[PATCH 3.12-rc7] KVM: Fix modprobe failure for kvm_intel/kvm_amd

Tim Gardner
2013-10-29T15:14:10Z

The x86 specific kvm init creates a new conflicting
debugfs directory which causes modprobe issues
with kvm_intel and kvm_amd. For example,

sudo modprobe kvm_amd
modprobe: ERROR: could not insert 'kvm_amd': Bad address

The simplest fix is to just rename the directory. The following
KVM config options are set:

CONFIG_KVM_GUEST=y
CONFIG_KVM_DEBUG_FS=y
CONFIG_HAVE_KVM=y
CONFIG_HAVE_KVM_IRQCHIP=y
CONFIG_HAVE_KVM_IRQ_ROUTING=y
CONFIG_HAVE_KVM_EVENTFD=y
CONFIG_KVM_APIC_ARCHITECTURE=y
CONFIG_KVM_MMIO=y
CONFIG_KVM_ASYNC_PF=y
CONFIG_HAVE_KVM_MSI=y
CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT=y
CONFIG_KVM=m
CONFIG_KVM_INTEL=m
CONFIG_KVM_AMD=m
# CONFIG_KVM_MMU_AUDIT is not set
CONFIG_KVM_DEVICE_ASSIGNMENT=y

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Gleb Natapov <gleb@redhat.com>
Cc: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
---

There is likely a more elegant and complicated way to solve this
problem, but a simple rename for a debug feature seems best,
especially for an -rc7.

arch/x86/kernel/kvm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index a0e2a8a..d17895a 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -609,7 +609,7 @@ static struct dentry *d_kvm_debug;

struct dentry *kvm_init_debugfs(void)
{
- d_kvm_debug = debugfs_create_dir("kvm", NULL);
+ d_kvm_debug = debugfs_create_dir("kvm-x86", NULL);
if (!d_kvm_debug)
printk(KERN_WARNING "Could not create 'kvm' debugfs directory\n");

--
1.7.9.5