Commit 09db28b8 authored Dec 29, 2006 by Yoshimi Ichiyanagi Committed by Linus Torvalds Dec 30, 2006

[PATCH] KVM: Initialize kvm_arch_ops on unload



The latest version of kvm doesn't initialize kvm_arch_ops in kvm_init(), which
causes an error with the following sequence.

1. Load the supported arch's module.
2. Load the unsupported arch's module.$B!!(B(loading error)
3. Unload the unsupported arch's module.

You'll get the following error message after step 3.  "BUG: unable to handle
to handle kernel paging request at virtual address xxxxxxxx"

The problem here is that the unsupported arch's module overwrites kvm_arch_ops
of the supported arch's module at step 2.

This patch initializes kvm_arch_ops upon loading architecture specific kvm
module, and prevents overwriting kvm_arch_ops when kvm_arch_ops is already set
correctly.

Signed-off-by: Avi Kivity <avi@qumranet.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

parent a9058ecd

drivers/kvm/kvm_main.c

+6 −0

Original line number	Original line	Diff line number	Diff line
	@@ -1865,6 +1865,11 @@ int kvm_init_arch(struct kvm_arch_ops ops, struct module module)
	{		{
	int r;		int r;

			if (kvm_arch_ops) {
			printk(KERN_ERR "kvm: already loaded the other module\n");
			return -EEXIST;
			}

	kvm_arch_ops = ops;		kvm_arch_ops = ops;

	if (!kvm_arch_ops->cpu_has_kvm_support()) {		if (!kvm_arch_ops->cpu_has_kvm_support()) {
	@@ -1907,6 +1912,7 @@ void kvm_exit_arch(void)
	unregister_reboot_notifier(&kvm_reboot_notifier);		unregister_reboot_notifier(&kvm_reboot_notifier);
	on_each_cpu(kvm_arch_ops->hardware_disable, 0, 0, 1);		on_each_cpu(kvm_arch_ops->hardware_disable, 0, 0, 1);
	kvm_arch_ops->hardware_unsetup();		kvm_arch_ops->hardware_unsetup();
			kvm_arch_ops = NULL;
	}		}

	static __init int kvm_init(void)		static __init int kvm_init(void)