On Tue, Mar 14, 2017 at 03:05:27PM -0600, Alex Williamson wrote:
> On Fri, 10 Mar 2017 14:53:37 +1100
> Alexey Kardashevskiy <aik@xxxxxxxxx> 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 tables
> > will be mirrored automatically to the hardware and there is no interface
> > 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 mode.
> >
> > 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.
> >
> > 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 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().
> >
> > 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 <aik@xxxxxxxxx>
> > ---
> > 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
> >
> > v7:
> > * added realmode-friendly WARN_ON_ONCE_RM
> >
> > 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 fixed 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(-)
> >
> > 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:
> >
> > 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 tracking
> > + 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:
> >
> > -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;
>
> kvm_vfio_spapr_tce_liobn does not exist. s/_liobn//?
>
> > + @flags are not supported now, must be zero;
>
> 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;
> > };
> >
> > +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];
> > };
> >
> > 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 tablefd,
> > + struct vfio_group *group);
> > +extern void kvm_spapr_tce_release_iommu_group(struct kvm *kvm,
> > + struct vfio_group *group);
> >
> > 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
> >
> > enum kvm_device_type {
> > KVM_DEV_TYPE_FSL_MPIC_20 = 1,
> > @@ -1109,6 +1110,13 @@ enum kvm_device_type {
> > KVM_DEV_TYPE_MAX,
> > };
> >
> > +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 <linux/hugetlb.h>
> > #include <linux/list.h>
> > #include <linux/anon_inodes.h>
> > +#include <linux/iommu.h>
> > +#include <linux/file.h>
> > +#include <linux/vfio.h>
> > +#include <linux/module.h>
> >
> > #include <asm/tlbflush.h>
> > #include <asm/kvm_ppc.h>
> > @@ -40,6 +44,36 @@
> > #include <asm/udbg.h>
> > #include <asm/iommu.h>
> > #include <asm/tce.h>
> > +#include <asm/mmu_context.h>
> > +
> > +static void kvm_vfio_group_put_external_user(struct vfio_group *vfio_group)
> > +{
> > + void (*fn)(struct vfio_group *);
> > +
> > + fn = 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_group)
> > +{
> > + int (*fn)(struct vfio_group *);
> > + int ret = -1;
> > +
> > + fn = symbol_get(vfio_external_user_iommu_id);
> > + if (!fn)
> > + return ret;
> > +
> > + ret = fn(vfio_group);
> > +
> > + symbol_put(vfio_external_user_iommu_id);
> > +
> > + return ret;
> > +}
>
>
> 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.
>
> >
> > 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;
> > }
> >
> > +static void kvm_spapr_tce_iommu_table_free(struct rcu_head *head)
> > +{
> > + struct kvmppc_spapr_tce_iommu_table *stit = 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 != 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 tablefd,
> > + struct vfio_group *group)
> > +{
> > + struct kvmppc_spapr_tce_table *stt = NULL;
> > + bool found = false;
> > + struct iommu_table *tbl = NULL;
> > + struct iommu_table_group *table_group;
> > + long i, ret = 0;
> > + struct kvmppc_spapr_tce_iommu_table *stit;
> > + struct fd f;
> > + int group_id;
> > + struct iommu_group *grp;
> > +
> > + group_id = kvm_vfio_external_user_iommu_id(group);
> > + grp = iommu_group_get_by_id(group_id);
> > + if (WARN_ON(!grp))
> > + return -EIO;
> > +
> > + f = fdget(tablefd);
> > + if (!f.file) {
> > + ret = -EBADF;
> > + goto put_exit;
> > + }
> > +
> > + list_for_each_entry_rcu(stt, &kvm->arch.spapr_tce_tables, list) {
> > + if (stt == f.file->private_data) {
> > + found = true;
> > + break;
> > + }
> > + }
> > +
> > + fdput(f);
> > +
> > + if (!found) {
> > + ret = -EINVAL;
> > + goto put_exit;
> > + }
> > +
> > + table_group = iommu_group_get_iommudata(grp);
> > + if (WARN_ON(!table_group)) {
> > + ret = -EFAULT;
> > + goto put_exit;
> > + }
> > +
> > + for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
> > + struct iommu_table *tbltmp = 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 == stt->page_shift) &&
> > + (tbltmp->it_offset == stt->offset) &&
> > + (tbltmp->it_size == stt->size)) {
> > + tbl = tbltmp;
> > + break;
> > + }
> > + }
> > + if (!tbl) {
> > + ret = -EINVAL;
> > + goto put_exit;
> > + }
> > +
> > + list_for_each_entry_rcu(stit, &stt->iommu_tables, next) {
> > + if ((stit->tbl == tbl) && (stit->group == group)) {
> > + ret = -EBUSY;
> > + goto put_exit;
> > + }
> > + }
> > +
> > + iommu_table_get(tbl);
> > +
> > + stit = kzalloc(sizeof(*stit), GFP_KERNEL);
> > + stit->tbl = tbl;
> > + stit->group = 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 = container_of(head,
> > @@ -133,6 +291,8 @@ static int kvm_spapr_tce_release(struct inode *inode, struct file *filp)
> >
> > list_del_rcu(&stt->list);
> >
> > + kvm_spapr_tce_liobn_release_iommu_group(stt, NULL /* release all */);
> > +
> > kvm_put_kvm(stt->kvm);
> >
> > kvmppc_account_memlimit(
> > @@ -183,6 +343,7 @@ long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm,
> > stt->offset = args->offset;
> > stt->size = size;
> > stt->kvm = kvm;
> > + INIT_LIST_HEAD_RCU(&stt->iommu_tables);
> >
> > for (i = 0; i < npages; i++) {
> > stt->pages[i] = alloc_page(GFP_KERNEL | __GFP_ZERO);
> > @@ -211,11 +372,101 @@ long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm,
> > return ret;
> > }
> >
> > +static void kvmppc_clear_tce(struct iommu_table *tbl, unsigned long entry)
> > +{
> > + unsigned long hpa = 0;
> > + enum dma_data_direction dir = 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 = NULL;
> > + const unsigned long pgsize = 1ULL << tbl->it_page_shift;
> > + unsigned long *pua = IOMMU_TABLE_USERSPACE_ENTRY(tbl, entry);
> > +
> > + if (!pua)
> > + /* it_userspace allocation might be delayed */
> > + return H_TOO_HARD;
> > +
> > + mem = mm_iommu_lookup(kvm->mm, *pua, pgsize);
> > + if (!mem)
> > + return H_TOO_HARD;
> > +
> > + mm_iommu_mapped_dec(mem);
> > +
> > + *pua = 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 = DMA_NONE;
> > + unsigned long hpa = 0;
> > + long ret;
> > +
> > + if (WARN_ON_ONCE(iommu_tce_xchg(tbl, entry, &hpa, &dir)))
> > + return H_HARDWARE;
> > +
> > + if (dir == DMA_NONE)
> > + return H_SUCCESS;
> > +
> > + ret = kvmppc_tce_iommu_mapped_dec(kvm, tbl, entry);
> > + if (ret != 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 = 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 = 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 = iommu_tce_xchg(tbl, entry, &hpa, &dir);
> > + if (WARN_ON_ONCE(ret)) {
> > + mm_iommu_mapped_dec(mem);
> > + return H_HARDWARE;
> > + }
> > +
> > + if (dir != DMA_NONE)
> > + kvmppc_tce_iommu_mapped_dec(kvm, tbl, entry);
> > +
> > + *pua = 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 = 0;
> > + enum dma_data_direction dir;
> >
> > /* udbg_printf("H_PUT_TCE(): liobn=0x%lx ioba=0x%lx, tce=0x%lx\n", */
> > /* liobn, ioba, tce); */
> > @@ -232,7 +483,35 @@ long kvmppc_h_put_tce(struct kvm_vcpu *vcpu, unsigned long liobn,
> > if (ret != H_SUCCESS)
> > return ret;
> >
> > - kvmppc_tce_put(stt, ioba >> stt->page_shift, tce);
> > + dir = iommu_tce_direction(tce);
> > + if ((dir != DMA_NONE) && kvmppc_gpa_to_ua(vcpu->kvm,
> > + tce & ~(TCE_PCI_READ | TCE_PCI_WRITE), &ua, NULL))
> > + return H_PARAMETER;
> > +
> > + entry = ioba >> stt->page_shift;
> > +
> > + list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
> > + if (dir == DMA_NONE) {
> > + ret = kvmppc_tce_iommu_unmap(vcpu->kvm,
> > + stit->tbl, entry);
> > + } else {
> > + idx = srcu_read_lock(&vcpu->kvm->srcu);
> > + ret = kvmppc_tce_iommu_map(vcpu->kvm, stit->tbl,
> > + entry, ua, dir);
> > + srcu_read_unlock(&vcpu->kvm->srcu, idx);
> > + }
> > +
> > + if (ret == H_SUCCESS)
> > + continue;
> > +
> > + if (ret == H_TOO_HARD)
> > + return ret;
> > +
> > + WARN_ON_ONCE(1);
> > + kvmppc_clear_tce(stit->tbl, entry);
> > + }
> > +
> > + kvmppc_tce_put(stt, entry, tce);
> >
> > return H_SUCCESS;
> > }
> > @@ -247,6 +526,7 @@ long kvmppc_h_put_tce_indirect(struct kvm_vcpu *vcpu,
> > unsigned long entry, ua = 0;
> > u64 __user *tces;
> > u64 tce;
> > + struct kvmppc_spapr_tce_iommu_table *stit;
> >
> > stt = kvmppc_find_table(vcpu->kvm, liobn);
> > if (!stt)
> > @@ -285,6 +565,26 @@ long kvmppc_h_put_tce_indirect(struct kvm_vcpu *vcpu,
> > if (ret != H_SUCCESS)
> > goto unlock_exit;
> >
> > + 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 = kvmppc_tce_iommu_map(vcpu->kvm,
> > + stit->tbl, entry + i, ua,
> > + iommu_tce_direction(tce));
> > +
> > + if (ret == H_SUCCESS)
> > + continue;
> > +
> > + if (ret == H_TOO_HARD)
> > + goto unlock_exit;
> > +
> > + WARN_ON_ONCE(1);
> > + kvmppc_clear_tce(stit->tbl, entry);
> > + }
> > +
> > kvmppc_tce_put(stt, entry + i, tce);
> > }
> >
> > @@ -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;
> >
> > stt = 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;
> >
> > + list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
> > + unsigned long entry = ioba >> stit->tbl->it_page_shift;
> > +
> > + for (i = 0; i < npages; ++i) {
> > + ret = kvmppc_tce_iommu_unmap(vcpu->kvm,
> > + stit->tbl, entry + i);
> > +
> > + if (ret == H_SUCCESS)
> > + continue;
> > +
> > + if (ret == H_TOO_HARD)
> > + return ret;
> > +
> > + WARN_ON_ONCE(1);
> > + kvmppc_clear_tce(stit->tbl, entry);
> > + }
> > + }
> > +
> > for (i = 0; i < npages; ++i, ioba += (1ULL << stt->page_shift))
> > kvmppc_tce_put(stt, ioba >> stt->page_shift, tce_value);
> >
> > diff --git a/arch/powerpc/kvm/book3s_64_vio_hv.c b/arch/powerpc/kvm/book3s_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 <asm/iommu.h>
> > #include <asm/tce.h>
> >
> > +#ifdef CONFIG_BUG
> > +
> > +#define WARN_ON_ONCE_RM(condition) ({ \
> > + static bool __section(.data.unlikely) __warned; \
> > + int __ret_warn_once = !!(condition); \
> > + \
> > + if (unlikely(__ret_warn_once && !__warned)) { \
> > + __warned = 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 = !!(condition); \
> > + unlikely(__ret_warn_on); \
> > +})
> > +
> > +#endif
> > +
> > #define TCES_PER_PAGE (PAGE_SIZE / sizeof(u64))
> >
> > /*
> > @@ -161,11 +186,117 @@ long kvmppc_gpa_to_ua(struct kvm *kvm, unsigned long gpa,
> > EXPORT_SYMBOL_GPL(kvmppc_gpa_to_ua);
> >
> > #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
> > +static void kvmppc_rm_clear_tce(struct iommu_table *tbl, unsigned long entry)
> > +{
> > + unsigned long hpa = 0;
> > + enum dma_data_direction dir = 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 = NULL;
> > + const unsigned long pgsize = 1ULL << tbl->it_page_shift;
> > + unsigned long *pua = IOMMU_TABLE_USERSPACE_ENTRY(tbl, entry);
> > +
> > + if (!pua)
> > + /* it_userspace allocation might be delayed */
> > + return H_TOO_HARD;
> > +
> > + pua = (void *) vmalloc_to_phys(pua);
> > + if (WARN_ON_ONCE_RM(!pua))
> > + return H_HARDWARE;
> > +
> > + mem = mm_iommu_lookup_rm(kvm->mm, *pua, pgsize);
> > + if (!mem)
> > + return H_TOO_HARD;
> > +
> > + mm_iommu_mapped_dec(mem);
> > +
> > + *pua = 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 = DMA_NONE;
> > + unsigned long hpa = 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 == DMA_NONE)
> > + return H_SUCCESS;
> > +
> > + ret = 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 = 0;
> > + unsigned long *pua = 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 = 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 = (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 = 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 != DMA_NONE)
> > + kvmppc_rm_tce_iommu_mapped_dec(kvm, tbl, entry);
> > +
> > + *pua = 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 = 0;
> > + enum dma_data_direction dir;
> >
> > /* udbg_printf("H_PUT_TCE(): liobn=0x%lx ioba=0x%lx, tce=0x%lx\n", */
> > /* liobn, ioba, tce); */
> > @@ -182,7 +313,32 @@ long kvmppc_rm_h_put_tce(struct kvm_vcpu *vcpu, unsigned long liobn,
> > if (ret != H_SUCCESS)
> > return ret;
> >
> > - kvmppc_tce_put(stt, ioba >> stt->page_shift, tce);
> > + dir = iommu_tce_direction(tce);
> > + if ((dir != DMA_NONE) && kvmppc_gpa_to_ua(vcpu->kvm,
> > + tce & ~(TCE_PCI_READ | TCE_PCI_WRITE), &ua, NULL))
> > + return H_PARAMETER;
> > +
> > + entry = ioba >> stt->page_shift;
> > +
> > + list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
> > + if (dir == DMA_NONE)
> > + ret = kvmppc_rm_tce_iommu_unmap(vcpu->kvm,
> > + stit->tbl, entry);
> > + else
> > + ret = kvmppc_rm_tce_iommu_map(vcpu->kvm,
> > + stit->tbl, entry, ua, dir);
> > +
> > + if (ret == H_SUCCESS)
> > + continue;
> > +
> > + if (ret == H_TOO_HARD)
> > + return ret;
> > +
> > + WARN_ON_ONCE_RM(1);
> > + kvmppc_rm_clear_tce(stit->tbl, entry);
> > + }
> > +
> > + kvmppc_tce_put(stt, entry, tce);
> >
> > return H_SUCCESS;
> > }
> > @@ -223,6 +379,7 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu,
> > unsigned long tces, entry, ua = 0;
> > unsigned long *rmap = NULL;
> > bool prereg = false;
> > + struct kvmppc_spapr_tce_iommu_table *stit;
> >
> > stt = 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;
> >
> > rmap = (void *) vmalloc_to_phys(rmap);
> > + if (WARN_ON_ONCE_RM(!rmap))
> > + return H_HARDWARE;
> >
> > /*
> > * Synchronize with the MMU notifier callbacks in
> > @@ -293,6 +452,27 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu,
> > if (ret != H_SUCCESS)
> > goto unlock_exit;
> >
> > + ua = 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 = kvmppc_rm_tce_iommu_map(vcpu->kvm,
> > + stit->tbl, entry + i, ua,
> > + iommu_tce_direction(tce));
> > +
> > + if (ret == H_SUCCESS)
> > + continue;
> > +
> > + if (ret == 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);
> > }
> >
> > @@ -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;
> >
> > stt = 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;
> >
> > + list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
> > + unsigned long entry = ioba >> stit->tbl->it_page_shift;
> > +
> > + for (i = 0; i < npages; ++i) {
> > + ret = kvmppc_rm_tce_iommu_unmap(vcpu->kvm,
> > + stit->tbl, entry + i);
> > +
> > + if (ret == H_SUCCESS)
> > + continue;
> > +
> > + if (ret == H_TOO_HARD)
> > + return ret;
> > +
> > + WARN_ON_ONCE_RM(1);
> > + kvmppc_rm_clear_tce(stit->tbl, entry);
> > + }
> > + }
> > +
> > for (i = 0; i < npages; ++i, ioba += (1ULL << stt->page_shift))
> > kvmppc_tce_put(stt, ioba >> stt->page_shift, tce_value);
> >
> > 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, 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 <linux/vfio.h>
> > #include "vfio.h"
> >
> > +#ifdef CONFIG_SPAPR_TCE_IOMMU
> > +#include <asm/kvm_ppc.h>
> > +#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 *dev, long attr, u64 arg)
> >
> > mutex_unlock(&kv->lock);
> >
> > +#ifdef CONFIG_SPAPR_TCE_IOMMU
> > + kvm_spapr_tce_release_iommu_group(dev->kvm, vfio_group);
> > +#endif
> > kvm_vfio_group_set_kvm(vfio_group, NULL);
> >
> > 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);
> >
> > 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 = dev->private;
> > + struct vfio_group *vfio_group;
> > + struct kvm_vfio_group *kvg;
> > + struct fd f;
> > +
> > + minsz = 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 = fdget(param.groupfd);
> > + if (!f.file)
> > + return -EBADF;
> > +
> > + vfio_group = kvm_vfio_group_get_external_user(f.file);
> > + fdput(f);
> > +
> > + if (IS_ERR(vfio_group))
> > + return PTR_ERR(vfio_group);
> > +
> > + ret = -ENOENT;
> > +
> > + mutex_lock(&kv->lock);
> > +
> > + list_for_each_entry(kvg, &kv->group_list, node) {
> > + if (kvg->vfio_group != vfio_group)
> > + continue;
> > +
> > + ret = kvm_spapr_tce_attach_iommu_group(dev->kvm,
> > + param.tablefd, vfio_group);
> > +
> > + break;
> > + }
> > +
> > + mutex_unlock(&kv->lock);
> > +
> > + return ret;
> > + }
> > +#endif /* CONFIG_SPAPR_TCE_IOMMU */
>
>
> 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
> kvm_vfio_group_put_external_user(). Thanks,
>
> Alex
>
> > }
> >
> > 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;
> > }
> >
> > @@ -257,6 +314,9 @@ static void kvm_vfio_destroy(struct kvm_device *dev)
> > struct kvm_vfio_group *kvg, *tmp;
> >
> > 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);
>
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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