Commit 91a2c34b authored Oct 26, 2020 by Santosh Shukla Committed by Marc Zyngier Oct 29, 2020

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: 6d674e28 ("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.com

parent 2f40c460

arch/arm64/kvm/mmu.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -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

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