Commit c6c4f961 authored Sep 27, 2020 by Li RongQing Committed by Paolo Bonzini Nov 08, 2020

KVM: x86/mmu: fix counting of rmap entries in pte_list_add



Fix an off-by-one style bug in pte_list_add() where it failed to
account the last full set of SPTEs, i.e. when desc->sptes is full
and desc->more is NULL.

Merge the two "PTE_LIST_EXT-1" checks as part of the fix to avoid
an extra comparison.

Signed-off-by: Li RongQing <lirongqing@baidu.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <1601196297-24104-1-git-send-email-lirongqing@baidu.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

parent ff2bb93f

arch/x86/kvm/mmu/mmu.c

+7 −5

Original line number	Diff line number	Diff line
		@@ -856,13 +856,15 @@ static int pte_list_add(struct kvm_vcpu vcpu, u64 spte,
		} else {
		rmap_printk("pte_list_add: %p %llx many->many\n", spte, *spte);
		desc = (struct pte_list_desc *)(rmap_head->val & ~1ul);
		while (desc->sptes[PTE_LIST_EXT-1] && desc->more) {
		desc = desc->more;
		while (desc->sptes[PTE_LIST_EXT-1]) {
		count += PTE_LIST_EXT;
		}
		if (desc->sptes[PTE_LIST_EXT-1]) {

		if (!desc->more) {
		desc->more = mmu_alloc_pte_list_desc(vcpu);
		desc = desc->more;
		break;
		}
		desc = desc->more;
		}
		for (i = 0; desc->sptes[i]; ++i)
		++count;

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