Commit 5679b803 authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

KVM: SVM: keep DR6 synchronized with vcpu->arch.dr6 



kvm_x86_ops.set_dr6 is only ever called with vcpu->arch.dr6 as the
second argument.  Ensure that the VMCB value is synchronized to
vcpu->arch.dr6 on #DB (both "normal" and nested) and nested vmentry, so
that the current value of DR6 is always available in vcpu->arch.dr6.
The get_dr6 callback can just access vcpu->arch.dr6 and becomes redundant.

Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 2c19dba6

arch/x86/include/asm/kvm_host.h

+1 −1
Original line number Diff line number Diff line
@@ -1093,7 +1093,6 @@ struct kvm_x86_ops { 
	void (*set_idt)(struct kvm_vcpu *vcpu, struct desc_ptr *dt);

	void (*get_gdt)(struct kvm_vcpu *vcpu, struct desc_ptr *dt);

	void (*set_gdt)(struct kvm_vcpu *vcpu, struct desc_ptr *dt);

	u64 (*get_dr6)(struct kvm_vcpu *vcpu);

	void (*set_dr6)(struct kvm_vcpu *vcpu, unsigned long value);

	void (*sync_dirty_debug_regs)(struct kvm_vcpu *vcpu);

	void (*set_dr7)(struct kvm_vcpu *vcpu, unsigned long value);
@@ -1624,6 +1623,7 @@ int kvm_pv_send_ipi(struct kvm *kvm, unsigned long ipi_bitmap_low, 


void kvm_define_shared_msr(unsigned index, u32 msr);

int kvm_set_shared_msr(unsigned index, u64 val, u64 mask);

void kvm_update_dr6(struct kvm_vcpu *vcpu);



u64 kvm_scale_tsc(struct kvm_vcpu *vcpu, u64 tsc);

u64 kvm_read_l1_tsc(struct kvm_vcpu *vcpu, u64 host_tsc);

arch/x86/kvm/svm/nested.c

+16 −8
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 
#include <linux/kernel.h>



#include <asm/msr-index.h>

#include <asm/debugreg.h>



#include "kvm_emulate.h"

#include "trace.h"
@@ -267,7 +268,8 @@ void enter_svm_guest_mode(struct vcpu_svm *svm, u64 vmcb_gpa, 
	svm->vmcb->save.rsp = nested_vmcb->save.rsp;

	svm->vmcb->save.rip = nested_vmcb->save.rip;

	svm->vmcb->save.dr7 = nested_vmcb->save.dr7;

	svm->vmcb->save.dr6 = nested_vmcb->save.dr6;

	svm->vcpu.arch.dr6  = nested_vmcb->save.dr6;

	kvm_update_dr6(&svm->vcpu);

	svm->vmcb->save.cpl = nested_vmcb->save.cpl;



	svm->nested.vmcb_msrpm = nested_vmcb->control.msrpm_base_pa & ~0x0fffULL;
@@ -482,7 +484,7 @@ int nested_svm_vmexit(struct vcpu_svm *svm) 
	nested_vmcb->save.rsp    = vmcb->save.rsp;

	nested_vmcb->save.rax    = vmcb->save.rax;

	nested_vmcb->save.dr7    = vmcb->save.dr7;

	nested_vmcb->save.dr6    = vmcb->save.dr6;

	nested_vmcb->save.dr6    = svm->vcpu.arch.dr6;

	nested_vmcb->save.cpl    = vmcb->save.cpl;



	nested_vmcb->control.int_ctl           = vmcb->control.int_ctl;
@@ -606,7 +608,7 @@ static int nested_svm_exit_handled_msr(struct vcpu_svm *svm) 
/* DB exceptions for our internal use must not cause vmexit */

static int nested_svm_intercept_db(struct vcpu_svm *svm)

{

	unsigned long dr6;

	unsigned long dr6 = svm->vmcb->save.dr6;



	/* Always catch it and pass it to userspace if debugging.  */

	if (svm->vcpu.guest_debug &
@@ -615,22 +617,28 @@ static int nested_svm_intercept_db(struct vcpu_svm *svm) 


	/* if we're not singlestepping, it's not ours */

	if (!svm->nmi_singlestep)

		return NESTED_EXIT_DONE;

		goto reflected_db;



	/* if it's not a singlestep exception, it's not ours */

	if (kvm_get_dr(&svm->vcpu, 6, &dr6))

		return NESTED_EXIT_DONE;

	if (!(dr6 & DR6_BS))

		return NESTED_EXIT_DONE;

		goto reflected_db;



	/* if the guest is singlestepping, it should get the vmexit */

	if (svm->nmi_singlestep_guest_rflags & X86_EFLAGS_TF) {

		disable_nmi_singlestep(svm);

		return NESTED_EXIT_DONE;

		goto reflected_db;

	}



	/* it's ours, the nested hypervisor must not see this one */

	return NESTED_EXIT_HOST;



reflected_db:

	/*

	 * Synchronize guest DR6 here just like in db_interception; it will

	 * be moved into the nested VMCB by nested_svm_vmexit.

	 */

	svm->vcpu.arch.dr6 = dr6;

	return NESTED_EXIT_DONE;

}



static int nested_svm_intercept_ioio(struct vcpu_svm *svm)

arch/x86/kvm/svm/svm.c

+2 −7
Original line number Diff line number Diff line
@@ -1672,11 +1672,6 @@ static void new_asid(struct vcpu_svm *svm, struct svm_cpu_data *sd) 
	mark_dirty(svm->vmcb, VMCB_ASID);

}



static u64 svm_get_dr6(struct kvm_vcpu *vcpu)

{

	return to_svm(vcpu)->vmcb->save.dr6;

}



static void svm_set_dr6(struct kvm_vcpu *vcpu, unsigned long value)

{

	struct vcpu_svm *svm = to_svm(vcpu);
@@ -1693,7 +1688,7 @@ static void svm_sync_dirty_debug_regs(struct kvm_vcpu *vcpu) 
	get_debugreg(vcpu->arch.db[1], 1);

	get_debugreg(vcpu->arch.db[2], 2);

	get_debugreg(vcpu->arch.db[3], 3);

	vcpu->arch.dr6 = svm_get_dr6(vcpu);

	vcpu->arch.dr6 = svm->vmcb->save.dr6;

	vcpu->arch.dr7 = svm->vmcb->save.dr7;



	vcpu->arch.switch_db_regs &= ~KVM_DEBUGREG_WONT_EXIT;
@@ -1739,6 +1734,7 @@ static int db_interception(struct vcpu_svm *svm) 
	if (!(svm->vcpu.guest_debug &

	      (KVM_GUESTDBG_SINGLESTEP | KVM_GUESTDBG_USE_HW_BP)) &&

		!svm->nmi_singlestep) {

		vcpu->arch.dr6 = svm->vmcb->save.dr6;

		kvm_queue_exception(&svm->vcpu, DB_VECTOR);

		return 1;

	}
@@ -3931,7 +3927,6 @@ static struct kvm_x86_ops svm_x86_ops __initdata = { 
	.set_idt = svm_set_idt,

	.get_gdt = svm_get_gdt,

	.set_gdt = svm_set_gdt,

	.get_dr6 = svm_get_dr6,

	.set_dr6 = svm_set_dr6,

	.set_dr7 = svm_set_dr7,

	.sync_dirty_debug_regs = svm_sync_dirty_debug_regs,

arch/x86/kvm/vmx/vmx.c

+0 −6
Original line number Diff line number Diff line
@@ -4965,11 +4965,6 @@ static int handle_dr(struct kvm_vcpu *vcpu) 
	return kvm_skip_emulated_instruction(vcpu);

}



static u64 vmx_get_dr6(struct kvm_vcpu *vcpu)

{

	return vcpu->arch.dr6;

}



static void vmx_set_dr6(struct kvm_vcpu *vcpu, unsigned long val)

{

}
@@ -7736,7 +7731,6 @@ static struct kvm_x86_ops vmx_x86_ops __initdata = { 
	.set_idt = vmx_set_idt,

	.get_gdt = vmx_get_gdt,

	.set_gdt = vmx_set_gdt,

	.get_dr6 = vmx_get_dr6,

	.set_dr6 = vmx_set_dr6,

	.set_dr7 = vmx_set_dr7,

	.sync_dirty_debug_regs = vmx_sync_dirty_debug_regs,

arch/x86/kvm/x86.c

+2 −6
Original line number Diff line number Diff line
@@ -104,7 +104,6 @@ static u64 __read_mostly cr4_reserved_bits = CR4_RESERVED_BITS; 
                                    KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK)



static void update_cr8_intercept(struct kvm_vcpu *vcpu);

static void kvm_update_dr6(struct kvm_vcpu *vcpu);

static void process_nmi(struct kvm_vcpu *vcpu);

static void enter_smm(struct kvm_vcpu *vcpu);

static void __kvm_set_rflags(struct kvm_vcpu *vcpu, unsigned long rflags);
@@ -1048,7 +1047,7 @@ static void kvm_update_dr0123(struct kvm_vcpu *vcpu) 
	}

}



static void kvm_update_dr6(struct kvm_vcpu *vcpu)

void kvm_update_dr6(struct kvm_vcpu *vcpu)

{

	if (!(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP))

		kvm_x86_ops.set_dr6(vcpu, vcpu->arch.dr6);
@@ -1129,10 +1128,7 @@ int kvm_get_dr(struct kvm_vcpu *vcpu, int dr, unsigned long *val) 
	case 4:

		/* fall through */

	case 6:

		if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)

		*val = vcpu->arch.dr6;

		else

			*val = kvm_x86_ops.get_dr6(vcpu);

		break;

	case 5:

		/* fall through */

CRA Git | Maintained and supported by SUSTech CRA and CCSE