[patch 2/5] KVM: reintroduce guest mode bit and unify remote request code

Marcelo Tosatti
2009-08-27T01:31:40Z

[-- Attachment #1: reintroduce-guest-mode --]
[-- Type: text/plain, Size: 4840 bytes --]

Split KVM_REQ_KICKED in two bits: KVM_VCPU_KICKED, to indicate
whether a vcpu has been IPI'ed, and KVM_VCPU_GUEST_MODE, in a separate
vcpu_state variable.

Unify remote requests with kvm_vcpu_kick.

Synchronous requests wait on KVM_VCPU_GUEST_MODE, via wait_on_bit/wake_up_bit.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

Index: kvm/arch/x86/kvm/x86.c
===================================================================
--- kvm.orig/arch/x86/kvm/x86.c
+++ kvm/arch/x86/kvm/x86.c
@@ -3586,11 +3586,14 @@ static int vcpu_enter_guest(struct kvm_v

local_irq_disable();

- clear_bit(KVM_REQ_KICK, &vcpu->requests);
- smp_mb__after_clear_bit();
+ set_bit(KVM_VCPU_GUEST_MODE, &vcpu->vcpu_state);
+ barrier();

if (vcpu->requests || need_resched() || signal_pending(current)) {
- set_bit(KVM_REQ_KICK, &vcpu->requests);
+ clear_bit(KVM_VCPU_KICKED, &vcpu->vcpu_state);
+ clear_bit(KVM_VCPU_GUEST_MODE, &vcpu->vcpu_state);
+ smp_mb__after_clear_bit();
+ wake_up_bit(&vcpu->vcpu_state, KVM_VCPU_GUEST_MODE);
local_irq_enable();
preempt_enable();
r = 1;
@@ -3642,7 +3645,10 @@ static int vcpu_enter_guest(struct kvm_v
set_debugreg(vcpu->arch.host_dr6, 6);
set_debugreg(vcpu->arch.host_dr7, 7);

- set_bit(KVM_REQ_KICK, &vcpu->requests);
+ clear_bit(KVM_VCPU_KICKED, &vcpu->vcpu_state);
+ clear_bit(KVM_VCPU_GUEST_MODE, &vcpu->vcpu_state);
+ smp_mb__after_clear_bit();
+ wake_up_bit(&vcpu->vcpu_state, KVM_VCPU_GUEST_MODE);
local_irq_enable();

++vcpu->stat.exits;
Index: kvm/include/linux/kvm_host.h
===================================================================
--- kvm.orig/include/linux/kvm_host.h
+++ kvm/include/linux/kvm_host.h
@@ -42,6 +42,9 @@

#define KVM_USERSPACE_IRQ_SOURCE_ID 0

+#define KVM_VCPU_GUEST_MODE 0
+#define KVM_VCPU_KICKED 1
+
struct kvm;
struct kvm_vcpu;
extern struct kmem_cache *kvm_vcpu_cache;
@@ -83,6 +86,7 @@ struct kvm_vcpu {
int cpu;
struct kvm_run *run;
unsigned long requests;
+ unsigned long vcpu_state;
unsigned long guest_debug;
int fpu_active;
int guest_fpu_loaded;
@@ -362,6 +366,7 @@ void kvm_arch_sync_events(struct kvm *kv

int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu);
void kvm_vcpu_kick(struct kvm_vcpu *vcpu);
+void kvm_vcpu_ipi(struct kvm_vcpu *vcpu);

int kvm_is_mmio_pfn(pfn_t pfn);

Index: kvm/virt/kvm/kvm_main.c
===================================================================
--- kvm.orig/virt/kvm/kvm_main.c
+++ kvm/virt/kvm/kvm_main.c
@@ -119,18 +119,26 @@ void vcpu_put(struct kvm_vcpu *vcpu)

void kvm_vcpu_kick(struct kvm_vcpu *vcpu)
{
- int me;
- int cpu = vcpu->cpu;
-
if (waitqueue_active(&vcpu->wq)) {
wake_up_interruptible(&vcpu->wq);
++vcpu->stat.halt_wakeup;
}
+ kvm_vcpu_ipi(vcpu);
+}
+
+void kvm_vcpu_ipi(struct kvm_vcpu *vcpu)
+{
+ int me;
+ int cpu = vcpu->cpu;

me = get_cpu();
- if (cpu != me && (unsigned)cpu < nr_cpu_ids && cpu_online(cpu))
- if (!test_and_set_bit(KVM_REQ_KICK, &vcpu->requests))
- smp_send_reschedule(cpu);
+ if (cpu != me && (unsigned)cpu < nr_cpu_ids && cpu_online(cpu)) {
+ if (test_bit(KVM_VCPU_GUEST_MODE, &vcpu->vcpu_state)) {
+ if (!test_and_set_bit(KVM_VCPU_KICKED,
+ &vcpu->vcpu_state))
+ smp_send_reschedule(cpu);
+ }
+ }
put_cpu();
}

@@ -168,6 +176,30 @@ static bool make_all_cpus_request(struct
return called;
}

+static int kvm_req_wait(void *unused)
+{
+ cpu_relax();
+ return 0;
+}
+
+static void kvm_vcpu_request(struct kvm_vcpu *vcpu, unsigned int req)
+{
+ set_bit(req, &vcpu->requests);
+ barrier();
+ kvm_vcpu_ipi(vcpu);
+ wait_on_bit(&vcpu->vcpu_state, KVM_VCPU_GUEST_MODE, kvm_req_wait,
+ TASK_UNINTERRUPTIBLE);
+}
+
+static void kvm_vcpus_request(struct kvm *kvm, unsigned int req)
+{
+ int i;
+ struct kvm_vcpu *vcpu;
+
+ kvm_for_each_vcpu(i, vcpu, kvm)
+ kvm_vcpu_request(vcpu, req);
+}
+
void kvm_flush_remote_tlbs(struct kvm *kvm)
{
if (make_all_cpus_request(kvm, KVM_REQ_TLB_FLUSH))
Index: kvm/arch/ia64/kvm/kvm-ia64.c
===================================================================
--- kvm.orig/arch/ia64/kvm/kvm-ia64.c
+++ kvm/arch/ia64/kvm/kvm-ia64.c
@@ -655,12 +655,13 @@ again:
host_ctx = kvm_get_host_context(vcpu);
guest_ctx = kvm_get_guest_context(vcpu);

- clear_bit(KVM_REQ_KICK, &vcpu->requests);
-
r = kvm_vcpu_pre_transition(vcpu);
if (r < 0)
goto vcpu_run_fail;

+ set_bit(KVM_VCPU_GUEST_MODE, &vcpu->vcpu_state);
+ barrier();
+
up_read(&vcpu->kvm->slots_lock);
kvm_guest_enter();

@@ -672,7 +673,10 @@ again:
kvm_vcpu_post_transition(vcpu);

vcpu->arch.launched = 1;
- set_bit(KVM_REQ_KICK, &vcpu->requests);
+ clear_bit(KVM_VCPU_KICKED, &vcpu->vcpu_state);
+ clear_bit(KVM_VCPU_GUEST_MODE, &vcpu->vcpu_state);
+ smp_mb__after_clear_bit();
+ wake_up_bit(&vcpu->vcpu_state, KVM_VCPU_GUEST_MODE);
local_irq_enable();

/*

--