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| author | Avi Kivity <avi@redhat.com> | 2012-04-18 16:03:04 +0400 |
|---|---|---|
| committer | Marcelo Tosatti <mtosatti@redhat.com> | 2012-04-19 06:42:27 +0400 |
| commit | 2225fd56049643c1a7d645c0ce9d499d43c7974e (patch) | |
| tree | 968ee8ee689d619c663d49ad5f7cc150d38daab5 | |
| parent | 32f6daad4651a748a58a3ab6da0611862175722f (diff) | |
| download | linux-2225fd56049643c1a7d645c0ce9d499d43c7974e.tar.xz | |
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>
| -rw-r--r-- | arch/x86/kvm/vmx.c | 5 |
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, msr->mask); + preempt_enable(); + } break; } ret = kvm_set_msr_common(vcpu, msr_index, data); |