queue-4.19/kvm-x86-svm-report-msr_ia32_mcg_ext_ctl-as-unsupport.patch

   1 From ea2417f13474d37e347682bcf860c2fb67640845 Mon Sep 17 00:00:00 2001
   2 From: Vitaly Kuznetsov <vkuznets@redhat.com>
   3 Date: Wed, 19 Dec 2018 12:06:13 +0100
   4 Subject: KVM: x86: svm: report MSR_IA32_MCG_EXT_CTL as unsupported
   5 MIME-Version: 1.0
   6 Content-Type: text/plain; charset=UTF-8
   7 Content-Transfer-Encoding: 8bit
   8
   9 [ Upstream commit e87555e550cef4941579cd879759a7c0dee24e68 ]
  10
  11 AMD doesn't seem to implement MSR_IA32_MCG_EXT_CTL and svm code in kvm
  12 knows nothing about it, however, this MSR is among emulated_msrs and
  13 thus returned with KVM_GET_MSR_INDEX_LIST. The consequent KVM_GET_MSRS,
  14 of course, fails.
  15
  16 Report the MSR as unsupported to not confuse userspace.
  17
  18 Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
  19 Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
  20 Signed-off-by: Sasha Levin <sashal@kernel.org>
  21 ---
  22  arch/x86/kvm/svm.c | 7 +++++++
  23  1 file changed, 7 insertions(+)
  24
  25 diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
  26 index f1d3fe5a0c65..02ac8fa0cd6d 100644
  27 --- a/arch/x86/kvm/svm.c
  28 +++ b/arch/x86/kvm/svm.c
  29 @@ -5837,6 +5837,13 @@ static bool svm_cpu_has_accelerated_tpr(void)
  30
  31  static bool svm_has_emulated_msr(int index)
  32  {
  33 +       switch (index) {
  34 +       case MSR_IA32_MCG_EXT_CTL:
  35 +               return false;
  36 +       default:
  37 +               break;
  38 +       }
  39 +
  40         return true;
  41  }
  42
  43 --
  44 2.19.1
  45