From 9c695d42dbd465bcaa865603b411a73c60e60978 Mon Sep 17 00:00:00 2001 From: Alex Williamson Date: Mon, 10 Dec 2012 10:32:51 -0700 Subject: [PATCH] KVM: Check userspace_addr when modifying a memory slot The API documents that only flags and guest physical memory space can be modified on an existing slot, but we don't enforce that the userspace address cannot be modified. Instead we just ignore it. This means that a user may think they've successfully moved both the guest and user addresses, when in fact only the guest address changed. Check and error instead. Reviewed-by: Gleb Natapov Signed-off-by: Alex Williamson Signed-off-by: Marcelo Tosatti --- virt/kvm/kvm_main.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 3caf8162eb6b..e4d358195e54 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -784,13 +784,19 @@ int __kvm_set_memory_region(struct kvm *kvm, r = -ENOMEM; - /* Allocate if a slot is being created */ + /* + * Allocate if a slot is being created. If modifying a slot, + * the userspace_addr cannot change. + */ if (!old.npages) { new.user_alloc = user_alloc; new.userspace_addr = mem->userspace_addr; if (kvm_arch_create_memslot(&new, npages)) goto out_free; + } else if (npages && mem->userspace_addr != old.userspace_addr) { + r = -EINVAL; + goto out_free; } /* Allocate page dirty bitmap if needed */ -- 2.20.1