linux-kernel - [PATCH v4 04/11] KVM: x86/mmu: Handle error PFNs in kvm_faultin

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Date:   Wed, 12 Oct 2022 18:16:55 +0000
From:   Sean Christopherson <seanjc@...gle.com>
To:     Sean Christopherson <seanjc@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>
Cc:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
        David Matlack <dmatlack@...gle.com>,
        Isaku Yamahata <isaku.yamahata@...el.com>
Subject: [PATCH v4 04/11] KVM: x86/mmu: Handle error PFNs in kvm_faultin_pfn()

From: David Matlack <dmatlack@...gle.com>

Handle error PFNs in kvm_faultin_pfn() rather than relying on the caller
to invoke handle_abnormal_pfn() after kvm_faultin_pfn().
Opportunistically rename kvm_handle_bad_page() to kvm_handle_error_pfn()
to make it more consistent with is_error_pfn().

This commit moves KVM closer to being able to drop
handle_abnormal_pfn(), which will reduce the amount of duplicate code in
the various page fault handlers.

No functional change intended.

Signed-off-by: David Matlack <dmatlack@...gle.com>
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/mmu/mmu.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 72c3dc1884f6..6417a909181c 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -3155,7 +3155,7 @@ static void kvm_send_hwpoison_signal(unsigned long address, struct task_struct *
 	send_sig_mceerr(BUS_MCEERR_AR, (void __user *)address, PAGE_SHIFT, tsk);
 }
 
-static int kvm_handle_bad_page(struct kvm_vcpu *vcpu, gfn_t gfn, kvm_pfn_t pfn)
+static int kvm_handle_error_pfn(struct kvm_vcpu *vcpu, gfn_t gfn, kvm_pfn_t pfn)
 {
 	/*
 	 * Do not cache the mmio info caused by writing the readonly gfn
@@ -3176,10 +3176,6 @@ static int kvm_handle_bad_page(struct kvm_vcpu *vcpu, gfn_t gfn, kvm_pfn_t pfn)
 static int handle_abnormal_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault,
 			       unsigned int access)
 {
-	/* The pfn is invalid, report the error! */
-	if (unlikely(is_error_pfn(fault->pfn)))
-		return kvm_handle_bad_page(vcpu, fault->gfn, fault->pfn);
-
 	if (unlikely(!fault->slot)) {
 		gva_t gva = fault->is_tdp ? 0 : fault->addr;
 
@@ -4201,10 +4197,19 @@ static int __kvm_faultin_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault
 
 static int kvm_faultin_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
 {
+	int ret;
+
 	fault->mmu_seq = vcpu->kvm->mmu_invalidate_seq;
 	smp_rmb();
 
-	return __kvm_faultin_pfn(vcpu, fault);
+	ret = __kvm_faultin_pfn(vcpu, fault);
+	if (ret != RET_PF_CONTINUE)
+		return ret;
+
+	if (unlikely(is_error_pfn(fault->pfn)))
+		return kvm_handle_error_pfn(vcpu, fault->gfn, fault->pfn);
+
+	return RET_PF_CONTINUE;
 }
 
 /*
-- 
2.38.0.rc1.362.ged0d419d3c-goog