From: Avi Kivity <avi@redhat.com>
To: Marcelo Tosatti <mtosatti@redhat.com>
Cc: kvm@vger.kernel.org, Jan Kiszka <jan.kiszka@siemens.com>
Subject: [PATCH] KVM: VMX: Conditionally reload debug register 6
Date: Tue, 1 Sep 2009 14:40:32 +0300 [thread overview]
Message-ID: <1251805232-16885-1-git-send-email-avi@redhat.com> (raw)
Only reload debug register 6 if we're running with the guest's
debug registers. Saves around 150 cycles from the guest lightweight
exit path.
Signed-off-by: Avi Kivity <avi@redhat.com>
---
arch/x86/kvm/vmx.c | 6 ++++--
1 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 05cd554..70b0c54 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3629,7 +3629,8 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu)
*/
vmcs_writel(HOST_CR0, read_cr0());
- set_debugreg(vcpu->arch.dr6, 6);
+ if (vcpu->arch.switch_db_regs)
+ set_debugreg(vcpu->arch.dr6, 6);
asm(
/* Store host registers */
@@ -3731,7 +3732,8 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu)
| (1 << VCPU_EXREG_PDPTR));
vcpu->arch.regs_dirty = 0;
- get_debugreg(vcpu->arch.dr6, 6);
+ if (vcpu->arch.switch_db_regs)
+ get_debugreg(vcpu->arch.dr6, 6);
vmx->idt_vectoring_info = vmcs_read32(IDT_VECTORING_INFO_FIELD);
if (vmx->rmode.irq.pending)
--
1.6.4.1
next reply other threads:[~2009-09-01 11:40 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-09-01 11:40 Avi Kivity [this message]
2009-09-01 11:43 ` [PATCH] KVM: VMX: Conditionally reload debug register 6 Jan Kiszka
2009-09-01 11:53 ` Avi Kivity
2009-09-01 12:32 ` Jan Kiszka
2009-09-01 12:54 ` Avi Kivity
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