From: Ryan Roberts Date: Mon, 5 Dec 2022 11:40:31 +0000 (+0000) Subject: KVM: arm64: Fix benign bug with incorrect use of VA_BITS X-Git-Tag: v6.6.7~3891^2~4^2~7^2 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=219072c09abde0f1d0a6ce091be375e8eb7d08f0;p=platform%2Fkernel%2Flinux-starfive.git KVM: arm64: Fix benign bug with incorrect use of VA_BITS get_user_mapping_size() uses kvm's pgtable library to walk a user space page table created by the kernel, and in doing so, passes metadata that the library needs, including ia_bits, which defines the size of the input address. For the case where the kernel is compiled for 52 VA bits but runs on HW that does not support LVA, it will fall back to 48 VA bits at runtime. Therefore we must use vabits_actual rather than VA_BITS to get the true address size. This is benign in the current code base because the pgtable library only uses it for error checking. Fixes: 6011cf68c885 ("KVM: arm64: Walk userspace page tables to compute the THP mapping size") Signed-off-by: Ryan Roberts Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20221205114031.3972780-1-ryan.roberts@arm.com --- diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index 4efb983..1ef0704 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -641,7 +641,7 @@ static int get_user_mapping_size(struct kvm *kvm, u64 addr) { struct kvm_pgtable pgt = { .pgd = (kvm_pte_t *)kvm->mm->pgd, - .ia_bits = VA_BITS, + .ia_bits = vabits_actual, .start_level = (KVM_PGTABLE_MAX_LEVELS - CONFIG_PGTABLE_LEVELS), .mm_ops = &kvm_user_mm_ops,