From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-20.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A5F29C43381 for ; Thu, 31 Dec 2020 03:46:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7F3EB20773 for ; Thu, 31 Dec 2020 03:46:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726571AbgLaDql (ORCPT ); Wed, 30 Dec 2020 22:46:41 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:25104 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726512AbgLaDql (ORCPT ); Wed, 30 Dec 2020 22:46:41 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1609386312; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=bh2WeHtNFUrcj+cFefYDAaNlYKz3BFmb0mOhLPmImtQ=; b=RpXnNhEiuS4kN+hwG/rTdNF1gKfjuXd2xnNloxKWBjHPp+QDl/Y0YlXp+xO8SdT2x8PQyh pPhjGmawgYI+YWBNDyRCfuynrKNEf9aVX81Dg2ZN3Sl3ASSatt6AqjZV7Zmx6WCCodrOh8 Pvauj5VRbBCCagG30zNQd259Rlo4L8k= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-446-m68aS1qhNjKchVbBScDvtQ-1; Wed, 30 Dec 2020 22:45:10 -0500 X-MC-Unique: m68aS1qhNjKchVbBScDvtQ-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 20EED800D62; Thu, 31 Dec 2020 03:45:09 +0000 (UTC) Received: from [10.72.12.236] (ovpn-12-236.pek2.redhat.com [10.72.12.236]) by smtp.corp.redhat.com (Postfix) with ESMTP id ACF6F50DDB; Thu, 31 Dec 2020 03:45:02 +0000 (UTC) Subject: Re: [RFC 1/2] KVM: add initial support for KVM_SET_IOREGION To: Elena Afanasova , kvm@vger.kernel.org Cc: stefanha@redhat.com, jag.raman@oracle.com, elena.ufimtseva@oracle.com References: From: Jason Wang Message-ID: Date: Thu, 31 Dec 2020 11:45:01 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 2020/12/29 下午6:02, Elena Afanasova wrote: > This vm ioctl adds or removes an ioregionfd MMIO/PIO region. How about FAST_MMIO? > Guest > read and write accesses are dispatched through the given ioregionfd > instead of returning from ioctl(KVM_RUN). Regions can be deleted by > setting fds to -1. > > Signed-off-by: Elena Afanasova > --- > arch/x86/kvm/Kconfig | 1 + > arch/x86/kvm/Makefile | 1 + > arch/x86/kvm/x86.c | 1 + > include/linux/kvm_host.h | 17 +++ > include/uapi/linux/kvm.h | 23 ++++ > virt/kvm/Kconfig | 3 + > virt/kvm/eventfd.c | 25 +++++ > virt/kvm/eventfd.h | 14 +++ > virt/kvm/ioregion.c | 233 +++++++++++++++++++++++++++++++++++++++ > virt/kvm/ioregion.h | 15 +++ > virt/kvm/kvm_main.c | 20 +++- > 11 files changed, 350 insertions(+), 3 deletions(-) > create mode 100644 virt/kvm/eventfd.h > create mode 100644 virt/kvm/ioregion.c > create mode 100644 virt/kvm/ioregion.h > > diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig > index f92dfd8ef10d..b914ef375199 100644 > --- a/arch/x86/kvm/Kconfig > +++ b/arch/x86/kvm/Kconfig > @@ -33,6 +33,7 @@ config KVM > select HAVE_KVM_IRQ_BYPASS > select HAVE_KVM_IRQ_ROUTING > select HAVE_KVM_EVENTFD > + select KVM_IOREGION > select KVM_ASYNC_PF > select USER_RETURN_NOTIFIER > select KVM_MMIO > diff --git a/arch/x86/kvm/Makefile b/arch/x86/kvm/Makefile > index b804444e16d4..b3b17dc9f7d4 100644 > --- a/arch/x86/kvm/Makefile > +++ b/arch/x86/kvm/Makefile > @@ -12,6 +12,7 @@ KVM := ../../../virt/kvm > kvm-y += $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o \ > $(KVM)/eventfd.o $(KVM)/irqchip.o $(KVM)/vfio.o > kvm-$(CONFIG_KVM_ASYNC_PF) += $(KVM)/async_pf.o > +kvm-$(CONFIG_KVM_IOREGION) += $(KVM)/ioregion.o > > kvm-y += x86.o emulate.o i8259.o irq.o lapic.o \ > i8254.o ioapic.o irq_comm.o cpuid.o pmu.o mtrr.o \ > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index e545a8a613b1..ddb28f5ca252 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -3739,6 +3739,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) > case KVM_CAP_X86_USER_SPACE_MSR: > case KVM_CAP_X86_MSR_FILTER: > case KVM_CAP_ENFORCE_PV_FEATURE_CPUID: > + case KVM_CAP_IOREGIONFD: > r = 1; > break; > case KVM_CAP_SYNC_REGS: > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > index 7f2e2a09ebbd..7cd667dddba9 100644 > --- a/include/linux/kvm_host.h > +++ b/include/linux/kvm_host.h > @@ -470,6 +470,10 @@ struct kvm { > struct mutex resampler_lock; > } irqfds; > struct list_head ioeventfds; > +#endif > +#ifdef CONFIG_KVM_IOREGION > + struct list_head ioregions_mmio; > + struct list_head ioregions_pio; > #endif > struct kvm_vm_stat stat; > struct kvm_arch arch; > @@ -1262,6 +1266,19 @@ static inline int kvm_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args) > > #endif /* CONFIG_HAVE_KVM_EVENTFD */ > > +#ifdef CONFIG_KVM_IOREGION > +void kvm_ioregionfd_init(struct kvm *kvm); > +int kvm_ioregionfd(struct kvm *kvm, struct kvm_ioregion *args); > + > +#else > + > +static inline void kvm_ioregionfd_init(struct kvm *kvm) {} > +static inline int kvm_ioregionfd(struct kvm *kvm, struct kvm_ioregion *args) > +{ > + return -ENOSYS; > +} > +#endif > + > void kvm_arch_irq_routing_update(struct kvm *kvm); > > static inline void kvm_make_request(int req, struct kvm_vcpu *vcpu) > diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h > index ca41220b40b8..81e775778c66 100644 > --- a/include/uapi/linux/kvm.h > +++ b/include/uapi/linux/kvm.h > @@ -732,6 +732,27 @@ struct kvm_ioeventfd { > __u8 pad[36]; > }; > > +enum { > + kvm_ioregion_flag_nr_pio, > + kvm_ioregion_flag_nr_posted_writes, > + kvm_ioregion_flag_nr_max, > +}; > + > +#define KVM_IOREGION_PIO (1 << kvm_ioregion_flag_nr_pio) > +#define KVM_IOREGION_POSTED_WRITES (1 << kvm_ioregion_flag_nr_posted_writes) > + > +#define KVM_IOREGION_VALID_FLAG_MASK ((1 << kvm_ioregion_flag_nr_max) - 1) > + > +struct kvm_ioregion { > + __u64 guest_paddr; /* guest physical address */ > + __u64 memory_size; /* bytes */ > + __u64 user_data; What will this field do? Is it a token? > + __s32 rfd; > + __s32 wfd; > + __u32 flags; > + __u8 pad[28]; > +}; Is this possible to register the same fd with multiple GPA ranges? If not, do we need to check for fd collision? > + > #define KVM_X86_DISABLE_EXITS_MWAIT (1 << 0) > #define KVM_X86_DISABLE_EXITS_HLT (1 << 1) > #define KVM_X86_DISABLE_EXITS_PAUSE (1 << 2) > @@ -1053,6 +1074,7 @@ struct kvm_ppc_resize_hpt { > #define KVM_CAP_X86_USER_SPACE_MSR 188 > #define KVM_CAP_X86_MSR_FILTER 189 > #define KVM_CAP_ENFORCE_PV_FEATURE_CPUID 190 > +#define KVM_CAP_IOREGIONFD 191 > > #ifdef KVM_CAP_IRQ_ROUTING > > @@ -1308,6 +1330,7 @@ struct kvm_vfio_spapr_tce { > struct kvm_userspace_memory_region) > #define KVM_SET_TSS_ADDR _IO(KVMIO, 0x47) > #define KVM_SET_IDENTITY_MAP_ADDR _IOW(KVMIO, 0x48, __u64) > +#define KVM_SET_IOREGION _IOW(KVMIO, 0x49, struct kvm_ioregion) > > /* enable ucontrol for s390 */ > struct kvm_s390_ucas_mapping { > diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig > index 1c37ccd5d402..5e6620bbf000 100644 > --- a/virt/kvm/Kconfig > +++ b/virt/kvm/Kconfig > @@ -17,6 +17,9 @@ config HAVE_KVM_EVENTFD > bool > select EVENTFD > > +config KVM_IOREGION > + bool > + > config KVM_MMIO > bool > > diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c > index c2323c27a28b..aadb73903f8b 100644 > --- a/virt/kvm/eventfd.c > +++ b/virt/kvm/eventfd.c > @@ -27,6 +27,7 @@ > #include > > #include > +#include "ioregion.h" > > #ifdef CONFIG_HAVE_KVM_IRQFD > > @@ -755,6 +756,23 @@ static const struct kvm_io_device_ops ioeventfd_ops = { > .destructor = ioeventfd_destructor, > }; > > +#ifdef CONFIG_KVM_IOREGION > +/* assumes kvm->slots_lock held */ > +bool kvm_eventfd_collides(struct kvm *kvm, int bus_idx, > + u64 start, u64 size) > +{ > + struct _ioeventfd *_p; > + > + list_for_each_entry(_p, &kvm->ioeventfds, list) > + if (_p->bus_idx == bus_idx && > + overlap(start, size, _p->addr, > + !_p->length ? 8 : _p->length)) > + return true; > + > + return false; > +} > +#endif > + > /* assumes kvm->slots_lock held */ > static bool > ioeventfd_check_collision(struct kvm *kvm, struct _ioeventfd *p) > @@ -770,6 +788,13 @@ ioeventfd_check_collision(struct kvm *kvm, struct _ioeventfd *p) > _p->datamatch == p->datamatch)))) > return true; > > +#ifdef CONFIG_KVM_IOREGION > + if (p->bus_idx == KVM_MMIO_BUS || p->bus_idx == KVM_PIO_BUS) > + if (kvm_ioregion_collides(kvm, p->bus_idx, p->addr, > + !p->length ? 8 : p->length)) > + return true; > +#endif > + > return false; > } > > diff --git a/virt/kvm/eventfd.h b/virt/kvm/eventfd.h > new file mode 100644 > index 000000000000..73a621eebae3 > --- /dev/null > +++ b/virt/kvm/eventfd.h > @@ -0,0 +1,14 @@ > +/* SPDX-License-Identifier: GPL-2.0-only */ > +#ifndef __KVM_EVENTFD_H__ > +#define __KVM_EVENTFD_H__ > + > +#ifdef CONFIG_KVM_IOREGION > +bool kvm_eventfd_collides(struct kvm *kvm, int bus_idx, u64 start, u64 size); > +#else > +static inline bool > +kvm_eventfd_collides(struct kvm *kvm, int bus_idx, u64 start, u64 size) > +{ > + return false; > +} > +#endif > +#endif > diff --git a/virt/kvm/ioregion.c b/virt/kvm/ioregion.c > new file mode 100644 > index 000000000000..a200c3761343 > --- /dev/null > +++ b/virt/kvm/ioregion.c > @@ -0,0 +1,233 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +#include > +#include > +#include > +#include "eventfd.h" > + > +void > +kvm_ioregionfd_init(struct kvm *kvm) > +{ > + INIT_LIST_HEAD(&kvm->ioregions_mmio); > + INIT_LIST_HEAD(&kvm->ioregions_pio); > +} > + > +struct ioregion { > + struct list_head list; > + u64 paddr; > + u64 size; > + struct file *rf; > + struct file *wf; > + u64 user_data; > + struct kvm_io_device dev; > + bool posted_writes; > +}; > + > +static inline struct ioregion * > +to_ioregion(struct kvm_io_device *dev) > +{ > + return container_of(dev, struct ioregion, dev); > +} > + > +/* assumes kvm->slots_lock held */ > +static void > +ioregion_release(struct ioregion *p) > +{ > + fput(p->rf); > + fput(p->wf); > + list_del(&p->list); > + kfree(p); > +} > + > +static int > +ioregion_read(struct kvm_vcpu *vcpu, struct kvm_io_device *this, gpa_t addr, > + int len, void *val) > +{ > + return 0; > +} > + > +static int > +ioregion_write(struct kvm_vcpu *vcpu, struct kvm_io_device *this, gpa_t addr, > + int len, const void *val) > +{ > + return 0; > +} > + > +/* > + * This function is called as KVM is completely shutting down. We do not > + * need to worry about locking just nuke anything we have as quickly as possible > + */ > +static void > +ioregion_destructor(struct kvm_io_device *this) > +{ > + struct ioregion *p = to_ioregion(this); > + > + ioregion_release(p); > +} > + > +static const struct kvm_io_device_ops ioregion_ops = { > + .read = ioregion_read, > + .write = ioregion_write, > + .destructor = ioregion_destructor, > +}; > + > +static inline struct list_head * > +get_ioregion_list(struct kvm *kvm, enum kvm_bus bus_idx) > +{ > + return (bus_idx == KVM_MMIO_BUS) ? > + &kvm->ioregions_mmio : &kvm->ioregions_pio; > +} > + > +/* check for not overlapping case and reverse */ > +inline bool > +overlap(u64 start1, u64 size1, u64 start2, u64 size2) > +{ > + u64 end1 = start1 + size1 - 1; > + u64 end2 = start2 + size2 - 1; > + > + return !(end1 < start2 || start1 >= end2); > +} > + > +/* assumes kvm->slots_lock held */ > +bool > +kvm_ioregion_collides(struct kvm *kvm, int bus_idx, > + u64 start, u64 size) > +{ > + struct ioregion *_p; > + struct list_head *ioregions; > + > + ioregions = get_ioregion_list(kvm, bus_idx); > + list_for_each_entry(_p, ioregions, list) > + if (overlap(start, size, _p->paddr, _p->size)) > + return true; > + > + return false; > +} > + > +/* assumes kvm->slots_lock held */ > +static bool > +ioregion_collision(struct kvm *kvm, struct ioregion *p, enum kvm_bus bus_idx) > +{ > + if (kvm_ioregion_collides(kvm, bus_idx, p->paddr, p->size) || > + kvm_eventfd_collides(kvm, bus_idx, p->paddr, p->size)) > + return true; > + > + return false; > +} > + > +static enum kvm_bus > +get_bus_from_flags(__u32 flags) > +{ > + if (flags & KVM_IOREGION_PIO) > + return KVM_PIO_BUS; > + return KVM_MMIO_BUS; > +} > + > +int > +kvm_set_ioregion(struct kvm *kvm, struct kvm_ioregion *args) > +{ > + struct ioregion *p; > + bool is_posted_writes; > + struct file *rfile, *wfile; > + enum kvm_bus bus_idx; > + int ret = 0; > + > + if (!args->memory_size) > + return -EINVAL; > + if ((args->guest_paddr + args->memory_size - 1) < args->guest_paddr) > + return -EINVAL; > + if (args->flags & ~KVM_IOREGION_VALID_FLAG_MASK) > + return -EINVAL; > + > + rfile = fget(args->rfd); > + if (!rfile) > + return -EBADF; > + wfile = fget(args->wfd); > + if (!wfile) { > + fput(rfile); > + return -EBADF; > + } > + if ((rfile->f_flags & O_NONBLOCK) || (wfile->f_flags & O_NONBLOCK)) { > + ret = -EINVAL; > + goto fail; > + } Instead of checking nonblocking, can we poll here? > + p = kzalloc(sizeof(*p), GFP_KERNEL_ACCOUNT); > + if (!p) { > + ret = -ENOMEM; > + goto fail; > + } > + > + INIT_LIST_HEAD(&p->list); > + p->paddr = args->guest_paddr; > + p->size = args->memory_size; > + p->user_data = args->user_data; > + p->rf = rfile; > + p->wf = wfile; > + is_posted_writes = args->flags & KVM_IOREGION_POSTED_WRITES; > + p->posted_writes = is_posted_writes ? true : false; > + bus_idx = get_bus_from_flags(args->flags); > + > + mutex_lock(&kvm->slots_lock); > + > + if (ioregion_collision(kvm, p, bus_idx)) { > + ret = -EEXIST; > + goto unlock_fail; > + } > + kvm_iodevice_init(&p->dev, &ioregion_ops); > + ret = kvm_io_bus_register_dev(kvm, bus_idx, p->paddr, p->size, > + &p->dev); > + if (ret < 0) > + goto unlock_fail; We probably need to register to FAST_MMIO when bus_idx is MMIO. > + list_add_tail(&p->list, get_ioregion_list(kvm, bus_idx)); > + > + mutex_unlock(&kvm->slots_lock); > + > + return 0; > + > +unlock_fail: > + mutex_unlock(&kvm->slots_lock); > + kfree(p); > +fail: > + fput(rfile); > + fput(wfile); > + > + return ret; > +} > + > +static int > +kvm_rm_ioregion(struct kvm *kvm, struct kvm_ioregion *args) > +{ > + struct ioregion *p, *tmp; > + enum kvm_bus bus_idx; > + int ret = -ENOENT; > + struct list_head *ioregions; > + > + if (args->rfd != -1 || args->wfd != -1) > + return -EINVAL; If we want to use ioregion fd for doorbell, rfd is probably not necessary here. Thanks > + > + bus_idx = get_bus_from_flags(args->flags); > + ioregions = get_ioregion_list(kvm, bus_idx); > + > + mutex_lock(&kvm->slots_lock); > + > + list_for_each_entry_safe(p, tmp, ioregions, list) { > + if (p->paddr == args->guest_paddr && > + p->size == args->memory_size) { > + kvm_io_bus_unregister_dev(kvm, bus_idx, &p->dev); > + ioregion_release(p); > + ret = 0; > + break; > + } > + } > + > + mutex_unlock(&kvm->slots_lock); > + > + return ret; > +} > + > +int > +kvm_ioregionfd(struct kvm *kvm, struct kvm_ioregion *args) > +{ > + if (args->rfd == -1 || args->wfd == -1) > + return kvm_rm_ioregion(kvm, args); > + return kvm_set_ioregion(kvm, args); > +} > diff --git a/virt/kvm/ioregion.h b/virt/kvm/ioregion.h > new file mode 100644 > index 000000000000..23ffa812ec7a > --- /dev/null > +++ b/virt/kvm/ioregion.h > @@ -0,0 +1,15 @@ > +/* SPDX-License-Identifier: GPL-2.0-only */ > +#ifndef __KVM_IOREGION_H__ > +#define __KVM_IOREGION_H__ > + > +#ifdef CONFIG_KVM_IOREGION > +inline bool overlap(u64 start1, u64 size1, u64 start2, u64 size2); > +bool kvm_ioregion_collides(struct kvm *kvm, int bus_idx, u64 start, u64 size); > +#else > +static inline bool > +kvm_ioregion_collides(struct kvm *kvm, int bus_idx, u64 start, u64 size) > +{ > + return false; > +} > +#endif > +#endif > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index 2541a17ff1c4..385d8ec6350d 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -747,6 +747,7 @@ static struct kvm *kvm_create_vm(unsigned long type) > mmgrab(current->mm); > kvm->mm = current->mm; > kvm_eventfd_init(kvm); > + kvm_ioregionfd_init(kvm); > mutex_init(&kvm->lock); > mutex_init(&kvm->irq_lock); > mutex_init(&kvm->slots_lock); > @@ -3708,6 +3709,16 @@ static long kvm_vm_ioctl(struct file *filp, > r = kvm_vm_ioctl_set_memory_region(kvm, &kvm_userspace_mem); > break; > } > + case KVM_SET_IOREGION: { > + struct kvm_ioregion data; > + > + r = -EFAULT; > + if (copy_from_user(&data, argp, sizeof(data))) > + goto out; > + > + r = kvm_ioregionfd(kvm, &data); > + break; > + } > case KVM_GET_DIRTY_LOG: { > struct kvm_dirty_log log; > > @@ -4301,9 +4312,12 @@ int kvm_io_bus_register_dev(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr, > if (!bus) > return -ENOMEM; > > - /* exclude ioeventfd which is limited by maximum fd */ > - if (bus->dev_count - bus->ioeventfd_count > NR_IOBUS_DEVS - 1) > - return -ENOSPC; > + /* enforce hard limit if kmemcg is disabled and > + * exclude ioeventfd which is limited by maximum fd > + */ > + if (!memcg_kmem_enabled()) > + if (bus->dev_count - bus->ioeventfd_count > NR_IOBUS_DEVS - 1) > + return -ENOSPC; > > new_bus = kmalloc(struct_size(bus, range, bus->dev_count + 1), > GFP_KERNEL_ACCOUNT);