kvm-fix-invalid-secondary-exec-controls.patch

   1 From 29282fde80d44e587f8c152b10049a56e61659f0 Mon Sep 17 00:00:00 2001
   2 From: Takashi Iwai <tiwai@suse.de>
   3 Date: Fri, 09 Nov 2012 14:20:17 +0000
   4 Subject: KVM: x86: Fix invalid secondary exec controls in vmx_cpuid_update()
   5
   6 The commit [ad756a16: KVM: VMX: Implement PCID/INVPCID for guests with
   7 EPT] introduced the unconditional access to SECONDARY_VM_EXEC_CONTROL,
   8 and this triggers kernel warnings like below on old CPUs:
   9
  10     vmwrite error: reg 401e value a0568000 (err 12)
  11     Pid: 13649, comm: qemu-kvm Not tainted 3.7.0-rc4-test2+ #154
  12     Call Trace:
  13      [<ffffffffa0558d86>] vmwrite_error+0x27/0x29 [kvm_intel]
  14      [<ffffffffa054e8cb>] vmcs_writel+0x1b/0x20 [kvm_intel]
  15      [<ffffffffa054f114>] vmx_cpuid_update+0x74/0x170 [kvm_intel]
  16      [<ffffffffa03629b6>] kvm_vcpu_ioctl_set_cpuid2+0x76/0x90 [kvm]
  17      [<ffffffffa0341c67>] kvm_arch_vcpu_ioctl+0xc37/0xed0 [kvm]
  18      [<ffffffff81143f7c>] ? __vunmap+0x9c/0x110
  19      [<ffffffffa0551489>] ? vmx_vcpu_load+0x39/0x1a0 [kvm_intel]
  20      [<ffffffffa0340ee2>] ? kvm_arch_vcpu_load+0x52/0x1a0 [kvm]
  21      [<ffffffffa032dcd4>] ? vcpu_load+0x74/0xd0 [kvm]
  22      [<ffffffffa032deb0>] kvm_vcpu_ioctl+0x110/0x5e0 [kvm]
  23      [<ffffffffa032e93d>] ? kvm_dev_ioctl+0x4d/0x4a0 [kvm]
  24      [<ffffffff8117dc6f>] do_vfs_ioctl+0x8f/0x530
  25      [<ffffffff81139d76>] ? remove_vma+0x56/0x60
  26      [<ffffffff8113b708>] ? do_munmap+0x328/0x400
  27      [<ffffffff81187c8c>] ? fget_light+0x4c/0x100
  28      [<ffffffff8117e1a1>] sys_ioctl+0x91/0xb0
  29      [<ffffffff815a942d>] system_call_fastpath+0x1a/0x1f
  30
  31 This patch adds a check for the availability of secondary exec
  32 control to avoid these warnings.
  33
  34 Cc: <stable@vger.kernel.org> [v3.6+]
  35 Signed-off-by: Takashi Iwai <tiwai@suse.de>
  36 Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
  37 ---
  38 diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
  39 index ad6b1dd..f858159 100644
  40 --- a/arch/x86/kvm/vmx.c
  41 +++ b/arch/x86/kvm/vmx.c
  42 @@ -6549,19 +6549,22 @@ static void vmx_cpuid_update(struct kvm_vcpu *vcpu)
  43                 }
  44         }
  45
  46 -       exec_control = vmcs_read32(SECONDARY_VM_EXEC_CONTROL);
  47         /* Exposing INVPCID only when PCID is exposed */
  48         best = kvm_find_cpuid_entry(vcpu, 0x7, 0);
  49         if (vmx_invpcid_supported() &&
  50             best && (best->ebx & bit(X86_FEATURE_INVPCID)) &&
  51             guest_cpuid_has_pcid(vcpu)) {
  52 +               exec_control = vmcs_read32(SECONDARY_VM_EXEC_CONTROL);
  53                 exec_control |= SECONDARY_EXEC_ENABLE_INVPCID;
  54                 vmcs_write32(SECONDARY_VM_EXEC_CONTROL,
  55                              exec_control);
  56         } else {
  57 -               exec_control &= ~SECONDARY_EXEC_ENABLE_INVPCID;
  58 -               vmcs_write32(SECONDARY_VM_EXEC_CONTROL,
  59 -                            exec_control);
  60 +               if (cpu_has_secondary_exec_ctrls()) {
  61 +                       exec_control = vmcs_read32(SECONDARY_VM_EXEC_CONTROL);
  62 +                       exec_control &= ~SECONDARY_EXEC_ENABLE_INVPCID;
  63 +                       vmcs_write32(SECONDARY_VM_EXEC_CONTROL,
  64 +                                    exec_control);
  65 +               }
  66                 if (best)
  67                         best->ebx &= ~bit(X86_FEATURE_INVPCID);
  68         }
  69 --
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