linux-kernel - [PATCH v3 23/31] KVM: MMU: inline set_spte in FNAME(sync

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Message-Id: <20210924163152.289027-24-pbonzini@redhat.com>
Date:   Fri, 24 Sep 2021 12:31:44 -0400
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     dmatlack@...gle.com, seanjc@...gle.com
Subject: [PATCH v3 23/31] KVM: MMU: inline set_spte in FNAME(sync_page)

Since the two callers of set_spte do different things with the results,
inlining it actually makes the code simpler to reason about.  For example,
FNAME(sync_page) already has a struct kvm_mmu_page *, but set_spte had to
fish it back out of sptep's private page data.

Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
 arch/x86/kvm/mmu/mmu.c         | 21 ---------------------
 arch/x86/kvm/mmu/paging_tmpl.h | 21 ++++++++++++---------
 2 files changed, 12 insertions(+), 30 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 6ba7c60bd4f8..19c2fd2189a3 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -2674,27 +2674,6 @@ int mmu_try_to_unsync_pages(struct kvm_vcpu *vcpu, gfn_t gfn, bool can_unsync,
 	return 0;
 }
 
-static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
-		    unsigned int pte_access, int level,
-		    gfn_t gfn, kvm_pfn_t pfn, bool speculative,
-		    bool can_unsync, bool host_writable)
-{
-	u64 spte;
-	struct kvm_mmu_page *sp;
-	int ret;
-
-	sp = sptep_to_sp(sptep);
-
-	ret = make_spte(vcpu, pte_access, level, gfn, pfn, *sptep, speculative,
-			can_unsync, host_writable, sp_ad_disabled(sp), &spte);
-
-	if (*sptep == spte)
-		ret |= SET_SPTE_SPURIOUS;
-	else if (mmu_spte_update(sptep, spte))
-		ret |= SET_SPTE_NEED_REMOTE_TLB_FLUSH;
-	return ret;
-}
-
 static int mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
 			unsigned int pte_access, bool write_fault, int level,
 			gfn_t gfn, kvm_pfn_t pfn, bool speculative,
diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
index e4c7bf3deac8..500962dceda0 100644
--- a/arch/x86/kvm/mmu/paging_tmpl.h
+++ b/arch/x86/kvm/mmu/paging_tmpl.h
@@ -1061,7 +1061,7 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
 	int i;
 	bool host_writable;
 	gpa_t first_pte_gpa;
-	int set_spte_ret = 0;
+	bool flush = false;
 
 	/*
 	 * Ignore various flags when verifying that it's safe to sync a shadow
@@ -1091,6 +1091,7 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
 	first_pte_gpa = FNAME(get_level1_sp_gpa)(sp);
 
 	for (i = 0; i < PT64_ENT_PER_PAGE; i++) {
+		u64 *sptep, spte;
 		unsigned pte_access;
 		pt_element_t gpte;
 		gpa_t pte_gpa;
@@ -1106,7 +1107,7 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
 			return -1;
 
 		if (FNAME(prefetch_invalid_gpte)(vcpu, sp, &sp->spt[i], gpte)) {
-			set_spte_ret |= SET_SPTE_NEED_REMOTE_TLB_FLUSH;
+			flush = true;
 			continue;
 		}
 
@@ -1120,19 +1121,21 @@ 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]);
-			set_spte_ret |= SET_SPTE_NEED_REMOTE_TLB_FLUSH;
+			flush = true;
 			continue;
 		}
 
-		host_writable = sp->spt[i] & shadow_host_writable_mask;
+		sptep = &sp->spt[i];
+		spte = *sptep;
+		host_writable = spte & shadow_host_writable_mask;
+		make_spte(vcpu, pte_access, PG_LEVEL_4K, gfn,
+			  spte_to_pfn(spte), spte, true, false,
+			  host_writable, sp_ad_disabled(sp), &spte);
 
-		set_spte_ret |= set_spte(vcpu, &sp->spt[i],
-					 pte_access, PG_LEVEL_4K,
-					 gfn, spte_to_pfn(sp->spt[i]),
-					 true, false, host_writable);
+		flush |= mmu_spte_update(sptep, spte);
 	}
 
-	return set_spte_ret & SET_SPTE_NEED_REMOTE_TLB_FLUSH;
+	return flush;
 }
 
 #undef pt_element_t
-- 
2.27.0