Commit adad0d02 authored Sep 19, 2016 by Colin Ian King Committed by Paolo Bonzini Sep 20, 2016

kvm: svm: fix unsigned compare less than zero comparison



vm_data->avic_vm_id is a u32, so the check for a error
return (less than zero) such as -EAGAIN from
avic_get_next_vm_id currently has no effect whatsoever.
Fix this by using a temporary int for the comparison
and assign vm_data->avic_vm_id to this. I used an explicit
u32 cast in the assignment to show why vm_data->avic_vm_id
cannot be used in the assign/compare steps.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

parent 095cf55d

arch/x86/kvm/svm.c

+5 −4

Original line number	Diff line number	Diff line
		@@ -1412,7 +1412,7 @@ static void avic_vm_destroy(struct kvm *kvm)
		static int avic_vm_init(struct kvm *kvm)
		{
		unsigned long flags;
		int err = -ENOMEM;
		int vm_id, err = -ENOMEM;
		struct kvm_arch *vm_data = &kvm->arch;
		struct page *p_page;
		struct page *l_page;
		@@ -1420,9 +1420,10 @@ static int avic_vm_init(struct kvm *kvm)
		if (!avic)
		return 0;

		vm_data->avic_vm_id = avic_get_next_vm_id();
		if (vm_data->avic_vm_id < 0)
		return vm_data->avic_vm_id;
		vm_id = avic_get_next_vm_id();
		if (vm_id < 0)
		return vm_id;
		vm_data->avic_vm_id = (u32)vm_id;

		/* Allocating physical APIC ID table (4KB) */
		p_page = alloc_page(GFP_KERNEL);

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