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Mon, 22 Aug 2022 08:36:03 +0000 (GMT) Received: from [9.171.10.26] (unknown [9.171.10.26]) by d06av25.portsmouth.uk.ibm.com (Postfix) with ESMTP; Mon, 22 Aug 2022 08:36:03 +0000 (GMT) Message-ID: <388e7af7-be76-61a3-a9ce-9a148097610e@linux.ibm.com> Date: Mon, 22 Aug 2022 10:36:03 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.3.0 Subject: Re: [PATCH v2] KVM: s390: pci: Hook to access KVM lowlevel from VFIO Content-Language: en-US To: Randy Dunlap , mjrosato@linux.ibm.com Cc: linux-kernel@vger.kernel.org, lkp@intel.com, borntraeger@linux.ibm.com, farman@linux.ibm.com, linux-s390@vger.kernel.org, kvm@vger.kernel.org, gor@linux.ibm.com, hca@linux.ibm.com, schnelle@linux.ibm.com, frankja@linux.ibm.com, alex.williamson@redhat.com, cohuck@redhat.com References: <20220819122945.9309-1-pmorel@linux.ibm.com> <0bea8b2c-3345-e475-01f7-fd9c44096244@infradead.org> From: Pierre Morel In-Reply-To: <0bea8b2c-3345-e475-01f7-fd9c44096244@infradead.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: 3WOxVt9VlURVIiO71LjIWo_pDSyUMHk9 X-Proofpoint-ORIG-GUID: KJhfxuCNCsMQiYYq1V0c_lSoKffrfNLH X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.895,Hydra:6.0.517,FMLib:17.11.122.1 definitions=2022-08-22_04,2022-08-18_01,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 mlxscore=0 phishscore=0 priorityscore=1501 lowpriorityscore=0 bulkscore=0 suspectscore=0 adultscore=0 malwarescore=0 mlxlogscore=999 impostorscore=0 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2207270000 definitions=main-2208220036 Precedence: bulk List-ID: X-Mailing-List: linux-s390@vger.kernel.org On 8/19/22 23:10, Randy Dunlap wrote: > > > On 8/19/22 05:29, Pierre Morel wrote: >> We have a cross dependency between KVM and VFIO when using >> s390 vfio_pci_zdev extensions for PCI passthrough >> To be able to keep both subsystem modular we add a registering >> hook inside the S390 core code. >> >> This fixes a build problem when VFIO is built-in and KVM is built >> as a module. >> >> Reported-by: Randy Dunlap >> Reported-by: kernel test robot >> Reviewed-by: Matthew Rosato >> Reviewed-by: Niklas Schnelle >> Signed-off-by: Pierre Morel >> Fixes: 09340b2fca007 ("KVM: s390: pci: add routines to start/stop interpretive execution") >> Cc: > > Acked-by: Randy Dunlap # build-tested > > Thanks. Thanks Randy, Regards, Pierre > >> --- >> arch/s390/include/asm/kvm_host.h | 17 ++++++----------- >> arch/s390/kvm/pci.c | 12 ++++++++---- >> arch/s390/pci/Makefile | 2 +- >> arch/s390/pci/pci_kvm_hook.c | 11 +++++++++++ >> drivers/vfio/pci/vfio_pci_zdev.c | 8 ++++++-- >> 5 files changed, 32 insertions(+), 18 deletions(-) >> create mode 100644 arch/s390/pci/pci_kvm_hook.c >> >> diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h >> index f39092e0ceaa..b1e98a9ed152 100644 >> --- a/arch/s390/include/asm/kvm_host.h >> +++ b/arch/s390/include/asm/kvm_host.h >> @@ -1038,16 +1038,11 @@ static inline void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu) {} >> #define __KVM_HAVE_ARCH_VM_FREE >> void kvm_arch_free_vm(struct kvm *kvm); >> >> -#ifdef CONFIG_VFIO_PCI_ZDEV_KVM >> -int kvm_s390_pci_register_kvm(struct zpci_dev *zdev, struct kvm *kvm); >> -void kvm_s390_pci_unregister_kvm(struct zpci_dev *zdev); >> -#else >> -static inline int kvm_s390_pci_register_kvm(struct zpci_dev *dev, >> - struct kvm *kvm) >> -{ >> - return -EPERM; >> -} >> -static inline void kvm_s390_pci_unregister_kvm(struct zpci_dev *dev) {} >> -#endif >> +struct zpci_kvm_hook { >> + int (*kvm_register)(void *opaque, struct kvm *kvm); >> + void (*kvm_unregister)(void *opaque); >> +}; >> + >> +extern struct zpci_kvm_hook zpci_kvm_hook; >> >> #endif >> diff --git a/arch/s390/kvm/pci.c b/arch/s390/kvm/pci.c >> index 4946fb7757d6..bb8c335d17b9 100644 >> --- a/arch/s390/kvm/pci.c >> +++ b/arch/s390/kvm/pci.c >> @@ -431,8 +431,9 @@ static void kvm_s390_pci_dev_release(struct zpci_dev *zdev) >> * available, enable them and let userspace indicate whether or not they will >> * be used (specify SHM bit to disable). >> */ >> -int kvm_s390_pci_register_kvm(struct zpci_dev *zdev, struct kvm *kvm) >> +static int kvm_s390_pci_register_kvm(void *opaque, struct kvm *kvm) >> { >> + struct zpci_dev *zdev = opaque; >> int rc; >> >> if (!zdev) >> @@ -510,10 +511,10 @@ int kvm_s390_pci_register_kvm(struct zpci_dev *zdev, struct kvm *kvm) >> kvm_put_kvm(kvm); >> return rc; >> } >> -EXPORT_SYMBOL_GPL(kvm_s390_pci_register_kvm); >> >> -void kvm_s390_pci_unregister_kvm(struct zpci_dev *zdev) >> +static void kvm_s390_pci_unregister_kvm(void *opaque) >> { >> + struct zpci_dev *zdev = opaque; >> struct kvm *kvm; >> >> if (!zdev) >> @@ -566,7 +567,6 @@ void kvm_s390_pci_unregister_kvm(struct zpci_dev *zdev) >> >> kvm_put_kvm(kvm); >> } >> -EXPORT_SYMBOL_GPL(kvm_s390_pci_unregister_kvm); >> >> void kvm_s390_pci_init_list(struct kvm *kvm) >> { >> @@ -678,6 +678,8 @@ int kvm_s390_pci_init(void) >> >> spin_lock_init(&aift->gait_lock); >> mutex_init(&aift->aift_lock); >> + zpci_kvm_hook.kvm_register = kvm_s390_pci_register_kvm; >> + zpci_kvm_hook.kvm_unregister = kvm_s390_pci_unregister_kvm; >> >> return 0; >> } >> @@ -685,6 +687,8 @@ int kvm_s390_pci_init(void) >> void kvm_s390_pci_exit(void) >> { >> mutex_destroy(&aift->aift_lock); >> + zpci_kvm_hook.kvm_register = NULL; >> + zpci_kvm_hook.kvm_unregister = NULL; >> >> kfree(aift); >> } >> diff --git a/arch/s390/pci/Makefile b/arch/s390/pci/Makefile >> index bf557a1b789c..5ae31ca9dd44 100644 >> --- a/arch/s390/pci/Makefile >> +++ b/arch/s390/pci/Makefile >> @@ -5,5 +5,5 @@ >> >> obj-$(CONFIG_PCI) += pci.o pci_irq.o pci_dma.o pci_clp.o pci_sysfs.o \ >> pci_event.o pci_debug.o pci_insn.o pci_mmio.o \ >> - pci_bus.o >> + pci_bus.o pci_kvm_hook.o >> obj-$(CONFIG_PCI_IOV) += pci_iov.o >> diff --git a/arch/s390/pci/pci_kvm_hook.c b/arch/s390/pci/pci_kvm_hook.c >> new file mode 100644 >> index 000000000000..ff34baf50a3e >> --- /dev/null >> +++ b/arch/s390/pci/pci_kvm_hook.c >> @@ -0,0 +1,11 @@ >> +// SPDX-License-Identifier: GPL-2.0-only >> +/* >> + * VFIO ZPCI devices support >> + * >> + * Copyright (C) IBM Corp. 2022. All rights reserved. >> + * Author(s): Pierre Morel >> + */ >> +#include >> + >> +struct zpci_kvm_hook zpci_kvm_hook; >> +EXPORT_SYMBOL_GPL(zpci_kvm_hook); >> diff --git a/drivers/vfio/pci/vfio_pci_zdev.c b/drivers/vfio/pci/vfio_pci_zdev.c >> index e163aa9f6144..0cbdcd14f1c8 100644 >> --- a/drivers/vfio/pci/vfio_pci_zdev.c >> +++ b/drivers/vfio/pci/vfio_pci_zdev.c >> @@ -151,7 +151,10 @@ int vfio_pci_zdev_open_device(struct vfio_pci_core_device *vdev) >> if (!vdev->vdev.kvm) >> return 0; >> >> - return kvm_s390_pci_register_kvm(zdev, vdev->vdev.kvm); >> + if (zpci_kvm_hook.kvm_register) >> + return zpci_kvm_hook.kvm_register(zdev, vdev->vdev.kvm); >> + >> + return -ENOENT; >> } >> >> void vfio_pci_zdev_close_device(struct vfio_pci_core_device *vdev) >> @@ -161,5 +164,6 @@ void vfio_pci_zdev_close_device(struct vfio_pci_core_device *vdev) >> if (!zdev || !vdev->vdev.kvm) >> return; >> >> - kvm_s390_pci_unregister_kvm(zdev); >> + if (zpci_kvm_hook.kvm_unregister) >> + zpci_kvm_hook.kvm_unregister(zdev); >> } > -- Pierre Morel IBM Lab Boeblingen