From mboxrd@z Thu Jan 1 00:00:00 1970 From: Carsten Otte Subject: [patch 07/12] [PATCH] kvm-s390-ucontrol: interface to inject faults on a vcpu page table Date: Thu, 01 Dec 2011 13:57:39 +0100 Message-ID: <20111201130409.545995661@de.ibm.com> References: <20111201125732.085553111@de.ibm.com> Cc: Christian Borntraeger , Heiko Carstens , Martin Schwidefsky , Cornelia Huck , KVM , Joachim von Buttlar , Jens Freimann , Constantin Werner To: Avi Kivity , Marcelo Tossati Return-path: Received: from e06smtp11.uk.ibm.com ([195.75.94.107]:49494 "EHLO e06smtp11.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753749Ab1LANEN (ORCPT ); Thu, 1 Dec 2011 08:04:13 -0500 Received: from /spool/local by e06smtp11.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 1 Dec 2011 13:04:12 -0000 Received: from d06av02.portsmouth.uk.ibm.com (d06av02.portsmouth.uk.ibm.com [9.149.37.228]) by d06nrmr1307.portsmouth.uk.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id pB1D4A512711642 for ; Thu, 1 Dec 2011 13:04:10 GMT Received: from d06av02.portsmouth.uk.ibm.com (loopback [127.0.0.1]) by d06av02.portsmouth.uk.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id pB1D49Kg023111 for ; Thu, 1 Dec 2011 06:04:10 -0700 Content-Disposition: inline; filename=guest-fault-interface.patch Sender: kvm-owner@vger.kernel.org List-ID: This patch allows the user to fault in pages on a virtual cpus address space for user controlled virtual machines. Typically this is superfluous because userspace can just create a mapping and let the kernel's page fault logic take are of it. There is one exception: SIE won't start if the lowcore is not present. Normally the kernel takes care of this [handle_validity() in arch/s390/kvm/intercept.c] but since the kernel does not handle intercepts for user controlled virtual machines, userspace needs to be able to handle this condition. Signed-off-by: Carsten Otte --- --- arch/s390/kvm/kvm-s390.c | 6 ++++++ include/linux/kvm.h | 1 + 2 files changed, 7 insertions(+) --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -777,6 +777,12 @@ long kvm_arch_vcpu_ioctl(struct file *fi break; } #endif + case KVM_S390_VCPU_FAULT: { + r = gmap_fault(arg, vcpu->arch.gmap); + if (!IS_ERR_VALUE(r)) + r = 0; + break; + } default: r = -EINVAL; } --- a/include/linux/kvm.h +++ b/include/linux/kvm.h @@ -669,6 +669,7 @@ struct kvm_s390_ucas_mapping { #define KVM_S390_ENABLE_UCONTROL _IO(KVMIO, 0x49) #define KVM_S390_UCAS_MAP _IOW(KVMIO, 0x50, struct kvm_s390_ucas_mapping) #define KVM_S390_UCAS_UNMAP _IOW(KVMIO, 0x51, struct kvm_s390_ucas_mapping) +#define KVM_S390_VCPU_FAULT _IOW(KVMIO, 0x52, unsigned long) /* Device model IOC */ #define KVM_CREATE_IRQCHIP _IO(KVMIO, 0x60)