From: Santosh Shukla sashukla@nvidia.com

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@kernel.org Signed-off-by: Santosh Shukla sashukla@nvidia.com [maz: rewritten commit message] Signed-off-by: Marc Zyngier maz@kernel.org Reviewed-by: Gavin Shan gshan@redhat.com Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/1603711447-11998-2-git-send-email-sashukla@nvidia.... --- arch/arm64/kvm/mmu.c | 1 + 1 file changed, 1 insertion(+)

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