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Thu, 31 Mar 2022 13:29:01 +0000 (GMT) Received: from [9.145.159.108] (unknown [9.145.159.108]) by d06av25.portsmouth.uk.ibm.com (Postfix) with ESMTP; Thu, 31 Mar 2022 13:29:01 +0000 (GMT) Message-ID: Date: Thu, 31 Mar 2022 15:29:01 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.7.0 Subject: Re: [PATCH v9 10/18] KVM: s390: pv: add mmu_notifier Content-Language: en-US To: Claudio Imbrenda , kvm@vger.kernel.org Cc: borntraeger@de.ibm.com, thuth@redhat.com, pasic@linux.ibm.com, david@redhat.com, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, scgl@linux.ibm.com, mimu@linux.ibm.com, nrb@linux.ibm.com References: <20220330122605.247613-1-imbrenda@linux.ibm.com> <20220330122605.247613-11-imbrenda@linux.ibm.com> From: Janosch Frank In-Reply-To: <20220330122605.247613-11-imbrenda@linux.ibm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: ilE7Me97X4zrsw58cHoxwHwgFYcZCyQ9 X-Proofpoint-GUID: A8b2e3zOFbHtocakk7k0sQ_EeOUsOfhf X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.850,Hydra:6.0.425,FMLib:17.11.64.514 definitions=2022-03-31_05,2022-03-31_01,2022-02-23_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 spamscore=0 lowpriorityscore=0 mlxlogscore=999 phishscore=0 malwarescore=0 adultscore=0 mlxscore=0 priorityscore=1501 clxscore=1015 suspectscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2202240000 definitions=main-2203310073 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 3/30/22 14:25, Claudio Imbrenda wrote: > Add an mmu_notifier for protected VMs. The callback function is > triggered when the mm is torn down, and will attempt to convert all > protected vCPUs to non-protected. This allows the mm teardown to use > the destroy page UVC instead of export. > > Also make KVM select CONFIG_MMU_NOTIFIER, needed to use mmu_notifiers. > > Signed-off-by: Claudio Imbrenda Acked-by: Janosch Frank > --- > arch/s390/include/asm/kvm_host.h | 2 ++ > arch/s390/kvm/Kconfig | 1 + > arch/s390/kvm/kvm-s390.c | 5 ++++- > arch/s390/kvm/pv.c | 26 ++++++++++++++++++++++++++ > 4 files changed, 33 insertions(+), 1 deletion(-) > > diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h > index a22c9266ea05..1bccb8561ba9 100644 > --- a/arch/s390/include/asm/kvm_host.h > +++ b/arch/s390/include/asm/kvm_host.h > @@ -19,6 +19,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -921,6 +922,7 @@ struct kvm_s390_pv { > u64 guest_len; > unsigned long stor_base; > void *stor_var; > + struct mmu_notifier mmu_notifier; > }; > > struct kvm_arch{ > diff --git a/arch/s390/kvm/Kconfig b/arch/s390/kvm/Kconfig > index 2e84d3922f7c..33f4ff909476 100644 > --- a/arch/s390/kvm/Kconfig > +++ b/arch/s390/kvm/Kconfig > @@ -34,6 +34,7 @@ config KVM > select SRCU > select KVM_VFIO > select INTERVAL_TREE > + select MMU_NOTIFIER > help > Support hosting paravirtualized guest machines using the SIE > virtualization capability on the mainframe. This should work > diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c > index 21fcca09e9bf..446f89db93a1 100644 > --- a/arch/s390/kvm/kvm-s390.c > +++ b/arch/s390/kvm/kvm-s390.c > @@ -32,6 +32,7 @@ > #include > #include > #include > +#include > > #include > #include > @@ -2833,8 +2834,10 @@ void kvm_arch_destroy_vm(struct kvm *kvm) > * can mess with the pv state. To avoid lockdep_assert_held from > * complaining we do not use kvm_s390_pv_is_protected. > */ > - if (kvm_s390_pv_get_handle(kvm)) > + if (kvm_s390_pv_get_handle(kvm)) { > kvm_s390_pv_deinit_vm(kvm, &rc, &rrc); > + mmu_notifier_unregister(&kvm->arch.pv.mmu_notifier, kvm->mm); > + } > debug_unregister(kvm->arch.dbf); > free_page((unsigned long)kvm->arch.sie_page2); > if (!kvm_is_ucontrol(kvm)) > diff --git a/arch/s390/kvm/pv.c b/arch/s390/kvm/pv.c > index 76ef33a277d3..788b96b36931 100644 > --- a/arch/s390/kvm/pv.c > +++ b/arch/s390/kvm/pv.c > @@ -14,6 +14,7 @@ > #include > #include > #include > +#include > #include "kvm-s390.h" > > static void kvm_s390_clear_pv_state(struct kvm *kvm) > @@ -192,6 +193,26 @@ int kvm_s390_pv_deinit_vm(struct kvm *kvm, u16 *rc, u16 *rrc) > return -EIO; > } > > +static void kvm_s390_pv_mmu_notifier_release(struct mmu_notifier *subscription, > + struct mm_struct *mm) > +{ > + struct kvm *kvm = container_of(subscription, struct kvm, arch.pv.mmu_notifier); > + u16 dummy; > + > + /* > + * No locking is needed since this is the last thread of the last user of this > + * struct mm. > + * When the struct kvm gets deinitialized, this notifier is also > + * unregistered. This means that if this notifier runs, then the > + * struct kvm is still valid. > + */ > + kvm_s390_cpus_from_pv(kvm, &dummy, &dummy); > +} > + > +static const struct mmu_notifier_ops kvm_s390_pv_mmu_notifier_ops = { > + .release = kvm_s390_pv_mmu_notifier_release, > +}; > + > int kvm_s390_pv_init_vm(struct kvm *kvm, u16 *rc, u16 *rrc) > { > struct uv_cb_cgc uvcb = { > @@ -233,6 +254,11 @@ int kvm_s390_pv_init_vm(struct kvm *kvm, u16 *rc, u16 *rrc) > return -EIO; > } > kvm->arch.gmap->guest_handle = uvcb.guest_handle; > + /* Add the notifier only once. No races because we hold kvm->lock */ > + if (kvm->arch.pv.mmu_notifier.ops != &kvm_s390_pv_mmu_notifier_ops) { > + kvm->arch.pv.mmu_notifier.ops = &kvm_s390_pv_mmu_notifier_ops; > + mmu_notifier_register(&kvm->arch.pv.mmu_notifier, kvm->mm); > + } > return 0; > } >