path: root/virt
diff options
authorMark Rutland <mark.rutland@arm.com>2018-11-09 15:07:11 +0000
committerMarc Zyngier <marc.zyngier@arm.com>2018-12-18 14:11:37 +0000
commitbd7d95cafb499e24903b7d21f9eeb2c5208160c2 (patch)
tree854152408fc000dcb53d6256d8843d2656468506 /virt
parent0d640732dbebed0f10f18526de21652931f0b2f2 (diff)
arm64: KVM: Consistently advance singlestep when emulating instructions
When we emulate a guest instruction, we don't advance the hardware singlestep state machine, and thus the guest will receive a software step exception after a next instruction which is not emulated by the host. We bodge around this in an ad-hoc fashion. Sometimes we explicitly check whether userspace requested a single step, and fake a debug exception from within the kernel. Other times, we advance the HW singlestep state rely on the HW to generate the exception for us. Thus, the observed step behaviour differs for host and guest. Let's make this simpler and consistent by always advancing the HW singlestep state machine when we skip an instruction. Thus we can rely on the hardware to generate the singlestep exception for us, and never need to explicitly check for an active-pending step, nor do we need to fake a debug exception from the guest. Cc: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@arm.com> Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Diffstat (limited to 'virt')
2 files changed, 5 insertions, 3 deletions
diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
index 23774970c9df..4adcee5fc126 100644
--- a/virt/kvm/arm/arm.c
+++ b/virt/kvm/arm/arm.c
@@ -674,8 +674,6 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
ret = kvm_handle_mmio_return(vcpu, vcpu->run);
if (ret)
return ret;
- if (kvm_arm_handle_step_debug(vcpu, vcpu->run))
- return 0;
if (run->immediate_exit)
diff --git a/virt/kvm/arm/hyp/vgic-v3-sr.c b/virt/kvm/arm/hyp/vgic-v3-sr.c
index 616e5a433ab0..9652c453480f 100644
--- a/virt/kvm/arm/hyp/vgic-v3-sr.c
+++ b/virt/kvm/arm/hyp/vgic-v3-sr.c
@@ -1012,8 +1012,10 @@ int __hyp_text __vgic_v3_perform_cpuif_access(struct kvm_vcpu *vcpu)
esr = kvm_vcpu_get_hsr(vcpu);
if (vcpu_mode_is_32bit(vcpu)) {
- if (!kvm_condition_valid(vcpu))
+ if (!kvm_condition_valid(vcpu)) {
+ __kvm_skip_instr(vcpu);
return 1;
+ }
sysreg = esr_cp15_to_sysreg(esr);
} else {
@@ -1123,6 +1125,8 @@ int __hyp_text __vgic_v3_perform_cpuif_access(struct kvm_vcpu *vcpu)
rt = kvm_vcpu_sys_get_rt(vcpu);
fn(vcpu, vmcr, rt);
+ __kvm_skip_instr(vcpu);
return 1;