Commit b742c1e6 authored by Ladi Prosek's avatar Ladi Prosek Committed by Radim Krčmář
Browse files

KVM: SVM: handle singlestep exception when skipping emulated instructions 



kvm_skip_emulated_instruction handles the singlestep debug exception
which is something we almost always want. This commit (specifically
the change in rdmsr_interception) makes the debug.flat KVM unit test
pass on AMD.

Two call sites still call skip_emulated_instruction directly:

* In svm_queue_exception where it's used only for moving the rip forward

* In task_switch_interception which is analogous to handle_task_switch
  in VMX

Signed-off-by: default avatarLadi Prosek <lprosek@redhat.com>
Signed-off-by: default avatarRadim Krčmář <rkrcmar@redhat.com>
parent fb530729

arch/x86/kvm/svm.c

+33 −26
Original line number Diff line number Diff line
@@ -2267,7 +2267,7 @@ static int io_interception(struct vcpu_svm *svm) 
{

	struct kvm_vcpu *vcpu = &svm->vcpu;

	u32 io_info = svm->vmcb->control.exit_info_1; /* address size bug? */

	int size, in, string;

	int size, in, string, ret;

	unsigned port;



	++svm->vcpu.stat.io_exits;
@@ -2279,10 +2279,16 @@ static int io_interception(struct vcpu_svm *svm) 
	port = io_info >> 16;

	size = (io_info & SVM_IOIO_SIZE_MASK) >> SVM_IOIO_SIZE_SHIFT;

	svm->next_rip = svm->vmcb->control.exit_info_2;

	skip_emulated_instruction(&svm->vcpu);

	ret = kvm_skip_emulated_instruction(&svm->vcpu);



	return in ? kvm_fast_pio_in(vcpu, size, port)

		  : kvm_fast_pio_out(vcpu, size, port);

	/*

	 * TODO: we might be squashing a KVM_GUESTDBG_SINGLESTEP-triggered

	 * KVM_EXIT_DEBUG here.

	 */

	if (in)

		return kvm_fast_pio_in(vcpu, size, port) && ret;

	else

		return kvm_fast_pio_out(vcpu, size, port) && ret;

}



static int nmi_interception(struct vcpu_svm *svm)
@@ -3055,6 +3061,7 @@ static int vmload_interception(struct vcpu_svm *svm) 
{

	struct vmcb *nested_vmcb;

	struct page *page;

	int ret;



	if (nested_svm_check_permissions(svm))

		return 1;
@@ -3064,18 +3071,19 @@ static int vmload_interception(struct vcpu_svm *svm) 
		return 1;



	svm->next_rip = kvm_rip_read(&svm->vcpu) + 3;

	skip_emulated_instruction(&svm->vcpu);

	ret = kvm_skip_emulated_instruction(&svm->vcpu);



	nested_svm_vmloadsave(nested_vmcb, svm->vmcb);

	nested_svm_unmap(page);



	return 1;

	return ret;

}



static int vmsave_interception(struct vcpu_svm *svm)

{

	struct vmcb *nested_vmcb;

	struct page *page;

	int ret;



	if (nested_svm_check_permissions(svm))

		return 1;
@@ -3085,12 +3093,12 @@ static int vmsave_interception(struct vcpu_svm *svm) 
		return 1;



	svm->next_rip = kvm_rip_read(&svm->vcpu) + 3;

	skip_emulated_instruction(&svm->vcpu);

	ret = kvm_skip_emulated_instruction(&svm->vcpu);



	nested_svm_vmloadsave(svm->vmcb, nested_vmcb);

	nested_svm_unmap(page);



	return 1;

	return ret;

}



static int vmrun_interception(struct vcpu_svm *svm)
@@ -3123,25 +3131,29 @@ failed: 


static int stgi_interception(struct vcpu_svm *svm)

{

	int ret;



	if (nested_svm_check_permissions(svm))

		return 1;



	svm->next_rip = kvm_rip_read(&svm->vcpu) + 3;

	skip_emulated_instruction(&svm->vcpu);

	ret = kvm_skip_emulated_instruction(&svm->vcpu);

	kvm_make_request(KVM_REQ_EVENT, &svm->vcpu);



	enable_gif(svm);



	return 1;

	return ret;

}



static int clgi_interception(struct vcpu_svm *svm)

{

	int ret;



	if (nested_svm_check_permissions(svm))

		return 1;



	svm->next_rip = kvm_rip_read(&svm->vcpu) + 3;

	skip_emulated_instruction(&svm->vcpu);

	ret = kvm_skip_emulated_instruction(&svm->vcpu);



	disable_gif(svm);
@@ -3152,7 +3164,7 @@ static int clgi_interception(struct vcpu_svm *svm) 
		mark_dirty(svm->vmcb, VMCB_INTR);

	}



	return 1;

	return ret;

}



static int invlpga_interception(struct vcpu_svm *svm)
@@ -3166,8 +3178,7 @@ static int invlpga_interception(struct vcpu_svm *svm) 
	kvm_mmu_invlpg(vcpu, kvm_register_read(&svm->vcpu, VCPU_REGS_RAX));



	svm->next_rip = kvm_rip_read(&svm->vcpu) + 3;

	skip_emulated_instruction(&svm->vcpu);

	return 1;

	return kvm_skip_emulated_instruction(&svm->vcpu);

}



static int skinit_interception(struct vcpu_svm *svm)
@@ -3190,7 +3201,7 @@ static int xsetbv_interception(struct vcpu_svm *svm) 


	if (kvm_set_xcr(&svm->vcpu, index, new_bv) == 0) {

		svm->next_rip = kvm_rip_read(&svm->vcpu) + 3;

		skip_emulated_instruction(&svm->vcpu);

		return kvm_skip_emulated_instruction(&svm->vcpu);

	}



	return 1;
@@ -3286,8 +3297,7 @@ static int invlpg_interception(struct vcpu_svm *svm) 
		return emulate_instruction(&svm->vcpu, 0) == EMULATE_DONE;



	kvm_mmu_invlpg(&svm->vcpu, svm->vmcb->control.exit_info_1);

	skip_emulated_instruction(&svm->vcpu);

	return 1;

	return kvm_skip_emulated_instruction(&svm->vcpu);

}



static int emulate_on_interception(struct vcpu_svm *svm)
@@ -3437,9 +3447,7 @@ static int dr_interception(struct vcpu_svm *svm) 
		kvm_register_write(&svm->vcpu, reg, val);

	}



	skip_emulated_instruction(&svm->vcpu);



	return 1;

	return kvm_skip_emulated_instruction(&svm->vcpu);

}



static int cr8_write_interception(struct vcpu_svm *svm)
@@ -3562,6 +3570,7 @@ static int rdmsr_interception(struct vcpu_svm *svm) 
	if (svm_get_msr(&svm->vcpu, &msr_info)) {

		trace_kvm_msr_read_ex(ecx);

		kvm_inject_gp(&svm->vcpu, 0);

		return 1;

	} else {

		trace_kvm_msr_read(ecx, msr_info.data);
@@ -3570,9 +3579,8 @@ static int rdmsr_interception(struct vcpu_svm *svm) 
		kvm_register_write(&svm->vcpu, VCPU_REGS_RDX,

				   msr_info.data >> 32);

		svm->next_rip = kvm_rip_read(&svm->vcpu) + 2;

		skip_emulated_instruction(&svm->vcpu);

		return kvm_skip_emulated_instruction(&svm->vcpu);

	}

	return 1;

}



static int svm_set_vm_cr(struct kvm_vcpu *vcpu, u64 data)
@@ -3698,11 +3706,11 @@ static int wrmsr_interception(struct vcpu_svm *svm) 
	if (kvm_set_msr(&svm->vcpu, &msr)) {

		trace_kvm_msr_write_ex(ecx, data);

		kvm_inject_gp(&svm->vcpu, 0);

		return 1;

	} else {

		trace_kvm_msr_write(ecx, data);

		skip_emulated_instruction(&svm->vcpu);

		return kvm_skip_emulated_instruction(&svm->vcpu);

	}

	return 1;

}



static int msr_interception(struct vcpu_svm *svm)
@@ -3731,8 +3739,7 @@ static int pause_interception(struct vcpu_svm *svm) 


static int nop_interception(struct vcpu_svm *svm)

{

	skip_emulated_instruction(&(svm->vcpu));

	return 1;

	return kvm_skip_emulated_instruction(&(svm->vcpu));

}



static int monitor_interception(struct vcpu_svm *svm)

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