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From:   Sean Christopherson <sean.j.christopherson@intel.com>
To:     Marc Zyngier <maz@kernel.org>, Paul Mackerras <paulus@ozlabs.org>,
        Christian Borntraeger <borntraeger@de.ibm.com>,
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        Cornelia Huck <cohuck@redhat.com>,
        Claudio Imbrenda <imbrenda@linux.ibm.com>,
        Sean Christopherson <sean.j.christopherson@intel.com>,
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        Wanpeng Li <wanpengli@tencent.com>,
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        Junaid Shahid <junaids@google.com>,
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        Christoffer Dall <christoffer.dall@arm.com>
Subject: [PATCH 06/21] KVM: x86/mmu: Move fast_page_fault() call above mmu_topup_memory_caches()
Date:   Fri,  5 Jun 2020 14:38:38 -0700
Message-Id: <20200605213853.14959-7-sean.j.christopherson@intel.com>
In-Reply-To: <20200605213853.14959-1-sean.j.christopherson@intel.com>
References: <20200605213853.14959-1-sean.j.christopherson@intel.com>
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Avoid refilling the memory caches and potentially slow reclaim/swap when
handling a fast page fault, which does not need to allocate any new
objects.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
 arch/x86/kvm/mmu/mmu.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 5e773564ab20..4b4c3234d623 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4095,6 +4095,9 @@ static int direct_page_fault(struct kvm_vcpu *vcpu, gpa_t gpa, u32 error_code,
 	if (page_fault_handle_page_track(vcpu, error_code, gfn))
 		return RET_PF_EMULATE;
 
+	if (fast_page_fault(vcpu, gpa, error_code))
+		return RET_PF_RETRY;
+
 	r = mmu_topup_memory_caches(vcpu);
 	if (r)
 		return r;
@@ -4102,9 +4105,6 @@ static int direct_page_fault(struct kvm_vcpu *vcpu, gpa_t gpa, u32 error_code,
 	if (lpage_disallowed)
 		max_level = PG_LEVEL_4K;
 
-	if (fast_page_fault(vcpu, gpa, error_code))
-		return RET_PF_RETRY;
-
 	mmu_seq = vcpu->kvm->mmu_notifier_seq;
 	smp_rmb();
 
-- 
2.26.0