svn commit: r242065 - in projects/bhyve/sys/amd64/vmm: . intel
Neel Natu
neel at FreeBSD.org
Thu Oct 25 04:29:22 UTC 2012
Author: neel
Date: Thu Oct 25 04:29:21 2012
New Revision: 242065
URL: http://svn.freebsd.org/changeset/base/242065
Log:
If the guest vcpu wants to idle then use that opportunity to relinquish the
host cpu to the scheduler until the guest is ready to run again.
This implies that the host cpu utilization will now closely mirror the actual
load imposed by the guest vcpu.
Also, the vcpu mutex now needs to be of type MTX_SPIN since we need to acquire
it inside a critical section.
Obtained from: NetApp
Modified:
projects/bhyve/sys/amd64/vmm/intel/vmx.c
projects/bhyve/sys/amd64/vmm/vmm.c
Modified: projects/bhyve/sys/amd64/vmm/intel/vmx.c
==============================================================================
--- projects/bhyve/sys/amd64/vmm/intel/vmx.c Thu Oct 25 04:21:05 2012 (r242064)
+++ projects/bhyve/sys/amd64/vmm/intel/vmx.c Thu Oct 25 04:29:21 2012 (r242065)
@@ -159,6 +159,8 @@ static int cap_monitor_trap;
/* statistics */
static VMM_STAT_DEFINE(VCPU_MIGRATIONS, "vcpu migration across host cpus");
static VMM_STAT_DEFINE(VMEXIT_EXTINT, "vm exits due to external interrupt");
+static VMM_STAT_DEFINE(VMEXIT_HLT_IGNORED, "number of times hlt was ignored");
+static VMM_STAT_DEFINE(VMEXIT_HLT, "number of times hlt was intercepted");
#ifdef KTR
static const char *
@@ -1203,11 +1205,11 @@ vmx_lapic_fault(struct vm *vm, int cpu,
static int
vmx_exit_process(struct vmx *vmx, int vcpu, struct vm_exit *vmexit)
{
- int handled;
+ int error, handled;
struct vmcs *vmcs;
struct vmxctx *vmxctx;
uint32_t eax, ecx, edx;
- uint64_t qual, gpa, cr3;
+ uint64_t qual, gpa, cr3, intr_info;
handled = 0;
vmcs = &vmx->vmcs[vcpu];
@@ -1240,7 +1242,20 @@ vmx_exit_process(struct vmx *vmx, int vc
}
break;
case EXIT_REASON_HLT:
- vmexit->exitcode = VM_EXITCODE_HLT;
+ vmm_stat_incr(vmx->vm, vcpu, VMEXIT_HLT, 1);
+ /*
+ * If there is an event waiting to be injected then there is
+ * no need to 'hlt'.
+ */
+ error = vmread(VMCS_ENTRY_INTR_INFO, &intr_info);
+ if (error)
+ panic("vmx_exit_process: vmread(intrinfo) %d", error);
+
+ if (intr_info & VMCS_INTERRUPTION_INFO_VALID) {
+ handled = 1;
+ vmm_stat_incr(vmx->vm, vcpu, VMEXIT_HLT_IGNORED, 1);
+ } else
+ vmexit->exitcode = VM_EXITCODE_HLT;
break;
case EXIT_REASON_MTF:
vmexit->exitcode = VM_EXITCODE_MTRAP;
Modified: projects/bhyve/sys/amd64/vmm/vmm.c
==============================================================================
--- projects/bhyve/sys/amd64/vmm/vmm.c Thu Oct 25 04:21:05 2012 (r242064)
+++ projects/bhyve/sys/amd64/vmm/vmm.c Thu Oct 25 04:29:21 2012 (r242065)
@@ -58,6 +58,7 @@ __FBSDID("$FreeBSD$");
#include "vmm_msr.h"
#include "vmm_ipi.h"
#include "vmm_stat.h"
+#include "vmm_lapic.h"
#include "io/ppt.h"
#include "io/iommu.h"
@@ -92,9 +93,9 @@ do { \
vm->vcpu[vcpuid].pincpu = host_cpuid; \
} while(0)
-#define vcpu_lock_init(v) mtx_init(&((v)->mtx), "vcpu lock", 0, MTX_DEF)
-#define vcpu_lock(v) mtx_lock(&((v)->mtx))
-#define vcpu_unlock(v) mtx_unlock(&((v)->mtx))
+#define vcpu_lock_init(v) mtx_init(&((v)->mtx), "vcpu lock", 0, MTX_SPIN)
+#define vcpu_lock(v) mtx_lock_spin(&((v)->mtx))
+#define vcpu_unlock(v) mtx_unlock_spin(&((v)->mtx))
#define VM_MAX_MEMORY_SEGMENTS 2
@@ -651,13 +652,16 @@ save_guest_fpustate(struct vcpu *vcpu)
fpu_start_emulating();
}
+static VMM_STAT_DEFINE(VCPU_IDLE_TICKS, "number of ticks vcpu was idle");
+
int
vm_run(struct vm *vm, struct vm_run *vmrun)
{
- int error, vcpuid;
+ int error, vcpuid, sleepticks, t;
struct vcpu *vcpu;
struct pcb *pcb;
- uint64_t tscval;
+ uint64_t tscval, rip;
+ struct vm_exit *vme;
vcpuid = vmrun->cpuid;
@@ -665,7 +669,9 @@ vm_run(struct vm *vm, struct vm_run *vmr
return (EINVAL);
vcpu = &vm->vcpu[vcpuid];
-
+ vme = &vmrun->vm_exit;
+ rip = vmrun->rip;
+restart:
critical_enter();
tscval = rdtsc();
@@ -677,7 +683,7 @@ vm_run(struct vm *vm, struct vm_run *vmr
restore_guest_fpustate(vcpu);
vcpu->hostcpu = curcpu;
- error = VMRUN(vm->cookie, vcpuid, vmrun->rip);
+ error = VMRUN(vm->cookie, vcpuid, rip);
vcpu->hostcpu = NOCPU;
save_guest_fpustate(vcpu);
@@ -686,10 +692,52 @@ vm_run(struct vm *vm, struct vm_run *vmr
vmm_stat_incr(vm, vcpuid, VCPU_TOTAL_RUNTIME, rdtsc() - tscval);
/* copy the exit information */
- bcopy(&vcpu->exitinfo, &vmrun->vm_exit, sizeof(struct vm_exit));
+ bcopy(&vcpu->exitinfo, vme, sizeof(struct vm_exit));
critical_exit();
+ /*
+ * Oblige the guest's desire to 'hlt' by sleeping until the vcpu
+ * is ready to run.
+ */
+ if (error == 0 && vme->exitcode == VM_EXITCODE_HLT) {
+ vcpu_lock(vcpu);
+
+ /*
+ * Figure out the number of host ticks until the next apic
+ * timer interrupt in the guest.
+ */
+ sleepticks = lapic_timer_tick(vm, vcpuid);
+
+ /*
+ * If the guest local apic timer is disabled then sleep for
+ * a long time but not forever.
+ */
+ if (sleepticks < 0)
+ sleepticks = hz;
+
+ /*
+ * Do a final check for pending NMI or interrupts before
+ * really putting this thread to sleep.
+ *
+ * These interrupts could have happened any time after we
+ * returned from VMRUN() and before we grabbed the vcpu lock.
+ */
+ if (!vm_nmi_pending(vm, vcpuid) &&
+ lapic_pending_intr(vm, vcpuid) < 0) {
+ if (sleepticks <= 0)
+ panic("invalid sleepticks %d", sleepticks);
+ t = ticks;
+ msleep_spin(vcpu, &vcpu->mtx, "vmidle", sleepticks);
+ vmm_stat_incr(vm, vcpuid, VCPU_IDLE_TICKS, ticks - t);
+ }
+
+ vcpu_unlock(vcpu);
+
+ rip = vme->rip + vme->inst_length;
+ goto restart;
+ }
+
return (error);
}
@@ -709,7 +757,7 @@ vm_inject_event(struct vm *vm, int vcpui
return (VMINJECT(vm->cookie, vcpuid, type, vector, code, code_valid));
}
-VMM_STAT_DEFINE(VCPU_NMI_COUNT, "number of NMIs delivered to vcpu");
+static VMM_STAT_DEFINE(VCPU_NMI_COUNT, "number of NMIs delivered to vcpu");
int
vm_inject_nmi(struct vm *vm, int vcpuid)
@@ -935,16 +983,25 @@ vm_interrupt_hostcpu(struct vm *vm, int
vcpu = &vm->vcpu[vcpuid];
- /*
- * XXX racy but the worst case is that we'll send an unnecessary IPI
- * to the 'hostcpu'.
- *
- * We cannot use vcpu_is_running() here because it acquires vcpu->mtx
- * which is not allowed inside a critical section.
- */
+ vcpu_lock(vcpu);
hostcpu = vcpu->hostcpu;
- if (hostcpu == NOCPU || hostcpu == curcpu)
- return;
-
- ipi_cpu(hostcpu, vmm_ipinum);
+ if (hostcpu == NOCPU) {
+ /*
+ * If the vcpu is 'RUNNING' but without a valid 'hostcpu' then
+ * the host thread must be sleeping waiting for an event to
+ * kick the vcpu out of 'hlt'.
+ *
+ * XXX this is racy because the condition exists right before
+ * and after calling VMRUN() in vm_run(). The wakeup() is
+ * benign in this case.
+ */
+ if (vcpu->state == VCPU_RUNNING)
+ wakeup_one(vcpu);
+ } else {
+ if (vcpu->state != VCPU_RUNNING)
+ panic("invalid vcpu state %d", vcpu->state);
+ if (hostcpu != curcpu)
+ ipi_cpu(hostcpu, vmm_ipinum);
+ }
+ vcpu_unlock(vcpu);
}
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