The patch below does not apply to the 5.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable@xxxxxxxxxxxxxxx>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 91a2c34b7d6fadc9c5d9433c620ea4c32ee7cae8 Mon Sep 17 00:00:00 2001 From: Santosh Shukla <sashukla@xxxxxxxxxx> Date: Mon, 26 Oct 2020 16:54:07 +0530 Subject: [PATCH] KVM: arm64: Force PTE mapping on fault resulting in a device mapping VFIO allows a device driver to resolve a fault by mapping a MMIO range. This can be subsequently result in user_mem_abort() to try and compute a huge mapping based on the MMIO pfn, which is a sure recipe for things to go wrong. Instead, force a PTE mapping when the pfn faulted in has a device mapping. Fixes: 6d674e28f642 ("KVM: arm/arm64: Properly handle faulting of device mappings") Suggested-by: Marc Zyngier <maz@xxxxxxxxxx> Signed-off-by: Santosh Shukla <sashukla@xxxxxxxxxx> [maz: rewritten commit message] Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx> Reviewed-by: Gavin Shan <gshan@xxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Link: https://lore.kernel.org/r/1603711447-11998-2-git-send-email-sashukla@xxxxxxxxxx diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index e431d2d8e368..c7c6df6309d5 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -851,6 +851,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, if (kvm_is_device_pfn(pfn)) { device = true; + force_pte = true; } else if (logging_active && !write_fault) { /* * Only actually map the page as writable if this was a write