[PATCH v2 5/7] KVM: handle more completed apfs if possible

Xiao Guangrong
2010-11-01T08:58:14Z

If it's no need to inject async #PF to PV guest we can handle
more completed apfs at one time, so we can retry guest #PF
as early as possible

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
---
arch/x86/include/asm/kvm_host.h | 3 ++-
arch/x86/kvm/x86.c | 8 ++++++--
virt/kvm/async_pf.c | 28 ++++++++++++++++------------
3 files changed, 24 insertions(+), 15 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 1be0058..c95b3ff 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -818,7 +818,8 @@ bool kvm_is_linear_rip(struct kvm_vcpu *vcpu, unsigned long linear_rip);

void kvm_arch_async_page_not_present(struct kvm_vcpu *vcpu,
struct kvm_async_pf *work);
-void kvm_arch_async_page_present(struct kvm_vcpu *vcpu,
+/* return true if we can handle more completed apfs, false otherwise */
+bool kvm_arch_async_page_present(struct kvm_vcpu *vcpu,
struct kvm_async_pf *work);
void kvm_arch_async_page_ready(struct kvm_vcpu *vcpu,
struct kvm_async_pf *work);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 4da8485..189664a 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6265,7 +6265,7 @@ void kvm_arch_async_page_not_present(struct kvm_vcpu *vcpu,
}
}

-void kvm_arch_async_page_present(struct kvm_vcpu *vcpu,
+bool kvm_arch_async_page_present(struct kvm_vcpu *vcpu,
struct kvm_async_pf *work)
{
trace_kvm_async_pf_ready(work->arch.token, work->gva);
@@ -6274,13 +6274,17 @@ void kvm_arch_async_page_present(struct kvm_vcpu *vcpu,
else
kvm_del_async_pf_gfn(vcpu, work->arch.gfn);

+ vcpu->arch.apf.halted = false;
+
if ((vcpu->arch.apf.msr_val & KVM_ASYNC_PF_ENABLED) &&
!apf_put_user(vcpu, KVM_PV_REASON_PAGE_READY)) {
vcpu->arch.fault.error_code = 0;
vcpu->arch.fault.address = work->arch.token;
kvm_inject_page_fault(vcpu);
+ return false;
}
- vcpu->arch.apf.halted = false;
+
+ return true;
}

bool kvm_arch_can_inject_async_page_present(struct kvm_vcpu *vcpu)
diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c
index 60df9e0..d57ec92 100644
--- a/virt/kvm/async_pf.c
+++ b/virt/kvm/async_pf.c
@@ -123,25 +123,29 @@ void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu)
void kvm_check_async_pf_completion(struct kvm_vcpu *vcpu)
{
struct kvm_async_pf *work;
+ bool ret;

if (list_empty_careful(&vcpu->async_pf.done) ||
!kvm_arch_can_inject_async_page_present(vcpu))
return;

- spin_lock(&vcpu->async_pf.lock);
- work = list_first_entry(&vcpu->async_pf.done, typeof(*work), link);
- list_del(&work->link);
- spin_unlock(&vcpu->async_pf.lock);
+ do {
+ spin_lock(&vcpu->async_pf.lock);
+ work = list_first_entry(&vcpu->async_pf.done, typeof(*work),
+ link);
+ list_del(&work->link);
+ spin_unlock(&vcpu->async_pf.lock);

- if (work->page)
- kvm_arch_async_page_ready(vcpu, work);
- kvm_arch_async_page_present(vcpu, work);
+ if (work->page)
+ kvm_arch_async_page_ready(vcpu, work);
+ ret = kvm_arch_async_page_present(vcpu, work);

- list_del(&work->queue);
- vcpu->async_pf.queued--;
- if (work->page)
- put_page(work->page);
- kmem_cache_free(async_pf_cache, work);
+ list_del(&work->queue);
+ vcpu->async_pf.queued--;
+ if (work->page)
+ put_page(work->page);
+ kmem_cache_free(async_pf_cache, work);
+ } while (ret && !list_empty_careful(&vcpu->async_pf.done));
}

int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn,
--
1.7.0.4