From: Peter Xu <peterx@redhat.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: peterx@redhat.com, Maxim Levitsky <mlevitsk@redhat.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Sean Christopherson <seanjc@google.com>,
Paolo Bonzini <pbonzini@redhat.com>
Subject: [PATCH v2 9/9] KVM: X86: Optimize zapping rmap
Date: Fri, 25 Jun 2021 11:34:19 -0400 [thread overview]
Message-ID: <20210625153419.43671-1-peterx@redhat.com> (raw)
In-Reply-To: <20210625153214.43106-1-peterx@redhat.com>
Using rmap_get_first() and rmap_remove() for zapping a huge rmap list could be
slow. The easy way is to travers the rmap list, collecting the a/d bits and
free the slots along the way.
Provide a pte_list_destroy() and do exactly that.
Signed-off-by: Peter Xu <peterx@redhat.com>
---
arch/x86/kvm/mmu/mmu.c | 45 +++++++++++++++++++++++++++++++-----------
1 file changed, 33 insertions(+), 12 deletions(-)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index ba0258bdebc4..45aac78dcabc 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -1014,6 +1014,38 @@ unsigned int pte_list_count(struct kvm_rmap_head *rmap_head)
return count;
}
+/* Return true if rmap existed and callback called, false otherwise */
+static bool pte_list_destroy(struct kvm_rmap_head *rmap_head,
+ int (*callback)(u64 *sptep))
+{
+ struct pte_list_desc *desc, *next;
+ int i;
+
+ if (!rmap_head->val)
+ return false;
+
+ if (!(rmap_head->val & 1)) {
+ if (callback)
+ callback((u64 *)rmap_head->val);
+ goto out;
+ }
+
+ desc = (struct pte_list_desc *)(rmap_head->val & ~1ul);
+
+ while (desc) {
+ if (callback)
+ for (i = 0; i < desc->spte_count; i++)
+ callback(desc->sptes[i]);
+ next = desc->more;
+ mmu_free_pte_list_desc(desc);
+ desc = next;
+ }
+out:
+ /* rmap_head is meaningless now, remember to reset it */
+ rmap_head->val = 0;
+ return true;
+}
+
static struct kvm_rmap_head *__gfn_to_rmap(gfn_t gfn, int level,
struct kvm_memory_slot *slot)
{
@@ -1403,18 +1435,7 @@ static bool rmap_write_protect(struct kvm_vcpu *vcpu, u64 gfn)
static bool kvm_zap_rmapp(struct kvm *kvm, struct kvm_rmap_head *rmap_head,
struct kvm_memory_slot *slot)
{
- u64 *sptep;
- struct rmap_iterator iter;
- bool flush = false;
-
- while ((sptep = rmap_get_first(rmap_head, &iter))) {
- rmap_printk("spte %p %llx.\n", sptep, *sptep);
-
- pte_list_remove(rmap_head, sptep);
- flush = true;
- }
-
- return flush;
+ return pte_list_destroy(rmap_head, mmu_spte_clear_track_bits);
}
static bool kvm_unmap_rmapp(struct kvm *kvm, struct kvm_rmap_head *rmap_head,
--
2.31.1
next prev parent reply other threads:[~2021-06-25 15:34 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-25 15:32 [PATCH v2 0/9] KVM: X86: Some light optimizations on rmap logic Peter Xu
2021-06-25 15:32 ` [PATCH v2 1/9] KVM: X86: Add per-vm stat for max rmap list size Peter Xu
2021-06-25 15:32 ` [PATCH v2 2/9] KVM: Introduce kvm_get_kvm_safe() Peter Xu
2021-07-26 13:42 ` Paolo Bonzini
2021-06-25 15:32 ` [PATCH v2 3/9] KVM: Allow to have arch-specific per-vm debugfs files Peter Xu
2021-06-25 15:32 ` [PATCH v2 4/9] KVM: X86: Introduce pte_list_count() helper Peter Xu
2021-06-25 15:32 ` [PATCH v2 5/9] KVM: X86: Introduce kvm_mmu_slot_lpages() helpers Peter Xu
2021-06-25 15:32 ` [PATCH v2 6/9] KVM: X86: Introduce mmu_rmaps_stat per-vm debugfs file Peter Xu
2021-06-25 15:34 ` [PATCH v2 7/9] KVM: X86: MMU: Tune PTE_LIST_EXT to be bigger Peter Xu
2021-07-28 21:01 ` Sean Christopherson
2021-06-25 15:34 ` [PATCH v2 8/9] KVM: X86: Optimize pte_list_desc with per-array counter Peter Xu
2021-07-28 21:04 ` Sean Christopherson
2021-07-28 21:51 ` Peter Xu
2021-07-29 9:33 ` Paolo Bonzini
2021-07-29 15:53 ` Peter Xu
2021-07-30 15:45 ` Peter Xu
2021-06-25 15:34 ` Peter Xu [this message]
2021-07-28 21:39 ` [PATCH v2 9/9] KVM: X86: Optimize zapping rmap Sean Christopherson
2021-07-28 22:01 ` Peter Xu
2021-07-28 22:31 ` Sean Christopherson
2021-07-29 9:35 ` Paolo Bonzini
2021-07-26 13:05 ` [PATCH v2 0/9] KVM: X86: Some light optimizations on rmap logic Paolo Bonzini
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