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Commit fd7373cc authored by Jan Kiszka's avatar Jan Kiszka Committed by Marcelo Tosatti
Browse files

KVM: VMX: Clean up DR6 emulation 



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: default avatarJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
parent 138ac8d8

arch/x86/kvm/vmx.c

+6 −17
Original line number Diff line number Diff line
@@ -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 << 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);