From 3fb884ffe921c99483a84b0175f3c03f048e9069 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Wed, 2 Sep 2020 11:18:29 +0100 Subject: [PATCH] KVM: arm64: Do not try to map PUDs when they are folded into PMD For the obscure cases where PMD and PUD are the same size (64kB pages with 42bit VA, for example, which results in only two levels of page tables), we can't map anything as a PUD, because there is... erm... no PUD to speak of. Everything is either a PMD or a PTE. So let's only try and map a PUD when its size is different from that of a PMD. Cc: stable@vger.kernel.org Fixes: b8e0ba7c8bea ("KVM: arm64: Add support for creating PUD hugepages at stage 2") Reported-by: Gavin Shan Reported-by: Eric Auger Reviewed-by: Alexandru Elisei Reviewed-by: Gavin Shan Tested-by: Gavin Shan Tested-by: Eric Auger Tested-by: Alexandru Elisei Signed-off-by: Marc Zyngier --- arch/arm64/kvm/mmu.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index 0121ef2c7c8d..16b8660ddbcc 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -1964,7 +1964,12 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, (fault_status == FSC_PERM && stage2_is_exec(mmu, fault_ipa, vma_pagesize)); - if (vma_pagesize == PUD_SIZE) { + /* + * If PUD_SIZE == PMD_SIZE, there is no real PUD level, and + * all we have is a 2-level page table. Trying to map a PUD in + * this case would be fatally wrong. + */ + if (PUD_SIZE != PMD_SIZE && vma_pagesize == PUD_SIZE) { pud_t new_pud = kvm_pfn_pud(pfn, mem_type); new_pud = kvm_pud_mkhuge(new_pud);