linux-kernel - [PATCH 04/10] KVM: x86: MMU: Remove is_rmap_spte() and use is_shadow_present

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Date:	Thu, 12 Nov 2015 20:51:56 +0900
From:	Takuya Yoshikawa <yoshikawa_takuya_b1@....ntt.co.jp>
To:	pbonzini@...hat.com
Cc:	kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 04/10] KVM: x86: MMU: Remove is_rmap_spte() and use
 is_shadow_present_pte()

is_rmap_spte(), originally named is_rmap_pte(), was introduced when the
simple reverse mapping was implemented by commit cd4a4e5374110444
("[PATCH] KVM: MMU: Implement simple reverse mapping").  At that point,
its role was clear and only rmap_add() and rmap_remove() were using it
to select sptes that need to be reverse-mapped.

Independently of that, is_shadow_present_pte() was first introduced by
commit c7addb902054195b ("KVM: Allow not-present guest page faults to
bypass kvm") to do bypass_guest_pf optimization, which does not exist
any more.

These two seem to have changed their roles somewhat, and is_rmap_spte()
just calls is_shadow_present_pte() now.

Since using both of them with no clear distinction just makes the code
confusing, remove is_rmap_spte().

Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@....ntt.co.jp>
---
 arch/x86/kvm/mmu.c       | 13 ++++---------
 arch/x86/kvm/mmu_audit.c |  2 +-
 2 files changed, 5 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index c229356..e8cfdc4 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -311,11 +311,6 @@ static int is_large_pte(u64 pte)
 	return pte & PT_PAGE_SIZE_MASK;
 }
 
-static int is_rmap_spte(u64 pte)
-{
-	return is_shadow_present_pte(pte);
-}
-
 static int is_last_spte(u64 pte, int level)
 {
 	if (level == PT_PAGE_TABLE_LEVEL)
@@ -540,7 +535,7 @@ static bool mmu_spte_update(u64 *sptep, u64 new_spte)
 	u64 old_spte = *sptep;
 	bool ret = false;
 
-	WARN_ON(!is_rmap_spte(new_spte));
+	WARN_ON(!is_shadow_present_pte(new_spte));
 
 	if (!is_shadow_present_pte(old_spte)) {
 		mmu_spte_set(sptep, new_spte);
@@ -595,7 +590,7 @@ static int mmu_spte_clear_track_bits(u64 *sptep)
 	else
 		old_spte = __update_clear_spte_slow(sptep, 0ull);
 
-	if (!is_rmap_spte(old_spte))
+	if (!is_shadow_present_pte(old_spte))
 		return 0;
 
 	pfn = spte_to_pfn(old_spte);
@@ -2575,7 +2570,7 @@ static bool mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep, unsigned pte_access,
 	pgprintk("%s: spte %llx write_fault %d gfn %llx\n", __func__,
 		 *sptep, write_fault, gfn);
 
-	if (is_rmap_spte(*sptep)) {
+	if (is_shadow_present_pte(*sptep)) {
 		/*
 		 * If we overwrite a PTE page pointer with a 2MB PMD, unlink
 		 * the parent of the now unreachable PTE.
@@ -2919,7 +2914,7 @@ static bool fast_page_fault(struct kvm_vcpu *vcpu, gva_t gva, int level,
 	 * If the mapping has been changed, let the vcpu fault on the
 	 * same address again.
 	 */
-	if (!is_rmap_spte(spte)) {
+	if (!is_shadow_present_pte(spte)) {
 		ret = true;
 		goto exit;
 	}
diff --git a/arch/x86/kvm/mmu_audit.c b/arch/x86/kvm/mmu_audit.c
index 03d518e..90ee420 100644
--- a/arch/x86/kvm/mmu_audit.c
+++ b/arch/x86/kvm/mmu_audit.c
@@ -183,7 +183,7 @@ static void check_mappings_rmap(struct kvm *kvm, struct kvm_mmu_page *sp)
 		return;
 
 	for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
-		if (!is_rmap_spte(sp->spt[i]))
+		if (!is_shadow_present_pte(sp->spt[i]))
 			continue;
 
 		inspect_spte_has_rmap(kvm, sp->spt + i);
-- 
2.1.0

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