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x86/kvm/hyper-v: Add support for synthetic debugger interface 

Add support for Hyper-V synthetic debugger (syndbg) interface.
The syndbg interface is using MSRs to emulate a way to send/recv packets
data.

The debug transport dll (kdvm/kdnet) will identify if Hyper-V is enabled
and if it supports the synthetic debugger interface it will attempt to
use it, instead of trying to initialize a network adapter.

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Jon Doron <arilou@gmail.com>
Message-Id: <20200529134543.1127440-4-arilou@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Jon Doron 2020-05-29 16:45:40 +03:00 committed by Paolo Bonzini
parent 22ad0026d0
commit f97f5a56f5
7 changed files with 258 additions and 3 deletions
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16
Documentation/virt/kvm/api.rst
View File

@ -5070,6 +5070,7 @@ EOI was received.
struct kvm_hyperv_exit {
#define KVM_EXIT_HYPERV_SYNIC 1
#define KVM_EXIT_HYPERV_HCALL 2
#define KVM_EXIT_HYPERV_SYNDBG 3
__u32 type;
__u32 pad1;
union {
@ -5085,6 +5086,15 @@ EOI was received.
__u64 result;
__u64 params[2];
} hcall;
struct {
__u32 msr;
__u32 pad2;
__u64 control;
__u64 status;
__u64 send_page;
__u64 recv_page;
__u64 pending_page;
} syndbg;
} u;
};
/* KVM_EXIT_HYPERV */
@ -5101,6 +5111,12 @@ Hyper-V SynIC state change. Notification is used to remap SynIC
event/message pages and to enable/disable SynIC messages/events processing
in userspace.
- KVM_EXIT_HYPERV_SYNDBG -- synchronously notify user-space about
Hyper-V Synthetic debugger state change. Notification is used to either update
the pending_page location or to send a control command (send the buffer located
in send_page or recv a buffer to recv_page).
::
/* KVM_EXIT_ARM_NISV */

13
arch/x86/include/asm/kvm_host.h
View File

@ -863,6 +863,18 @@ struct kvm_apic_map {
struct kvm_lapic *phys_map[];
};
/* Hyper-V synthetic debugger (SynDbg)*/
struct kvm_hv_syndbg {
struct {
u64 control;
u64 status;
u64 send_page;
u64 recv_page;
u64 pending_page;
} control;
u64 options;
};
/* Hyper-V emulation context */
struct kvm_hv {
struct mutex hv_lock;
@ -886,6 +898,7 @@ struct kvm_hv {
atomic_t num_mismatched_vp_indexes;
struct hv_partition_assist_pg *hv_pa_pg;
struct kvm_hv_syndbg hv_syndbg;
};
enum kvm_irqchip_mode {

158
arch/x86/kvm/hyperv.c
View File

@ -21,6 +21,7 @@
#include "x86.h"
#include "lapic.h"
#include "ioapic.h"
#include "cpuid.h"
#include "hyperv.h"
#include <linux/cpu.h>
@ -266,6 +267,123 @@ static int synic_set_msr(struct kvm_vcpu_hv_synic *synic,
return ret;
}
static bool kvm_hv_is_syndbg_enabled(struct kvm_vcpu *vcpu)
{
struct kvm_cpuid_entry2 *entry;
entry = kvm_find_cpuid_entry(vcpu,
HYPERV_CPUID_SYNDBG_PLATFORM_CAPABILITIES,
0);
if (!entry)
return false;
return entry->eax & HV_X64_SYNDBG_CAP_ALLOW_KERNEL_DEBUGGING;
}
static int kvm_hv_syndbg_complete_userspace(struct kvm_vcpu *vcpu)
{
struct kvm *kvm = vcpu->kvm;
struct kvm_hv *hv = &kvm->arch.hyperv;
if (vcpu->run->hyperv.u.syndbg.msr == HV_X64_MSR_SYNDBG_CONTROL)
hv->hv_syndbg.control.status =
vcpu->run->hyperv.u.syndbg.status;
return 1;
}
static void syndbg_exit(struct kvm_vcpu *vcpu, u32 msr)
{
struct kvm_hv_syndbg *syndbg = vcpu_to_hv_syndbg(vcpu);
struct kvm_vcpu_hv *hv_vcpu = &vcpu->arch.hyperv;
hv_vcpu->exit.type = KVM_EXIT_HYPERV_SYNDBG;
hv_vcpu->exit.u.syndbg.msr = msr;
hv_vcpu->exit.u.syndbg.control = syndbg->control.control;
hv_vcpu->exit.u.syndbg.send_page = syndbg->control.send_page;
hv_vcpu->exit.u.syndbg.recv_page = syndbg->control.recv_page;
hv_vcpu->exit.u.syndbg.pending_page = syndbg->control.pending_page;
vcpu->arch.complete_userspace_io =
kvm_hv_syndbg_complete_userspace;
kvm_make_request(KVM_REQ_HV_EXIT, vcpu);
}
static int syndbg_set_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data, bool host)
{
struct kvm_hv_syndbg *syndbg = vcpu_to_hv_syndbg(vcpu);
if (!kvm_hv_is_syndbg_enabled(vcpu) && !host)
return 1;
trace_kvm_hv_syndbg_set_msr(vcpu->vcpu_id,
vcpu_to_hv_vcpu(vcpu)->vp_index, msr, data);
switch (msr) {
case HV_X64_MSR_SYNDBG_CONTROL:
syndbg->control.control = data;
if (!host)
syndbg_exit(vcpu, msr);
break;
case HV_X64_MSR_SYNDBG_STATUS:
syndbg->control.status = data;
break;
case HV_X64_MSR_SYNDBG_SEND_BUFFER:
syndbg->control.send_page = data;
break;
case HV_X64_MSR_SYNDBG_RECV_BUFFER:
syndbg->control.recv_page = data;
break;
case HV_X64_MSR_SYNDBG_PENDING_BUFFER:
syndbg->control.pending_page = data;
if (!host)
syndbg_exit(vcpu, msr);
break;
case HV_X64_MSR_SYNDBG_OPTIONS:
syndbg->options = data;
break;
default:
break;
}
return 0;
}
static int syndbg_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata, bool host)
{
struct kvm_hv_syndbg *syndbg = vcpu_to_hv_syndbg(vcpu);
if (!kvm_hv_is_syndbg_enabled(vcpu) && !host)
return 1;
switch (msr) {
case HV_X64_MSR_SYNDBG_CONTROL:
*pdata = syndbg->control.control;
break;
case HV_X64_MSR_SYNDBG_STATUS:
*pdata = syndbg->control.status;
break;
case HV_X64_MSR_SYNDBG_SEND_BUFFER:
*pdata = syndbg->control.send_page;
break;
case HV_X64_MSR_SYNDBG_RECV_BUFFER:
*pdata = syndbg->control.recv_page;
break;
case HV_X64_MSR_SYNDBG_PENDING_BUFFER:
*pdata = syndbg->control.pending_page;
break;
case HV_X64_MSR_SYNDBG_OPTIONS:
*pdata = syndbg->options;
break;
default:
break;
}
trace_kvm_hv_syndbg_get_msr(vcpu->vcpu_id,
vcpu_to_hv_vcpu(vcpu)->vp_index, msr,
*pdata);
return 0;
}
static int synic_get_msr(struct kvm_vcpu_hv_synic *synic, u32 msr, u64 *pdata,
bool host)
{
@ -800,6 +918,8 @@ static bool kvm_hv_msr_partition_wide(u32 msr)
case HV_X64_MSR_REENLIGHTENMENT_CONTROL:
case HV_X64_MSR_TSC_EMULATION_CONTROL:
case HV_X64_MSR_TSC_EMULATION_STATUS:
case HV_X64_MSR_SYNDBG_OPTIONS:
case HV_X64_MSR_SYNDBG_CONTROL ... HV_X64_MSR_SYNDBG_PENDING_BUFFER:
r = true;
break;
}
@ -1061,6 +1181,9 @@ static int kvm_hv_set_msr_pw(struct kvm_vcpu *vcpu, u32 msr, u64 data,
if (!host)
return 1;
break;
case HV_X64_MSR_SYNDBG_OPTIONS:
case HV_X64_MSR_SYNDBG_CONTROL ... HV_X64_MSR_SYNDBG_PENDING_BUFFER:
return syndbg_set_msr(vcpu, msr, data, host);
default:
vcpu_unimpl(vcpu, "Hyper-V unhandled wrmsr: 0x%x data 0x%llx\n",
msr, data);
@ -1190,7 +1313,8 @@ static int kvm_hv_set_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data, bool host)
return 0;
}
static int kvm_hv_get_msr_pw(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata)
static int kvm_hv_get_msr_pw(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata,
bool host)
{
u64 data = 0;
struct kvm *kvm = vcpu->kvm;
@ -1227,6 +1351,9 @@ static int kvm_hv_get_msr_pw(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata)
case HV_X64_MSR_TSC_EMULATION_STATUS:
data = hv->hv_tsc_emulation_status;
break;
case HV_X64_MSR_SYNDBG_OPTIONS:
case HV_X64_MSR_SYNDBG_CONTROL ... HV_X64_MSR_SYNDBG_PENDING_BUFFER:
return syndbg_get_msr(vcpu, msr, pdata, host);
default:
vcpu_unimpl(vcpu, "Hyper-V unhandled rdmsr: 0x%x\n", msr);
return 1;
@ -1316,7 +1443,7 @@ int kvm_hv_get_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata, bool host)
int r;
mutex_lock(&vcpu->kvm->arch.hyperv.hv_lock);
r = kvm_hv_get_msr_pw(vcpu, msr, pdata);
r = kvm_hv_get_msr_pw(vcpu, msr, pdata, host);
mutex_unlock(&vcpu->kvm->arch.hyperv.hv_lock);
return r;
} else
@ -1795,6 +1922,9 @@ int kvm_vcpu_ioctl_get_hv_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid2 *cpuid,
{ .function = HYPERV_CPUID_FEATURES },
{ .function = HYPERV_CPUID_ENLIGHTMENT_INFO },
{ .function = HYPERV_CPUID_IMPLEMENT_LIMITS },
{ .function = HYPERV_CPUID_SYNDBG_VENDOR_AND_MAX_FUNCTIONS },
{ .function = HYPERV_CPUID_SYNDBG_INTERFACE },
{ .function = HYPERV_CPUID_SYNDBG_PLATFORM_CAPABILITIES },
{ .function = HYPERV_CPUID_NESTED_FEATURES },
};
int i, nent = ARRAY_SIZE(cpuid_entries);
@ -1820,7 +1950,7 @@ int kvm_vcpu_ioctl_get_hv_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid2 *cpuid,
case HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS:
memcpy(signature, "Linux KVM Hv", 12);
ent->eax = HYPERV_CPUID_NESTED_FEATURES;
ent->eax = HYPERV_CPUID_SYNDBG_PLATFORM_CAPABILITIES;
ent->ebx = signature[0];
ent->ecx = signature[1];
ent->edx = signature[2];
@ -1859,6 +1989,10 @@ int kvm_vcpu_ioctl_get_hv_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid2 *cpuid,
ent->edx |= HV_FEATURE_FREQUENCY_MSRS_AVAILABLE;
ent->edx |= HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE;
ent->ebx |= HV_X64_DEBUGGING;
ent->edx |= HV_X64_GUEST_DEBUGGING_AVAILABLE;
ent->edx |= HV_FEATURE_DEBUG_MSRS_AVAILABLE;
/*
* Direct Synthetic timers only make sense with in-kernel
* LAPIC
@ -1902,6 +2036,24 @@ int kvm_vcpu_ioctl_get_hv_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid2 *cpuid,
break;
case HYPERV_CPUID_SYNDBG_VENDOR_AND_MAX_FUNCTIONS:
memcpy(signature, "Linux KVM Hv", 12);
ent->eax = 0;
ent->ebx = signature[0];
ent->ecx = signature[1];
ent->edx = signature[2];
break;
case HYPERV_CPUID_SYNDBG_INTERFACE:
memcpy(signature, "VS#1\0\0\0\0\0\0\0\0", 12);
ent->eax = signature[0];
break;
case HYPERV_CPUID_SYNDBG_PLATFORM_CAPABILITIES:
ent->eax |= HV_X64_SYNDBG_CAP_ALLOW_KERNEL_DEBUGGING;
break;
default:
break;
}

5
arch/x86/kvm/hyperv.h
View File

@ -73,6 +73,11 @@ static inline struct kvm_vcpu *synic_to_vcpu(struct kvm_vcpu_hv_synic *synic)
return hv_vcpu_to_vcpu(container_of(synic, struct kvm_vcpu_hv, synic));
}
static inline struct kvm_hv_syndbg *vcpu_to_hv_syndbg(struct kvm_vcpu *vcpu)
{
return &vcpu->kvm->arch.hyperv.hv_syndbg;
}
int kvm_hv_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data, bool host);
int kvm_hv_get_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata, bool host);

51
arch/x86/kvm/trace.h
View File

@ -1541,6 +1541,57 @@ TRACE_EVENT(kvm_nested_vmenter_failed,
__print_symbolic(__entry->err, VMX_VMENTER_INSTRUCTION_ERRORS))
);
/*
* Tracepoint for syndbg_set_msr.
*/
TRACE_EVENT(kvm_hv_syndbg_set_msr,
TP_PROTO(int vcpu_id, u32 vp_index, u32 msr, u64 data),
TP_ARGS(vcpu_id, vp_index, msr, data),
TP_STRUCT__entry(
__field(int, vcpu_id)
__field(u32, vp_index)
__field(u32, msr)
__field(u64, data)
),
TP_fast_assign(
__entry->vcpu_id = vcpu_id;
__entry->vp_index = vp_index;
__entry->msr = msr;
__entry->data = data;
),
TP_printk("vcpu_id %d vp_index %u msr 0x%x data 0x%llx",
__entry->vcpu_id, __entry->vp_index, __entry->msr,
__entry->data)
);
/*
* Tracepoint for syndbg_get_msr.
*/
TRACE_EVENT(kvm_hv_syndbg_get_msr,
TP_PROTO(int vcpu_id, u32 vp_index, u32 msr, u64 data),
TP_ARGS(vcpu_id, vp_index, msr, data),
TP_STRUCT__entry(
__field(int, vcpu_id)
__field(u32, vp_index)
__field(u32, msr)
__field(u64, data)
),
TP_fast_assign(
__entry->vcpu_id = vcpu_id;
__entry->vp_index = vp_index;
__entry->msr = msr;
__entry->data = data;
),
TP_printk("vcpu_id %d vp_index %u msr 0x%x data 0x%llx",
__entry->vcpu_id, __entry->vp_index, __entry->msr,
__entry->data)
);
#endif /* _TRACE_KVM_H */
#undef TRACE_INCLUDE_PATH

8
arch/x86/kvm/x86.c
View File

@ -1246,6 +1246,10 @@ static const u32 emulated_msrs_all[] = {
HV_X64_MSR_VP_ASSIST_PAGE,
HV_X64_MSR_REENLIGHTENMENT_CONTROL, HV_X64_MSR_TSC_EMULATION_CONTROL,
HV_X64_MSR_TSC_EMULATION_STATUS,
HV_X64_MSR_SYNDBG_OPTIONS,
HV_X64_MSR_SYNDBG_CONTROL, HV_X64_MSR_SYNDBG_STATUS,
HV_X64_MSR_SYNDBG_SEND_BUFFER, HV_X64_MSR_SYNDBG_RECV_BUFFER,
HV_X64_MSR_SYNDBG_PENDING_BUFFER,
MSR_KVM_ASYNC_PF_EN, MSR_KVM_STEAL_TIME,
MSR_KVM_PV_EOI_EN, MSR_KVM_ASYNC_PF_INT, MSR_KVM_ASYNC_PF_ACK,
@ -3011,6 +3015,8 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
*/
break;
case HV_X64_MSR_GUEST_OS_ID ... HV_X64_MSR_SINT15:
case HV_X64_MSR_SYNDBG_CONTROL ... HV_X64_MSR_SYNDBG_PENDING_BUFFER:
case HV_X64_MSR_SYNDBG_OPTIONS:
case HV_X64_MSR_CRASH_P0 ... HV_X64_MSR_CRASH_P4:
case HV_X64_MSR_CRASH_CTL:
case HV_X64_MSR_STIMER0_CONFIG ... HV_X64_MSR_STIMER3_COUNT:
@ -3272,6 +3278,8 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
msr_info->data = 0x20000000;
break;
case HV_X64_MSR_GUEST_OS_ID ... HV_X64_MSR_SINT15:
case HV_X64_MSR_SYNDBG_CONTROL ... HV_X64_MSR_SYNDBG_PENDING_BUFFER:
case HV_X64_MSR_SYNDBG_OPTIONS:
case HV_X64_MSR_CRASH_P0 ... HV_X64_MSR_CRASH_P4:
case HV_X64_MSR_CRASH_CTL:
case HV_X64_MSR_STIMER0_CONFIG ... HV_X64_MSR_STIMER3_COUNT:

10
include/uapi/linux/kvm.h
View File

@ -188,6 +188,7 @@ struct kvm_s390_cmma_log {
struct kvm_hyperv_exit {
#define KVM_EXIT_HYPERV_SYNIC 1
#define KVM_EXIT_HYPERV_HCALL 2
#define KVM_EXIT_HYPERV_SYNDBG 3
__u32 type;
__u32 pad1;
union {
@ -203,6 +204,15 @@ struct kvm_hyperv_exit {
__u64 result;
__u64 params[2];
} hcall;
struct {
__u32 msr;
__u32 pad2;
__u64 control;
__u64 status;
__u64 send_page;
__u64 recv_page;
__u64 pending_page;
} syndbg;
} u;
};