Author: neel
Date: Sat Jul 26 02:53:51 2014
New Revision: 269109
URL: http://svnweb.freebsd.org/changeset/base/269109
Log:
If a vcpu has issued a HLT instruction with interrupts disabled then it sleeps
forever in vm_handle_hlt().
This is usually not an issue as long as one of the other vcpus properly resets
or powers off the virtual machine. However, if the bhyve(8) process is killed
with a signal the halted vcpu cannot be woken up because it's sleep cannot be
interrupted.
Fix this by waking up periodically and returning from vm_handle_hlt() if
TDF_ASTPENDING is set.
Reported by: Leon Dang
Sponsored by: Nahanni Systems
Modified:
head/sys/amd64/include/vmm.h
head/sys/amd64/vmm/intel/vmx.c
head/sys/amd64/vmm/vmm.c
Modified: head/sys/amd64/include/vmm.h
==============================================================================
--- head/sys/amd64/include/vmm.h Sat Jul 26 02:51:46 2014
(r269108)
+++ head/sys/amd64/include/vmm.h Sat Jul 26 02:53:51 2014
(r269109)
@@ -270,6 +270,14 @@ vcpu_is_running(struct vm *vm, int vcpu,
return (vcpu_get_state(vm, vcpu, hostcpu) == VCPU_RUNNING);
}
+#ifdef _SYS_PROC_H_
+static int __inline
+vcpu_should_yield(struct vm *vm, int vcpu)
+{
+ return (curthread->td_flags & (TDF_ASTPENDING | TDF_NEEDRESCHED));
+}
+#endif
+
void *vcpu_stats(struct vm *vm, int vcpu);
void vcpu_notify_event(struct vm *vm, int vcpuid, bool lapic_intr);
struct vmspace *vm_get_vmspace(struct vm *vm);
Modified: head/sys/amd64/vmm/intel/vmx.c
==============================================================================
--- head/sys/amd64/vmm/intel/vmx.c Sat Jul 26 02:51:46 2014
(r269108)
+++ head/sys/amd64/vmm/intel/vmx.c Sat Jul 26 02:53:51 2014
(r269109)
@@ -2559,7 +2559,7 @@ vmx_run(void *arg, int vcpu, register_t
break;
}
- if (curthread->td_flags & (TDF_ASTPENDING | TDF_NEEDRESCHED)) {
+ if (vcpu_should_yield(vm, vcpu)) {
enable_intr();
vm_exit_astpending(vmx->vm, vcpu, vmcs_guest_rip());
vmx_astpending_trace(vmx, vcpu, vmexit->rip);
Modified: head/sys/amd64/vmm/vmm.c
==============================================================================
--- head/sys/amd64/vmm/vmm.c Sat Jul 26 02:51:46 2014 (r269108)
+++ head/sys/amd64/vmm/vmm.c Sat Jul 26 02:53:51 2014 (r269109)
@@ -1105,6 +1105,10 @@ vm_handle_hlt(struct vm *vm, int vcpuid,
}
}
+ /* Don't go to sleep if the vcpu thread needs to yield */
+ if (vcpu_should_yield(vm, vcpuid))
+ break;
+
/*
* Some Linux guests implement "halt" by having all vcpus
* execute HLT with interrupts disabled. 'halted_cpus' keeps
@@ -1128,7 +1132,11 @@ vm_handle_hlt(struct vm *vm, int vcpuid,
t = ticks;
vcpu_require_state_locked(vcpu, VCPU_SLEEPING);
- msleep_spin(vcpu, &vcpu->mtx, wmesg, 0);
+ /*
+ * XXX msleep_spin() cannot be interrupted by signals so
+ * wake up periodically to check pending signals.
+ */
+ msleep_spin(vcpu, &vcpu->mtx, wmesg, hz);
vcpu_require_state_locked(vcpu, VCPU_FROZEN);
vmm_stat_incr(vm, vcpuid, VCPU_IDLE_TICKS, ticks - t);
}
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