From: Gleb Natapov <gleb@redhat.com>
To: Avi Kivity <avi@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>,
kvm@vger.kernel.org, Jan Kiszka <jan.kiszka@siemens.com>
Subject: Re: [PATCH 4/9] KVM: VMX: Cache cpl
Date: Tue, 8 Mar 2011 16:38:28 +0200 [thread overview]
Message-ID: <20110308143828.GF2504@redhat.com> (raw)
In-Reply-To: <4D763D36.9050202@redhat.com>
On Tue, Mar 08, 2011 at 04:29:10PM +0200, Avi Kivity wrote:
> On 03/08/2011 04:20 PM, Gleb Natapov wrote:
> >On Tue, Mar 08, 2011 at 03:57:40PM +0200, Avi Kivity wrote:
> >> We may read the cpl quite often in the same vmexit (instruction privilege
> >> check, memory access checks for instruction and operands), so we gain
> >> a bit if we cache the value.
> >>
> >Shouldn't VCPU_EXREG_CPL be cleared in vmx_set_efer too?
>
> I anticipated that question (which really means that a comment is
> needed). Flipping EFER.LMA is done by flipping CR0.PG (and doesn't
> affect cpl. in any case).
>
Ah, so you can't clear LMA by writing to EFER.
--
Gleb.
next prev parent reply other threads:[~2011-03-08 14:38 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-08 13:57 [PATCH 0/9] Some vmx vmexit optimizations Avi Kivity
2011-03-08 13:57 ` [PATCH 1/9] KVM: Use kvm_get_rflags() and kvm_set_rflags() instead of the raw versions Avi Kivity
2011-03-08 13:57 ` [PATCH 2/9] KVM: VMX: Optimize vmx_get_rflags() Avi Kivity
2011-03-08 13:57 ` [PATCH 3/9] KVM: VMX: Optimize vmx_get_cpl() Avi Kivity
2011-03-08 13:57 ` [PATCH 4/9] KVM: VMX: Cache cpl Avi Kivity
2011-03-08 14:20 ` Gleb Natapov
2011-03-08 14:29 ` Avi Kivity
2011-03-08 14:38 ` Gleb Natapov [this message]
2011-03-08 13:57 ` [PATCH 5/9] KVM: VMX: Avoid vmx_recover_nmi_blocking() when unneeded Avi Kivity
2011-03-08 13:57 ` [PATCH 6/9] KVM: VMX: Qualify check for host NMI Avi Kivity
2011-03-08 13:57 ` [PATCH 7/9] KVM: VMX: Refactor vmx_complete_atomic_exit() Avi Kivity
2011-03-15 21:40 ` Marcelo Tosatti
2011-03-21 8:55 ` Avi Kivity
2011-03-08 13:57 ` [PATCH 8/9] KVM: VMX: Don't VMREAD VM_EXIT_INTR_INFO unconditionally Avi Kivity
2011-03-08 13:57 ` [PATCH 9/9] KVM: VMX: Use cached VM_EXIT_INTR_INFO in handle_exception Avi Kivity
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