x86/kvm/hyper-v: Add support for synthetic debugger via hypercalls (b187038b) · Commits · 戴 / test

There is another mode for the synthetic debugger which uses hypercalls to send/recv network data instead of the MSR interface. This interface is much slower and less recommended since you might get a lot of VMExits while KDVM polling for new packets to recv, rather than simply checking the pending page to see if there is data avialble and then request. Reviewed-by:

Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by:

Jon Doron <arilou@gmail.com> Message-Id: <20200529134543.1127440-6-arilou@gmail.com> Signed-off-by:

Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/hyperv.c

+28 −0

Original line number	Diff line number	Diff line
		@@ -1835,6 +1835,34 @@ int kvm_hv_hypercall(struct kvm_vcpu *vcpu)
		}
		ret = kvm_hv_send_ipi(vcpu, ingpa, outgpa, true, false);
		break;
		case HVCALL_POST_DEBUG_DATA:
		case HVCALL_RETRIEVE_DEBUG_DATA:
		if (unlikely(fast)) {
		ret = HV_STATUS_INVALID_PARAMETER;
		break;
		}
		fallthrough;
		case HVCALL_RESET_DEBUG_SESSION: {
		struct kvm_hv_syndbg *syndbg = vcpu_to_hv_syndbg(vcpu);

		if (!kvm_hv_is_syndbg_enabled(vcpu)) {
		ret = HV_STATUS_INVALID_HYPERCALL_CODE;
		break;
		}

		if (!(syndbg->options & HV_X64_SYNDBG_OPTION_USE_HCALLS)) {
		ret = HV_STATUS_OPERATION_DENIED;
		break;
		}
		vcpu->run->exit_reason = KVM_EXIT_HYPERV;
		vcpu->run->hyperv.type = KVM_EXIT_HYPERV_HCALL;
		vcpu->run->hyperv.u.hcall.input = param;
		vcpu->run->hyperv.u.hcall.params[0] = ingpa;
		vcpu->run->hyperv.u.hcall.params[1] = outgpa;
		vcpu->arch.complete_userspace_io =
		kvm_hv_hypercall_complete_userspace;
		return 0;
		}
		default:
		ret = HV_STATUS_INVALID_HYPERCALL_CODE;
		break;

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