From: "Maciej S. Szmigiero" <mail@maciej.szmigiero.name>
To: Paolo Bonzini <pbonzini@redhat.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>,
Igor Mammedov <imammedo@redhat.com>,
Marc Zyngier <maz@kernel.org>, James Morse <james.morse@arm.com>,
Julien Thierry <julien.thierry.kdev@gmail.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Huacai Chen <chenhuacai@kernel.org>,
Aleksandar Markovic <aleksandar.qemu.devel@gmail.com>,
Paul Mackerras <paulus@ozlabs.org>,
Christian Borntraeger <borntraeger@de.ibm.com>,
Janosch Frank <frankja@linux.ibm.com>,
David Hildenbrand <david@redhat.com>,
Cornelia Huck <cohuck@redhat.com>,
Claudio Imbrenda <imbrenda@linux.ibm.com>,
Joerg Roedel <joro@8bytes.org>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v5 13/13] KVM: Optimize overlapping memslots check
Date: Mon, 20 Sep 2021 23:39:01 +0200 [thread overview]
Message-ID: <4f8718fc8da57ab799e95ef7c2060f8be0f2391f.1632171479.git.maciej.szmigiero@oracle.com> (raw)
In-Reply-To: <cover.1632171478.git.maciej.szmigiero@oracle.com>
From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com>
Do a quick lookup for possibly overlapping gfns when creating or moving
a memslot instead of performing a linear scan of the whole memslot set.
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
---
virt/kvm/kvm_main.c | 36 +++++++++++++++++++++++++++---------
1 file changed, 27 insertions(+), 9 deletions(-)
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 5fea467d6fec..78dad8c6376f 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1667,6 +1667,30 @@ static int kvm_delete_memslot(struct kvm *kvm,
return kvm_set_memslot(kvm, mem, old, &new, as_id, KVM_MR_DELETE);
}
+static bool kvm_check_memslot_overlap(struct kvm_memslots *slots,
+ struct kvm_memory_slot *nslot)
+{
+ int idx = slots->node_idx;
+ gfn_t nend = nslot->base_gfn + nslot->npages;
+ struct rb_node *node;
+
+ kvm_for_each_memslot_in_gfn_range(node, slots, nslot->base_gfn, nend) {
+ struct kvm_memory_slot *cslot;
+ gfn_t cend;
+
+ cslot = container_of(node, struct kvm_memory_slot, gfn_node[idx]);
+ cend = cslot->base_gfn + cslot->npages;
+ if (cslot->id == nslot->id)
+ continue;
+
+ /* kvm_for_each_in_gfn_no_more() guarantees that cslot->base_gfn < nend */
+ if (cend > nslot->base_gfn)
+ return true;
+ }
+
+ return false;
+}
+
/*
* Allocate some memory and give it an address in the guest physical address
* space.
@@ -1752,16 +1776,10 @@ int __kvm_set_memory_region(struct kvm *kvm,
}
if ((change == KVM_MR_CREATE) || (change == KVM_MR_MOVE)) {
- int bkt;
-
/* Check for overlaps */
- kvm_for_each_memslot(tmp, bkt, __kvm_memslots(kvm, as_id)) {
- if (tmp->id == id)
- continue;
- if (!((new.base_gfn + new.npages <= tmp->base_gfn) ||
- (new.base_gfn >= tmp->base_gfn + tmp->npages)))
- return -EEXIST;
- }
+ if (kvm_check_memslot_overlap(__kvm_memslots(kvm, as_id),
+ &new))
+ return -EEXIST;
}
/* Allocate/free page dirty bitmap as needed */
next prev parent reply other threads:[~2021-09-20 21:43 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-20 21:38 [PATCH v5 00/13] KVM: Scalable memslots implementation Maciej S. Szmigiero
2021-09-20 21:38 ` [PATCH v5 01/13] KVM: x86: Cache total page count to avoid traversing the memslot array Maciej S. Szmigiero
2021-10-19 22:24 ` Sean Christopherson
2021-10-19 22:31 ` Sean Christopherson
2021-10-20 18:40 ` Maciej S. Szmigiero
2021-10-20 18:41 ` Maciej S. Szmigiero
2021-10-20 19:01 ` Sean Christopherson
2021-11-01 22:29 ` Sean Christopherson
2021-11-03 11:59 ` Maciej S. Szmigiero
2021-11-03 14:47 ` Sean Christopherson
2021-11-03 15:38 ` Maciej S. Szmigiero
2021-09-20 21:38 ` [PATCH v5 02/13] KVM: x86: Don't call kvm_mmu_change_mmu_pages() if the count hasn't changed Maciej S. Szmigiero
2021-09-20 21:38 ` [PATCH v5 03/13] KVM: Add "old" memslot parameter to kvm_arch_prepare_memory_region() Maciej S. Szmigiero
2021-09-20 21:38 ` [PATCH v5 04/13] KVM: x86: Move n_memslots_pages recalc " Maciej S. Szmigiero
2021-10-19 22:38 ` Sean Christopherson
2021-10-20 18:41 ` Maciej S. Szmigiero
2021-09-20 21:38 ` [PATCH v5 05/13] KVM: Integrate gfn_to_memslot_approx() into search_memslots() Maciej S. Szmigiero
2021-10-19 23:38 ` Sean Christopherson
2021-10-20 18:41 ` Maciej S. Szmigiero
2021-09-20 21:38 ` [PATCH v5 06/13] KVM: Move WARN on invalid memslot index to update_memslots() Maciej S. Szmigiero
2021-10-19 23:42 ` Sean Christopherson
2021-09-20 21:38 ` [PATCH v5 07/13] KVM: Just resync arch fields when slots_arch_lock gets reacquired Maciej S. Szmigiero
2021-10-19 23:55 ` Sean Christopherson
2021-10-20 18:41 ` Maciej S. Szmigiero
2021-10-20 18:57 ` Sean Christopherson
2021-10-20 18:58 ` Maciej S. Szmigiero
2021-09-20 21:38 ` [PATCH v5 08/13] KVM: Resolve memslot ID via a hash table instead of via a static array Maciej S. Szmigiero
2021-10-20 0:43 ` Sean Christopherson
2021-10-20 18:42 ` Maciej S. Szmigiero
2021-10-20 22:39 ` Sean Christopherson
2021-10-21 14:15 ` Maciej S. Szmigiero
2021-09-20 21:38 ` [PATCH v5 09/13] KVM: Use interval tree to do fast hva lookup in memslots Maciej S. Szmigiero
2021-10-26 18:19 ` Sean Christopherson
2021-10-26 18:46 ` Maciej S. Szmigiero
2021-09-20 21:38 ` [PATCH v5 10/13] KVM: s390: Introduce kvm_s390_get_gfn_end() Maciej S. Szmigiero
2021-09-20 21:38 ` [PATCH v5 11/13] KVM: Keep memslots in tree-based structures instead of array-based ones Maciej S. Szmigiero
2021-10-27 0:36 ` Sean Christopherson
2021-10-27 23:54 ` Sean Christopherson
2021-10-28 22:22 ` Sean Christopherson
2021-09-20 21:39 ` [PATCH v5 12/13] KVM: Optimize gfn lookup in kvm_zap_gfn_range() Maciej S. Szmigiero
2021-10-20 23:47 ` Sean Christopherson
2021-10-21 14:16 ` Maciej S. Szmigiero
2021-10-21 16:30 ` Sean Christopherson
2021-10-21 21:44 ` Maciej S. Szmigiero
2021-09-20 21:39 ` Maciej S. Szmigiero [this message]
2021-10-26 18:59 ` [PATCH v5 13/13] KVM: Optimize overlapping memslots check Sean Christopherson
2021-10-27 13:48 ` Maciej S. Szmigiero
2021-10-28 17:53 ` Sean Christopherson
2021-10-29 16:23 ` Maciej S. Szmigiero
2021-10-30 0:32 ` Sean Christopherson
2021-10-19 22:07 ` [PATCH v5 00/13] KVM: Scalable memslots implementation Sean Christopherson
2021-10-20 18:40 ` Maciej S. Szmigiero
2021-10-20 19:58 ` Sean Christopherson
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