[PATCH 2/2] arm/arm64: KVM: Ensure memslots are within KVM_PHYS_SIZE
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From: catalin.marinas@arm.com (Catalin Marinas)
Date: 2014-09-30 12:46:51
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On Thu, Sep 25, 2014 at 08:42:54PM +0100, Christoffer Dall wrote:
quoted hunk ↗ jump to hunk
When creating or moving a memslot, make sure the IPA space is within the addressable range of the guest. Otherwise, user space can create too large a memslot and KVM would try to access potentially unallocated page table entries when inserting entries in the Stage-2 page tables. Signed-off-by: Christoffer Dall <redacted> --- arch/arm/kvm/mmu.c | 8 ++++++++ 1 file changed, 8 insertions(+)diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c index 4532f5f..52a311a 100644 --- a/arch/arm/kvm/mmu.c +++ b/arch/arm/kvm/mmu.c@@ -975,6 +975,9 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu, struct kvm_run *run) goto out_unlock; } + /* Userspace should not be able to register out-of-bounds IPAs */
I think "userspace" is a bit misleading (should be "guests").
+ VM_BUG_ON(fault_ipa >= KVM_PHYS_SIZE);
Can guests not generate IPA addresses higher than KVM_PHYS_SIZE? I don't see why this wouldn't be possible when PARange > 40. -- Catalin