On 13/01/17 10:53, David Gibson wrote:
> On Thu, Jan 12, 2017 at 07:09:01PM +1100, Alexey Kardashevskiy wrote:
>> On 12/01/17 16:04, David Gibson wrote:
>>> On Tue, Dec 20, 2016 at 05:52:29PM +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.
>>>>
>>>> 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, this is done to simplify the cleanup and can be
>>>> improved later.
>>>>
>>>> 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 <aik@xxxxxxxxx>
>>>> ---
>>>> Changes:
>>>> 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
>>>> ---
>>>>
>>>> This obsoletes:
>>>>
>>>> [PATCH kernel v2 08/11] KVM: PPC: Pass kvm* to kvmppc_find_table()
>>>> [PATCH kernel v2 09/11] vfio iommu: Add helpers to (un)register blocking notifiers per group
>>>> [PATCH kernel v2 11/11] KVM: PPC: Add in-kernel acceleration for VFIO
>>>>
>>>>
>>>> So I have not reposted the whole thing, should have I?
>>>>
>>>>
>>>> btw "F: virt/kvm/vfio.*" is missing MAINTAINERS.
>>>>
>>>>
>>>> ---
>>>> 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 | 286 +++++++++++++++++++++++++++++
>>>> arch/powerpc/kvm/book3s_64_vio_hv.c | 178 ++++++++++++++++++
>>>> arch/powerpc/kvm/powerpc.c | 2 +
>>>> virt/kvm/vfio.c | 88 +++++++++
>>>> 8 files changed, 594 insertions(+), 2 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;
>>>> + @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/include/asm/kvm_host.h
>>>> index 28350a294b1e..3d281b7ea369 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 0a21c8503974..936138b866e7 100644
>>>> --- a/arch/powerpc/include/asm/kvm_ppc.h
>>>> +++ b/arch/powerpc/include/asm/kvm_ppc.h
>>>> @@ -163,6 +163,10 @@ 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, struct iommu_group *grp);
>>>> +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 810f74317987..4088da4a575f 100644
>>>> --- a/include/uapi/linux/kvm.h
>>>> +++ b/include/uapi/linux/kvm.h
>>>> @@ -1068,6 +1068,7 @@ 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,
>>>> @@ -1089,6 +1090,13 @@ 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 15df8ae627d9..008c4aee4df6 100644
>>>> --- a/arch/powerpc/kvm/book3s_64_vio.c
>>>> +++ b/arch/powerpc/kvm/book3s_64_vio.c
>>>> @@ -27,6 +27,10 @@
>>>> #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>
>>>> @@ -39,6 +43,20 @@
>>>> #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 (!fn)
>>>
>>> I think this should have a WARN_ON(). If the vfio module is gone
>>> while you still have VFIO groups attached to a KVM table, something
>>> has gone horribly wrong.
>>>
>>>> + return;
>>>> +
>>>> + fn(vfio_group);
>>>> +
>>>> + symbol_put(vfio_group_put_external_user);
>>>> +}
>>>>
>>>> static unsigned long kvmppc_tce_pages(unsigned long iommu_pages)
>>>> {
>>>> @@ -90,6 +108,99 @@ 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);
>>>> +
>>>> + 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);
>>>> +
>>>> + iommu_table_put(stit->tbl);
>>>> + kvm_vfio_group_put_external_user(stit->group);
>>>> +
>>>> + 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 iommu_group *grp)
>>>
>>> Isn't passing both the vfio_group and the iommu_group redundant?
>>
>> vfio_group struct is internal to the vfio driver and there is no API to get
>> the iommu_group pointer from it.
>
> But in the caller you *do* derive the group from the vfio group by
> going via id (ugly, but workable I guess). Why not fold that logic
> into this function.
I could, either way looks equally ugly-ish to me, rework it?
>>>> +{
>>>> + struct kvmppc_spapr_tce_table *stt = NULL;
>>>> + bool found = false;
>>>> + struct iommu_table *tbl = NULL;
>>>> + struct iommu_table_group *table_group;
>>>> + long i;
>>>> + struct kvmppc_spapr_tce_iommu_table *stit;
>>>> + struct fd f;
>>>> +
>>>> + f = fdget(tablefd);
>>>> + if (!f.file)
>>>> + return -EBADF;
>>>> +
>>>> + 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)
>>>> + return -ENODEV;
>>>
>>> Not entirely sure if ENODEV is the right error, but I can't
>>> immediately think of a better one.
btw I still do not have a better candidate, can I keep this as is?
>>>
>>>> + table_group = iommu_group_get_iommudata(grp);
>>>> + if (!table_group)
>>>> + return -EFAULT;
>>>
>>> EFAULT is usually only returned when you pass a syscall a bad pointer,
>>> which doesn't look to be the case here. What situation does this
>>> error path actually represent?
>>
>>
>> "something went terribly wrong".
>
> In that case there should be a WARN_ON(). As long as it's something
> terribly wrong that can't be the user's fault.
>
>>>> +
>>>> + for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
>>>> + struct iommu_table *tbltmp = table_group->tables[i];
>>>> +
>>>> + if (!tbltmp)
>>>> + continue;
>>>> +
>>>> + if ((tbltmp->it_page_shift == stt->page_shift) &&
>>>> + (tbltmp->it_offset == stt->offset)) {
>>>> + tbl = tbltmp;
>>>> + break;
>>>> + }
>>>> + }
>>>> + if (!tbl)
>>>> + return -ENODEV;
>>>> +
>>>> + iommu_table_get(tbl);
>>>> +
>>>> + stit = kzalloc(sizeof(*stit), GFP_KERNEL);
>>>> + stit->tbl = tbl;
>>>> + stit->group = group;
>>>> +
>>>> + list_add_rcu(&stit->next, &stt->iommu_tables);
>>>
>>> Won't this add a separate stit entry for each group attached to the
>>> LIOBN, even if those groups share a single hardware iommu table -
>>> which is the likely case if those groups have all been put into the
>>> same container.
>>
>>
>> Correct. I am planning on optimizing this later.
>
> Hmm, ok.
>
>>>> + return 0;
>>>> +}
>>>> +
>>>> static void release_spapr_tce_table(struct rcu_head *head)
>>>> {
>>>> struct kvmppc_spapr_tce_table *stt = container_of(head,
>>>> @@ -132,6 +243,8 @@ 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(
>>>> @@ -181,6 +294,7 @@ 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);
>>>> @@ -209,11 +323,161 @@ long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm,
>>>> return ret;
>>>> }
>>>>
>>>> +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)
>>>> + return H_HARDWARE;
>>>> +
>>>> + mem = mm_iommu_lookup(kvm->mm, *pua, pgsize);
>>>> + if (!mem)
>>>> + return H_HARDWARE;
>>>
>>> IIUC, this error represents trying to unmap a page from the vIOMMU,
>>> and discovering that it wasn't preregistered in the first place, which
>>> shouldn't happen. So would a WARN_ON() make sense here as well as the
>>> H_HARDWARE.
>>>
>>>> + 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;
>>>> +
>>>> + if (iommu_tce_xchg(tbl, entry, &hpa, &dir))
>>>> + return H_HARDWARE;
>>>> +
>>>> + if (dir == DMA_NONE)
>>>> + return H_SUCCESS;
>>>> +
>>>> + return kvmppc_tce_iommu_mapped_dec(kvm, tbl, entry);
>>>> +}
>>>> +
>>>> +long kvmppc_tce_iommu_map(struct kvm *kvm, struct iommu_table *tbl,
>>>> + unsigned long entry, unsigned long gpa,
>>>> + enum dma_data_direction dir)
>>>> +{
>>>> + long ret;
>>>> + unsigned long hpa, ua, *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;
>>>> +
>>>> + if (kvmppc_gpa_to_ua(kvm, gpa, &ua, NULL))
>>>> + return H_HARDWARE;
>>>
>>> This would represent the guest trying to map a mad GPA, yes? In which
>>> case H_HARDWARE doesn't seem right. H_PARAMETER or H_PERMISSION, maybe.
>>>
>>>> + mem = mm_iommu_lookup(kvm->mm, ua, 1ULL << tbl->it_page_shift);
>>>> + if (!mem)
>>>> + return H_HARDWARE;
>>>
>>> Here H_HARDWARE seems right. IIUC this represents the guest trying to
>>> map an address which wasn't pre-registered. That would indicate a bug
>>> in qemu, which is hardware as far as the guest is concerned.
>>>
>>>> +
>>>> + if (mm_iommu_ua_to_hpa(mem, ua, &hpa))
>>>> + return H_HARDWARE;
>>>
>>> Not sure what this case represents.
>>
>> Preregistered memory not being able to translate userspace address to a
>> host physical. In virtual mode it is a simple bounds checker, in real mode
>> it also includes vmalloc_to_phys() failure.
>
> Ok. This caller is virtual mode only, isn't it? If we fail the
> bounds check, that sounds like a WARN_ON() + H_HARDWARE, since it
> means we've translated the GPA to an insane UA.
>
> If the translation just fails, that sounds like an H_TOO_HARD.
>
>>>> + if (mm_iommu_mapped_inc(mem))
>>>> + return H_HARDWARE;
>>>
>>> Or this.
>>
>> A preregistered memory area is in a process of disposal, no new mappings
>> are allowed.
>
> Ok, again under control of qemu, so H_HARDWARE is reasonable.
>
>>>> + ret = iommu_tce_xchg(tbl, entry, &hpa, &dir);
>>>> + if (ret) {
>>>> + mm_iommu_mapped_dec(mem);
>>>> + return H_TOO_HARD;
>>>> + }
>>>> +
>>>> + if (dir != DMA_NONE)
>>>> + kvmppc_tce_iommu_mapped_dec(kvm, tbl, entry);
>>>> +
>>>> + *pua = ua;
>>>> +
>>>> + return 0;
>>>> +}
>>>> +
>>>> +long kvmppc_h_put_tce_iommu(struct kvm_vcpu *vcpu,
>>>> + struct iommu_table *tbl,
>>>> + unsigned long liobn, unsigned long ioba,
>>>> + unsigned long tce)
>>>> +{
>>>> + long idx, ret = H_HARDWARE;
>>>> + const unsigned long entry = ioba >> tbl->it_page_shift;
>>>> + const unsigned long gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
>>>> + const enum dma_data_direction dir = iommu_tce_direction(tce);
>>>> +
>>>> + /* Clear TCE */
>>>> + if (dir == DMA_NONE) {
>>>> + if (iommu_tce_clear_param_check(tbl, ioba, 0, 1))
>>>> + return H_PARAMETER;
>>>> +
>>>> + return kvmppc_tce_iommu_unmap(vcpu->kvm, tbl, entry);
>>>> + }
>>>> +
>>>> + /* Put TCE */
>>>> + if (iommu_tce_put_param_check(tbl, ioba, gpa))
>>>> + return H_PARAMETER;
>>>> +
>>>> + idx = srcu_read_lock(&vcpu->kvm->srcu);
>>>> + ret = kvmppc_tce_iommu_map(vcpu->kvm, tbl, entry, gpa, dir);
>>>> + srcu_read_unlock(&vcpu->kvm->srcu, idx);
>>>> +
>>>> + return ret;
>>>> +}
>>>> +
>>>> +static long kvmppc_h_put_tce_indirect_iommu(struct kvm_vcpu *vcpu,
>>>> + struct iommu_table *tbl, unsigned long ioba,
>>>> + u64 __user *tces, unsigned long npages)
>>>> +{
>>>> + unsigned long i, ret, tce, gpa;
>>>> + const unsigned long entry = ioba >> tbl->it_page_shift;
>>>> +
>>>> + for (i = 0; i < npages; ++i) {
>>>> + gpa = be64_to_cpu(tces[i]) & ~(TCE_PCI_READ | TCE_PCI_WRITE);
>>>
>>> IIUC this is the virtual mode, not the real mode version. In which
>>> case you shouldn't be accessing tces[i] (a userspace pointeR) directly
>>> bit should instead be using get_user().
>>>
>>>> + if (iommu_tce_put_param_check(tbl, ioba +
>>>> + (i << tbl->it_page_shift), gpa))
>>>> + return H_PARAMETER;
>>>> + }
>>>> +
>>>> + for (i = 0; i < npages; ++i) {
>>>> + tce = be64_to_cpu(tces[i]);
>>>> + gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
>>>> +
>>>> + ret = kvmppc_tce_iommu_map(vcpu->kvm, tbl, entry + i, gpa,
>>>> + iommu_tce_direction(tce));
>>>> + if (ret != H_SUCCESS)
>>>> + return ret;
>>>> + }
>>>> +
>>>> + return H_SUCCESS;
>>>> +}
>>>> +
>>>> +long kvmppc_h_stuff_tce_iommu(struct kvm_vcpu *vcpu,
>>>> + struct iommu_table *tbl,
>>>> + unsigned long liobn, unsigned long ioba,
>>>> + unsigned long tce_value, unsigned long npages)
>>>> +{
>>>> + unsigned long i;
>>>> + const unsigned long entry = ioba >> tbl->it_page_shift;
>>>> +
>>>> + if (iommu_tce_clear_param_check(tbl, ioba, tce_value, npages))
>>>> + return H_PARAMETER;
>>>> +
>>>> + for (i = 0; i < npages; ++i)
>>>> + kvmppc_tce_iommu_unmap(vcpu->kvm, tbl, entry + i);
>>>> +
>>>> + return H_SUCCESS;
>>>> +}
>>>> +
>>>> 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;
>>>> + struct kvmppc_spapr_tce_iommu_table *stit;
>>>>
>>>> /* udbg_printf("H_PUT_TCE(): liobn=0x%lx ioba=0x%lx, tce=0x%lx\n", */
>>>> /* liobn, ioba, tce); */
>>>> @@ -230,6 +494,12 @@ long kvmppc_h_put_tce(struct kvm_vcpu *vcpu, unsigned long liobn,
>>>> if (ret != H_SUCCESS)
>>>> return ret;
>>>>
>>>> + list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
>>>
>>> As noted above, AFAICT there is one stit per group, rather than per
>>> backend IOMMU table, so if there are multiple groups in the same
>>> container (and therefore attached to the same LIOBN), won't this mean
>>> we duplicate this operation a bunch of times?
>>>
>>>> + ret = kvmppc_h_put_tce_iommu(vcpu, stit->tbl, liobn, ioba, tce);
>>>> + if (ret != H_SUCCESS)
>>>> + return ret;
>>>> + }
>>>> +
>>>> kvmppc_tce_put(stt, ioba >> stt->page_shift, tce);
>>>>
>>>> return H_SUCCESS;
>>>> @@ -245,6 +515,7 @@ 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)
>>>> @@ -272,6 +543,13 @@ long kvmppc_h_put_tce_indirect(struct kvm_vcpu *vcpu,
>>>> }
>>>> tces = (u64 __user *) ua;
>>>>
>>>> + list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
>>>> + ret = kvmppc_h_put_tce_indirect_iommu(vcpu,
>>>> + stit->tbl, ioba, tces, npages);
>>>> + if (ret != H_SUCCESS)
>>>> + goto unlock_exit;
>>>
>>> Hmm, I don't suppose you could simplify things by not having a
>>> put_tce_indirect() version of the whole backend iommu mapping
>>> function, but just a single-TCE version, and instead looping across
>>> the backend IOMMU tables as you put each indirect entry in .
>>>
>>>> + }
>>>> +
>>>> for (i = 0; i < npages; ++i) {
>>>> if (get_user(tce, tces + i)) {
>>>> ret = H_TOO_HARD;
>>>> @@ -299,6 +577,7 @@ 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)
>>>> @@ -312,6 +591,13 @@ 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) {
>>>> + ret = kvmppc_h_stuff_tce_iommu(vcpu, stit->tbl, liobn, ioba,
>>>> + tce_value, npages);
>>>> + if (ret != H_SUCCESS)
>>>> + return ret;
>>>> + }
>>>> +
>>>> 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 8a6834e6e1c8..4d6f01712a6d 100644
>>>> --- a/arch/powerpc/kvm/book3s_64_vio_hv.c
>>>> +++ b/arch/powerpc/kvm/book3s_64_vio_hv.c
>>>> @@ -190,11 +190,165 @@ static struct mm_iommu_table_group_mem_t *kvmppc_rm_iommu_lookup(
>>>> return mm_iommu_lookup_rm(vcpu->kvm->mm, ua, size);
>>>> }
>>>>
>>>> +static long kvmppc_rm_tce_iommu_mapped_dec(struct kvm_vcpu *vcpu,
>>>> + 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)
>>>> + return H_SUCCESS;
>>>
>>> What case is this? Not being able to find the userspace duesn't sound
>>> like a success.
>>>
>>>> + pua = (void *) vmalloc_to_phys(pua);
>>>> + if (!pua)
>>>> + return H_SUCCESS;
>>>
>>> And again..
>>>
>>>> + mem = kvmppc_rm_iommu_lookup(vcpu, *pua, pgsize);
>>>> + if (!mem)
>>>> + return H_HARDWARE;
>>>
>>> Should this have a WARN_ON?
>>>
>>>> + mm_iommu_mapped_dec(mem);
>>>> +
>>>> + *pua = 0;
>>>> +
>>>> + return H_SUCCESS;
>>>> +}
>>>> +
>>>> +static long kvmppc_rm_tce_iommu_unmap(struct kvm_vcpu *vcpu,
>>>> + struct iommu_table *tbl, unsigned long entry)
>>>> +{
>>>> + enum dma_data_direction dir = DMA_NONE;
>>>> + unsigned long hpa = 0;
>>>> +
>>>> + if (iommu_tce_xchg_rm(tbl, entry, &hpa, &dir))
>>>> + return H_HARDWARE;
>>>> +
>>>> + if (dir == DMA_NONE)
>>>> + return H_SUCCESS;
>>>> +
>>>> + return kvmppc_rm_tce_iommu_mapped_dec(vcpu, tbl, entry);
>>>> +}
>>>> +
>>>> +long kvmppc_rm_tce_iommu_map(struct kvm_vcpu *vcpu, struct iommu_table *tbl,
>>>> + unsigned long entry, unsigned long gpa,
>>>> + enum dma_data_direction dir)
>>>> +{
>>>> + long ret;
>>>> + unsigned long hpa = 0, ua;
>>>> + 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;
>>>> +
>>>> + if (kvmppc_gpa_to_ua(vcpu->kvm, gpa, &ua, NULL))
>>>> + return H_HARDWARE;
>>>
>>> Again H_HARDWARE doesn't seem right here.
>>>
>>>> + mem = kvmppc_rm_iommu_lookup(vcpu, ua, 1ULL << tbl->it_page_shift);
>>>> + if (!mem)
>>>> + return H_HARDWARE;
>>>> +
>>>> + if (mm_iommu_ua_to_hpa_rm(mem, ua, &hpa))
>>>> + return H_HARDWARE;
>>>> +
>>>> + pua = (void *) vmalloc_to_phys(pua);
>>>> + if (!pua)
>>>> + return H_HARDWARE;
>>>> +
>>>> + if (mm_iommu_mapped_inc(mem))
>>>> + return H_HARDWARE;
>>>> +
>>>> + ret = iommu_tce_xchg_rm(tbl, entry, &hpa, &dir);
>>>> + if (ret) {
>>>> + mm_iommu_mapped_dec(mem);
>>>> + return H_TOO_HARD;
>>>> + }
>>>> +
>>>> + if (dir != DMA_NONE)
>>>> + kvmppc_rm_tce_iommu_mapped_dec(vcpu, tbl, entry);
>>>> +
>>>> + *pua = ua;
>>>> +
>>>> + return 0;
>>>> +}
>>>> +EXPORT_SYMBOL_GPL(kvmppc_rm_tce_iommu_map);
>>>> +
>>>> +static long kvmppc_rm_h_put_tce_iommu(struct kvm_vcpu *vcpu,
>>>> + struct iommu_table *tbl, unsigned long liobn,
>>>> + unsigned long ioba, unsigned long tce)
>>>> +{
>>>> + const unsigned long entry = ioba >> tbl->it_page_shift;
>>>> + const unsigned long gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
>>>> + const enum dma_data_direction dir = iommu_tce_direction(tce);
>>>> +
>>>> + /* Clear TCE */
>>>> + if (dir == DMA_NONE) {
>>>> + if (iommu_tce_clear_param_check(tbl, ioba, 0, 1))
>>>> + return H_PARAMETER;
>>>> +
>>>> + return kvmppc_rm_tce_iommu_unmap(vcpu, tbl, entry);
>>>> + }
>>>> +
>>>> + /* Put TCE */
>>>> + if (iommu_tce_put_param_check(tbl, ioba, gpa))
>>>> + return H_PARAMETER;
>>>> +
>>>> + return kvmppc_rm_tce_iommu_map(vcpu, tbl, entry, gpa, dir);
>>>> +}
>>>> +
>>>> +static long kvmppc_rm_h_put_tce_indirect_iommu(struct kvm_vcpu *vcpu,
>>>> + struct iommu_table *tbl, unsigned long ioba,
>>>> + u64 *tces, unsigned long npages)
>>>> +{
>>>> + unsigned long i, ret, tce, gpa;
>>>> + const unsigned long entry = ioba >> tbl->it_page_shift;
>>>> +
>>>> + for (i = 0; i < npages; ++i) {
>>>> + gpa = be64_to_cpu(tces[i]) & ~(TCE_PCI_READ | TCE_PCI_WRITE);
>>>> +
>>>> + if (iommu_tce_put_param_check(tbl, ioba +
>>>> + (i << tbl->it_page_shift), gpa))
>>>> + return H_PARAMETER;
>>>> + }
>>>> +
>>>> + for (i = 0; i < npages; ++i) {
>>>> + tce = be64_to_cpu(tces[i]);
>>>> + gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
>>>> +
>>>> + ret = kvmppc_rm_tce_iommu_map(vcpu, tbl, entry + i, gpa,
>>>> + iommu_tce_direction(tce));
>>>> + if (ret != H_SUCCESS)
>>>> + return ret;
>>>> + }
>>>> +
>>>> + return H_SUCCESS;
>>>> +}
>>>> +
>>>> +static long kvmppc_rm_h_stuff_tce_iommu(struct kvm_vcpu *vcpu,
>>>> + struct iommu_table *tbl,
>>>> + unsigned long liobn, unsigned long ioba,
>>>> + unsigned long tce_value, unsigned long npages)
>>>> +{
>>>> + unsigned long i;
>>>> + const unsigned long entry = ioba >> tbl->it_page_shift;
>>>> +
>>>> + if (iommu_tce_clear_param_check(tbl, ioba, tce_value, npages))
>>>> + return H_PARAMETER;
>>>> +
>>>> + for (i = 0; i < npages; ++i)
>>>> + kvmppc_rm_tce_iommu_unmap(vcpu, tbl, entry + i);
>>>> +
>>>> + return H_SUCCESS;
>>>> +}
>>>> +
>>>> 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;
>>>>
>>>> /* udbg_printf("H_PUT_TCE(): liobn=0x%lx ioba=0x%lx, tce=0x%lx\n", */
>>>> /* liobn, ioba, tce); */
>>>> @@ -211,6 +365,13 @@ long kvmppc_rm_h_put_tce(struct kvm_vcpu *vcpu, unsigned long liobn,
>>>> if (ret != H_SUCCESS)
>>>> return ret;
>>>>
>>>> + list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
>>>> + ret = kvmppc_rm_h_put_tce_iommu(vcpu, stit->tbl,
>>>> + liobn, ioba, tce);
>>>> + if (ret != H_SUCCESS)
>>>> + return ret;
>>>> + }
>>>> +
>>>> kvmppc_tce_put(stt, ioba >> stt->page_shift, tce);
>>>>
>>>> return H_SUCCESS;
>>>> @@ -278,6 +439,7 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu,
>>>> * depend on hpt.
>>>> */
>>>> struct mm_iommu_table_group_mem_t *mem;
>>>> + struct kvmppc_spapr_tce_iommu_table *stit;
>>>>
>>>> if (kvmppc_gpa_to_ua(vcpu->kvm, tce_list, &ua, NULL))
>>>> return H_TOO_HARD;
>>>> @@ -285,6 +447,13 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu,
>>>> mem = kvmppc_rm_iommu_lookup(vcpu, ua, IOMMU_PAGE_SIZE_4K);
>>>> if (!mem || mm_iommu_ua_to_hpa_rm(mem, ua, &tces))
>>>> return H_TOO_HARD;
>>>> +
>>>> + list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
>>>> + ret = kvmppc_rm_h_put_tce_indirect_iommu(vcpu,
>>>> + stit->tbl, ioba, (u64 *)tces, npages);
>>>> + if (ret != H_SUCCESS)
>>>> + return ret;
>>>> + }
>>>> } else {
>>>> /*
>>>> * This is emulated devices case.
>>>> @@ -334,6 +503,8 @@ 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)
>>>> @@ -347,6 +518,13 @@ 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) {
>>>> + ret = kvmppc_rm_h_stuff_tce_iommu(vcpu, stit->tbl,
>>>> + liobn, ioba, tce_value, npages);
>>>> + if (ret != H_SUCCESS)
>>>> + return ret;
>>>> + }
>>>> +
>>>> 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 70963c845e96..0e555ba998c0 100644
>>>> --- a/arch/powerpc/kvm/powerpc.c
>>>> +++ b/arch/powerpc/kvm/powerpc.c
>>>> @@ -536,6 +536,8 @@ 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_ALLOC_HTAB:
>>>> case KVM_CAP_PPC_RTAS:
>>>> case KVM_CAP_PPC_FIXUP_HCALL:
>>>> diff --git a/virt/kvm/vfio.c b/virt/kvm/vfio.c
>>>> index d32f239eb471..3181054c8ff7 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;
>>>> @@ -89,6 +93,22 @@ static bool kvm_vfio_group_is_coherent(struct vfio_group *vfio_group)
>>>> return ret > 0;
>>>> }
>>>>
>>>> +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;
>>>> +}
>>>> +
>>>> /*
>>>> * 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 +231,9 @@ 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 +241,65 @@ 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) {
>>>> + int group_id;
>>>> + struct iommu_group *grp;
>>>> +
>>>> + if (kvg->vfio_group != vfio_group)
>>>> + continue;
>>>> +
>>>> + group_id = kvm_vfio_external_user_iommu_id(
>>>> + kvg->vfio_group);
>>>> + grp = iommu_group_get_by_id(group_id);
>>>> + if (!grp) {
>>>> + ret = -EFAULT;
>>>> + break;
>>>> + }
>>>> +
>>>> + ret = kvm_spapr_tce_attach_iommu_group(dev->kvm,
>>>> + param.tablefd, vfio_group, grp);
>>>> +
>>>> + iommu_group_put(grp);
>>>> + break;
>>>> + }
>>>> +
>>>> + mutex_unlock(&kv->lock);
>>>> +
>>>> + return ret;
>>>> + }
>>>> +#endif /* CONFIG_SPAPR_TCE_IOMMU */
>>>> }
>>>
>>> Don't you also need to add something to the KVM_DEV_VFIO_GROUP_DEL
>>> path to detach the group from all LIOBNs, Or else just fail if if
>>> there are LIOBNs attached. I think it would be a qemu bug not to
>>> detach the LIOBNs before removing the group, but we stil need to
>>> protect the host in that case.
>>
>>
>> Yeah, this bit is a bit tricky/ugly.
>>
>> kvm_spapr_tce_liobn_release_iommu_group() (called from
>> kvm_spapr_tce_fops::release()) drops references when a group is removed
>> from the VFIO KVM device so there is no KVM_DEV_VFIO_GROUP_UNSET_SPAPR_TCE
>> and no action from QEMU is required.
>
> IF qemu simply closes the group fd. Which it does now, but might not
> always. You still need to deal with the case where userspace does a
> KVM_DEV_VFIO_GROUP_DEL instead of closing the group fd.
This patch adds kvm_spapr_tce_release_iommu_group() to the
KVM_DEV_VFIO_GROUP_DEL handler.
>
>>
>>
>>
>>>>
>>>> return -ENXIO;
>>>> @@ -242,6 +324,9 @@ 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 +342,9 @@ 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);
>>>
>>
>>
>
>
>
>
--
Alexey
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