From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
eric van tassell <Eric.VanTassell@amd.com>,
Tom Lendacky <thomas.lendacky@amd.com>
Subject: [RFC PATCH 3/8] KVM: x86/mmu: Refactor handling of not-present SPTEs in mmu_set_spte()
Date: Fri, 31 Jul 2020 14:23:18 -0700 [thread overview]
Message-ID: <20200731212323.21746-4-sean.j.christopherson@intel.com> (raw)
In-Reply-To: <20200731212323.21746-1-sean.j.christopherson@intel.com>
Return early from mmu_set_spte() if the new SPTE is not-present so as to
reduce the indentation of the code that performs metadata updates, e.g.
rmap manipulation. Additional metadata updates will soon follow...
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
arch/x86/kvm/mmu/mmu.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 82f69a7456004..182f398036248 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -3126,12 +3126,14 @@ static int mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
if (!was_rmapped && is_large_pte(*sptep))
++vcpu->kvm->stat.lpages;
- if (is_shadow_present_pte(*sptep)) {
- if (!was_rmapped) {
- rmap_count = rmap_add(vcpu, sptep, gfn);
- if (rmap_count > RMAP_RECYCLE_THRESHOLD)
- rmap_recycle(vcpu, sptep, gfn);
- }
+ /* No additional tracking necessary for not-present SPTEs. */
+ if (!is_shadow_present_pte(*sptep))
+ return ret;
+
+ if (!was_rmapped) {
+ rmap_count = rmap_add(vcpu, sptep, gfn);
+ if (rmap_count > RMAP_RECYCLE_THRESHOLD)
+ rmap_recycle(vcpu, sptep, gfn);
}
return ret;
--
2.28.0
next prev parent reply other threads:[~2020-07-31 21:23 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-31 21:23 [RFC PATCH 0/8] KVM: x86/mmu: Introduce pinned SPTEs framework Sean Christopherson
2020-07-31 21:23 ` [RFC PATCH 1/8] KVM: x86/mmu: Return old SPTE from mmu_spte_clear_track_bits() Sean Christopherson
2020-07-31 21:23 ` [RFC PATCH 2/8] KVM: x86/mmu: Use bits 2:0 to check for present SPTEs Sean Christopherson
2020-07-31 21:23 ` Sean Christopherson [this message]
2020-07-31 21:23 ` [RFC PATCH 4/8] KVM: x86/mmu: Add infrastructure for pinning PFNs on demand Sean Christopherson
2020-07-31 21:23 ` [RFC PATCH 5/8] KVM: SVM: Use the KVM MMU SPTE pinning hooks to pin pages " Sean Christopherson
2020-07-31 21:23 ` [RFC PATCH 6/8] KVM: x86/mmu: Move 'pfn' variable to caller of direct_page_fault() Sean Christopherson
2020-07-31 21:23 ` [RFC PATCH 7/8] KVM: x86/mmu: Introduce kvm_mmu_map_tdp_page() for use by SEV Sean Christopherson
2020-07-31 21:23 ` [RFC PATCH 8/8] KVM: SVM: Pin SEV pages in MMU during sev_launch_update_data() Sean Christopherson
2020-08-03 3:00 ` [RFC PATCH 0/8] KVM: x86/mmu: Introduce pinned SPTEs framework Eric van Tassell
2020-08-03 15:00 ` Sean Christopherson
2020-08-03 15:52 ` Brijesh Singh
2020-08-03 17:16 ` Sean Christopherson
2020-08-04 19:40 ` Brijesh Singh
2020-10-27 3:22 ` Brijesh Singh
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