Commit 09db28b8 authored by Yoshimi Ichiyanagi's avatar Yoshimi Ichiyanagi Committed by Linus Torvalds

[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
Signed-off-by: default avatarAvi Kivity <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent a9058ecd
......@@ -1865,6 +1865,11 @@ int kvm_init_arch(struct kvm_arch_ops *ops, struct module *module)
int r;
if (kvm_arch_ops) {
printk(KERN_ERR "kvm: already loaded the other module\n");
return -EEXIST;
kvm_arch_ops = ops;
if (!kvm_arch_ops->cpu_has_kvm_support()) {
......@@ -1907,6 +1912,7 @@ void kvm_exit_arch(void)
on_each_cpu(kvm_arch_ops->hardware_disable, 0, 0, 1);
kvm_arch_ops = NULL;
static __init int kvm_init(void)
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