From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Gibson Subject: Re: [PATCH kernel v6 10/10] KVM: PPC: VFIO: Add in-kernel acceleration for VFIO Date: Mon, 6 Mar 2017 15:30:55 +1100 Message-ID: <20170306043055.GI12030@umbus.fritz.box> References: <20170302085644.41828-1-aik@ozlabs.ru> <20170302085644.41828-11-aik@ozlabs.ru> <20170303055927.GJ667@umbus.fritz.box> <56d7983d-50ff-36e8-c55b-4a6316fc26b6@ozlabs.ru> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="MFZs98Tklfu0WsCO" Cc: Paul Mackerras , Alex Williamson , linuxppc-dev@lists.ozlabs.org, kvm@vger.kernel.org, kvm-ppc@vger.kernel.org To: Alexey Kardashevskiy Return-path: Content-Disposition: inline In-Reply-To: <56d7983d-50ff-36e8-c55b-4a6316fc26b6@ozlabs.ru> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linuxppc-dev-bounces+glppe-linuxppc-embedded-2=m.gmane.org@lists.ozlabs.org Sender: "Linuxppc-dev" List-Id: kvm.vger.kernel.org --MFZs98Tklfu0WsCO Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Mar 03, 2017 at 06:09:25PM +1100, Alexey Kardashevskiy wrote: > On 03/03/17 16:59, David Gibson wrote: > > On Thu, Mar 02, 2017 at 07:56:44PM +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. > >> > >> 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. > >> > >> 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. > >> > >> 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 tab= les > >> will be mirrored automatically to the hardware and there is no interfa= ce > >> to report to the guest about possible failures. > >> > >> 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 m= ode. > >> > >> This does not implement the UNSET counterpart as there is no use for i= t - > >> 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. > >> > >> 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). > >> > >> This advertises the new KVM_CAP_SPAPR_TCE_VFIO capability to the user > >> space. > >> > >> This finally makes use of vfio_external_user_iommu_id() which was > >> introduced quite some time ago and was considered for removal. > >> > >> Tests show that this patch increases transmission speed from 220MB/s > >> to 750..1020MB/s on 10Gb network (Chelsea CXGB3 10Gb ethernet card). > >> > >> Signed-off-by: Alexey Kardashevskiy > >> --- > >> Changes: > >> v6: > >> * changed handling of errors returned by kvmppc_(rm_)tce_iommu_(un)map= () > >> * moved kvmppc_gpa_to_ua() to TCE validation > >> > >> 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 > >> > >> 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); > >> > >> v3: > >> * simplified not to use VFIO group notifiers > >> * reworked cleanup, should be cleaner/simpler now > >> > >> v2: > >> * reworked to use new VFIO notifiers > >> * now same iommu_table may appear in the list several times, to be fix= ed 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 | 321 ++++++++++++++++++++= ++++++++- > >> arch/powerpc/kvm/book3s_64_vio_hv.c | 165 ++++++++++++++- > >> arch/powerpc/kvm/powerpc.c | 2 + > >> virt/kvm/vfio.c | 60 ++++++ > >> 8 files changed, 585 insertions(+), 5 deletions(-) > >> > >> diff --git a/Documentation/virtual/kvm/devices/vfio.txt b/Documentatio= n/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 tr= acking > >> + 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; > >> + @flags are not supported now, must be zero; > >> + @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/includ= e/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 tab= lefd, > >> + 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/book3= s_64_vio.c > >> index 57dd036bd998..85927f467811 100644 > >> --- a/arch/powerpc/kvm/book3s_64_vio.c > >> +++ b/arch/powerpc/kvm/book3s_64_vio.c > >> @@ -27,6 +27,10 @@ > >> #include > >> #include > >> #include > >> +#include > >> +#include > >> +#include > >> +#include > >> =20 > >> #include > >> #include > >> @@ -39,6 +43,36 @@ > >> #include > >> #include > >> #include > >> +#include > >> + > >> +static void kvm_vfio_group_put_external_user(struct vfio_group *vfio_= group) > >> +{ > >> + 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_gr= oup) > >> +{ > >> + 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 > >> static unsigned long kvmppc_tce_pages(unsigned long iommu_pages) > >> { > >> @@ -90,6 +124,130 @@ 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 tab= lefd, > >> + 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, > >> @@ -132,6 +290,8 @@ static int kvm_spapr_tce_release(struct inode *ino= de, 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( > >> @@ -182,6 +342,7 @@ 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); > >> @@ -210,11 +371,99 @@ 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 e= ntry) > >> +{ > >> + 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 (WARN_ON_ONCE(!pua)) > >> + return H_HARDWARE; > >> + > >> + 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 (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) > >> + return H_TOO_HARD; > >=20 > > IIUC this is the virtual mode path, not the real mode patch. Under > > what circumstances could qemu succeed that KVM virtual mode couldn't, > > for either of the above failures? >=20 > The (!pua) failure is handled in tce_iommu_build_v2() from > drivers/vfio/vfio_iommu_spapr_tce.c as: >=20 >=20 > if (!tbl->it_userspace) { > ret =3D tce_iommu_userspace_view_alloc(tbl, container->mm); > if (ret) > return ret; > } Ah.. which is called from the ioctl() path but not the KVM hcall path, ok, I get it. > The (!mem) can succeed if the container is in VFIO_SPAPR_TCE_IOMMU mode > (not VFIO_SPAPR_TCE_v2_IOMMU). Remember that the userspace can call > ioctl(vfio_kvm_device, KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE) without having > memory preregistered so tables will appear in the > kvmppc_spapr_tce_iommu_table list in KVM. Ok. So in short, the userspace->ioctl() path will handle both v1 and v2 versions of the IOMMU interface, whereas the in-kernel implementation (both real and virtual) will only handle v2. Is that right? > >> + > >> + 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 (ret) { > >=20 > > It thought the xchg could basically never fail, so this should be > > another WARN_ON(). >=20 >=20 > Correct. >=20 >=20 > >> + mm_iommu_mapped_dec(mem); > >> + return H_TOO_HARD; > >> + } > >> + > >> + 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); */ > >> @@ -231,7 +480,35 @@ long kvmppc_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_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; > >> } > >> @@ -246,6 +523,7 @@ long kvmppc_h_put_tce_indirect(struct kvm_vcpu *vc= pu, > >> 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) > >> @@ -284,6 +562,26 @@ long kvmppc_h_put_tce_indirect(struct kvm_vcpu *v= cpu, > >> 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 > >> @@ -300,6 +598,7 @@ 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) > >> @@ -313,6 +612,24 @@ 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/bo= ok3s_64_vio_hv.c > >> index 440d3ab5dc32..3ad06badc552 100644 > >> --- a/arch/powerpc/kvm/book3s_64_vio_hv.c > >> +++ b/arch/powerpc/kvm/book3s_64_vio_hv.c > >> @@ -161,11 +161,108 @@ 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 lon= g 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 (WARN_ON_ONCE(!pua)) > >> + return H_HARDWARE; > >=20 > > So.. I know I encouraged WARN_ON()s, but is it safe to call WARN_ON() > > from real mode? >=20 > Ouch. Tried WARN_ON_ONCE(1) in kvmppc_rm_h_stuff_tce() and got "rcu_sched > detected stalls" straight away. Bother. Sorry I didn't think of that earlier. > What do I replace it with, in documenting purposes? >=20 > - if (WARN_ON_ONCE(!pua)) > + if (!pua) /* Not expected to fail */ So, I'd suggest adding a WARN_ON_RM() or whatever macro to wrap this at least. As you may have seen I discussed this with mpe on IRC and printk() should work, so you could just put a printk() and dump_stack() in there. > >> + > >> + pua =3D (void *) vmalloc_to_phys(pua); > >> + if (!pua) > >> + return H_TOO_HARD; > >> + > >> + 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)) > >> + return H_HARDWARE; > >> + > >> + 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_tab= le *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(mm_iommu_ua_to_hpa_rm(mem, ua, &hpa))) > >> + return H_HARDWARE; > >> + > >> + pua =3D (void *) vmalloc_to_phys(pua); > >> + if (WARN_ON_ONCE(!pua)) > >> + return H_HARDWARE; > >> + > >> + if (WARN_ON_ONCE(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); > >> + 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 +279,32 @@ long kvmppc_rm_h_put_tce(struct kvm_vcpu *vcpu, u= nsigned 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(1); > >> + kvmppc_rm_clear_tce(stit->tbl, entry); > >> + } > >> + > >> + kvmppc_tce_put(stt, entry, tce); > >> =20 > >> return H_SUCCESS; > >> } > >> @@ -223,6 +345,7 @@ 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) > >> @@ -293,6 +416,27 @@ 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(1); > >> + kvmppc_rm_clear_tce(stit->tbl, entry); > >> + } > >> + > >> kvmppc_tce_put(stt, entry + i, tce); > >> } > >> =20 > >> @@ -309,6 +453,7 @@ 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 +467,24 @@ 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(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 2b38d824e9e5..2bb01c8236fa 100644 > >> --- a/arch/powerpc/kvm/powerpc.c > >> +++ b/arch/powerpc/kvm/powerpc.c > >> @@ -537,6 +537,8 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, = long 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 *d= ev, 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 *= 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; > >> + 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 > >> return -ENXIO; > >> @@ -242,6 +296,9 @@ static int kvm_vfio_has_attr(struct kvm_device *de= v, > >> 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 *de= v) > >> 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 >=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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