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Subject[PATCH 1/5] Revert "KVM: Simplify kvm->tlbs_dirty handling"
Date
This reverts commit 5befdc385ddb2d5ae8995ad89004529a3acf58fc.

Since we will allow flush tlb out of mmu-lock in the later
patch

Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
---
arch/x86/kvm/paging_tmpl.h | 7 +++----
include/linux/kvm_host.h | 4 +---
virt/kvm/kvm_main.c | 5 ++++-
3 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index b1e6c1b..cba218a 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -913,8 +913,7 @@ static gpa_t FNAME(gva_to_gpa_nested)(struct kvm_vcpu *vcpu, gva_t vaddr,
* and kvm_mmu_notifier_invalidate_range_start detect the mapping page isn't
* used by guest then tlbs are not flushed, so guest is allowed to access the
* freed pages.
- * We set tlbs_dirty to let the notifier know this change and delay the flush
- * until such a case actually happens.
+ * And we increase kvm->tlbs_dirty to delay tlbs flush in this case.
*/
static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
{
@@ -943,7 +942,7 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
return -EINVAL;

if (FNAME(prefetch_invalid_gpte)(vcpu, sp, &sp->spt[i], gpte)) {
- vcpu->kvm->tlbs_dirty = true;
+ vcpu->kvm->tlbs_dirty++;
continue;
}

@@ -958,7 +957,7 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)

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

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 9816b68..f5937b8 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -401,9 +401,7 @@ struct kvm {
unsigned long mmu_notifier_seq;
long mmu_notifier_count;
#endif
- /* Protected by mmu_lock */
- bool tlbs_dirty;
-
+ long tlbs_dirty;
struct list_head devices;
};

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 5fd4cf8..f6a1e74 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -186,9 +186,12 @@ static bool make_all_cpus_request(struct kvm *kvm, unsigned int req)

void kvm_flush_remote_tlbs(struct kvm *kvm)
{
+ long dirty_count = kvm->tlbs_dirty;
+
+ smp_mb();
if (make_all_cpus_request(kvm, KVM_REQ_TLB_FLUSH))
++kvm->stat.remote_tlb_flush;
- kvm->tlbs_dirty = false;
+ cmpxchg(&kvm->tlbs_dirty, dirty_count, 0);
}
EXPORT_SYMBOL_GPL(kvm_flush_remote_tlbs);

--
1.8.1.4


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