;
case HV_X64_MSR_SYNDBG_OPTIONS:
env->msr_hv_syndbg_options = msrs[i].data;
break;
case MSR_MTRRdefType:
env->mtrr_deftype = msrs[i].data;
break;