path: root/arch
diff options
authorAvi Kivity <avi@redhat.com>2012-04-18 15:03:04 +0300
committerMarcelo Tosatti <mtosatti@redhat.com>2012-04-18 23:42:27 -0300
commit2225fd56049643c1a7d645c0ce9d499d43c7974e (patch)
tree968ee8ee689d619c663d49ad5f7cc150d38daab5 /arch
parent32f6daad4651a748a58a3ab6da0611862175722f (diff)
KVM: VMX: Fix kvm_set_shared_msr() called in preemptible context
kvm_set_shared_msr() may not be called in preemptible context, but vmx_set_msr() does so: BUG: using smp_processor_id() in preemptible [00000000] code: qemu-kvm/22713 caller is kvm_set_shared_msr+0x32/0xa0 [kvm] Pid: 22713, comm: qemu-kvm Not tainted 3.4.0-rc3+ #39 Call Trace: [<ffffffff8131fa82>] debug_smp_processor_id+0xe2/0x100 [<ffffffffa0328ae2>] kvm_set_shared_msr+0x32/0xa0 [kvm] [<ffffffffa03a103b>] vmx_set_msr+0x28b/0x2d0 [kvm_intel] ... Making kvm_set_shared_msr() work in preemptible is cleaner, but it's used in the fast path. Making two variants is overkill, so this patch just disables preemption around the call. Reported-by: Dave Jones <davej@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Diffstat (limited to 'arch')
1 files changed, 4 insertions, 1 deletions
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index ad85adfef843..4ff0ab9bc3c8 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2210,9 +2210,12 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 data)
msr = find_msr_entry(vmx, msr_index);
if (msr) {
msr->data = data;
- if (msr - vmx->guest_msrs < vmx->save_nmsrs)
+ if (msr - vmx->guest_msrs < vmx->save_nmsrs) {
+ preempt_disable();
kvm_set_shared_msr(msr->index, msr->data,
+ preempt_enable();
+ }
ret = kvm_set_msr_common(vcpu, msr_index, data);