linux-kernel - [PATCH v4 05/11] KVM: x86/mmu: Avoid memslot lookup during KVM_PFN_ERR

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Message-ID: <20221012181702.3663607-6-seanjc@google.com>
Date:   Wed, 12 Oct 2022 18:16:56 +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 05/11] KVM: x86/mmu: Avoid memslot lookup during
 KVM_PFN_ERR_HWPOISON handling

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

Pass the kvm_page_fault struct down to kvm_handle_error_pfn() to avoid a
memslot lookup when handling KVM_PFN_ERR_HWPOISON. Opportunistically
move the gfn_to_hva_memslot() call and @current down into
kvm_send_hwpoison_signal() to cut down on line lengths.

No functional change intended.

Signed-off-by: David Matlack <dmatlack@...gle.com>
Reviewed-by: Isaku Yamahata <isaku.yamahata@...el.com>
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/mmu/mmu.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 6417a909181c..07c3f83b3204 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -3150,23 +3150,25 @@ static int __direct_map(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
 	return ret;
 }
 
-static void kvm_send_hwpoison_signal(unsigned long address, struct task_struct *tsk)
+static void kvm_send_hwpoison_signal(struct kvm_memory_slot *slot, gfn_t gfn)
 {
-	send_sig_mceerr(BUS_MCEERR_AR, (void __user *)address, PAGE_SHIFT, tsk);
+	unsigned long hva = gfn_to_hva_memslot(slot, gfn);
+
+	send_sig_mceerr(BUS_MCEERR_AR, (void __user *)hva, PAGE_SHIFT, current);
 }
 
-static int kvm_handle_error_pfn(struct kvm_vcpu *vcpu, gfn_t gfn, kvm_pfn_t pfn)
+static int kvm_handle_error_pfn(struct kvm_page_fault *fault)
 {
 	/*
 	 * Do not cache the mmio info caused by writing the readonly gfn
 	 * into the spte otherwise read access on readonly gfn also can
 	 * caused mmio page fault and treat it as mmio access.
 	 */
-	if (pfn == KVM_PFN_ERR_RO_FAULT)
+	if (fault->pfn == KVM_PFN_ERR_RO_FAULT)
 		return RET_PF_EMULATE;
 
-	if (pfn == KVM_PFN_ERR_HWPOISON) {
-		kvm_send_hwpoison_signal(kvm_vcpu_gfn_to_hva(vcpu, gfn), current);
+	if (fault->pfn == KVM_PFN_ERR_HWPOISON) {
+		kvm_send_hwpoison_signal(fault->slot, fault->gfn);
 		return RET_PF_RETRY;
 	}
 
@@ -4207,7 +4209,7 @@ static int kvm_faultin_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
 		return ret;
 
 	if (unlikely(is_error_pfn(fault->pfn)))
-		return kvm_handle_error_pfn(vcpu, fault->gfn, fault->pfn);
+		return kvm_handle_error_pfn(fault);
 
 	return RET_PF_CONTINUE;
 }
-- 
2.38.0.rc1.362.ged0d419d3c-goog