diff mbox

[v2,09/11] KVM: MMU: simplify mmu_need_write_protect

Message ID 1450869954-30273-10-git-send-email-guangrong.xiao@linux.intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

Xiao Guangrong Dec. 23, 2015, 11:25 a.m. UTC
Now, all non-leaf shadow page are page tracked, if gfn is not tracked
there is no non-leaf shadow page of gfn is existed, we can directly
make the shadow page of gfn to unsync

Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
---
 arch/x86/kvm/mmu.c | 26 ++++++++------------------
 1 file changed, 8 insertions(+), 18 deletions(-)

Comments

Kai Huang Dec. 24, 2015, 8:36 a.m. UTC | #1
On 12/23/2015 07:25 PM, Xiao Guangrong wrote:
> Now, all non-leaf shadow page are page tracked, if gfn is not tracked
> there is no non-leaf shadow page of gfn is existed, we can directly
> make the shadow page of gfn to unsync
>
> Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
> ---
>   arch/x86/kvm/mmu.c | 26 ++++++++------------------
>   1 file changed, 8 insertions(+), 18 deletions(-)
>
> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> index 5a2ca73..f89e77f 100644
> --- a/arch/x86/kvm/mmu.c
> +++ b/arch/x86/kvm/mmu.c
> @@ -2461,41 +2461,31 @@ static void __kvm_unsync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
>   	kvm_mmu_mark_parents_unsync(sp);
>   }
>   
> -static void kvm_unsync_pages(struct kvm_vcpu *vcpu,  gfn_t gfn)
> +static bool kvm_unsync_pages(struct kvm_vcpu *vcpu, gfn_t gfn,
> +			     bool can_unsync)
>   {
>   	struct kvm_mmu_page *s;
>   
>   	for_each_gfn_indirect_valid_sp(vcpu->kvm, s, gfn) {
> +		if (!can_unsync)
> +			return true;
> +
>   		if (s->unsync)
>   			continue;
>   		WARN_ON(s->role.level != PT_PAGE_TABLE_LEVEL);
>   		__kvm_unsync_page(vcpu, s);
>   	}
> +
> +	return false;
>   }
I hate to say but it looks odd to me that kvm_unsync_pages takes a bool 
parameter called can_unsync, and return a bool (which looks like 
suggesting whether the unsync has succeeded or not). How about calling 
__kvm_unsync_pages directly in mmu_need_write_protect, and leave 
kvm_unsync_pages unchanged (or even remove it as looks it is used 
nowhere else) ? But again it's to you and Paolo.

Thanks,
-Kai
>   
>   static bool mmu_need_write_protect(struct kvm_vcpu *vcpu, gfn_t gfn,
>   				   bool can_unsync)
>   {
> -	struct kvm_mmu_page *s;
> -	bool need_unsync = false;
> -
>   	if (kvm_page_track_check_mode(vcpu, gfn, KVM_PAGE_TRACK_WRITE))
>   		return true;
>   
> -	for_each_gfn_indirect_valid_sp(vcpu->kvm, s, gfn) {
> -		if (!can_unsync)
> -			return true;
> -
> -		if (s->role.level != PT_PAGE_TABLE_LEVEL)
> -			return true;
> -
> -		if (!s->unsync)
> -			need_unsync = true;
> -	}
> -	if (need_unsync)
> -		kvm_unsync_pages(vcpu, gfn);
> -
> -	return false;
> +	return kvm_unsync_pages(vcpu, gfn, can_unsync);
>   }
>   
>   static bool kvm_is_mmio_pfn(pfn_t pfn)

--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
diff mbox

Patch

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 5a2ca73..f89e77f 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2461,41 +2461,31 @@  static void __kvm_unsync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
 	kvm_mmu_mark_parents_unsync(sp);
 }
 
-static void kvm_unsync_pages(struct kvm_vcpu *vcpu,  gfn_t gfn)
+static bool kvm_unsync_pages(struct kvm_vcpu *vcpu, gfn_t gfn,
+			     bool can_unsync)
 {
 	struct kvm_mmu_page *s;
 
 	for_each_gfn_indirect_valid_sp(vcpu->kvm, s, gfn) {
+		if (!can_unsync)
+			return true;
+
 		if (s->unsync)
 			continue;
 		WARN_ON(s->role.level != PT_PAGE_TABLE_LEVEL);
 		__kvm_unsync_page(vcpu, s);
 	}
+
+	return false;
 }
 
 static bool mmu_need_write_protect(struct kvm_vcpu *vcpu, gfn_t gfn,
 				   bool can_unsync)
 {
-	struct kvm_mmu_page *s;
-	bool need_unsync = false;
-
 	if (kvm_page_track_check_mode(vcpu, gfn, KVM_PAGE_TRACK_WRITE))
 		return true;
 
-	for_each_gfn_indirect_valid_sp(vcpu->kvm, s, gfn) {
-		if (!can_unsync)
-			return true;
-
-		if (s->role.level != PT_PAGE_TABLE_LEVEL)
-			return true;
-
-		if (!s->unsync)
-			need_unsync = true;
-	}
-	if (need_unsync)
-		kvm_unsync_pages(vcpu, gfn);
-
-	return false;
+	return kvm_unsync_pages(vcpu, gfn, can_unsync);
 }
 
 static bool kvm_is_mmio_pfn(pfn_t pfn)