From mboxrd@z Thu Jan  1 00:00:00 1970
From: Marcelo Tosatti <mtosatti@redhat.com>
Subject: Re: [PATCH v2] KVM: x86: Convert INIT and SIPI signals into
 synchronously handled requests
Date: Tue, 5 Mar 2013 20:16:41 -0300
Message-ID: <20130305231641.GA6846@amt.cnet>
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Cc: Gleb Natapov <gleb@redhat.com>, kvm <kvm@vger.kernel.org>,
	Paolo Bonzini <pbonzini@redhat.com>
To: Jan Kiszka <jan.kiszka@web.de>
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On Mon, Mar 04, 2013 at 10:41:43PM +0100, Jan Kiszka wrote:
> From: Jan Kiszka <jan.kiszka@siemens.com>
> 
> A VCPU sending INIT or SIPI to some other VCPU races for setting the
> remote VCPU's mp_state. When we were unlucky, KVM_MP_STATE_INIT_RECEIVED
> was overwritten by kvm_emulate_halt and, thus, got lost.
> 
> Fix this by raising requests on the sender side that will then be
> handled synchronously over the target VCPU context.
> 
> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>

Why is kvm_emulate_halt being executed from
KVM_MP_STATE_INIT_RECEIVED/KVM_MP_STATE_SIPI_RECEIVED again?

Why is it not true that the only valid transition from
KVM_MP_STATE_HALTED is from KVM_MP_STATE_RUNNABLE?

It would be good for KVM_MP_STATE_HALTED to indicate 
"guest executed HLT instruction" (which is impossible without INIT/SIPI
being received).