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[3/3] KVM: MMU: Use helpers to clean up walk_addr_generic()

Message ID 20110615020343.991f0b86.takuya.yoshikawa@gmail.com (mailing list archive)
State New, archived
Headers show

Commit Message

Takuya Yoshikawa June 14, 2011, 5:03 p.m. UTC
From: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>

Introduce two new helpers: set_accessed_bit() and is_last_gpte().

These names were suggested by Ingo and Avi.

Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
---
 arch/x86/kvm/paging_tmpl.h |   57 ++++++++++++++++++++++++++++++++-----------
 1 files changed, 42 insertions(+), 15 deletions(-)

Comments

Avi Kivity June 20, 2011, 12:02 p.m. UTC | #1
On 06/14/2011 08:03 PM, Takuya Yoshikawa wrote:
> From: Takuya Yoshikawa<yoshikawa.takuya@oss.ntt.co.jp>
>
> Introduce two new helpers: set_accessed_bit() and is_last_gpte().
>
> These names were suggested by Ingo and Avi.
>
> Cc: Ingo Molnar<mingo@elte.hu>
> Signed-off-by: Takuya Yoshikawa<yoshikawa.takuya@oss.ntt.co.jp>
> ---
>   arch/x86/kvm/paging_tmpl.h |   57 ++++++++++++++++++++++++++++++++-----------
>   1 files changed, 42 insertions(+), 15 deletions(-)
>
> diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
> index 92fe275..d655a4b6 100644
> --- a/arch/x86/kvm/paging_tmpl.h
> +++ b/arch/x86/kvm/paging_tmpl.h
> @@ -113,6 +113,43 @@ static unsigned FNAME(gpte_access)(struct kvm_vcpu *vcpu, pt_element_t gpte)
>   	return access;
>   }
>
> +static int FNAME(set_accessed_bit)(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
> +				   gfn_t table_gfn, unsigned index,
> +				   pt_element_t __user *ptep_user,
> +				   pt_element_t *ptep)
> +{
> +	int ret;
> +
> +	trace_kvm_mmu_set_accessed_bit(table_gfn, index, sizeof(*ptep));
> +	ret = FNAME(cmpxchg_gpte)(vcpu, mmu, ptep_user, index,
> +				  *ptep, *ptep|PT_ACCESSED_MASK);
> +	if (unlikely(ret))
> +		return ret;
> +
> +	mark_page_dirty(vcpu->kvm, table_gfn);
> +	*ptep |= PT_ACCESSED_MASK;
> +
> +	return 0;
> +}


I don't think this one is worthwhile, it takes 7 parameters!  If there's 
so much communication between caller and callee, it means they are too 
heavily tied up.


> +
> +static bool FNAME(is_last_gpte)(struct guest_walker *walker,
> +				struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
> +				pt_element_t gpte)
> +{
> +	if (walker->level == PT_PAGE_TABLE_LEVEL)
> +		return true;
> +
> +	if ((walker->level == PT_DIRECTORY_LEVEL)&&  is_large_pte(gpte)&&
> +	    (PTTYPE == 64 || is_pse(vcpu)))
> +		return true;
> +
> +	if ((walker->level == PT_PDPE_LEVEL)&&  is_large_pte(gpte)&&
> +	    (mmu->root_level == PT64_ROOT_LEVEL))
> +		return true;
> +
> +	return false;
> +}
> +

This one is much better.
diff mbox

Patch

diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 92fe275..d655a4b6 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -113,6 +113,43 @@  static unsigned FNAME(gpte_access)(struct kvm_vcpu *vcpu, pt_element_t gpte)
 	return access;
 }
 
+static int FNAME(set_accessed_bit)(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
+				   gfn_t table_gfn, unsigned index,
+				   pt_element_t __user *ptep_user,
+				   pt_element_t *ptep)
+{
+	int ret;
+
+	trace_kvm_mmu_set_accessed_bit(table_gfn, index, sizeof(*ptep));
+	ret = FNAME(cmpxchg_gpte)(vcpu, mmu, ptep_user, index,
+				  *ptep, *ptep|PT_ACCESSED_MASK);
+	if (unlikely(ret))
+		return ret;
+
+	mark_page_dirty(vcpu->kvm, table_gfn);
+	*ptep |= PT_ACCESSED_MASK;
+
+	return 0;
+}
+
+static bool FNAME(is_last_gpte)(struct guest_walker *walker,
+				struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
+				pt_element_t gpte)
+{
+	if (walker->level == PT_PAGE_TABLE_LEVEL)
+		return true;
+
+	if ((walker->level == PT_DIRECTORY_LEVEL) && is_large_pte(gpte) &&
+	    (PTTYPE == 64 || is_pse(vcpu)))
+		return true;
+
+	if ((walker->level == PT_PDPE_LEVEL) && is_large_pte(gpte) &&
+	    (mmu->root_level == PT64_ROOT_LEVEL))
+		return true;
+
+	return false;
+}
+
 /*
  * Fetch a guest pte for a guest virtual address
  */
@@ -214,31 +251,21 @@  retry_walk:
 
 		if (!eperm && unlikely(!(pte & PT_ACCESSED_MASK))) {
 			int ret;
-			trace_kvm_mmu_set_accessed_bit(table_gfn, index,
-						       sizeof(pte));
-			ret = FNAME(cmpxchg_gpte)(vcpu, mmu, ptep_user, index,
-						  pte, pte|PT_ACCESSED_MASK);
-			if (unlikely(ret < 0)) {
+
+			ret = FNAME(set_accessed_bit)(vcpu, mmu, table_gfn,
+						      index, ptep_user, &pte);
+			if (ret < 0) {
 				errcode |= PFERR_PRESENT_MASK;
 				goto error;
 			} else if (ret)
 				goto retry_walk;
-
-			mark_page_dirty(vcpu->kvm, table_gfn);
-			pte |= PT_ACCESSED_MASK;
 		}
 
 		pte_access = pt_access & FNAME(gpte_access)(vcpu, pte);
 
 		walker->ptes[walker->level - 1] = pte;
 
-		if ((walker->level == PT_PAGE_TABLE_LEVEL) ||
-		    ((walker->level == PT_DIRECTORY_LEVEL) &&
-				is_large_pte(pte) &&
-				(PTTYPE == 64 || is_pse(vcpu))) ||
-		    ((walker->level == PT_PDPE_LEVEL) &&
-				is_large_pte(pte) &&
-				mmu->root_level == PT64_ROOT_LEVEL)) {
+		if (FNAME(is_last_gpte)(walker, vcpu, mmu, pte)) {
 			int lvl = walker->level;
 			gpa_t real_gpa;
 			gfn_t gfn;