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When a vcpu is deactivated it must also unblock any rendezvous that may be

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blocked on it.

This is done by issuing a wakeup after clearing the 'vcpuid' from 'active_cpus'.
Also, use CPU_CLR_ATOMIC() to guarantee visibility of the updated 'active_cpus'
across all host cpus.
This commit is contained in:
Neel Natu 2014-03-18 02:49:28 +00:00
parent 0fcefb433d
commit 22d822c6b0
1 changed files with 46 additions and 12 deletions
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58
sys/amd64/vmm/vmm.c
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@ -130,7 +130,7 @@ struct vm {
* An active vcpu is one that has been started implicitly (BSP) or
* explicitly (AP) by sending it a startup ipi.
*/
cpuset_t active_cpus;
volatile cpuset_t active_cpus;
struct mtx rendezvous_mtx;
cpuset_t rendezvous_req_cpus;
@ -969,8 +969,12 @@ vm_handle_rendezvous(struct vm *vm, int vcpuid)
mtx_lock(&vm->rendezvous_mtx);
while (vm->rendezvous_func != NULL) {
/* 'rendezvous_req_cpus' must be a subset of 'active_cpus' */
CPU_AND(&vm->rendezvous_req_cpus, &vm->active_cpus);
if (vcpuid != -1 &&
CPU_ISSET(vcpuid, &vm->rendezvous_req_cpus)) {
CPU_ISSET(vcpuid, &vm->rendezvous_req_cpus) &&
!CPU_ISSET(vcpuid, &vm->rendezvous_done_cpus)) {
VCPU_CTR0(vm, vcpuid, "Calling rendezvous func");
(*vm->rendezvous_func)(vm, vcpuid, vm->rendezvous_arg);
CPU_SET(vcpuid, &vm->rendezvous_done_cpus);
@ -997,9 +1001,10 @@ vm_handle_hlt(struct vm *vm, int vcpuid, bool intr_disabled, bool *retu)
{
struct vm_exit *vmexit;
struct vcpu *vcpu;
int t, timo;
int t, timo, spindown;
vcpu = &vm->vcpu[vcpuid];
spindown = 0;
vcpu_lock(vcpu);
@ -1026,17 +1031,25 @@ vm_handle_hlt(struct vm *vm, int vcpuid, bool intr_disabled, bool *retu)
* Spindown the vcpu if the apic is disabled and it
* had entered the halted state.
*/
*retu = true;
vmexit = vm_exitinfo(vm, vcpuid);
vmexit->exitcode = VM_EXITCODE_SPINDOWN_CPU;
vm_deactivate_cpu(vm, vcpuid);
VCPU_CTR0(vm, vcpuid, "spinning down cpu");
spindown = 1;
}
vcpu_require_state_locked(vcpu, VCPU_FROZEN);
vmm_stat_incr(vm, vcpuid, VCPU_IDLE_TICKS, ticks - t);
}
vcpu_unlock(vcpu);
/*
* Since 'vm_deactivate_cpu()' grabs a sleep mutex we must call it
* outside the confines of the vcpu spinlock.
*/
if (spindown) {
*retu = true;
vmexit = vm_exitinfo(vm, vcpuid);
vmexit->exitcode = VM_EXITCODE_SPINDOWN_CPU;
vm_deactivate_cpu(vm, vcpuid);
VCPU_CTR0(vm, vcpuid, "spinning down cpu");
}
return (0);
}
@ -1541,16 +1554,37 @@ void
vm_activate_cpu(struct vm *vm, int vcpuid)
{
if (vcpuid >= 0 && vcpuid < VM_MAXCPU)
CPU_SET(vcpuid, &vm->active_cpus);
KASSERT(vcpuid >= 0 && vcpuid < VM_MAXCPU,
("vm_activate_cpu: invalid vcpuid %d", vcpuid));
KASSERT(!CPU_ISSET(vcpuid, &vm->active_cpus),
("vm_activate_cpu: vcpuid %d is already active", vcpuid));
VCPU_CTR0(vm, vcpuid, "activated");
CPU_SET_ATOMIC(vcpuid, &vm->active_cpus);
}
static void
vm_deactivate_cpu(struct vm *vm, int vcpuid)
{
if (vcpuid >= 0 && vcpuid < VM_MAXCPU)
CPU_CLR(vcpuid, &vm->active_cpus);
KASSERT(vcpuid >= 0 && vcpuid < VM_MAXCPU,
("vm_deactivate_cpu: invalid vcpuid %d", vcpuid));
KASSERT(CPU_ISSET(vcpuid, &vm->active_cpus),
("vm_deactivate_cpu: vcpuid %d is not active", vcpuid));
VCPU_CTR0(vm, vcpuid, "deactivated");
CPU_CLR_ATOMIC(vcpuid, &vm->active_cpus);
/*
* If a vcpu rendezvous is in progress then it could be blocked
* on 'vcpuid' - unblock it before disappearing forever.
*/
mtx_lock(&vm->rendezvous_mtx);
if (vm->rendezvous_func != NULL) {
VCPU_CTR0(vm, vcpuid, "unblock rendezvous after deactivation");
wakeup(&vm->rendezvous_func);
}
mtx_unlock(&vm->rendezvous_mtx);
}
cpuset_t