KVM: VMX: Gracefully handle faults on VMXON

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Gracefully handle faults on VMXON, e.g. #GP due to VMX being disabled by
BIOS, instead of letting the fault crash the system.  Now that KVM uses
cpufeatures to query support instead of reading MSR_IA32_FEAT_CTL
directly, it's possible for a bug in a different subsystem to cause KVM
to incorrectly attempt VMXON[*].  Crashing the system is especially
annoying if the system is configured such that hardware_enable() will
be triggered during boot.

Oppurtunistically rename @addr to @vmxon_pointer and use a named param
to reference it in the inline assembly.

Print 0xdeadbeef in the ultra-"rare" case that reading MSR_IA32_FEAT_CTL
also faults.

[*] https://lkml.kernel.org/r/20200226231615.13664-1-sean.j.christopherson@intel.com
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200321193751.24985-4-sean.j.christopherson@intel.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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Sean Christopherson 2020-03-21 12:37:51 -07:00 • committed by Paolo Bonzini

parent d260f9ef50

commit 4f6ea0a876

1 changed files with 21 additions and 3 deletions

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arch/x86/kvm/vmx/vmx.c

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