Re: [PATCH v2] KVM: VMX: Fix rflags cache during vCPU reset

[Paolo Bonzini]

On 05/12/2017 01:53, Wanpeng Li wrote:
>> That seems like a convoluted path to produce an illegal RFLAGS value.
>> What's to prevent syzkaller from simply clearing bit 1 of RFLAGS with
>> the KVM_SET_REGS ioctl?
> Yeah, it can happen. Which do you prefer, ioctl fails or |
> X86_EFLAGS_FIXED unconditionally in the ioctl handler in kvm?

I suspect somebody might be passing an all-zero regs struct to
KVM_SET_REGS, so ORing X86_EFLAGS_FIXED is better.

Thanks,

Paolo