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 3vrymg6ChnzDq7d for ; Mon, 27 Mar 2017 13:35:15 +1100 (AEDT) Date: Mon, 27 Mar 2017 13:35:05 +1100 From: David Gibson To: Alexey Kardashevskiy Cc: linuxppc-dev@lists.ozlabs.org, Alex Williamson , Paul Mackerras , kvm-ppc@vger.kernel.org, kvm@vger.kernel.org Subject: Re: [PATCH kernel v11 10/10] KVM: PPC: VFIO: Add in-kernel acceleration for VFIO Message-ID: <20170327023505.GS19078@umbus.fritz.box> References: <20170322042156.11756-1-aik@ozlabs.ru> <20170322042156.11756-11-aik@ozlabs.ru> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="RlgFhasKO3bfRJ5j" In-Reply-To: <20170322042156.11756-11-aik@ozlabs.ru> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , --RlgFhasKO3bfRJ5j Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Mar 22, 2017 at 03:21:56PM +1100, Alexey Kardashevskiy wrote: > 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 tables > 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 mode. >=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 > 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 Reviewed-by: David Gibson > --- > Changes: > v11: > * fixed vfio_group reference leak in KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE > handler >=20 > v10: > * fixed leaking references in virt/kvm/vfio.c > * moved code to helpers - kvm_vfio_group_get_iommu_group, kvm_spapr_tce_r= elease_vfio_group > * fixed possible race between referencing table and destroying it via > VFIO add/remove window ioctls() >=20 > v9: > * removed referencing a group in KVM, only referencing iommu_table's now > * fixed a reference leak in KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE handler > * fixed typo in vfio.txt > * removed @argsz and @flags from struct kvm_vfio_spapr_tce >=20 > 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 fixed = later > --- > Documentation/virtual/kvm/devices/vfio.txt | 18 +- > arch/powerpc/include/asm/kvm_host.h | 8 + > arch/powerpc/include/asm/kvm_ppc.h | 4 + > include/uapi/linux/kvm.h | 6 + > arch/powerpc/kvm/book3s_64_vio.c | 301 +++++++++++++++++++++++= +++++- > arch/powerpc/kvm/book3s_64_vio_hv.c | 201 ++++++++++++++++++- > arch/powerpc/kvm/powerpc.c | 2 + > virt/kvm/vfio.c | 105 ++++++++++ > 8 files changed, 640 insertions(+), 5 deletions(-) >=20 > diff --git a/Documentation/virtual/kvm/devices/vfio.txt b/Documentation/v= irtual/kvm/devices/vfio.txt > index ef51740c67ca..528c77c8022c 100644 > --- a/Documentation/virtual/kvm/devices/vfio.txt > +++ b/Documentation/virtual/kvm/devices/vfio.txt > @@ -16,7 +16,21 @@ 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 track= ing > + 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 { > + __s32 groupfd; > + __s32 tablefd; > + }; > + > + where > + @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/a= sm/kvm_host.h > index 7bba8f415627..178074e643e5 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 iommu_table *tbl; > + struct kref kref; > +}; > + > 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/as= m/kvm_ppc.h > index 72c2a155641f..cfd45714189e 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 tablef= d, > + struct iommu_group *grp); > +extern void kvm_spapr_tce_release_iommu_group(struct kvm *kvm, > + struct iommu_group *grp); > =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..0f8a5e6528aa 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 +1110,11 @@ enum kvm_device_type { > KVM_DEV_TYPE_MAX, > }; > =20 > +struct kvm_vfio_spapr_tce { > + __s32 groupfd; > + __s32 tablefd; > +}; > + > /* > * ioctls for VM fds > */ > diff --git a/arch/powerpc/kvm/book3s_64_vio.c b/arch/powerpc/kvm/book3s_6= 4_vio.c > index e96a4590464c..22c67a47eaab 100644 > --- a/arch/powerpc/kvm/book3s_64_vio.c > +++ b/arch/powerpc/kvm/book3s_64_vio.c > @@ -28,6 +28,8 @@ > #include > #include > #include > +#include > +#include > =20 > #include > #include > @@ -40,6 +42,7 @@ > #include > #include > #include > +#include > =20 > static unsigned long kvmppc_tce_pages(unsigned long iommu_pages) > { > @@ -91,6 +94,132 @@ 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_tce_table_put(stit->tbl); > + > + kfree(stit); > +} > + > +static void kvm_spapr_tce_liobn_put(struct kref *kref) > +{ > + struct kvmppc_spapr_tce_iommu_table *stit =3D container_of(kref, > + struct kvmppc_spapr_tce_iommu_table, kref); > + > + 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 iommu_group *grp) > +{ > + int i; > + struct kvmppc_spapr_tce_table *stt; > + struct kvmppc_spapr_tce_iommu_table *stit, *tmp; > + struct iommu_table_group *table_group =3D NULL; > + > + list_for_each_entry_rcu(stt, &kvm->arch.spapr_tce_tables, list) { > + > + table_group =3D iommu_group_get_iommudata(grp); > + if (WARN_ON(!table_group)) > + continue; > + > + list_for_each_entry_safe(stit, tmp, &stt->iommu_tables, next) { > + for (i =3D 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) { > + if (table_group->tables[i] !=3D stit->tbl) > + continue; > + > + kref_put(&stit->kref, kvm_spapr_tce_liobn_put); > + return; > + } > + } > + } > +} > + > +extern long kvm_spapr_tce_attach_iommu_group(struct kvm *kvm, int tablef= d, > + struct iommu_group *grp) > +{ > + 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; > + struct kvmppc_spapr_tce_iommu_table *stit; > + struct fd f; > + > + f =3D fdget(tablefd); > + if (!f.file) > + return -EBADF; > + > + 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) > + return -EINVAL; > + > + table_group =3D iommu_group_get_iommudata(grp); > + if (WARN_ON(!table_group)) > + return -EFAULT; > + > + 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)) { > + /* > + * Reference the table to avoid races with > + * add/remove DMA windows. > + */ > + tbl =3D iommu_tce_table_get(tbltmp); > + break; > + } > + } > + if (!tbl) > + return -EINVAL; > + > + list_for_each_entry_rcu(stit, &stt->iommu_tables, next) { > + if (tbl !=3D stit->tbl) > + continue; > + > + if (!kref_get_unless_zero(&stit->kref)) { > + /* stit is being destroyed */ > + iommu_tce_table_put(tbl); > + return -ENOTTY; > + } > + /* > + * The table is already known to this KVM, we just increased > + * its KVM reference counter and can return. > + */ > + return 0; > + } > + > + stit =3D kzalloc(sizeof(*stit), GFP_KERNEL); > + stit->tbl =3D tbl; > + kref_init(&stit->kref); > + > + list_add_rcu(&stit->next, &stt->iommu_tables); > + > + return 0; > +} > + > static void release_spapr_tce_table(struct rcu_head *head) > { > struct kvmppc_spapr_tce_table *stt =3D container_of(head, > @@ -130,9 +259,18 @@ static int kvm_spapr_tce_mmap(struct file *file, str= uct vm_area_struct *vma) > static int kvm_spapr_tce_release(struct inode *inode, struct file *filp) > { > struct kvmppc_spapr_tce_table *stt =3D filp->private_data; > + struct kvmppc_spapr_tce_iommu_table *stit, *tmp; > =20 > list_del_rcu(&stt->list); > =20 > + list_for_each_entry_safe(stit, tmp, &stt->iommu_tables, next) { > + WARN_ON(!kref_read(&stit->kref)); > + while (1) { > + if (kref_put(&stit->kref, kvm_spapr_tce_liobn_put)) > + break; > + } > + } > + > kvm_put_kvm(stt->kvm); > =20 > kvmppc_account_memlimit( > @@ -183,6 +321,7 @@ 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 +350,101 @@ long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm, > return ret; > } > =20 > +static void kvmppc_clear_tce(struct iommu_table *tbl, unsigned long entr= y) > +{ > + 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 +461,35 @@ long kvmppc_h_put_tce(struct kvm_vcpu *vcpu, unsigne= d 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 +504,7 @@ long kvmppc_h_put_tce_indirect(struct kvm_vcpu *vcpu, > 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 +543,26 @@ long kvmppc_h_put_tce_indirect(struct kvm_vcpu *vcpu, > 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 +579,7 @@ 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 +593,24 @@ 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/book3= s_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 lo= ng 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 e= ntry) > +{ > + 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_table = *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, unsi= gned 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 *vc= pu, > 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 *vc= pu, > 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 *v= cpu, > 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, lon= g 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..37d9118fd84b 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; > @@ -89,6 +93,47 @@ static bool kvm_vfio_group_is_coherent(struct vfio_gro= up *vfio_group) > return ret > 0; > } > =20 > +#ifdef CONFIG_SPAPR_TCE_IOMMU > +static int kvm_vfio_external_user_iommu_id(struct vfio_group *vfio_group) > +{ > + int (*fn)(struct vfio_group *); > + int ret =3D -EINVAL; > + > + 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; > +} > + > +static struct iommu_group *kvm_vfio_group_get_iommu_group( > + struct vfio_group *group) > +{ > + int group_id =3D kvm_vfio_external_user_iommu_id(group); > + > + if (group_id < 0) > + return NULL; > + > + return iommu_group_get_by_id(group_id); > +} > + > +static void kvm_spapr_tce_release_vfio_group(struct kvm *kvm, > + struct vfio_group *vfio_group) > +{ > + struct iommu_group *grp =3D kvm_vfio_group_get_iommu_group(vfio_group); > + > + if (WARN_ON_ONCE(!grp)) > + return; > + > + kvm_spapr_tce_release_iommu_group(kvm, grp); > + iommu_group_put(grp); > +} > +#endif > + > /* > * Groups can use the same or different IOMMU domains. If the same then > * adding a new group may change the coherency of groups we've previously > @@ -211,6 +256,9 @@ static int kvm_vfio_set_group(struct kvm_device *dev,= long attr, u64 arg) > =20 > mutex_unlock(&kv->lock); > =20 > +#ifdef CONFIG_SPAPR_TCE_IOMMU > + kvm_spapr_tce_release_vfio_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 +266,57 @@ static int kvm_vfio_set_group(struct kvm_device *dev= , 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; > + struct kvm_vfio *kv =3D dev->private; > + struct vfio_group *vfio_group; > + struct kvm_vfio_group *kvg; > + struct fd f; > + struct iommu_group *grp; > + > + if (copy_from_user(¶m, (void __user *)arg, > + sizeof(struct kvm_vfio_spapr_tce))) > + return -EFAULT; > + > + 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); > + > + grp =3D kvm_vfio_group_get_iommu_group(vfio_group); > + if (WARN_ON_ONCE(!grp)) { > + kvm_vfio_group_put_external_user(vfio_group); > + return -EIO; > + } > + > + 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, grp); > + break; > + } > + > + mutex_unlock(&kv->lock); > + > + iommu_group_put(grp); > + kvm_vfio_group_put_external_user(vfio_group); > + > + return ret; > + } > +#endif /* CONFIG_SPAPR_TCE_IOMMU */ > } > =20 > return -ENXIO; > @@ -242,6 +341,9 @@ 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 +359,9 @@ 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_vfio_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 David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. 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