From: Avi Kivity <avi@redhat.com>
Date: Wed, 18 Apr 2012 12:03:04 +0000 (+0300)
Subject: KVM: VMX: Fix kvm_set_shared_msr() called in preemptible context
X-Git-Tag: v3.4-rc4~25^2~1
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2225fd56049643c1a7d645c0ce9d499d43c7974e;p=pandora-kernel.git

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>
---

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