linux-kernel - [PATCH v3 28/31] KVM: MMU: pass struct kvm_page_fault to mmu_set

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Message-Id: <20210924163152.289027-29-pbonzini@redhat.com>
Date:   Fri, 24 Sep 2021 12:31:49 -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 28/31] KVM: MMU: pass struct kvm_page_fault to mmu_set_spte

mmu_set_spte is called for either PTE prefetching or page faults.  The
three boolean arguments write_fault, speculative and host_writable are
always respectively false/true/true for prefetching and coming from
a struct kvm_page_fault for page faults.

Let mmu_set_spte distinguish these two situation by accepting a
possibly NULL struct kvm_page_fault argument.

Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
 arch/x86/kvm/mmu/mmu.c         | 17 ++++++++++-------
 arch/x86/kvm/mmu/paging_tmpl.h | 13 +++----------
 2 files changed, 13 insertions(+), 17 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index c208f001c302..4b304f60cf44 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -2675,9 +2675,8 @@ int mmu_try_to_unsync_pages(struct kvm_vcpu *vcpu, gfn_t gfn, bool can_unsync,
 }
 
 static int mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
-			unsigned int pte_access, bool write_fault,
-			gfn_t gfn, kvm_pfn_t pfn, bool speculative,
-			bool host_writable)
+			unsigned int pte_access, gfn_t gfn,
+			kvm_pfn_t pfn, struct kvm_page_fault *fault)
 {
 	struct kvm_mmu_page *sp = sptep_to_sp(sptep);
 	int level = sp->role.level;
@@ -2687,6 +2686,11 @@ static int mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
 	bool wrprot;
 	u64 spte;
 
+	/* Prefetching always gets a writable pfn.  */
+	bool host_writable = !fault || fault->map_writable;
+	bool speculative = !fault || fault->prefault;
+	bool write_fault = fault && fault->write;
+
 	pgprintk("%s: spte %llx write_fault %d gfn %llx\n", __func__,
 		 *sptep, write_fault, gfn);
 
@@ -2778,8 +2782,8 @@ static int direct_pte_prefetch_many(struct kvm_vcpu *vcpu,
 		return -1;
 
 	for (i = 0; i < ret; i++, gfn++, start++) {
-		mmu_set_spte(vcpu, start, access, false, gfn,
-			     page_to_pfn(pages[i]), true, true);
+		mmu_set_spte(vcpu, start, access, gfn,
+			     page_to_pfn(pages[i]), NULL);
 		put_page(pages[i]);
 	}
 
@@ -2981,8 +2985,7 @@ static int __direct_map(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
 		return -EFAULT;
 
 	ret = mmu_set_spte(vcpu, it.sptep, ACC_ALL,
-			   fault->write, base_gfn, fault->pfn,
-			   fault->prefault, fault->map_writable);
+			   base_gfn, fault->pfn, fault);
 	if (ret == RET_PF_SPURIOUS)
 		return ret;
 
diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
index fbbaa3f5fb4e..8c07c42a4d73 100644
--- a/arch/x86/kvm/mmu/paging_tmpl.h
+++ b/arch/x86/kvm/mmu/paging_tmpl.h
@@ -578,13 +578,7 @@ FNAME(prefetch_gpte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
 	if (is_error_pfn(pfn))
 		return false;
 
-	/*
-	 * we call mmu_set_spte() with host_writable = true because
-	 * pte_prefetch_gfn_to_pfn always gets a writable pfn.
-	 */
-	mmu_set_spte(vcpu, spte, pte_access, false, gfn, pfn,
-		     true, true);
-
+	mmu_set_spte(vcpu, spte, pte_access, gfn, pfn, NULL);
 	kvm_release_pfn_clean(pfn);
 	return true;
 }
@@ -763,9 +757,8 @@ static int FNAME(fetch)(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault,
 	if (WARN_ON_ONCE(it.level != fault->goal_level))
 		return -EFAULT;
 
-	ret = mmu_set_spte(vcpu, it.sptep, gw->pte_access, fault->write,
-			   base_gfn, fault->pfn, fault->prefault,
-			   fault->map_writable);
+	ret = mmu_set_spte(vcpu, it.sptep, gw->pte_access,
+			   base_gfn, fault->pfn, fault);
 	if (ret == RET_PF_SPURIOUS)
 		return ret;
 
-- 
2.27.0