From f2cc327303b13a70311e823bd52aa0bca8c7ddbc Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Mon, 26 Jul 2021 16:35:49 +0100 Subject: KVM: arm64: Avoid mapping size adjustment on permission fault Since we only support PMD-sized mappings for THP, getting a permission fault on a level that results in a mapping being larger than PAGE_SIZE is a sure indication that we have already upgraded our mapping to a PMD. In this case, there is no need to try and parse userspace page tables, as the fault information already tells us everything. Signed-off-by: Marc Zyngier Reviewed-by: Alexandru Elisei Link: https://lore.kernel.org/r/20210726153552.1535838-4-maz@kernel.org --- arch/arm64/kvm/mmu.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) (limited to 'arch/arm64/kvm/mmu.c') diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index 183c107c06b2..116a2910a4a4 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -1076,9 +1076,14 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, * If we are not forced to use page mapping, check if we are * backed by a THP and thus use block mapping if possible. */ - if (vma_pagesize == PAGE_SIZE && !(force_pte || device)) - vma_pagesize = transparent_hugepage_adjust(kvm, memslot, hva, - &pfn, &fault_ipa); + if (vma_pagesize == PAGE_SIZE && !(force_pte || device)) { + if (fault_status == FSC_PERM && fault_granule > PAGE_SIZE) + vma_pagesize = fault_granule; + else + vma_pagesize = transparent_hugepage_adjust(kvm, memslot, + hva, &pfn, + &fault_ipa); + } if (fault_status != FSC_PERM && !device && kvm_has_mte(kvm)) { /* Check the VMM hasn't introduced a new VM_SHARED VMA */ -- cgit v1.2.3