From a4dfde33d7f8448d65d066392ecccbbf50d55fd8 Mon Sep 17 00:00:00 2001 From: Avi Kivity Date: Wed, 9 May 2012 16:10:46 +0300 Subject: [PATCH] KVM: VMX: Fix kvm_set_shared_msr() called in preemptible context (cherry picked from commit 2225fd56049643c1a7d645c0ce9d499d43c7974e) 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: [] debug_smp_processor_id+0xe2/0x100 [] kvm_set_shared_msr+0x32/0xa0 [kvm] [] 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 Signed-off-by: Avi Kivity Signed-off-by: Marcelo Tosatti Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/vmx.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 7f33e337b152..a7a6f6011002 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -2219,9 +2219,12 @@ 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, msr->mask); + preempt_enable(); + } break; } ret = kvm_set_msr_common(vcpu, msr_index, data); -- 2.39.5