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Mon, 09 May 2022 19:12:49 +0000 Received: from d06av26.portsmouth.uk.ibm.com (d06av26.portsmouth.uk.ibm.com [9.149.105.62]) by b06avi18626390.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 249IxEjl48366030 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 9 May 2022 18:59:14 GMT Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 3A74DAE04D; Mon, 9 May 2022 19:12:46 +0000 (GMT) Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id E7A0FAE045; Mon, 9 May 2022 19:12:45 +0000 (GMT) Received: from p-imbrenda (unknown [9.145.15.58]) by d06av26.portsmouth.uk.ibm.com (Postfix) with ESMTP; Mon, 9 May 2022 19:12:45 +0000 (GMT) Date: Mon, 9 May 2022 21:11:40 +0200 From: Claudio Imbrenda To: Janosch Frank Cc: kvm@vger.kernel.org, linux-s390@vger.kernel.org, borntraeger@linux.ibm.com Subject: Re: [PATCH 7/9] kvm: s390: Add CPU dump functionality Message-ID: <20220509211140.38f49000@p-imbrenda> In-Reply-To: <20220428130102.230790-8-frankja@linux.ibm.com> References: <20220428130102.230790-1-frankja@linux.ibm.com> <20220428130102.230790-8-frankja@linux.ibm.com> Organization: IBM X-Mailer: Claws Mail 3.18.0 (GTK+ 2.24.33; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: Ru6ROCiHgraWSlFUVpWgEdF43EuZAd7D X-Proofpoint-GUID: Ru6ROCiHgraWSlFUVpWgEdF43EuZAd7D X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.858,Hydra:6.0.486,FMLib:17.11.64.514 definitions=2022-05-09_05,2022-05-09_02,2022-02-23_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxlogscore=999 spamscore=0 mlxscore=0 bulkscore=0 clxscore=1015 priorityscore=1501 lowpriorityscore=0 adultscore=0 impostorscore=0 suspectscore=0 phishscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2202240000 definitions=main-2205090100 Precedence: bulk List-ID: X-Mailing-List: linux-s390@vger.kernel.org On Thu, 28 Apr 2022 13:01:00 +0000 Janosch Frank wrote: > The previous patch introduced the per-VM dump functions now let's > focus on dumping the VCPU state via the newly introduced > KVM_S390_PV_CPU_COMMAND ioctl which mirrors the VM UV ioctl and can be > extended with new commands later. > > Signed-off-by: Janosch Frank > --- > arch/s390/kvm/kvm-s390.c | 73 ++++++++++++++++++++++++++++++++++++++++ > arch/s390/kvm/kvm-s390.h | 1 + > arch/s390/kvm/pv.c | 16 +++++++++ > include/uapi/linux/kvm.h | 5 +++ > 4 files changed, 95 insertions(+) > > diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c > index 8984e8db33b4..d15ce38bef14 100644 > --- a/arch/s390/kvm/kvm-s390.c > +++ b/arch/s390/kvm/kvm-s390.c > @@ -5149,6 +5149,52 @@ long kvm_arch_vcpu_async_ioctl(struct file *filp, > return -ENOIOCTLCMD; > } > > +static int kvm_s390_handle_pv_vcpu_dump(struct kvm_vcpu *vcpu, > + struct kvm_pv_cmd *cmd) > +{ > + struct kvm_s390_pv_dmp dmp; > + void *data; > + int ret; > + > + /* Dump initialization is a prerequisite */ > + if (!vcpu->kvm->arch.pv.dumping) > + return -EINVAL; > + > + if (copy_from_user(&dmp, (__u8 __user *)cmd->data, sizeof(dmp))) > + return -EFAULT; > + > + /* We only handle this subcmd right now */ > + if (dmp.subcmd != KVM_PV_DUMP_CPU) > + return -EINVAL; > + > + /* CPU dump length is the same as create cpu storage donation. */ > + if (dmp.buff_len != uv_info.guest_cpu_stor_len) > + return -EINVAL; > + > + data = vzalloc(uv_info.guest_cpu_stor_len); > + if (!data) > + return -ENOMEM; > + > + ret = kvm_s390_pv_dump_cpu(vcpu, data, &cmd->rc, &cmd->rrc); > + > + VCPU_EVENT(vcpu, 3, "PROTVIRT DUMP CPU %d rc %x rrc %x", > + vcpu->vcpu_id, cmd->rc, cmd->rrc); > + > + if (ret) { > + vfree(data); > + return -EINVAL; > + } > + > + /* On success copy over the dump data */ > + if (copy_to_user((__u8 __user *)dmp.buff_addr, data, uv_info.guest_cpu_stor_len)) { > + vfree(data); > + return -EFAULT; > + } > + > + vfree(data); > + return 0; > +} > + > long kvm_arch_vcpu_ioctl(struct file *filp, > unsigned int ioctl, unsigned long arg) > { > @@ -5313,6 +5359,33 @@ long kvm_arch_vcpu_ioctl(struct file *filp, > irq_state.len); > break; > } > + case KVM_S390_PV_CPU_COMMAND: { > + struct kvm_pv_cmd cmd; > + > + r = -EINVAL; > + if (!is_prot_virt_host()) > + break; > + > + r = -EFAULT; > + if (copy_from_user(&cmd, argp, sizeof(cmd))) > + break; > + > + r = -EINVAL; > + if (cmd.flags) > + break; > + > + /* We only handle this cmd right now */ > + if (cmd.cmd != KVM_PV_DUMP) > + break; > + > + r = kvm_s390_handle_pv_vcpu_dump(vcpu, &cmd); > + > + /* Always copy over UV rc / rrc data */ > + if (copy_to_user((__u8 __user *)argp, &cmd.rc, > + sizeof(cmd.rc) + sizeof(cmd.rrc))) > + r = -EFAULT; > + break; > + } > default: > r = -ENOTTY; > } > diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h > index 2868dd0bba25..a39815184350 100644 > --- a/arch/s390/kvm/kvm-s390.h > +++ b/arch/s390/kvm/kvm-s390.h > @@ -250,6 +250,7 @@ int kvm_s390_pv_set_sec_parms(struct kvm *kvm, void *hdr, u64 length, u16 *rc, > int kvm_s390_pv_unpack(struct kvm *kvm, unsigned long addr, unsigned long size, > unsigned long tweak, u16 *rc, u16 *rrc); > int kvm_s390_pv_set_cpu_state(struct kvm_vcpu *vcpu, u8 state); > +int kvm_s390_pv_dump_cpu(struct kvm_vcpu *vcpu, void *buff, u16 *rc, u16 *rrc); > int kvm_s390_pv_dump_stor_state(struct kvm *kvm, void __user *buff_user, > u64 *gaddr, u64 buff_user_len, u16 *rc, u16 *rrc); > > diff --git a/arch/s390/kvm/pv.c b/arch/s390/kvm/pv.c > index d1635ed50078..9ab8192b9b23 100644 > --- a/arch/s390/kvm/pv.c > +++ b/arch/s390/kvm/pv.c > @@ -299,6 +299,22 @@ int kvm_s390_pv_set_cpu_state(struct kvm_vcpu *vcpu, u8 state) > return 0; > } > > +int kvm_s390_pv_dump_cpu(struct kvm_vcpu *vcpu, void *buff, u16 *rc, u16 *rrc) > +{ > + struct uv_cb_dump_cpu uvcb = { > + .header.cmd = UVC_CMD_DUMP_CPU, > + .header.len = sizeof(uvcb), > + .cpu_handle = vcpu->arch.pv.handle, > + .dump_area_origin = (u64)buff, > + }; > + int cc; > + > + cc = uv_call_sched(0, (u64)&uvcb); it's a small amount of data, but you use the _sched variant? and, why aren't you using the _sched variant in the previous patch (for DUMP_COMPLETE)? to be clear: I think the right thing is to always use the _sched variant unless there is a good reason not to (so please fix the previous patch) > + *rc = uvcb.header.rc; > + *rrc = uvcb.header.rrc; > + return cc; > +} > + > /* Size of the cache for the storage state dump data. 1MB for now */ > #define DUMP_BUFF_LEN HPAGE_SIZE > > diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h > index b34850907291..108bc7b7a71b 100644 > --- a/include/uapi/linux/kvm.h > +++ b/include/uapi/linux/kvm.h > @@ -1144,6 +1144,7 @@ struct kvm_ppc_resize_hpt { > #define KVM_CAP_S390_MEM_OP_EXTENSION 211 > #define KVM_CAP_PMU_CAPABILITY 212 > #define KVM_CAP_DISABLE_QUIRKS2 213 > +#define KVM_CAP_S390_PROTECTED_DUMP 214 > > #ifdef KVM_CAP_IRQ_ROUTING > > @@ -1649,6 +1650,7 @@ enum pv_cmd_dmp_id { > KVM_PV_DUMP_INIT, > KVM_PV_DUMP_CONFIG_STOR_STATE, > KVM_PV_DUMP_COMPLETE, > + KVM_PV_DUMP_CPU, > }; > > struct kvm_s390_pv_dmp { > @@ -2110,4 +2112,7 @@ struct kvm_stats_desc { > /* Available with KVM_CAP_XSAVE2 */ > #define KVM_GET_XSAVE2 _IOR(KVMIO, 0xcf, struct kvm_xsave) > > +/* Available with KVM_CAP_S390_PROTECTED_DUMP */ > +#define KVM_S390_PV_CPU_COMMAND _IOWR(KVMIO, 0xd0, struct kvm_pv_cmd) > + > #endif /* __LINUX_KVM_H */