KVM: VMX: Preserve host CR4.MCE value while in guest mode.

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The host's decision to enable machine check exceptions should remain
in force during non-root mode.  KVM was writing 0 to cr4 on VCPU reset
and passed a slightly-modified 0 to the vmcs.guest_cr4 value.

Tested: Built.
On earlier version, tested by injecting machine check
while a guest is spinning.

Before the change, if guest CR4.MCE==0, then the machine check is
escalated to Catastrophic Error (CATERR) and the machine dies.
If guest CR4.MCE==1, then the machine check causes VMEXIT and is
handled normally by host Linux. After the change, injecting a machine
check causes normal Linux machine check handling.

Signed-off-by: Ben Serebrin <serebrin@google.com>
Reviewed-by: Venkatesh Srinivas <venkateshs@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

...

This commit is contained in:

Ben Serebrin 2015-04-16 11:58:05 -07:00 • committed by Paolo Bonzini

parent decf63336e

commit 085e68eeaf

1 changed files with 10 additions and 2 deletions

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arch/x86/kvm/vmx.c

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