From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (ozlabs.org [IPv6:2401:3900:2:1::2]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3vjf6V2W1hzDqMd for ; Wed, 15 Mar 2017 15:40:18 +1100 (AEDT) Date: Wed, 15 Mar 2017 15:40:14 +1100 From: David Gibson To: Alex Williamson Cc: Alexey Kardashevskiy , linuxppc-dev@lists.ozlabs.org, Paul Mackerras , kvm-ppc@vger.kernel.org, kvm@vger.kernel.org Subject: Re: [PATCH kernel v8 10/10] KVM: PPC: VFIO: Add in-kernel acceleration for VFIO Message-ID: <20170315044014.GA12603@umbus.fritz.box> References: <20170310035337.22091-1-aik@ozlabs.ru> <20170310035337.22091-11-aik@ozlabs.ru> <20170314150527.1c46c3c8@t450s.home> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="J2SCkAp4GZ/dPZZf" In-Reply-To: <20170314150527.1c46c3c8@t450s.home> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , --J2SCkAp4GZ/dPZZf Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Mar 14, 2017 at 03:05:27PM -0600, Alex Williamson wrote: > On Fri, 10 Mar 2017 14:53:37 +1100 > Alexey Kardashevskiy wrote: >=20 > > This allows the host kernel to handle H_PUT_TCE, H_PUT_TCE_INDIRECT > > and H_STUFF_TCE requests targeted an IOMMU TCE table used for VFIO > > without passing them to user space which saves time on switching > > to user space and back. > >=20 > > This adds H_PUT_TCE/H_PUT_TCE_INDIRECT/H_STUFF_TCE handlers to KVM. > > KVM tries to handle a TCE request in the real mode, if failed > > it passes the request to the virtual mode to complete the operation. > > If it a virtual mode handler fails, the request is passed to > > the user space; this is not expected to happen though. > >=20 > > To avoid dealing with page use counters (which is tricky in real mode), > > this only accelerates SPAPR TCE IOMMU v2 clients which are required > > to pre-register the userspace memory. The very first TCE request will > > be handled in the VFIO SPAPR TCE driver anyway as the userspace view > > of the TCE table (iommu_table::it_userspace) is not allocated till > > the very first mapping happens and we cannot call vmalloc in real mode. > >=20 > > If we fail to update a hardware IOMMU table unexpected reason, we just > > clear it and move on as there is nothing really we can do about it - > > for example, if we hot plug a VFIO device to a guest, existing TCE tabl= es > > will be mirrored automatically to the hardware and there is no interface > > to report to the guest about possible failures. > >=20 > > This adds new attribute - KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE - to > > the VFIO KVM device. It takes a VFIO group fd and SPAPR TCE table fd > > and associates a physical IOMMU table with the SPAPR TCE table (which > > is a guest view of the hardware IOMMU table). The iommu_table object > > is cached and referenced so we do not have to look up for it in real mo= de. > >=20 > > This does not implement the UNSET counterpart as there is no use for it= - > > once the acceleration is enabled, the existing userspace won't > > disable it unless a VFIO container is destroyed; this adds necessary > > cleanup to the KVM_DEV_VFIO_GROUP_DEL handler. > >=20 > > As this creates a descriptor per IOMMU table-LIOBN couple (called > > kvmppc_spapr_tce_iommu_table), it is possible to have several > > descriptors with the same iommu_table (hardware IOMMU table) attached > > to the same LIOBN; we do not remove duplicates though as > > iommu_table_ops::exchange not just update a TCE entry (which is > > shared among IOMMU groups) but also invalidates the TCE cache > > (one per IOMMU group). > >=20 > > This advertises the new KVM_CAP_SPAPR_TCE_VFIO capability to the user > > space. > >=20 > > This adds real mode version of WARN_ON_ONCE() as the generic version > > causes problems with rcu_sched. Since we testing what vmalloc_to_phys() > > returns in the code, this also adds a check for already existing > > vmalloc_to_phys() call in kvmppc_rm_h_put_tce_indirect(). > >=20 > > This finally makes use of vfio_external_user_iommu_id() which was > > introduced quite some time ago and was considered for removal. > >=20 > > Tests show that this patch increases transmission speed from 220MB/s > > to 750..1020MB/s on 10Gb network (Chelsea CXGB3 10Gb ethernet card). > >=20 > > Signed-off-by: Alexey Kardashevskiy > > --- > > Changes: > > v8: > > * changed all (!pua) checks to return H_TOO_HARD as ioctl() is supposed > > to handle them > > * changed vmalloc_to_phys() callers to return H_HARDWARE > > * changed real mode iommu_tce_xchg_rm() callers to return H_TOO_HARD > > and added a comment about this in the code > > * changed virtual mode iommu_tce_xchg() callers to return H_HARDWARE > > and do WARN_ON > > * added WARN_ON_ONCE_RM(!rmap) in kvmppc_rm_h_put_tce_indirect() to > > have all vmalloc_to_phys() callsites covered > >=20 > > v7: > > * added realmode-friendly WARN_ON_ONCE_RM > >=20 > > v6: > > * changed handling of errors returned by kvmppc_(rm_)tce_iommu_(un)map() > > * moved kvmppc_gpa_to_ua() to TCE validation > >=20 > > v5: > > * changed error codes in multiple places > > * added bunch of WARN_ON() in places which should not really happen > > * adde a check that an iommu table is not attached already to LIOBN > > * dropped explicit calls to iommu_tce_clear_param_check/ > > iommu_tce_put_param_check as kvmppc_tce_validate/kvmppc_ioba_validate > > call them anyway (since the previous patch) > > * if we fail to update a hardware IOMMU table for unexpected reason, > > this just clears the entry > >=20 > > v4: > > * added note to the commit log about allowing multiple updates of > > the same IOMMU table; > > * instead of checking for if any memory was preregistered, this > > returns H_TOO_HARD if a specific page was not; > > * fixed comments from v3 about error handling in many places; > > * simplified TCE handlers and merged IOMMU parts inline - for example, > > there used to be kvmppc_h_put_tce_iommu(), now it is merged into > > kvmppc_h_put_tce(); this allows to check IOBA boundaries against > > the first attached table only (makes the code simpler); > >=20 > > v3: > > * simplified not to use VFIO group notifiers > > * reworked cleanup, should be cleaner/simpler now > >=20 > > v2: > > * reworked to use new VFIO notifiers > > * now same iommu_table may appear in the list several times, to be fixe= d later > > --- > > Documentation/virtual/kvm/devices/vfio.txt | 22 +- > > arch/powerpc/include/asm/kvm_host.h | 8 + > > arch/powerpc/include/asm/kvm_ppc.h | 4 + > > include/uapi/linux/kvm.h | 8 + > > arch/powerpc/kvm/book3s_64_vio.c | 323 +++++++++++++++++++++= +++++++- > > arch/powerpc/kvm/book3s_64_vio_hv.c | 201 +++++++++++++++++- > > arch/powerpc/kvm/powerpc.c | 2 + > > virt/kvm/vfio.c | 60 ++++++ > > 8 files changed, 623 insertions(+), 5 deletions(-) > >=20 > > diff --git a/Documentation/virtual/kvm/devices/vfio.txt b/Documentation= /virtual/kvm/devices/vfio.txt > > index ef51740c67ca..f95d867168ea 100644 > > --- a/Documentation/virtual/kvm/devices/vfio.txt > > +++ b/Documentation/virtual/kvm/devices/vfio.txt > > @@ -16,7 +16,25 @@ Groups: > > =20 > > KVM_DEV_VFIO_GROUP attributes: > > KVM_DEV_VFIO_GROUP_ADD: Add a VFIO group to VFIO-KVM device tracking > > + kvm_device_attr.addr points to an int32_t file descriptor > > + for the VFIO group. > > KVM_DEV_VFIO_GROUP_DEL: Remove a VFIO group from VFIO-KVM device tra= cking > > + kvm_device_attr.addr points to an int32_t file descriptor > > + for the VFIO group. > > + KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE: attaches a guest visible TCE table > > + allocated by sPAPR KVM. > > + kvm_device_attr.addr points to a struct: > > =20 > > -For each, kvm_device_attr.addr points to an int32_t file descriptor > > -for the VFIO group. > > + struct kvm_vfio_spapr_tce { > > + __u32 argsz; > > + __u32 flags; > > + __s32 groupfd; > > + __s32 tablefd; > > + }; > > + > > + where > > + @argsz is the size of kvm_vfio_spapr_tce_liobn; >=20 > kvm_vfio_spapr_tce_liobn does not exist. s/_liobn//? >=20 > > + @flags are not supported now, must be zero; >=20 > We do this argsz/flags thing on vfio ioctls because ioctls are a bit > more of a restricted resource. We don't want to burn through them so > we make them expandable. I don't know that we have that restriction > here and the ADD/DEL support certainly doesn't include it. Maybe this > isn't necessary? I didn't comment on this before, but I tend to agree with Alex here. > > + @groupfd is a file descriptor for a VFIO group; > > + @tablefd is a file descriptor for a TCE table allocated via > > + KVM_CREATE_SPAPR_TCE. > > diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include= /asm/kvm_host.h > > index 7bba8f415627..857ae2c6aa39 100644 > > --- a/arch/powerpc/include/asm/kvm_host.h > > +++ b/arch/powerpc/include/asm/kvm_host.h > > @@ -191,6 +191,13 @@ struct kvmppc_pginfo { > > atomic_t refcnt; > > }; > > =20 > > +struct kvmppc_spapr_tce_iommu_table { > > + struct rcu_head rcu; > > + struct list_head next; > > + struct vfio_group *group; > > + struct iommu_table *tbl; > > +}; > > + > > struct kvmppc_spapr_tce_table { > > struct list_head list; > > struct kvm *kvm; > > @@ -199,6 +206,7 @@ struct kvmppc_spapr_tce_table { > > u32 page_shift; > > u64 offset; /* in pages */ > > u64 size; /* window size in pages */ > > + struct list_head iommu_tables; > > struct page *pages[0]; > > }; > > =20 > > diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/= asm/kvm_ppc.h > > index 72c2a155641f..66de7e73b3d3 100644 > > --- a/arch/powerpc/include/asm/kvm_ppc.h > > +++ b/arch/powerpc/include/asm/kvm_ppc.h > > @@ -164,6 +164,10 @@ extern long kvmppc_prepare_vrma(struct kvm *kvm, > > extern void kvmppc_map_vrma(struct kvm_vcpu *vcpu, > > struct kvm_memory_slot *memslot, unsigned long porder); > > extern int kvmppc_pseries_do_hcall(struct kvm_vcpu *vcpu); > > +extern long kvm_spapr_tce_attach_iommu_group(struct kvm *kvm, int tabl= efd, > > + struct vfio_group *group); > > +extern void kvm_spapr_tce_release_iommu_group(struct kvm *kvm, > > + struct vfio_group *group); > > =20 > > extern long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm, > > struct kvm_create_spapr_tce_64 *args); > > diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h > > index f5a52ffb6b58..e743cb0d176e 100644 > > --- a/include/uapi/linux/kvm.h > > +++ b/include/uapi/linux/kvm.h > > @@ -1088,6 +1088,7 @@ struct kvm_device_attr { > > #define KVM_DEV_VFIO_GROUP 1 > > #define KVM_DEV_VFIO_GROUP_ADD 1 > > #define KVM_DEV_VFIO_GROUP_DEL 2 > > +#define KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE 3 > > =20 > > enum kvm_device_type { > > KVM_DEV_TYPE_FSL_MPIC_20 =3D 1, > > @@ -1109,6 +1110,13 @@ enum kvm_device_type { > > KVM_DEV_TYPE_MAX, > > }; > > =20 > > +struct kvm_vfio_spapr_tce { > > + __u32 argsz; > > + __u32 flags; > > + __s32 groupfd; > > + __s32 tablefd; > > +}; > > + > > /* > > * ioctls for VM fds > > */ > > diff --git a/arch/powerpc/kvm/book3s_64_vio.c b/arch/powerpc/kvm/book3s= _64_vio.c > > index e96a4590464c..be18cda01e1b 100644 > > --- a/arch/powerpc/kvm/book3s_64_vio.c > > +++ b/arch/powerpc/kvm/book3s_64_vio.c > > @@ -28,6 +28,10 @@ > > #include > > #include > > #include > > +#include > > +#include > > +#include > > +#include > > =20 > > #include > > #include > > @@ -40,6 +44,36 @@ > > #include > > #include > > #include > > +#include > > + > > +static void kvm_vfio_group_put_external_user(struct vfio_group *vfio_g= roup) > > +{ > > + void (*fn)(struct vfio_group *); > > + > > + fn =3D symbol_get(vfio_group_put_external_user); > > + if (WARN_ON(!fn)) > > + return; > > + > > + fn(vfio_group); > > + > > + symbol_put(vfio_group_put_external_user); > > +} > > + > > +static int kvm_vfio_external_user_iommu_id(struct vfio_group *vfio_gro= up) > > +{ > > + int (*fn)(struct vfio_group *); > > + int ret =3D -1; > > + > > + fn =3D symbol_get(vfio_external_user_iommu_id); > > + if (!fn) > > + return ret; > > + > > + ret =3D fn(vfio_group); > > + > > + symbol_put(vfio_external_user_iommu_id); > > + > > + return ret; > > +} >=20 >=20 > Ugh. This feels so wrong. Why can't you have kvm-vfio pass the > iommu_group? Why do you need to hold this additional vfio_group > reference? Keeping the vfio_group reference makes sense to me, since we don't want the vfio context for the group to go away while it's attached to the LIOBN. However, going via the iommu_id rather than just having an interface to directly grab the iommu group from the vfio_group seems bizarre to me. I'm ok with cleaning that up later, however. >=20 > > =20 > > static unsigned long kvmppc_tce_pages(unsigned long iommu_pages) > > { > > @@ -91,6 +125,130 @@ static long kvmppc_account_memlimit(unsigned long = stt_pages, bool inc) > > return ret; > > } > > =20 > > +static void kvm_spapr_tce_iommu_table_free(struct rcu_head *head) > > +{ > > + struct kvmppc_spapr_tce_iommu_table *stit =3D container_of(head, > > + struct kvmppc_spapr_tce_iommu_table, rcu); > > + > > + iommu_table_put(stit->tbl); > > + kvm_vfio_group_put_external_user(stit->group); > > + > > + kfree(stit); > > +} > > + > > +static void kvm_spapr_tce_liobn_release_iommu_group( > > + struct kvmppc_spapr_tce_table *stt, > > + struct vfio_group *group) > > +{ > > + struct kvmppc_spapr_tce_iommu_table *stit, *tmp; > > + > > + list_for_each_entry_safe(stit, tmp, &stt->iommu_tables, next) { > > + if (group && (stit->group !=3D group)) > > + continue; > > + > > + list_del_rcu(&stit->next); > > + > > + call_rcu(&stit->rcu, kvm_spapr_tce_iommu_table_free); > > + } > > +} > > + > > +extern void kvm_spapr_tce_release_iommu_group(struct kvm *kvm, > > + struct vfio_group *group) > > +{ > > + struct kvmppc_spapr_tce_table *stt; > > + > > + list_for_each_entry_rcu(stt, &kvm->arch.spapr_tce_tables, list) > > + kvm_spapr_tce_liobn_release_iommu_group(stt, group); > > +} > > + > > +extern long kvm_spapr_tce_attach_iommu_group(struct kvm *kvm, int tabl= efd, > > + struct vfio_group *group) > > +{ > > + struct kvmppc_spapr_tce_table *stt =3D NULL; > > + bool found =3D false; > > + struct iommu_table *tbl =3D NULL; > > + struct iommu_table_group *table_group; > > + long i, ret =3D 0; > > + struct kvmppc_spapr_tce_iommu_table *stit; > > + struct fd f; > > + int group_id; > > + struct iommu_group *grp; > > + > > + group_id =3D kvm_vfio_external_user_iommu_id(group); > > + grp =3D iommu_group_get_by_id(group_id); > > + if (WARN_ON(!grp)) > > + return -EIO; > > + > > + f =3D fdget(tablefd); > > + if (!f.file) { > > + ret =3D -EBADF; > > + goto put_exit; > > + } > > + > > + list_for_each_entry_rcu(stt, &kvm->arch.spapr_tce_tables, list) { > > + if (stt =3D=3D f.file->private_data) { > > + found =3D true; > > + break; > > + } > > + } > > + > > + fdput(f); > > + > > + if (!found) { > > + ret =3D -EINVAL; > > + goto put_exit; > > + } > > + > > + table_group =3D iommu_group_get_iommudata(grp); > > + if (WARN_ON(!table_group)) { > > + ret =3D -EFAULT; > > + goto put_exit; > > + } > > + > > + for (i =3D 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) { > > + struct iommu_table *tbltmp =3D table_group->tables[i]; > > + > > + if (!tbltmp) > > + continue; > > + > > + /* > > + * Make sure hardware table parameters are exactly the same; > > + * this is used in the TCE handlers where boundary checks > > + * use only the first attached table. > > + */ > > + if ((tbltmp->it_page_shift =3D=3D stt->page_shift) && > > + (tbltmp->it_offset =3D=3D stt->offset) && > > + (tbltmp->it_size =3D=3D stt->size)) { > > + tbl =3D tbltmp; > > + break; > > + } > > + } > > + if (!tbl) { > > + ret =3D -EINVAL; > > + goto put_exit; > > + } > > + > > + list_for_each_entry_rcu(stit, &stt->iommu_tables, next) { > > + if ((stit->tbl =3D=3D tbl) && (stit->group =3D=3D group)) { > > + ret =3D -EBUSY; > > + goto put_exit; > > + } > > + } > > + > > + iommu_table_get(tbl); > > + > > + stit =3D kzalloc(sizeof(*stit), GFP_KERNEL); > > + stit->tbl =3D tbl; > > + stit->group =3D group; > > + > > + list_add_rcu(&stit->next, &stt->iommu_tables); > > + > > +put_exit: > > + iommu_group_put(grp); > > + > > + return ret; > > +} > > + > > static void release_spapr_tce_table(struct rcu_head *head) > > { > > struct kvmppc_spapr_tce_table *stt =3D container_of(head, > > @@ -133,6 +291,8 @@ static int kvm_spapr_tce_release(struct inode *inod= e, struct file *filp) > > =20 > > list_del_rcu(&stt->list); > > =20 > > + kvm_spapr_tce_liobn_release_iommu_group(stt, NULL /* release all */); > > + > > kvm_put_kvm(stt->kvm); > > =20 > > kvmppc_account_memlimit( > > @@ -183,6 +343,7 @@ long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm, > > stt->offset =3D args->offset; > > stt->size =3D size; > > stt->kvm =3D kvm; > > + INIT_LIST_HEAD_RCU(&stt->iommu_tables); > > =20 > > for (i =3D 0; i < npages; i++) { > > stt->pages[i] =3D alloc_page(GFP_KERNEL | __GFP_ZERO); > > @@ -211,11 +372,101 @@ long kvm_vm_ioctl_create_spapr_tce(struct kvm *k= vm, > > return ret; > > } > > =20 > > +static void kvmppc_clear_tce(struct iommu_table *tbl, unsigned long en= try) > > +{ > > + unsigned long hpa =3D 0; > > + enum dma_data_direction dir =3D DMA_NONE; > > + > > + iommu_tce_xchg(tbl, entry, &hpa, &dir); > > +} > > + > > +static long kvmppc_tce_iommu_mapped_dec(struct kvm *kvm, > > + struct iommu_table *tbl, unsigned long entry) > > +{ > > + struct mm_iommu_table_group_mem_t *mem =3D NULL; > > + const unsigned long pgsize =3D 1ULL << tbl->it_page_shift; > > + unsigned long *pua =3D IOMMU_TABLE_USERSPACE_ENTRY(tbl, entry); > > + > > + if (!pua) > > + /* it_userspace allocation might be delayed */ > > + return H_TOO_HARD; > > + > > + mem =3D mm_iommu_lookup(kvm->mm, *pua, pgsize); > > + if (!mem) > > + return H_TOO_HARD; > > + > > + mm_iommu_mapped_dec(mem); > > + > > + *pua =3D 0; > > + > > + return H_SUCCESS; > > +} > > + > > +static long kvmppc_tce_iommu_unmap(struct kvm *kvm, > > + struct iommu_table *tbl, unsigned long entry) > > +{ > > + enum dma_data_direction dir =3D DMA_NONE; > > + unsigned long hpa =3D 0; > > + long ret; > > + > > + if (WARN_ON_ONCE(iommu_tce_xchg(tbl, entry, &hpa, &dir))) > > + return H_HARDWARE; > > + > > + if (dir =3D=3D DMA_NONE) > > + return H_SUCCESS; > > + > > + ret =3D kvmppc_tce_iommu_mapped_dec(kvm, tbl, entry); > > + if (ret !=3D H_SUCCESS) > > + iommu_tce_xchg(tbl, entry, &hpa, &dir); > > + > > + return ret; > > +} > > + > > +long kvmppc_tce_iommu_map(struct kvm *kvm, struct iommu_table *tbl, > > + unsigned long entry, unsigned long ua, > > + enum dma_data_direction dir) > > +{ > > + long ret; > > + unsigned long hpa, *pua =3D IOMMU_TABLE_USERSPACE_ENTRY(tbl, entry); > > + struct mm_iommu_table_group_mem_t *mem; > > + > > + if (!pua) > > + /* it_userspace allocation might be delayed */ > > + return H_TOO_HARD; > > + > > + mem =3D mm_iommu_lookup(kvm->mm, ua, 1ULL << tbl->it_page_shift); > > + if (!mem) > > + /* This only handles v2 IOMMU type, v1 is handled via ioctl() */ > > + return H_TOO_HARD; > > + > > + if (WARN_ON_ONCE(mm_iommu_ua_to_hpa(mem, ua, &hpa))) > > + return H_HARDWARE; > > + > > + if (mm_iommu_mapped_inc(mem)) > > + return H_CLOSED; > > + > > + ret =3D iommu_tce_xchg(tbl, entry, &hpa, &dir); > > + if (WARN_ON_ONCE(ret)) { > > + mm_iommu_mapped_dec(mem); > > + return H_HARDWARE; > > + } > > + > > + if (dir !=3D DMA_NONE) > > + kvmppc_tce_iommu_mapped_dec(kvm, tbl, entry); > > + > > + *pua =3D ua; > > + > > + return 0; > > +} > > + > > long kvmppc_h_put_tce(struct kvm_vcpu *vcpu, unsigned long liobn, > > unsigned long ioba, unsigned long tce) > > { > > struct kvmppc_spapr_tce_table *stt; > > - long ret; > > + long ret, idx; > > + struct kvmppc_spapr_tce_iommu_table *stit; > > + unsigned long entry, ua =3D 0; > > + enum dma_data_direction dir; > > =20 > > /* udbg_printf("H_PUT_TCE(): liobn=3D0x%lx ioba=3D0x%lx, tce=3D0x%lx\= n", */ > > /* liobn, ioba, tce); */ > > @@ -232,7 +483,35 @@ long kvmppc_h_put_tce(struct kvm_vcpu *vcpu, unsig= ned long liobn, > > if (ret !=3D H_SUCCESS) > > return ret; > > =20 > > - kvmppc_tce_put(stt, ioba >> stt->page_shift, tce); > > + dir =3D iommu_tce_direction(tce); > > + if ((dir !=3D DMA_NONE) && kvmppc_gpa_to_ua(vcpu->kvm, > > + tce & ~(TCE_PCI_READ | TCE_PCI_WRITE), &ua, NULL)) > > + return H_PARAMETER; > > + > > + entry =3D ioba >> stt->page_shift; > > + > > + list_for_each_entry_lockless(stit, &stt->iommu_tables, next) { > > + if (dir =3D=3D DMA_NONE) { > > + ret =3D kvmppc_tce_iommu_unmap(vcpu->kvm, > > + stit->tbl, entry); > > + } else { > > + idx =3D srcu_read_lock(&vcpu->kvm->srcu); > > + ret =3D kvmppc_tce_iommu_map(vcpu->kvm, stit->tbl, > > + entry, ua, dir); > > + srcu_read_unlock(&vcpu->kvm->srcu, idx); > > + } > > + > > + if (ret =3D=3D H_SUCCESS) > > + continue; > > + > > + if (ret =3D=3D H_TOO_HARD) > > + return ret; > > + > > + WARN_ON_ONCE(1); > > + kvmppc_clear_tce(stit->tbl, entry); > > + } > > + > > + kvmppc_tce_put(stt, entry, tce); > > =20 > > return H_SUCCESS; > > } > > @@ -247,6 +526,7 @@ long kvmppc_h_put_tce_indirect(struct kvm_vcpu *vcp= u, > > unsigned long entry, ua =3D 0; > > u64 __user *tces; > > u64 tce; > > + struct kvmppc_spapr_tce_iommu_table *stit; > > =20 > > stt =3D kvmppc_find_table(vcpu->kvm, liobn); > > if (!stt) > > @@ -285,6 +565,26 @@ long kvmppc_h_put_tce_indirect(struct kvm_vcpu *vc= pu, > > if (ret !=3D H_SUCCESS) > > goto unlock_exit; > > =20 > > + if (kvmppc_gpa_to_ua(vcpu->kvm, > > + tce & ~(TCE_PCI_READ | TCE_PCI_WRITE), > > + &ua, NULL)) > > + return H_PARAMETER; > > + > > + list_for_each_entry_lockless(stit, &stt->iommu_tables, next) { > > + ret =3D kvmppc_tce_iommu_map(vcpu->kvm, > > + stit->tbl, entry + i, ua, > > + iommu_tce_direction(tce)); > > + > > + if (ret =3D=3D H_SUCCESS) > > + continue; > > + > > + if (ret =3D=3D H_TOO_HARD) > > + goto unlock_exit; > > + > > + WARN_ON_ONCE(1); > > + kvmppc_clear_tce(stit->tbl, entry); > > + } > > + > > kvmppc_tce_put(stt, entry + i, tce); > > } > > =20 > > @@ -301,6 +601,7 @@ long kvmppc_h_stuff_tce(struct kvm_vcpu *vcpu, > > { > > struct kvmppc_spapr_tce_table *stt; > > long i, ret; > > + struct kvmppc_spapr_tce_iommu_table *stit; > > =20 > > stt =3D kvmppc_find_table(vcpu->kvm, liobn); > > if (!stt) > > @@ -314,6 +615,24 @@ long kvmppc_h_stuff_tce(struct kvm_vcpu *vcpu, > > if (tce_value & (TCE_PCI_WRITE | TCE_PCI_READ)) > > return H_PARAMETER; > > =20 > > + list_for_each_entry_lockless(stit, &stt->iommu_tables, next) { > > + unsigned long entry =3D ioba >> stit->tbl->it_page_shift; > > + > > + for (i =3D 0; i < npages; ++i) { > > + ret =3D kvmppc_tce_iommu_unmap(vcpu->kvm, > > + stit->tbl, entry + i); > > + > > + if (ret =3D=3D H_SUCCESS) > > + continue; > > + > > + if (ret =3D=3D H_TOO_HARD) > > + return ret; > > + > > + WARN_ON_ONCE(1); > > + kvmppc_clear_tce(stit->tbl, entry); > > + } > > + } > > + > > for (i =3D 0; i < npages; ++i, ioba +=3D (1ULL << stt->page_shift)) > > kvmppc_tce_put(stt, ioba >> stt->page_shift, tce_value); > > =20 > > diff --git a/arch/powerpc/kvm/book3s_64_vio_hv.c b/arch/powerpc/kvm/boo= k3s_64_vio_hv.c > > index 440d3ab5dc32..eda0a8f6fae8 100644 > > --- a/arch/powerpc/kvm/book3s_64_vio_hv.c > > +++ b/arch/powerpc/kvm/book3s_64_vio_hv.c > > @@ -40,6 +40,31 @@ > > #include > > #include > > =20 > > +#ifdef CONFIG_BUG > > + > > +#define WARN_ON_ONCE_RM(condition) ({ \ > > + static bool __section(.data.unlikely) __warned; \ > > + int __ret_warn_once =3D !!(condition); \ > > + \ > > + if (unlikely(__ret_warn_once && !__warned)) { \ > > + __warned =3D true; \ > > + pr_err("WARN_ON_ONCE_RM: (%s) at %s:%u\n", \ > > + __stringify(condition), \ > > + __func__, __LINE__); \ > > + dump_stack(); \ > > + } \ > > + unlikely(__ret_warn_once); \ > > +}) > > + > > +#else > > + > > +#define WARN_ON_ONCE_RM(condition) ({ \ > > + int __ret_warn_on =3D !!(condition); \ > > + unlikely(__ret_warn_on); \ > > +}) > > + > > +#endif > > + > > #define TCES_PER_PAGE (PAGE_SIZE / sizeof(u64)) > > =20 > > /* > > @@ -161,11 +186,117 @@ long kvmppc_gpa_to_ua(struct kvm *kvm, unsigned = long gpa, > > EXPORT_SYMBOL_GPL(kvmppc_gpa_to_ua); > > =20 > > #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE > > +static void kvmppc_rm_clear_tce(struct iommu_table *tbl, unsigned long= entry) > > +{ > > + unsigned long hpa =3D 0; > > + enum dma_data_direction dir =3D DMA_NONE; > > + > > + iommu_tce_xchg_rm(tbl, entry, &hpa, &dir); > > +} > > + > > +static long kvmppc_rm_tce_iommu_mapped_dec(struct kvm *kvm, > > + struct iommu_table *tbl, unsigned long entry) > > +{ > > + struct mm_iommu_table_group_mem_t *mem =3D NULL; > > + const unsigned long pgsize =3D 1ULL << tbl->it_page_shift; > > + unsigned long *pua =3D IOMMU_TABLE_USERSPACE_ENTRY(tbl, entry); > > + > > + if (!pua) > > + /* it_userspace allocation might be delayed */ > > + return H_TOO_HARD; > > + > > + pua =3D (void *) vmalloc_to_phys(pua); > > + if (WARN_ON_ONCE_RM(!pua)) > > + return H_HARDWARE; > > + > > + mem =3D mm_iommu_lookup_rm(kvm->mm, *pua, pgsize); > > + if (!mem) > > + return H_TOO_HARD; > > + > > + mm_iommu_mapped_dec(mem); > > + > > + *pua =3D 0; > > + > > + return H_SUCCESS; > > +} > > + > > +static long kvmppc_rm_tce_iommu_unmap(struct kvm *kvm, > > + struct iommu_table *tbl, unsigned long entry) > > +{ > > + enum dma_data_direction dir =3D DMA_NONE; > > + unsigned long hpa =3D 0; > > + long ret; > > + > > + if (iommu_tce_xchg_rm(tbl, entry, &hpa, &dir)) > > + /* > > + * real mode xchg can fail if struct page crosses > > + * a page boundary > > + */ > > + return H_TOO_HARD; > > + > > + if (dir =3D=3D DMA_NONE) > > + return H_SUCCESS; > > + > > + ret =3D kvmppc_rm_tce_iommu_mapped_dec(kvm, tbl, entry); > > + if (ret) > > + iommu_tce_xchg_rm(tbl, entry, &hpa, &dir); > > + > > + return ret; > > +} > > + > > +static long kvmppc_rm_tce_iommu_map(struct kvm *kvm, struct iommu_tabl= e *tbl, > > + unsigned long entry, unsigned long ua, > > + enum dma_data_direction dir) > > +{ > > + long ret; > > + unsigned long hpa =3D 0; > > + unsigned long *pua =3D IOMMU_TABLE_USERSPACE_ENTRY(tbl, entry); > > + struct mm_iommu_table_group_mem_t *mem; > > + > > + if (!pua) > > + /* it_userspace allocation might be delayed */ > > + return H_TOO_HARD; > > + > > + mem =3D mm_iommu_lookup_rm(kvm->mm, ua, 1ULL << tbl->it_page_shift); > > + if (!mem) > > + return H_TOO_HARD; > > + > > + if (WARN_ON_ONCE_RM(mm_iommu_ua_to_hpa_rm(mem, ua, &hpa))) > > + return H_HARDWARE; > > + > > + pua =3D (void *) vmalloc_to_phys(pua); > > + if (WARN_ON_ONCE_RM(!pua)) > > + return H_HARDWARE; > > + > > + if (WARN_ON_ONCE_RM(mm_iommu_mapped_inc(mem))) > > + return H_CLOSED; > > + > > + ret =3D iommu_tce_xchg_rm(tbl, entry, &hpa, &dir); > > + if (ret) { > > + mm_iommu_mapped_dec(mem); > > + /* > > + * real mode xchg can fail if struct page crosses > > + * a page boundary > > + */ > > + return H_TOO_HARD; > > + } > > + > > + if (dir !=3D DMA_NONE) > > + kvmppc_rm_tce_iommu_mapped_dec(kvm, tbl, entry); > > + > > + *pua =3D ua; > > + > > + return 0; > > +} > > + > > long kvmppc_rm_h_put_tce(struct kvm_vcpu *vcpu, unsigned long liobn, > > unsigned long ioba, unsigned long tce) > > { > > struct kvmppc_spapr_tce_table *stt; > > long ret; > > + struct kvmppc_spapr_tce_iommu_table *stit; > > + unsigned long entry, ua =3D 0; > > + enum dma_data_direction dir; > > =20 > > /* udbg_printf("H_PUT_TCE(): liobn=3D0x%lx ioba=3D0x%lx, tce=3D0x%lx\= n", */ > > /* liobn, ioba, tce); */ > > @@ -182,7 +313,32 @@ long kvmppc_rm_h_put_tce(struct kvm_vcpu *vcpu, un= signed long liobn, > > if (ret !=3D H_SUCCESS) > > return ret; > > =20 > > - kvmppc_tce_put(stt, ioba >> stt->page_shift, tce); > > + dir =3D iommu_tce_direction(tce); > > + if ((dir !=3D DMA_NONE) && kvmppc_gpa_to_ua(vcpu->kvm, > > + tce & ~(TCE_PCI_READ | TCE_PCI_WRITE), &ua, NULL)) > > + return H_PARAMETER; > > + > > + entry =3D ioba >> stt->page_shift; > > + > > + list_for_each_entry_lockless(stit, &stt->iommu_tables, next) { > > + if (dir =3D=3D DMA_NONE) > > + ret =3D kvmppc_rm_tce_iommu_unmap(vcpu->kvm, > > + stit->tbl, entry); > > + else > > + ret =3D kvmppc_rm_tce_iommu_map(vcpu->kvm, > > + stit->tbl, entry, ua, dir); > > + > > + if (ret =3D=3D H_SUCCESS) > > + continue; > > + > > + if (ret =3D=3D H_TOO_HARD) > > + return ret; > > + > > + WARN_ON_ONCE_RM(1); > > + kvmppc_rm_clear_tce(stit->tbl, entry); > > + } > > + > > + kvmppc_tce_put(stt, entry, tce); > > =20 > > return H_SUCCESS; > > } > > @@ -223,6 +379,7 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *= vcpu, > > unsigned long tces, entry, ua =3D 0; > > unsigned long *rmap =3D NULL; > > bool prereg =3D false; > > + struct kvmppc_spapr_tce_iommu_table *stit; > > =20 > > stt =3D kvmppc_find_table(vcpu->kvm, liobn); > > if (!stt) > > @@ -270,6 +427,8 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *= vcpu, > > return H_TOO_HARD; > > =20 > > rmap =3D (void *) vmalloc_to_phys(rmap); > > + if (WARN_ON_ONCE_RM(!rmap)) > > + return H_HARDWARE; > > =20 > > /* > > * Synchronize with the MMU notifier callbacks in > > @@ -293,6 +452,27 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu = *vcpu, > > if (ret !=3D H_SUCCESS) > > goto unlock_exit; > > =20 > > + ua =3D 0; > > + if (kvmppc_gpa_to_ua(vcpu->kvm, > > + tce & ~(TCE_PCI_READ | TCE_PCI_WRITE), > > + &ua, NULL)) > > + return H_PARAMETER; > > + > > + list_for_each_entry_lockless(stit, &stt->iommu_tables, next) { > > + ret =3D kvmppc_rm_tce_iommu_map(vcpu->kvm, > > + stit->tbl, entry + i, ua, > > + iommu_tce_direction(tce)); > > + > > + if (ret =3D=3D H_SUCCESS) > > + continue; > > + > > + if (ret =3D=3D H_TOO_HARD) > > + goto unlock_exit; > > + > > + WARN_ON_ONCE_RM(1); > > + kvmppc_rm_clear_tce(stit->tbl, entry); > > + } > > + > > kvmppc_tce_put(stt, entry + i, tce); > > } > > =20 > > @@ -309,6 +489,7 @@ long kvmppc_rm_h_stuff_tce(struct kvm_vcpu *vcpu, > > { > > struct kvmppc_spapr_tce_table *stt; > > long i, ret; > > + struct kvmppc_spapr_tce_iommu_table *stit; > > =20 > > stt =3D kvmppc_find_table(vcpu->kvm, liobn); > > if (!stt) > > @@ -322,6 +503,24 @@ long kvmppc_rm_h_stuff_tce(struct kvm_vcpu *vcpu, > > if (tce_value & (TCE_PCI_WRITE | TCE_PCI_READ)) > > return H_PARAMETER; > > =20 > > + list_for_each_entry_lockless(stit, &stt->iommu_tables, next) { > > + unsigned long entry =3D ioba >> stit->tbl->it_page_shift; > > + > > + for (i =3D 0; i < npages; ++i) { > > + ret =3D kvmppc_rm_tce_iommu_unmap(vcpu->kvm, > > + stit->tbl, entry + i); > > + > > + if (ret =3D=3D H_SUCCESS) > > + continue; > > + > > + if (ret =3D=3D H_TOO_HARD) > > + return ret; > > + > > + WARN_ON_ONCE_RM(1); > > + kvmppc_rm_clear_tce(stit->tbl, entry); > > + } > > + } > > + > > for (i =3D 0; i < npages; ++i, ioba +=3D (1ULL << stt->page_shift)) > > kvmppc_tce_put(stt, ioba >> stt->page_shift, tce_value); > > =20 > > diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c > > index 95c91a9de351..62bdd6c48107 100644 > > --- a/arch/powerpc/kvm/powerpc.c > > +++ b/arch/powerpc/kvm/powerpc.c > > @@ -538,6 +538,8 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, l= ong ext) > > #ifdef CONFIG_PPC_BOOK3S_64 > > case KVM_CAP_SPAPR_TCE: > > case KVM_CAP_SPAPR_TCE_64: > > + /* fallthrough */ > > + case KVM_CAP_SPAPR_TCE_VFIO: > > case KVM_CAP_PPC_RTAS: > > case KVM_CAP_PPC_FIXUP_HCALL: > > case KVM_CAP_PPC_ENABLE_HCALL: > > diff --git a/virt/kvm/vfio.c b/virt/kvm/vfio.c > > index d32f239eb471..2b7dc22265fe 100644 > > --- a/virt/kvm/vfio.c > > +++ b/virt/kvm/vfio.c > > @@ -20,6 +20,10 @@ > > #include > > #include "vfio.h" > > =20 > > +#ifdef CONFIG_SPAPR_TCE_IOMMU > > +#include > > +#endif > > + > > struct kvm_vfio_group { > > struct list_head node; > > struct vfio_group *vfio_group; > > @@ -211,6 +215,9 @@ static int kvm_vfio_set_group(struct kvm_device *de= v, long attr, u64 arg) > > =20 > > mutex_unlock(&kv->lock); > > =20 > > +#ifdef CONFIG_SPAPR_TCE_IOMMU > > + kvm_spapr_tce_release_iommu_group(dev->kvm, vfio_group); > > +#endif > > kvm_vfio_group_set_kvm(vfio_group, NULL); > > =20 > > kvm_vfio_group_put_external_user(vfio_group); > > @@ -218,6 +225,53 @@ static int kvm_vfio_set_group(struct kvm_device *d= ev, long attr, u64 arg) > > kvm_vfio_update_coherency(dev); > > =20 > > return ret; > > + > > +#ifdef CONFIG_SPAPR_TCE_IOMMU > > + case KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE: { > > + struct kvm_vfio_spapr_tce param; > > + unsigned long minsz; > > + struct kvm_vfio *kv =3D dev->private; > > + struct vfio_group *vfio_group; > > + struct kvm_vfio_group *kvg; > > + struct fd f; > > + > > + minsz =3D offsetofend(struct kvm_vfio_spapr_tce, tablefd); > > + > > + if (copy_from_user(¶m, (void __user *)arg, minsz)) > > + return -EFAULT; > > + > > + if (param.argsz < minsz || param.flags) > > + return -EINVAL; > > + > > + f =3D fdget(param.groupfd); > > + if (!f.file) > > + return -EBADF; > > + > > + vfio_group =3D kvm_vfio_group_get_external_user(f.file); > > + fdput(f); > > + > > + if (IS_ERR(vfio_group)) > > + return PTR_ERR(vfio_group); > > + > > + ret =3D -ENOENT; > > + > > + mutex_lock(&kv->lock); > > + > > + list_for_each_entry(kvg, &kv->group_list, node) { > > + if (kvg->vfio_group !=3D vfio_group) > > + continue; > > + > > + ret =3D kvm_spapr_tce_attach_iommu_group(dev->kvm, > > + param.tablefd, vfio_group); > > + > > + break; > > + } > > + > > + mutex_unlock(&kv->lock); > > + > > + return ret; > > + } > > +#endif /* CONFIG_SPAPR_TCE_IOMMU */ >=20 >=20 > The group reference is leaked if kvm_spapr_tce_attach_iommu_group() > fails. Good catch. > My preference would be to not hold that separate group > reference in the spapr code anyway, having a parallel life cycle over > there is confusing and results in ugliness like duplicating=20 > kvm_vfio_group_put_external_user(). Thanks, >=20 > Alex >=20 > > } > > =20 > > return -ENXIO; > > @@ -242,6 +296,9 @@ static int kvm_vfio_has_attr(struct kvm_device *dev, > > switch (attr->attr) { > > case KVM_DEV_VFIO_GROUP_ADD: > > case KVM_DEV_VFIO_GROUP_DEL: > > +#ifdef CONFIG_SPAPR_TCE_IOMMU > > + case KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE: > > +#endif > > return 0; > > } > > =20 > > @@ -257,6 +314,9 @@ static void kvm_vfio_destroy(struct kvm_device *dev) > > struct kvm_vfio_group *kvg, *tmp; > > =20 > > list_for_each_entry_safe(kvg, tmp, &kv->group_list, node) { > > +#ifdef CONFIG_SPAPR_TCE_IOMMU > > + kvm_spapr_tce_release_iommu_group(dev->kvm, kvg->vfio_group); > > +#endif > > kvm_vfio_group_set_kvm(kvg->vfio_group, NULL); > > kvm_vfio_group_put_external_user(kvg->vfio_group); > > list_del(&kvg->node); >=20 --=20 David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. 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