Re: [PATCH] KVM: nVMX: Reset RFLAGS on VM-exit

[Nadav Har'El <nyh@math.technion.ac.il>]

On Sun, Mar 03, 2013, Jan Kiszka wrote about "[PATCH] KVM: nVMX: Reset RFLAGS on VM-exit":
> From: Jan Kiszka <jan.kiszka@siemens.com>
> 
> Ouch, how could this work so well that far? We need to clear RFLAGS to
> the reset value as specified by the SDM. Particularly, IF must be off
> after VM-exit!

nested_vmx_succeed() or nested_vmx_fail*() were already clearing some of
the fields that I understood was necessary to clear. But they did not clear
the IF - I never realised (and didn't verify now) that this is part of the
spec. And since L1 KVM anyways enters L2 with interrupts disabled, nested KVM
would not see a difference.

> +	vmx_set_rflags(vcpu, 0x02);

There's a macro X86_EFLAGS_BIT1 which you can use for this 0x02.


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Nadav Har'El                        |         Sunday, Mar 3 2013, 22 Adar 5773
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