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From: Avi Kivity <avi@redhat.com>
To: Marcelo Tosatti <mtosatti@redhat.com>, kvm@vger.kernel.org
Subject: [PATCH 0/3] Optimize STI; HLT while an interrupt is pending
Date: Mon, 14 Feb 2011 16:42:14 +0200	[thread overview]
Message-ID: <1297694537-9268-1-git-send-email-avi@redhat.com> (raw)

If the guest executes the following code sequence

   CLI
   ...
   (interrupt becomes pending)
   STI
   HLT

then we will exit on HLT, enter the guest, and exit immediately again on
virtual interrupt pending.  As this is wasteful, this patch set short
circuits the whole operation to inject the interrupt immediately.

(as I've seen this occur very rarely in ftrace, compared to what I saw
before I wrote the patch, please don't apply patches 2 and 3 until I've
had a chance to benchmark it)

Avi Kivity (3):
  KVM: VMX: Cache CPU_BASED_VM_EXEC_CONTROL VMCS field
  KVM: VMX: Short circuit STI; HLT while an interrupt is pending
  KVM: SVM: Short circuit STI; HLT while an interrupt is pending

 arch/x86/kvm/svm.c |    9 +++++++
 arch/x86/kvm/vmx.c |   69 ++++++++++++++++++++++++++++-----------------------
 2 files changed, 47 insertions(+), 31 deletions(-)


             reply	other threads:[~2011-02-14 14:42 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-02-14 14:42 Avi Kivity [this message]
2011-02-14 14:42 ` [PATCH 1/3] KVM: VMX: Cache CPU_BASED_VM_EXEC_CONTROL VMCS field Avi Kivity
2011-02-14 14:42 ` [PATCH 2/3] KVM: VMX: Short circuit STI; HLT while an interrupt is pending Avi Kivity
2011-02-15 20:36   ` Marcelo Tosatti
2011-02-16  9:01     ` Avi Kivity
2011-02-16 16:51       ` Marcelo Tosatti
2011-02-17  9:12         ` Avi Kivity
2011-02-17 16:16           ` Marcelo Tosatti
2011-02-20  9:04             ` Avi Kivity
2011-02-14 14:42 ` [PATCH 3/3] KVM: SVM: " Avi Kivity

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