Commit 5762cb10 authored by Sean Christopherson's avatar Sean Christopherson Committed by David Woodhouse
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KVM: Do not partially reinitialize gfn=>pfn cache during activation 



Don't partially reinitialize a gfn=>pfn cache when activating the cache,
and instead assert that the cache is not valid during activation.  Bug
the VM if the assertion fails, as use-after-free and/or data corruption
is all but guaranteed if KVM ends up with a valid-but-inactive cache.

Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Signed-off-by: default avatarDavid Woodhouse <dwmw@amazon.co.uk>
parent 9f87791d

virt/kvm/pfncache.c

+4 −4
Original line number Diff line number Diff line
@@ -345,6 +345,8 @@ void kvm_gpc_init(struct gfn_to_pfn_cache *gpc, struct kvm *kvm, 
	gpc->kvm = kvm;

	gpc->vcpu = vcpu;

	gpc->usage = usage;

	gpc->pfn = KVM_PFN_ERR_FAULT;

	gpc->uhva = KVM_HVA_ERR_BAD;

}

EXPORT_SYMBOL_GPL(kvm_gpc_init);
@@ -353,10 +355,8 @@ int kvm_gpc_activate(struct gfn_to_pfn_cache *gpc, gpa_t gpa, unsigned long len) 
	struct kvm *kvm = gpc->kvm;



	if (!gpc->active) {

		gpc->khva = NULL;

		gpc->pfn = KVM_PFN_ERR_FAULT;

		gpc->uhva = KVM_HVA_ERR_BAD;

		gpc->valid = false;

		if (KVM_BUG_ON(gpc->valid, kvm))

			return -EIO;



		spin_lock(&kvm->gpc_lock);

		list_add(&gpc->list, &kvm->gpc_list);