lkml.org 
[lkml]   [2010]   [Nov]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH v3 6/6] KVM: MMU: delay flush all tlbs on sync_page path
Quote from Avi:
| I don't think we need to flush immediately; set a "tlb dirty" bit somewhere
| that is cleareded when we flush the tlb. kvm_mmu_notifier_invalidate_page()
| can consult the bit and force a flush if set.

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
---
arch/x86/kvm/paging_tmpl.h | 4 ++--
include/linux/kvm_host.h | 7 +++++++
virt/kvm/kvm_main.c | 8 +++++++-
3 files changed, 16 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index dfb906f..d5c302a 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -781,14 +781,14 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
gfn = gpte_to_gfn(gpte);

if (FNAME(map_invalid_gpte)(vcpu, sp, &sp->spt[i], gpte)) {
- kvm_flush_remote_tlbs(vcpu->kvm);
+ kvm_mark_tlbs_dirty(vcpu->kvm);
continue;
}

if (gfn != sp->gfns[i]) {
drop_spte(vcpu->kvm, &sp->spt[i],
shadow_trap_nonpresent_pte);
- kvm_flush_remote_tlbs(vcpu->kvm);
+ kvm_mark_tlbs_dirty(vcpu->kvm);
continue;
}

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 4bd663d..82d449b 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -249,6 +249,7 @@ struct kvm {
struct mmu_notifier mmu_notifier;
unsigned long mmu_notifier_seq;
long mmu_notifier_count;
+ atomic_t tlbs_dirty;
#endif
};

@@ -377,6 +378,12 @@ void kvm_vcpu_on_spin(struct kvm_vcpu *vcpu);
void kvm_resched(struct kvm_vcpu *vcpu);
void kvm_load_guest_fpu(struct kvm_vcpu *vcpu);
void kvm_put_guest_fpu(struct kvm_vcpu *vcpu);
+
+static inline void kvm_mark_tlbs_dirty(struct kvm *kvm)
+{
+ atomic_inc(&kvm->tlbs_dirty);
+}
+
void kvm_flush_remote_tlbs(struct kvm *kvm);
void kvm_reload_remote_mmus(struct kvm *kvm);

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index fb93ff9..2962569 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -168,8 +168,12 @@ static bool make_all_cpus_request(struct kvm *kvm, unsigned int req)

void kvm_flush_remote_tlbs(struct kvm *kvm)
{
+ int dirty_count = atomic_read(&kvm->tlbs_dirty);
+
+ smp_mb();
if (make_all_cpus_request(kvm, KVM_REQ_TLB_FLUSH))
++kvm->stat.remote_tlb_flush;
+ atomic_sub(dirty_count, &kvm->tlbs_dirty);
}

void kvm_reload_remote_mmus(struct kvm *kvm)
@@ -249,7 +253,8 @@ static void kvm_mmu_notifier_invalidate_page(struct mmu_notifier *mn,
idx = srcu_read_lock(&kvm->srcu);
spin_lock(&kvm->mmu_lock);
kvm->mmu_notifier_seq++;
- need_tlb_flush = kvm_unmap_hva(kvm, address);
+ need_tlb_flush = kvm_unmap_hva(kvm, address) |
+ atomic_read(&kvm->tlbs_dirty);
spin_unlock(&kvm->mmu_lock);
srcu_read_unlock(&kvm->srcu, idx);

@@ -293,6 +298,7 @@ static void kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn,
kvm->mmu_notifier_count++;
for (; start < end; start += PAGE_SIZE)
need_tlb_flush |= kvm_unmap_hva(kvm, start);
+ need_tlb_flush |= atomic_read(&kvm->tlbs_dirty);
spin_unlock(&kvm->mmu_lock);
srcu_read_unlock(&kvm->srcu, idx);

--
1.7.0.4


\
 
 \ /
  Last update: 2010-11-19 10:03    [from the cache]
©2003-2014 Jasper Spaans. Advertise on this site