qemu/target/i386/kvm/hyperv.c
Maciej S. Szmigiero ec19444a53 hyperv: fix SynIC SINT assertion failure on guest reset
Resetting a guest that has Hyper-V VMBus support enabled triggers a QEMU
assertion failure:
hw/hyperv/hyperv.c:131: synic_reset: Assertion `QLIST_EMPTY(&synic->sint_routes)' failed.

This happens both on normal guest reboot or when using "system_reset" HMP
command.

The failing assertion was introduced by commit 64ddecc88b ("hyperv: SControl is optional to enable SynIc")
to catch dangling SINT routes on SynIC reset.

The root cause of this problem is that the SynIC itself is reset before
devices using SINT routes have chance to clean up these routes.

Since there seems to be no existing mechanism to force reset callbacks (or
methods) to be executed in specific order let's use a similar method that
is already used to reset another interrupt controller (APIC) after devices
have been reset - by invoking the SynIC reset from the machine reset
handler via a new x86_cpu_after_reset() function co-located with
the existing x86_cpu_reset() in target/i386/cpu.c.
Opportunistically move the APIC reset handler there, too.

Fixes: 64ddecc88b ("hyperv: SControl is optional to enable SynIc") # exposed the bug
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Message-Id: <cb57cee2e29b20d06f81dce054cbcea8b5d497e8.1664552976.git.maciej.szmigiero@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-10-18 13:58:04 +02:00

152 lines
4.8 KiB
C

/*
* QEMU KVM Hyper-V support
*
* Copyright (C) 2015 Andrey Smetanin <asmetanin@virtuozzo.com>
*
* Authors:
* Andrey Smetanin <asmetanin@virtuozzo.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 "qemu/main-loop.h"
#include "hyperv.h"
#include "hw/hyperv/hyperv.h"
#include "hyperv-proto.h"
int hyperv_x86_synic_add(X86CPU *cpu)
{
hyperv_synic_add(CPU(cpu));
return 0;
}
/*
* All devices possibly using SynIC have to be reset before calling this to let
* them remove their SINT routes first.
*/
void hyperv_x86_synic_reset(X86CPU *cpu)
{
hyperv_synic_reset(CPU(cpu));
}
void hyperv_x86_synic_update(X86CPU *cpu)
{
CPUX86State *env = &cpu->env;
bool enable = env->msr_hv_synic_control & HV_SYNIC_ENABLE;
hwaddr msg_page_addr = (env->msr_hv_synic_msg_page & HV_SIMP_ENABLE) ?
(env->msr_hv_synic_msg_page & TARGET_PAGE_MASK) : 0;
hwaddr event_page_addr = (env->msr_hv_synic_evt_page & HV_SIEFP_ENABLE) ?
(env->msr_hv_synic_evt_page & TARGET_PAGE_MASK) : 0;
hyperv_synic_update(CPU(cpu), enable, msg_page_addr, event_page_addr);
}
static void async_synic_update(CPUState *cs, run_on_cpu_data data)
{
qemu_mutex_lock_iothread();
hyperv_x86_synic_update(X86_CPU(cs));
qemu_mutex_unlock_iothread();
}
int kvm_hv_handle_exit(X86CPU *cpu, struct kvm_hyperv_exit *exit)
{
CPUX86State *env = &cpu->env;
switch (exit->type) {
case KVM_EXIT_HYPERV_SYNIC:
if (!hyperv_feat_enabled(cpu, HYPERV_FEAT_SYNIC)) {
return -1;
}
switch (exit->u.synic.msr) {
case HV_X64_MSR_SCONTROL:
env->msr_hv_synic_control = exit->u.synic.control;
break;
case HV_X64_MSR_SIMP:
env->msr_hv_synic_msg_page = exit->u.synic.msg_page;
break;
case HV_X64_MSR_SIEFP:
env->msr_hv_synic_evt_page = exit->u.synic.evt_page;
break;
default:
return -1;
}
/*
* this will run in this cpu thread before it returns to KVM, but in a
* safe environment (i.e. when all cpus are quiescent) -- this is
* necessary because memory hierarchy is being changed
*/
async_safe_run_on_cpu(CPU(cpu), async_synic_update, RUN_ON_CPU_NULL);
return 0;
case KVM_EXIT_HYPERV_HCALL: {
uint16_t code = exit->u.hcall.input & 0xffff;
bool fast = exit->u.hcall.input & HV_HYPERCALL_FAST;
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(in_param, fast);
break;
case HV_SIGNAL_EVENT:
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;
}
}