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KVM: VMX: Clean up DR6 emulation

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As we trap all debug register accesses, we do not need to switch real
DR6 at all. Clean up update_exception_bitmap at this chance, too.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
This commit is contained in:
Jan Kiszka 2010-01-20 18:20:20 +01:00 committed by Marcelo Tosatti
parent 138ac8d88f
commit fd7373cce7
1 changed files with 6 additions and 17 deletions
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23
arch/x86/kvm/vmx.c
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@ -579,17 +579,12 @@ static void update_exception_bitmap(struct kvm_vcpu *vcpu)
{
u32 eb;
eb = (1u << PF_VECTOR) | (1u << UD_VECTOR) | (1u << MC_VECTOR)
| (1u << NM_VECTOR);
/*
* Unconditionally intercept #DB so we can maintain dr6 without
* reading it every exit.
*/
eb |= 1u << DB_VECTOR;
if (vcpu->guest_debug & KVM_GUESTDBG_ENABLE) {
if (vcpu->guest_debug & KVM_GUESTDBG_USE_SW_BP)
eb |= 1u << BP_VECTOR;
}
eb = (1u << PF_VECTOR) | (1u << UD_VECTOR) | (1u << MC_VECTOR) |
(1u << NM_VECTOR) | (1u << DB_VECTOR);
if ((vcpu->guest_debug &
(KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_SW_BP)) ==
(KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_SW_BP))
eb |= 1u << BP_VECTOR;
if (to_vmx(vcpu)->rmode.vm86_active)
eb = ~0;
if (enable_ept)
@ -3777,9 +3772,6 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu)
*/
vmcs_writel(HOST_CR0, read_cr0());
if (vcpu->arch.switch_db_regs)
set_debugreg(vcpu->arch.dr6, 6);
asm(
/* Store host registers */
"push %%"R"dx; push %%"R"bp;"
@ -3880,9 +3872,6 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu)
| (1 << VCPU_EXREG_PDPTR));
vcpu->arch.regs_dirty = 0;
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)
fixup_rmode_irq(vmx);