* [PATCH kernel v5 00/10] powerpc/kvm/vfio: Enable in-kernel acceleration
@ 2017-02-22 8:21 Alexey Kardashevskiy
2017-02-22 8:21 ` [PATCH kernel v5 01/10] powerpc/mmu: Add real mode support for IOMMU preregistered memory Alexey Kardashevskiy
` (9 more replies)
0 siblings, 10 replies; 21+ messages in thread
From: Alexey Kardashevskiy @ 2017-02-22 8:21 UTC (permalink / raw)
To: linuxppc-dev
Cc: Alexey Kardashevskiy, Alex Williamson, David Gibson,
Paul Mackerras, kvm-ppc, kvm
This is my current queue of patches to add acceleration of TCE
updates in KVM.
This is based on the v4.10 release.
Please comment. Thanks.
Changes:
v5:
* replaced "KVM: PPC: Separate TCE validation from update" with
"KVM: PPC: iommu: Unify TCE checking"
* changed already reviewed "powerpc/iommu/vfio_spapr_tce: Cleanup iommu_table disposal"
* reworked "KVM: PPC: VFIO: Add in-kernel acceleration for VFIO"
* more details in individual commit logs
v4:
* addressed comments from v3
* updated subject lines with correct component names
* regrouped the patchset in order:
- powerpc fixes;
- vfio_spapr_tce driver fixes;
- KVM/PPC fixes;
- KVM+PPC+VFIO;
* everything except last 2 patches have "Reviewed-By: David"
v3:
* there was no full repost, only last patch was posted
v2:
* 11/11 reworked to use new notifiers, it is rather RFC as it still has
a issue;
* got 09/11, 10/11 to use notifiers in 11/11;
* added rb: David to most of patches and added a comment in 05/11.
Alexey Kardashevskiy (10):
powerpc/mmu: Add real mode support for IOMMU preregistered memory
powerpc/powernv/iommu: Add real mode version of
iommu_table_ops::exchange()
powerpc/iommu/vfio_spapr_tce: Cleanup iommu_table disposal
powerpc/vfio_spapr_tce: Add reference counting to iommu_table
KVM: PPC: Reserve KVM_CAP_SPAPR_TCE_VFIO capability number
KVM: PPC: Enable IOMMU_API for KVM_BOOK3S_64 permanently
KVM: PPC: Pass kvm* to kvmppc_find_table()
KVM: PPC: Use preregistered memory API to access TCE list
KVM: PPC: iommu: Unify TCE checking
KVM: PPC: VFIO: Add in-kernel acceleration for VFIO
Documentation/virtual/kvm/devices/vfio.txt | 22 +-
arch/powerpc/include/asm/iommu.h | 32 ++-
arch/powerpc/include/asm/kvm_host.h | 8 +
arch/powerpc/include/asm/kvm_ppc.h | 12 +-
arch/powerpc/include/asm/mmu_context.h | 4 +
include/uapi/linux/kvm.h | 9 +
arch/powerpc/kernel/iommu.c | 86 +++++---
arch/powerpc/kvm/book3s_64_vio.c | 314 ++++++++++++++++++++++++++++-
arch/powerpc/kvm/book3s_64_vio_hv.c | 254 ++++++++++++++++++-----
arch/powerpc/kvm/powerpc.c | 2 +
arch/powerpc/mm/mmu_context_iommu.c | 39 ++++
arch/powerpc/platforms/powernv/pci-ioda.c | 46 +++--
arch/powerpc/platforms/powernv/pci.c | 1 +
arch/powerpc/platforms/pseries/iommu.c | 3 +-
arch/powerpc/platforms/pseries/vio.c | 2 +-
drivers/vfio/vfio_iommu_spapr_tce.c | 2 +-
virt/kvm/vfio.c | 60 ++++++
arch/powerpc/kvm/Kconfig | 1 +
18 files changed, 787 insertions(+), 110 deletions(-)
--
2.11.0
^ permalink raw reply [flat|nested] 21+ messages in thread
* [PATCH kernel v5 01/10] powerpc/mmu: Add real mode support for IOMMU preregistered memory
2017-02-22 8:21 [PATCH kernel v5 00/10] powerpc/kvm/vfio: Enable in-kernel acceleration Alexey Kardashevskiy
@ 2017-02-22 8:21 ` Alexey Kardashevskiy
2017-02-22 8:21 ` [PATCH kernel v5 02/10] powerpc/powernv/iommu: Add real mode version of iommu_table_ops::exchange() Alexey Kardashevskiy
` (8 subsequent siblings)
9 siblings, 0 replies; 21+ messages in thread
From: Alexey Kardashevskiy @ 2017-02-22 8:21 UTC (permalink / raw)
To: linuxppc-dev
Cc: Alexey Kardashevskiy, Alex Williamson, David Gibson,
Paul Mackerras, kvm-ppc, kvm
This makes mm_iommu_lookup() able to work in realmode by replacing
list_for_each_entry_rcu() (which can do debug stuff which can fail in
real mode) with list_for_each_entry_lockless().
This adds realmode version of mm_iommu_ua_to_hpa() which adds
explicit vmalloc'd-to-linear address conversion.
Unlike mm_iommu_ua_to_hpa(), mm_iommu_ua_to_hpa_rm() can fail.
This changes mm_iommu_preregistered() to receive @mm as in real mode
@current does not always have a correct pointer.
This adds realmode version of mm_iommu_lookup() which receives @mm
(for the same reason as for mm_iommu_preregistered()) and uses
lockless version of list_for_each_entry_rcu().
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
---
arch/powerpc/include/asm/mmu_context.h | 4 ++++
arch/powerpc/mm/mmu_context_iommu.c | 39 ++++++++++++++++++++++++++++++++++
2 files changed, 43 insertions(+)
diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h
index b9e3f0aca261..c70c8272523d 100644
--- a/arch/powerpc/include/asm/mmu_context.h
+++ b/arch/powerpc/include/asm/mmu_context.h
@@ -29,10 +29,14 @@ extern void mm_iommu_init(struct mm_struct *mm);
extern void mm_iommu_cleanup(struct mm_struct *mm);
extern struct mm_iommu_table_group_mem_t *mm_iommu_lookup(struct mm_struct *mm,
unsigned long ua, unsigned long size);
+extern struct mm_iommu_table_group_mem_t *mm_iommu_lookup_rm(
+ struct mm_struct *mm, unsigned long ua, unsigned long size);
extern struct mm_iommu_table_group_mem_t *mm_iommu_find(struct mm_struct *mm,
unsigned long ua, unsigned long entries);
extern long mm_iommu_ua_to_hpa(struct mm_iommu_table_group_mem_t *mem,
unsigned long ua, unsigned long *hpa);
+extern long mm_iommu_ua_to_hpa_rm(struct mm_iommu_table_group_mem_t *mem,
+ unsigned long ua, unsigned long *hpa);
extern long mm_iommu_mapped_inc(struct mm_iommu_table_group_mem_t *mem);
extern void mm_iommu_mapped_dec(struct mm_iommu_table_group_mem_t *mem);
#endif
diff --git a/arch/powerpc/mm/mmu_context_iommu.c b/arch/powerpc/mm/mmu_context_iommu.c
index 104bad029ce9..631d32f5937b 100644
--- a/arch/powerpc/mm/mmu_context_iommu.c
+++ b/arch/powerpc/mm/mmu_context_iommu.c
@@ -314,6 +314,25 @@ struct mm_iommu_table_group_mem_t *mm_iommu_lookup(struct mm_struct *mm,
}
EXPORT_SYMBOL_GPL(mm_iommu_lookup);
+struct mm_iommu_table_group_mem_t *mm_iommu_lookup_rm(struct mm_struct *mm,
+ unsigned long ua, unsigned long size)
+{
+ struct mm_iommu_table_group_mem_t *mem, *ret = NULL;
+
+ list_for_each_entry_lockless(mem, &mm->context.iommu_group_mem_list,
+ next) {
+ if ((mem->ua <= ua) &&
+ (ua + size <= mem->ua +
+ (mem->entries << PAGE_SHIFT))) {
+ ret = mem;
+ break;
+ }
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(mm_iommu_lookup_rm);
+
struct mm_iommu_table_group_mem_t *mm_iommu_find(struct mm_struct *mm,
unsigned long ua, unsigned long entries)
{
@@ -345,6 +364,26 @@ long mm_iommu_ua_to_hpa(struct mm_iommu_table_group_mem_t *mem,
}
EXPORT_SYMBOL_GPL(mm_iommu_ua_to_hpa);
+long mm_iommu_ua_to_hpa_rm(struct mm_iommu_table_group_mem_t *mem,
+ unsigned long ua, unsigned long *hpa)
+{
+ const long entry = (ua - mem->ua) >> PAGE_SHIFT;
+ void *va = &mem->hpas[entry];
+ unsigned long *pa;
+
+ if (entry >= mem->entries)
+ return -EFAULT;
+
+ pa = (void *) vmalloc_to_phys(va);
+ if (!pa)
+ return -EFAULT;
+
+ *hpa = *pa | (ua & ~PAGE_MASK);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(mm_iommu_ua_to_hpa_rm);
+
long mm_iommu_mapped_inc(struct mm_iommu_table_group_mem_t *mem)
{
if (atomic64_inc_not_zero(&mem->mapped))
--
2.11.0
^ permalink raw reply related [flat|nested] 21+ messages in thread
* [PATCH kernel v5 02/10] powerpc/powernv/iommu: Add real mode version of iommu_table_ops::exchange()
2017-02-22 8:21 [PATCH kernel v5 00/10] powerpc/kvm/vfio: Enable in-kernel acceleration Alexey Kardashevskiy
2017-02-22 8:21 ` [PATCH kernel v5 01/10] powerpc/mmu: Add real mode support for IOMMU preregistered memory Alexey Kardashevskiy
@ 2017-02-22 8:21 ` Alexey Kardashevskiy
2017-02-22 8:21 ` [PATCH kernel v5 03/10] powerpc/iommu/vfio_spapr_tce: Cleanup iommu_table disposal Alexey Kardashevskiy
` (7 subsequent siblings)
9 siblings, 0 replies; 21+ messages in thread
From: Alexey Kardashevskiy @ 2017-02-22 8:21 UTC (permalink / raw)
To: linuxppc-dev
Cc: Alexey Kardashevskiy, Alex Williamson, David Gibson,
Paul Mackerras, kvm-ppc, kvm
In real mode, TCE tables are invalidated using special
cache-inhibited store instructions which are not available in
virtual mode
This defines and implements exchange_rm() callback. This does not
define set_rm/clear_rm/flush_rm callbacks as there is no user for those -
exchange/exchange_rm are only to be used by KVM for VFIO.
The exchange_rm callback is defined for IODA1/IODA2 powernv platforms.
This replaces list_for_each_entry_rcu with its lockless version as
from now on pnv_pci_ioda2_tce_invalidate() can be called in
the real mode too.
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
---
arch/powerpc/include/asm/iommu.h | 7 +++++++
arch/powerpc/kernel/iommu.c | 23 +++++++++++++++++++++++
arch/powerpc/platforms/powernv/pci-ioda.c | 26 +++++++++++++++++++++++++-
3 files changed, 55 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h
index 2c1d50792944..4554699aec02 100644
--- a/arch/powerpc/include/asm/iommu.h
+++ b/arch/powerpc/include/asm/iommu.h
@@ -64,6 +64,11 @@ struct iommu_table_ops {
long index,
unsigned long *hpa,
enum dma_data_direction *direction);
+ /* Real mode */
+ int (*exchange_rm)(struct iommu_table *tbl,
+ long index,
+ unsigned long *hpa,
+ enum dma_data_direction *direction);
#endif
void (*clear)(struct iommu_table *tbl,
long index, long npages);
@@ -208,6 +213,8 @@ extern void iommu_del_device(struct device *dev);
extern int __init tce_iommu_bus_notifier_init(void);
extern long iommu_tce_xchg(struct iommu_table *tbl, unsigned long entry,
unsigned long *hpa, enum dma_data_direction *direction);
+extern long iommu_tce_xchg_rm(struct iommu_table *tbl, unsigned long entry,
+ unsigned long *hpa, enum dma_data_direction *direction);
#else
static inline void iommu_register_group(struct iommu_table_group *table_group,
int pci_domain_number,
diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index 5f202a566ec5..9bace5df05d5 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -1004,6 +1004,29 @@ long iommu_tce_xchg(struct iommu_table *tbl, unsigned long entry,
}
EXPORT_SYMBOL_GPL(iommu_tce_xchg);
+long iommu_tce_xchg_rm(struct iommu_table *tbl, unsigned long entry,
+ unsigned long *hpa, enum dma_data_direction *direction)
+{
+ long ret;
+
+ ret = tbl->it_ops->exchange_rm(tbl, entry, hpa, direction);
+
+ if (!ret && ((*direction == DMA_FROM_DEVICE) ||
+ (*direction == DMA_BIDIRECTIONAL))) {
+ struct page *pg = realmode_pfn_to_page(*hpa >> PAGE_SHIFT);
+
+ if (likely(pg)) {
+ SetPageDirty(pg);
+ } else {
+ tbl->it_ops->exchange_rm(tbl, entry, hpa, direction);
+ ret = -EFAULT;
+ }
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(iommu_tce_xchg_rm);
+
int iommu_take_ownership(struct iommu_table *tbl)
{
unsigned long flags, i, sz = (tbl->it_size + 7) >> 3;
diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index 1e92ec954321..133c7f300c12 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -1860,6 +1860,17 @@ static int pnv_ioda1_tce_xchg(struct iommu_table *tbl, long index,
return ret;
}
+
+static int pnv_ioda1_tce_xchg_rm(struct iommu_table *tbl, long index,
+ unsigned long *hpa, enum dma_data_direction *direction)
+{
+ long ret = pnv_tce_xchg(tbl, index, hpa, direction);
+
+ if (!ret)
+ pnv_pci_p7ioc_tce_invalidate(tbl, index, 1, true);
+
+ return ret;
+}
#endif
static void pnv_ioda1_tce_free(struct iommu_table *tbl, long index,
@@ -1874,6 +1885,7 @@ static struct iommu_table_ops pnv_ioda1_iommu_ops = {
.set = pnv_ioda1_tce_build,
#ifdef CONFIG_IOMMU_API
.exchange = pnv_ioda1_tce_xchg,
+ .exchange_rm = pnv_ioda1_tce_xchg_rm,
#endif
.clear = pnv_ioda1_tce_free,
.get = pnv_tce_get,
@@ -1948,7 +1960,7 @@ static void pnv_pci_ioda2_tce_invalidate(struct iommu_table *tbl,
{
struct iommu_table_group_link *tgl;
- list_for_each_entry_rcu(tgl, &tbl->it_group_list, next) {
+ list_for_each_entry_lockless(tgl, &tbl->it_group_list, next) {
struct pnv_ioda_pe *pe = container_of(tgl->table_group,
struct pnv_ioda_pe, table_group);
struct pnv_phb *phb = pe->phb;
@@ -2004,6 +2016,17 @@ static int pnv_ioda2_tce_xchg(struct iommu_table *tbl, long index,
return ret;
}
+
+static int pnv_ioda2_tce_xchg_rm(struct iommu_table *tbl, long index,
+ unsigned long *hpa, enum dma_data_direction *direction)
+{
+ long ret = pnv_tce_xchg(tbl, index, hpa, direction);
+
+ if (!ret)
+ pnv_pci_ioda2_tce_invalidate(tbl, index, 1, true);
+
+ return ret;
+}
#endif
static void pnv_ioda2_tce_free(struct iommu_table *tbl, long index,
@@ -2024,6 +2047,7 @@ static struct iommu_table_ops pnv_ioda2_iommu_ops = {
.set = pnv_ioda2_tce_build,
#ifdef CONFIG_IOMMU_API
.exchange = pnv_ioda2_tce_xchg,
+ .exchange_rm = pnv_ioda2_tce_xchg_rm,
#endif
.clear = pnv_ioda2_tce_free,
.get = pnv_tce_get,
--
2.11.0
^ permalink raw reply related [flat|nested] 21+ messages in thread
* [PATCH kernel v5 03/10] powerpc/iommu/vfio_spapr_tce: Cleanup iommu_table disposal
2017-02-22 8:21 [PATCH kernel v5 00/10] powerpc/kvm/vfio: Enable in-kernel acceleration Alexey Kardashevskiy
2017-02-22 8:21 ` [PATCH kernel v5 01/10] powerpc/mmu: Add real mode support for IOMMU preregistered memory Alexey Kardashevskiy
2017-02-22 8:21 ` [PATCH kernel v5 02/10] powerpc/powernv/iommu: Add real mode version of iommu_table_ops::exchange() Alexey Kardashevskiy
@ 2017-02-22 8:21 ` Alexey Kardashevskiy
2017-02-23 3:31 ` David Gibson
2017-02-22 8:21 ` [PATCH kernel v5 04/10] powerpc/vfio_spapr_tce: Add reference counting to iommu_table Alexey Kardashevskiy
` (6 subsequent siblings)
9 siblings, 1 reply; 21+ messages in thread
From: Alexey Kardashevskiy @ 2017-02-22 8:21 UTC (permalink / raw)
To: linuxppc-dev
Cc: Alexey Kardashevskiy, Alex Williamson, David Gibson,
Paul Mackerras, kvm-ppc, kvm
At the moment iommu_table can be disposed by either calling
iommu_table_free() directly or it_ops::free(); the only implementation
of free() is in IODA2 - pnv_ioda2_table_free() - and it calls
iommu_table_free() anyway.
As we are going to have reference counting on tables, we need an unified
way of disposing tables.
This moves it_ops::free() call into iommu_free_table() and makes use
of the latter. The free() callback now handles only platform-specific
data.
As from now on the iommu_free_table() calls it_ops->free(), we need
to have it_ops initialized before calling iommu_free_table() so this
moves this initialization in pnv_pci_ioda2_create_table().
This should cause no behavioral change.
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
Changes:
v5:
* moved "tbl->it_ops = &pnv_ioda2_iommu_ops" earlier and updated
the commit log
---
arch/powerpc/kernel/iommu.c | 4 ++++
arch/powerpc/platforms/powernv/pci-ioda.c | 10 ++++------
drivers/vfio/vfio_iommu_spapr_tce.c | 2 +-
3 files changed, 9 insertions(+), 7 deletions(-)
diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index 9bace5df05d5..bc142d87130f 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -719,6 +719,9 @@ void iommu_free_table(struct iommu_table *tbl, const char *node_name)
if (!tbl)
return;
+ if (tbl->it_ops->free)
+ tbl->it_ops->free(tbl);
+
if (!tbl->it_map) {
kfree(tbl);
return;
@@ -745,6 +748,7 @@ void iommu_free_table(struct iommu_table *tbl, const char *node_name)
/* free table */
kfree(tbl);
}
+EXPORT_SYMBOL_GPL(iommu_free_table);
/* Creates TCEs for a user provided buffer. The user buffer must be
* contiguous real kernel storage (not vmalloc). The address passed here
diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index 133c7f300c12..27801c61ebdb 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -1423,7 +1423,6 @@ static void pnv_pci_ioda2_release_dma_pe(struct pci_dev *dev, struct pnv_ioda_pe
iommu_group_put(pe->table_group.group);
BUG_ON(pe->table_group.group);
}
- pnv_pci_ioda2_table_free_pages(tbl);
iommu_free_table(tbl, of_node_full_name(dev->dev.of_node));
}
@@ -2040,7 +2039,6 @@ static void pnv_ioda2_tce_free(struct iommu_table *tbl, long index,
static void pnv_ioda2_table_free(struct iommu_table *tbl)
{
pnv_pci_ioda2_table_free_pages(tbl);
- iommu_free_table(tbl, "pnv");
}
static struct iommu_table_ops pnv_ioda2_iommu_ops = {
@@ -2317,6 +2315,8 @@ static long pnv_pci_ioda2_create_table(struct iommu_table_group *table_group,
if (!tbl)
return -ENOMEM;
+ tbl->it_ops = &pnv_ioda2_iommu_ops;
+
ret = pnv_pci_ioda2_table_alloc_pages(nid,
bus_offset, page_shift, window_size,
levels, tbl);
@@ -2325,8 +2325,6 @@ static long pnv_pci_ioda2_create_table(struct iommu_table_group *table_group,
return ret;
}
- tbl->it_ops = &pnv_ioda2_iommu_ops;
-
*ptbl = tbl;
return 0;
@@ -2367,7 +2365,7 @@ static long pnv_pci_ioda2_setup_default_config(struct pnv_ioda_pe *pe)
if (rc) {
pe_err(pe, "Failed to configure 32-bit TCE table, err %ld\n",
rc);
- pnv_ioda2_table_free(tbl);
+ iommu_free_table(tbl, "");
return rc;
}
@@ -2455,7 +2453,7 @@ static void pnv_ioda2_take_ownership(struct iommu_table_group *table_group)
pnv_pci_ioda2_unset_window(&pe->table_group, 0);
if (pe->pbus)
pnv_ioda_setup_bus_dma(pe, pe->pbus, false);
- pnv_ioda2_table_free(tbl);
+ iommu_free_table(tbl, "pnv");
}
static void pnv_ioda2_release_ownership(struct iommu_table_group *table_group)
diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
index 59b3f62a2d64..ffab01874a22 100644
--- a/drivers/vfio/vfio_iommu_spapr_tce.c
+++ b/drivers/vfio/vfio_iommu_spapr_tce.c
@@ -677,7 +677,7 @@ static void tce_iommu_free_table(struct tce_container *container,
unsigned long pages = tbl->it_allocated_size >> PAGE_SHIFT;
tce_iommu_userspace_view_free(tbl, container->mm);
- tbl->it_ops->free(tbl);
+ iommu_free_table(tbl, "");
decrement_locked_vm(container->mm, pages);
}
--
2.11.0
^ permalink raw reply related [flat|nested] 21+ messages in thread
* [PATCH kernel v5 04/10] powerpc/vfio_spapr_tce: Add reference counting to iommu_table
2017-02-22 8:21 [PATCH kernel v5 00/10] powerpc/kvm/vfio: Enable in-kernel acceleration Alexey Kardashevskiy
` (2 preceding siblings ...)
2017-02-22 8:21 ` [PATCH kernel v5 03/10] powerpc/iommu/vfio_spapr_tce: Cleanup iommu_table disposal Alexey Kardashevskiy
@ 2017-02-22 8:21 ` Alexey Kardashevskiy
2017-02-22 8:21 ` [PATCH kernel v5 05/10] KVM: PPC: Reserve KVM_CAP_SPAPR_TCE_VFIO capability number Alexey Kardashevskiy
` (5 subsequent siblings)
9 siblings, 0 replies; 21+ messages in thread
From: Alexey Kardashevskiy @ 2017-02-22 8:21 UTC (permalink / raw)
To: linuxppc-dev
Cc: Alexey Kardashevskiy, Alex Williamson, David Gibson,
Paul Mackerras, kvm-ppc, kvm
So far iommu_table obejcts were only used in virtual mode and had
a single owner. We are going to change this by implementing in-kernel
acceleration of DMA mapping requests. The proposed acceleration
will handle requests in real mode and KVM will keep references to tables.
This adds a kref to iommu_table and defines new helpers to update it.
This replaces iommu_free_table() with iommu_table_put() and makes
iommu_free_table() static. iommu_table_get() is not used in this patch
but it will be in the following patch.
Since this touches prototypes, this also removes @node_name parameter as
it has never been really useful on powernv and carrying it for
the pseries platform code to iommu_free_table() seems to be quite
useless as well.
This should cause no behavioral change.
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
---
arch/powerpc/include/asm/iommu.h | 5 +++--
arch/powerpc/kernel/iommu.c | 24 +++++++++++++++++++-----
arch/powerpc/platforms/powernv/pci-ioda.c | 14 +++++++-------
arch/powerpc/platforms/powernv/pci.c | 1 +
arch/powerpc/platforms/pseries/iommu.c | 3 ++-
arch/powerpc/platforms/pseries/vio.c | 2 +-
drivers/vfio/vfio_iommu_spapr_tce.c | 2 +-
7 files changed, 34 insertions(+), 17 deletions(-)
diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h
index 4554699aec02..82e77ebf85f4 100644
--- a/arch/powerpc/include/asm/iommu.h
+++ b/arch/powerpc/include/asm/iommu.h
@@ -119,6 +119,7 @@ struct iommu_table {
struct list_head it_group_list;/* List of iommu_table_group_link */
unsigned long *it_userspace; /* userspace view of the table */
struct iommu_table_ops *it_ops;
+ struct kref it_kref;
};
#define IOMMU_TABLE_USERSPACE_ENTRY(tbl, entry) \
@@ -151,8 +152,8 @@ static inline void *get_iommu_table_base(struct device *dev)
extern int dma_iommu_dma_supported(struct device *dev, u64 mask);
-/* Frees table for an individual device node */
-extern void iommu_free_table(struct iommu_table *tbl, const char *node_name);
+extern void iommu_table_get(struct iommu_table *tbl);
+extern void iommu_table_put(struct iommu_table *tbl);
/* Initializes an iommu_table based in values set in the passed-in
* structure
diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index bc142d87130f..d02b8d22fb50 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -711,13 +711,13 @@ struct iommu_table *iommu_init_table(struct iommu_table *tbl, int nid)
return tbl;
}
-void iommu_free_table(struct iommu_table *tbl, const char *node_name)
+static void iommu_table_free(struct kref *kref)
{
unsigned long bitmap_sz;
unsigned int order;
+ struct iommu_table *tbl;
- if (!tbl)
- return;
+ tbl = container_of(kref, struct iommu_table, it_kref);
if (tbl->it_ops->free)
tbl->it_ops->free(tbl);
@@ -736,7 +736,7 @@ void iommu_free_table(struct iommu_table *tbl, const char *node_name)
/* verify that table contains no entries */
if (!bitmap_empty(tbl->it_map, tbl->it_size))
- pr_warn("%s: Unexpected TCEs for %s\n", __func__, node_name);
+ pr_warn("%s: Unexpected TCEs\n", __func__);
/* calculate bitmap size in bytes */
bitmap_sz = BITS_TO_LONGS(tbl->it_size) * sizeof(unsigned long);
@@ -748,7 +748,21 @@ void iommu_free_table(struct iommu_table *tbl, const char *node_name)
/* free table */
kfree(tbl);
}
-EXPORT_SYMBOL_GPL(iommu_free_table);
+
+void iommu_table_get(struct iommu_table *tbl)
+{
+ kref_get(&tbl->it_kref);
+}
+EXPORT_SYMBOL_GPL(iommu_table_get);
+
+void iommu_table_put(struct iommu_table *tbl)
+{
+ if (!tbl)
+ return;
+
+ kref_put(&tbl->it_kref, iommu_table_free);
+}
+EXPORT_SYMBOL_GPL(iommu_table_put);
/* Creates TCEs for a user provided buffer. The user buffer must be
* contiguous real kernel storage (not vmalloc). The address passed here
diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index 27801c61ebdb..db3aea42e8b5 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -1423,7 +1423,7 @@ static void pnv_pci_ioda2_release_dma_pe(struct pci_dev *dev, struct pnv_ioda_pe
iommu_group_put(pe->table_group.group);
BUG_ON(pe->table_group.group);
}
- iommu_free_table(tbl, of_node_full_name(dev->dev.of_node));
+ iommu_table_put(tbl);
}
static void pnv_ioda_release_vf_PE(struct pci_dev *pdev)
@@ -2225,7 +2225,7 @@ static void pnv_pci_ioda1_setup_dma_pe(struct pnv_phb *phb,
__free_pages(tce_mem, get_order(tce32_segsz * segs));
if (tbl) {
pnv_pci_unlink_table_and_group(tbl, &pe->table_group);
- iommu_free_table(tbl, "pnv");
+ iommu_table_put(tbl);
}
}
@@ -2321,7 +2321,7 @@ static long pnv_pci_ioda2_create_table(struct iommu_table_group *table_group,
bus_offset, page_shift, window_size,
levels, tbl);
if (ret) {
- iommu_free_table(tbl, "pnv");
+ iommu_table_put(tbl);
return ret;
}
@@ -2365,7 +2365,7 @@ static long pnv_pci_ioda2_setup_default_config(struct pnv_ioda_pe *pe)
if (rc) {
pe_err(pe, "Failed to configure 32-bit TCE table, err %ld\n",
rc);
- iommu_free_table(tbl, "");
+ iommu_table_put(tbl);
return rc;
}
@@ -2453,7 +2453,7 @@ static void pnv_ioda2_take_ownership(struct iommu_table_group *table_group)
pnv_pci_ioda2_unset_window(&pe->table_group, 0);
if (pe->pbus)
pnv_ioda_setup_bus_dma(pe, pe->pbus, false);
- iommu_free_table(tbl, "pnv");
+ iommu_table_put(tbl);
}
static void pnv_ioda2_release_ownership(struct iommu_table_group *table_group)
@@ -3426,7 +3426,7 @@ static void pnv_pci_ioda1_release_pe_dma(struct pnv_ioda_pe *pe)
}
free_pages(tbl->it_base, get_order(tbl->it_size << 3));
- iommu_free_table(tbl, "pnv");
+ iommu_table_put(tbl);
}
static void pnv_pci_ioda2_release_pe_dma(struct pnv_ioda_pe *pe)
@@ -3453,7 +3453,7 @@ static void pnv_pci_ioda2_release_pe_dma(struct pnv_ioda_pe *pe)
}
pnv_pci_ioda2_table_free_pages(tbl);
- iommu_free_table(tbl, "pnv");
+ iommu_table_put(tbl);
}
static void pnv_ioda_free_pe_seg(struct pnv_ioda_pe *pe,
diff --git a/arch/powerpc/platforms/powernv/pci.c b/arch/powerpc/platforms/powernv/pci.c
index 3f7f267a3d04..6dec900465ce 100644
--- a/arch/powerpc/platforms/powernv/pci.c
+++ b/arch/powerpc/platforms/powernv/pci.c
@@ -767,6 +767,7 @@ struct iommu_table *pnv_pci_table_alloc(int nid)
tbl = kzalloc_node(sizeof(struct iommu_table), GFP_KERNEL, nid);
INIT_LIST_HEAD_RCU(&tbl->it_group_list);
+ kref_init(&tbl->it_kref);
return tbl;
}
diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
index dc2577fc5fbb..47f0501a94f9 100644
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -74,6 +74,7 @@ static struct iommu_table_group *iommu_pseries_alloc_group(int node)
goto fail_exit;
INIT_LIST_HEAD_RCU(&tbl->it_group_list);
+ kref_init(&tbl->it_kref);
tgl->table_group = table_group;
list_add_rcu(&tgl->next, &tbl->it_group_list);
@@ -115,7 +116,7 @@ static void iommu_pseries_free_group(struct iommu_table_group *table_group,
BUG_ON(table_group->group);
}
#endif
- iommu_free_table(tbl, node_name);
+ iommu_table_put(tbl);
kfree(table_group);
}
diff --git a/arch/powerpc/platforms/pseries/vio.c b/arch/powerpc/platforms/pseries/vio.c
index 2c8fb3ec989e..41e8aa5c0d6a 100644
--- a/arch/powerpc/platforms/pseries/vio.c
+++ b/arch/powerpc/platforms/pseries/vio.c
@@ -1318,7 +1318,7 @@ static void vio_dev_release(struct device *dev)
struct iommu_table *tbl = get_iommu_table_base(dev);
if (tbl)
- iommu_free_table(tbl, of_node_full_name(dev->of_node));
+ iommu_table_put(tbl);
of_node_put(dev->of_node);
kfree(to_vio_dev(dev));
}
diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
index ffab01874a22..b0d455cc7776 100644
--- a/drivers/vfio/vfio_iommu_spapr_tce.c
+++ b/drivers/vfio/vfio_iommu_spapr_tce.c
@@ -677,7 +677,7 @@ static void tce_iommu_free_table(struct tce_container *container,
unsigned long pages = tbl->it_allocated_size >> PAGE_SHIFT;
tce_iommu_userspace_view_free(tbl, container->mm);
- iommu_free_table(tbl, "");
+ iommu_table_put(tbl);
decrement_locked_vm(container->mm, pages);
}
--
2.11.0
^ permalink raw reply related [flat|nested] 21+ messages in thread
* [PATCH kernel v5 05/10] KVM: PPC: Reserve KVM_CAP_SPAPR_TCE_VFIO capability number
2017-02-22 8:21 [PATCH kernel v5 00/10] powerpc/kvm/vfio: Enable in-kernel acceleration Alexey Kardashevskiy
` (3 preceding siblings ...)
2017-02-22 8:21 ` [PATCH kernel v5 04/10] powerpc/vfio_spapr_tce: Add reference counting to iommu_table Alexey Kardashevskiy
@ 2017-02-22 8:21 ` Alexey Kardashevskiy
2017-02-22 8:21 ` [PATCH kernel v5 06/10] KVM: PPC: Enable IOMMU_API for KVM_BOOK3S_64 permanently Alexey Kardashevskiy
` (4 subsequent siblings)
9 siblings, 0 replies; 21+ messages in thread
From: Alexey Kardashevskiy @ 2017-02-22 8:21 UTC (permalink / raw)
To: linuxppc-dev
Cc: Alexey Kardashevskiy, Alex Williamson, David Gibson,
Paul Mackerras, kvm-ppc, kvm
This adds a capability number for in-kernel support for VFIO on
SPAPR platform.
The capability will tell the user space whether in-kernel handlers of
H_PUT_TCE can handle VFIO-targeted requests or not. If not, the user space
must not attempt allocating a TCE table in the host kernel via
the KVM_CREATE_SPAPR_TCE KVM ioctl because in that case TCE requests
will not be passed to the user space which is desired action in
the situation like that.
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
---
include/uapi/linux/kvm.h | 1 +
1 file changed, 1 insertion(+)
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index cac48eda1075..a2c9bb5a0ead 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -871,6 +871,7 @@ struct kvm_ppc_smmu_info {
#define KVM_CAP_S390_USER_INSTR0 130
#define KVM_CAP_MSI_DEVID 131
#define KVM_CAP_PPC_HTM 132
+#define KVM_CAP_SPAPR_TCE_VFIO 133
#ifdef KVM_CAP_IRQ_ROUTING
--
2.11.0
^ permalink raw reply related [flat|nested] 21+ messages in thread
* [PATCH kernel v5 06/10] KVM: PPC: Enable IOMMU_API for KVM_BOOK3S_64 permanently
2017-02-22 8:21 [PATCH kernel v5 00/10] powerpc/kvm/vfio: Enable in-kernel acceleration Alexey Kardashevskiy
` (4 preceding siblings ...)
2017-02-22 8:21 ` [PATCH kernel v5 05/10] KVM: PPC: Reserve KVM_CAP_SPAPR_TCE_VFIO capability number Alexey Kardashevskiy
@ 2017-02-22 8:21 ` Alexey Kardashevskiy
2017-02-22 8:21 ` [PATCH kernel v5 07/10] KVM: PPC: Pass kvm* to kvmppc_find_table() Alexey Kardashevskiy
` (3 subsequent siblings)
9 siblings, 0 replies; 21+ messages in thread
From: Alexey Kardashevskiy @ 2017-02-22 8:21 UTC (permalink / raw)
To: linuxppc-dev
Cc: Alexey Kardashevskiy, Alex Williamson, David Gibson,
Paul Mackerras, kvm-ppc, kvm
It does not make much sense to have KVM in book3s-64 and
not to have IOMMU bits for PCI pass through support as it costs little
and allows VFIO to function on book3s KVM.
Having IOMMU_API always enabled makes it unnecessary to have a lot of
"#ifdef IOMMU_API" in arch/powerpc/kvm/book3s_64_vio*. With those
ifdef's we could have only user space emulated devices accelerated
(but not VFIO) which do not seem to be very useful.
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
---
arch/powerpc/kvm/Kconfig | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/powerpc/kvm/Kconfig b/arch/powerpc/kvm/Kconfig
index 029be26b5a17..65a471de96de 100644
--- a/arch/powerpc/kvm/Kconfig
+++ b/arch/powerpc/kvm/Kconfig
@@ -67,6 +67,7 @@ config KVM_BOOK3S_64
select KVM_BOOK3S_64_HANDLER
select KVM
select KVM_BOOK3S_PR_POSSIBLE if !KVM_BOOK3S_HV_POSSIBLE
+ select SPAPR_TCE_IOMMU if IOMMU_SUPPORT
---help---
Support running unmodified book3s_64 and book3s_32 guest kernels
in virtual machines on book3s_64 host processors.
--
2.11.0
^ permalink raw reply related [flat|nested] 21+ messages in thread
* [PATCH kernel v5 07/10] KVM: PPC: Pass kvm* to kvmppc_find_table()
2017-02-22 8:21 [PATCH kernel v5 00/10] powerpc/kvm/vfio: Enable in-kernel acceleration Alexey Kardashevskiy
` (5 preceding siblings ...)
2017-02-22 8:21 ` [PATCH kernel v5 06/10] KVM: PPC: Enable IOMMU_API for KVM_BOOK3S_64 permanently Alexey Kardashevskiy
@ 2017-02-22 8:21 ` Alexey Kardashevskiy
2017-02-22 8:21 ` [PATCH kernel v5 08/10] KVM: PPC: Use preregistered memory API to access TCE list Alexey Kardashevskiy
` (2 subsequent siblings)
9 siblings, 0 replies; 21+ messages in thread
From: Alexey Kardashevskiy @ 2017-02-22 8:21 UTC (permalink / raw)
To: linuxppc-dev
Cc: Alexey Kardashevskiy, Alex Williamson, David Gibson,
Paul Mackerras, kvm-ppc, kvm
The guest view TCE tables are per KVM anyway (not per VCPU) so pass kvm*
there. This will be used in the following patches where we will be
attaching VFIO containers to LIOBNs via ioctl() to KVM (rather than
to VCPU).
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
---
arch/powerpc/include/asm/kvm_ppc.h | 2 +-
arch/powerpc/kvm/book3s_64_vio.c | 7 ++++---
arch/powerpc/kvm/book3s_64_vio_hv.c | 13 +++++++------
3 files changed, 12 insertions(+), 10 deletions(-)
diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h
index 2da67bf1f2ec..37bc9e7e90ba 100644
--- a/arch/powerpc/include/asm/kvm_ppc.h
+++ b/arch/powerpc/include/asm/kvm_ppc.h
@@ -167,7 +167,7 @@ extern int kvmppc_pseries_do_hcall(struct kvm_vcpu *vcpu);
extern long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm,
struct kvm_create_spapr_tce_64 *args);
extern struct kvmppc_spapr_tce_table *kvmppc_find_table(
- struct kvm_vcpu *vcpu, unsigned long liobn);
+ struct kvm *kvm, unsigned long liobn);
extern long kvmppc_ioba_validate(struct kvmppc_spapr_tce_table *stt,
unsigned long ioba, unsigned long npages);
extern long kvmppc_tce_validate(struct kvmppc_spapr_tce_table *tt,
diff --git a/arch/powerpc/kvm/book3s_64_vio.c b/arch/powerpc/kvm/book3s_64_vio.c
index c379ff5a4438..15df8ae627d9 100644
--- a/arch/powerpc/kvm/book3s_64_vio.c
+++ b/arch/powerpc/kvm/book3s_64_vio.c
@@ -212,12 +212,13 @@ long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm,
long kvmppc_h_put_tce(struct kvm_vcpu *vcpu, unsigned long liobn,
unsigned long ioba, unsigned long tce)
{
- struct kvmppc_spapr_tce_table *stt = kvmppc_find_table(vcpu, liobn);
+ struct kvmppc_spapr_tce_table *stt;
long ret;
/* udbg_printf("H_PUT_TCE(): liobn=0x%lx ioba=0x%lx, tce=0x%lx\n", */
/* liobn, ioba, tce); */
+ stt = kvmppc_find_table(vcpu->kvm, liobn);
if (!stt)
return H_TOO_HARD;
@@ -245,7 +246,7 @@ long kvmppc_h_put_tce_indirect(struct kvm_vcpu *vcpu,
u64 __user *tces;
u64 tce;
- stt = kvmppc_find_table(vcpu, liobn);
+ stt = kvmppc_find_table(vcpu->kvm, liobn);
if (!stt)
return H_TOO_HARD;
@@ -299,7 +300,7 @@ long kvmppc_h_stuff_tce(struct kvm_vcpu *vcpu,
struct kvmppc_spapr_tce_table *stt;
long i, ret;
- stt = kvmppc_find_table(vcpu, liobn);
+ stt = kvmppc_find_table(vcpu->kvm, liobn);
if (!stt)
return H_TOO_HARD;
diff --git a/arch/powerpc/kvm/book3s_64_vio_hv.c b/arch/powerpc/kvm/book3s_64_vio_hv.c
index e4c4ea973e57..918af76ab2b6 100644
--- a/arch/powerpc/kvm/book3s_64_vio_hv.c
+++ b/arch/powerpc/kvm/book3s_64_vio_hv.c
@@ -48,10 +48,9 @@
* WARNING: This will be called in real or virtual mode on HV KVM and virtual
* mode on PR KVM
*/
-struct kvmppc_spapr_tce_table *kvmppc_find_table(struct kvm_vcpu *vcpu,
+struct kvmppc_spapr_tce_table *kvmppc_find_table(struct kvm *kvm,
unsigned long liobn)
{
- struct kvm *kvm = vcpu->kvm;
struct kvmppc_spapr_tce_table *stt;
list_for_each_entry_lockless(stt, &kvm->arch.spapr_tce_tables, list)
@@ -182,12 +181,13 @@ EXPORT_SYMBOL_GPL(kvmppc_gpa_to_ua);
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 = kvmppc_find_table(vcpu, liobn);
+ struct kvmppc_spapr_tce_table *stt;
long ret;
/* udbg_printf("H_PUT_TCE(): liobn=0x%lx ioba=0x%lx, tce=0x%lx\n", */
/* liobn, ioba, tce); */
+ stt = kvmppc_find_table(vcpu->kvm, liobn);
if (!stt)
return H_TOO_HARD;
@@ -240,7 +240,7 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu,
unsigned long tces, entry, ua = 0;
unsigned long *rmap = NULL;
- stt = kvmppc_find_table(vcpu, liobn);
+ stt = kvmppc_find_table(vcpu->kvm, liobn);
if (!stt)
return H_TOO_HARD;
@@ -301,7 +301,7 @@ long kvmppc_rm_h_stuff_tce(struct kvm_vcpu *vcpu,
struct kvmppc_spapr_tce_table *stt;
long i, ret;
- stt = kvmppc_find_table(vcpu, liobn);
+ stt = kvmppc_find_table(vcpu->kvm, liobn);
if (!stt)
return H_TOO_HARD;
@@ -322,12 +322,13 @@ long kvmppc_rm_h_stuff_tce(struct kvm_vcpu *vcpu,
long kvmppc_h_get_tce(struct kvm_vcpu *vcpu, unsigned long liobn,
unsigned long ioba)
{
- struct kvmppc_spapr_tce_table *stt = kvmppc_find_table(vcpu, liobn);
+ struct kvmppc_spapr_tce_table *stt;
long ret;
unsigned long idx;
struct page *page;
u64 *tbl;
+ stt = kvmppc_find_table(vcpu->kvm, liobn);
if (!stt)
return H_TOO_HARD;
--
2.11.0
^ permalink raw reply related [flat|nested] 21+ messages in thread
* [PATCH kernel v5 08/10] KVM: PPC: Use preregistered memory API to access TCE list
2017-02-22 8:21 [PATCH kernel v5 00/10] powerpc/kvm/vfio: Enable in-kernel acceleration Alexey Kardashevskiy
` (6 preceding siblings ...)
2017-02-22 8:21 ` [PATCH kernel v5 07/10] KVM: PPC: Pass kvm* to kvmppc_find_table() Alexey Kardashevskiy
@ 2017-02-22 8:21 ` Alexey Kardashevskiy
2017-02-22 8:21 ` [PATCH kernel v5 09/10] KVM: PPC: iommu: Unify TCE checking Alexey Kardashevskiy
2017-02-22 8:21 ` [PATCH kernel v5 10/10] KVM: PPC: VFIO: Add in-kernel acceleration for VFIO Alexey Kardashevskiy
9 siblings, 0 replies; 21+ messages in thread
From: Alexey Kardashevskiy @ 2017-02-22 8:21 UTC (permalink / raw)
To: linuxppc-dev
Cc: Alexey Kardashevskiy, Alex Williamson, David Gibson,
Paul Mackerras, kvm-ppc, kvm
VFIO on sPAPR already implements guest memory pre-registration
when the entire guest RAM gets pinned. This can be used to translate
the physical address of a guest page containing the TCE list
from H_PUT_TCE_INDIRECT.
This makes use of the pre-registrered memory API to access TCE list
pages in order to avoid unnecessary locking on the KVM memory
reverse map as we know that all of guest memory is pinned and
we have a flat array mapping GPA to HPA which makes it simpler and
quicker to index into that array (even with looking up the
kernel page tables in vmalloc_to_phys) than it is to find the memslot,
lock the rmap entry, look up the user page tables, and unlock the rmap
entry. Note that the rmap pointer is initialized to NULL
where declared (not in this patch).
If a requested chunk of memory has not been preregistered, this will
fall back to non-preregistered case and lock rmap.
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
---
Changes:
v4:
* removed oneline inlines
* now falls back to locking rmap if TCE list is not in preregistered memory
v2:
* updated the commit log with David's comment
---
arch/powerpc/kvm/book3s_64_vio_hv.c | 58 +++++++++++++++++++++++++++----------
1 file changed, 42 insertions(+), 16 deletions(-)
diff --git a/arch/powerpc/kvm/book3s_64_vio_hv.c b/arch/powerpc/kvm/book3s_64_vio_hv.c
index 918af76ab2b6..0f145fc7a3a5 100644
--- a/arch/powerpc/kvm/book3s_64_vio_hv.c
+++ b/arch/powerpc/kvm/book3s_64_vio_hv.c
@@ -239,6 +239,7 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu,
long i, ret = H_SUCCESS;
unsigned long tces, entry, ua = 0;
unsigned long *rmap = NULL;
+ bool prereg = false;
stt = kvmppc_find_table(vcpu->kvm, liobn);
if (!stt)
@@ -259,23 +260,47 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu,
if (ret != H_SUCCESS)
return ret;
- if (kvmppc_gpa_to_ua(vcpu->kvm, tce_list, &ua, &rmap))
- return H_TOO_HARD;
+ if (mm_iommu_preregistered(vcpu->kvm->mm)) {
+ /*
+ * We get here if guest memory was pre-registered which
+ * is normally VFIO case and gpa->hpa translation does not
+ * depend on hpt.
+ */
+ struct mm_iommu_table_group_mem_t *mem;
- rmap = (void *) vmalloc_to_phys(rmap);
+ if (kvmppc_gpa_to_ua(vcpu->kvm, tce_list, &ua, NULL))
+ return H_TOO_HARD;
- /*
- * Synchronize with the MMU notifier callbacks in
- * book3s_64_mmu_hv.c (kvm_unmap_hva_hv etc.).
- * While we have the rmap lock, code running on other CPUs
- * cannot finish unmapping the host real page that backs
- * this guest real page, so we are OK to access the host
- * real page.
- */
- lock_rmap(rmap);
- if (kvmppc_rm_ua_to_hpa(vcpu, ua, &tces)) {
- ret = H_TOO_HARD;
- goto unlock_exit;
+ mem = mm_iommu_lookup_rm(vcpu->kvm->mm, ua, IOMMU_PAGE_SIZE_4K);
+ if (mem)
+ prereg = mm_iommu_ua_to_hpa_rm(mem, ua, &tces) == 0;
+ }
+
+ if (!prereg) {
+ /*
+ * This is usually a case of a guest with emulated devices only
+ * when TCE list is not in preregistered memory.
+ * We do not require memory to be preregistered in this case
+ * so lock rmap and do __find_linux_pte_or_hugepte().
+ */
+ if (kvmppc_gpa_to_ua(vcpu->kvm, tce_list, &ua, &rmap))
+ return H_TOO_HARD;
+
+ rmap = (void *) vmalloc_to_phys(rmap);
+
+ /*
+ * Synchronize with the MMU notifier callbacks in
+ * book3s_64_mmu_hv.c (kvm_unmap_hva_hv etc.).
+ * While we have the rmap lock, code running on other CPUs
+ * cannot finish unmapping the host real page that backs
+ * this guest real page, so we are OK to access the host
+ * real page.
+ */
+ lock_rmap(rmap);
+ if (kvmppc_rm_ua_to_hpa(vcpu, ua, &tces)) {
+ ret = H_TOO_HARD;
+ goto unlock_exit;
+ }
}
for (i = 0; i < npages; ++i) {
@@ -289,7 +314,8 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu,
}
unlock_exit:
- unlock_rmap(rmap);
+ if (rmap)
+ unlock_rmap(rmap);
return ret;
}
--
2.11.0
^ permalink raw reply related [flat|nested] 21+ messages in thread
* [PATCH kernel v5 09/10] KVM: PPC: iommu: Unify TCE checking
2017-02-22 8:21 [PATCH kernel v5 00/10] powerpc/kvm/vfio: Enable in-kernel acceleration Alexey Kardashevskiy
` (7 preceding siblings ...)
2017-02-22 8:21 ` [PATCH kernel v5 08/10] KVM: PPC: Use preregistered memory API to access TCE list Alexey Kardashevskiy
@ 2017-02-22 8:21 ` Alexey Kardashevskiy
2017-02-23 4:40 ` David Gibson
2017-02-22 8:21 ` [PATCH kernel v5 10/10] KVM: PPC: VFIO: Add in-kernel acceleration for VFIO Alexey Kardashevskiy
9 siblings, 1 reply; 21+ messages in thread
From: Alexey Kardashevskiy @ 2017-02-22 8:21 UTC (permalink / raw)
To: linuxppc-dev
Cc: Alexey Kardashevskiy, Alex Williamson, David Gibson,
Paul Mackerras, kvm-ppc, kvm
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
arch/powerpc/include/asm/iommu.h | 20 +++++++++++++++-----
arch/powerpc/include/asm/kvm_ppc.h | 6 ++++--
arch/powerpc/kernel/iommu.c | 37 +++++++++++++------------------------
arch/powerpc/kvm/book3s_64_vio_hv.c | 31 +++++++------------------------
4 files changed, 39 insertions(+), 55 deletions(-)
diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h
index 82e77ebf85f4..d4396d1d89df 100644
--- a/arch/powerpc/include/asm/iommu.h
+++ b/arch/powerpc/include/asm/iommu.h
@@ -296,11 +296,21 @@ static inline void iommu_restore(void)
#endif
/* The API to support IOMMU operations for VFIO */
-extern int iommu_tce_clear_param_check(struct iommu_table *tbl,
- unsigned long ioba, unsigned long tce_value,
- unsigned long npages);
-extern int iommu_tce_put_param_check(struct iommu_table *tbl,
- unsigned long ioba, unsigned long tce);
+extern int iommu_tce_check_ioba(unsigned long page_shift,
+ unsigned long offset, unsigned long size,
+ unsigned long ioba, unsigned long npages);
+extern int iommu_tce_check_tce(unsigned long page_shift,
+ unsigned long tce);
+
+#define iommu_tce_clear_param_check(tbl, ioba, tce_value, npages) \
+ (iommu_tce_check_ioba((tbl)->it_page_shift, \
+ (tbl)->it_offset, (tbl)->it_size, \
+ (ioba), (npages)) || (tce_value))
+#define iommu_tce_put_param_check(tbl, ioba, tce) \
+ (iommu_tce_check_ioba((tbl)->it_page_shift, \
+ (tbl)->it_offset, (tbl)->it_size, \
+ (ioba), 1) || \
+ iommu_tce_check_tce((tbl)->it_page_shift, (tce)))
extern void iommu_flush_tce(struct iommu_table *tbl);
extern int iommu_take_ownership(struct iommu_table *tbl);
diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h
index 37bc9e7e90ba..e04b7fb8ccaa 100644
--- a/arch/powerpc/include/asm/kvm_ppc.h
+++ b/arch/powerpc/include/asm/kvm_ppc.h
@@ -168,8 +168,10 @@ extern long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm,
struct kvm_create_spapr_tce_64 *args);
extern struct kvmppc_spapr_tce_table *kvmppc_find_table(
struct kvm *kvm, unsigned long liobn);
-extern long kvmppc_ioba_validate(struct kvmppc_spapr_tce_table *stt,
- unsigned long ioba, unsigned long npages);
+#define kvmppc_ioba_validate(stt, ioba, npages) \
+ (iommu_tce_check_ioba((stt)->page_shift, (stt)->offset, \
+ (stt)->size, (ioba), (npages)) ? \
+ H_PARAMETER : H_SUCCESS)
extern long kvmppc_tce_validate(struct kvmppc_spapr_tce_table *tt,
unsigned long tce);
extern long kvmppc_gpa_to_ua(struct kvm *kvm, unsigned long gpa,
diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index d02b8d22fb50..a419bd3997ba 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -960,47 +960,36 @@ void iommu_flush_tce(struct iommu_table *tbl)
}
EXPORT_SYMBOL_GPL(iommu_flush_tce);
-int iommu_tce_clear_param_check(struct iommu_table *tbl,
- unsigned long ioba, unsigned long tce_value,
- unsigned long npages)
+int iommu_tce_check_ioba(unsigned long page_shift,
+ unsigned long offset, unsigned long size,
+ unsigned long ioba, unsigned long npages)
{
- /* tbl->it_ops->clear() does not support any value but 0 */
- if (tce_value)
- return -EINVAL;
+ unsigned long mask = (1 << page_shift) - 1;
- if (ioba & ~IOMMU_PAGE_MASK(tbl))
+ if (ioba & mask)
return -EINVAL;
- ioba >>= tbl->it_page_shift;
- if (ioba < tbl->it_offset)
+ ioba >>= page_shift;
+ if (ioba < offset)
return -EINVAL;
- if ((ioba + npages) > (tbl->it_offset + tbl->it_size))
+ if ((ioba + 1) > (offset + size))
return -EINVAL;
return 0;
}
-EXPORT_SYMBOL_GPL(iommu_tce_clear_param_check);
+EXPORT_SYMBOL_GPL(iommu_tce_check_ioba);
-int iommu_tce_put_param_check(struct iommu_table *tbl,
- unsigned long ioba, unsigned long tce)
+int iommu_tce_check_tce(unsigned long page_shift, unsigned long tce)
{
- if (tce & ~IOMMU_PAGE_MASK(tbl))
- return -EINVAL;
-
- if (ioba & ~IOMMU_PAGE_MASK(tbl))
- return -EINVAL;
-
- ioba >>= tbl->it_page_shift;
- if (ioba < tbl->it_offset)
- return -EINVAL;
+ unsigned long mask = (1 << page_shift) - 1;
- if ((ioba + 1) > (tbl->it_offset + tbl->it_size))
+ if (tce & mask)
return -EINVAL;
return 0;
}
-EXPORT_SYMBOL_GPL(iommu_tce_put_param_check);
+EXPORT_SYMBOL_GPL(iommu_tce_check_tce);
long iommu_tce_xchg(struct iommu_table *tbl, unsigned long entry,
unsigned long *hpa, enum dma_data_direction *direction)
diff --git a/arch/powerpc/kvm/book3s_64_vio_hv.c b/arch/powerpc/kvm/book3s_64_vio_hv.c
index 0f145fc7a3a5..92d769f4eaea 100644
--- a/arch/powerpc/kvm/book3s_64_vio_hv.c
+++ b/arch/powerpc/kvm/book3s_64_vio_hv.c
@@ -62,27 +62,6 @@ struct kvmppc_spapr_tce_table *kvmppc_find_table(struct kvm *kvm,
EXPORT_SYMBOL_GPL(kvmppc_find_table);
/*
- * Validates IO address.
- *
- * WARNING: This will be called in real-mode on HV KVM and virtual
- * mode on PR KVM
- */
-long kvmppc_ioba_validate(struct kvmppc_spapr_tce_table *stt,
- unsigned long ioba, unsigned long npages)
-{
- unsigned long mask = (1ULL << stt->page_shift) - 1;
- unsigned long idx = ioba >> stt->page_shift;
-
- if ((ioba & mask) || (idx < stt->offset) ||
- (idx - stt->offset + npages > stt->size) ||
- (idx + npages < idx))
- return H_PARAMETER;
-
- return H_SUCCESS;
-}
-EXPORT_SYMBOL_GPL(kvmppc_ioba_validate);
-
-/*
* Validates TCE address.
* At the moment flags and page mask are validated.
* As the host kernel does not access those addresses (just puts them
@@ -95,10 +74,14 @@ EXPORT_SYMBOL_GPL(kvmppc_ioba_validate);
*/
long kvmppc_tce_validate(struct kvmppc_spapr_tce_table *stt, unsigned long tce)
{
- unsigned long page_mask = ~((1ULL << stt->page_shift) - 1);
- unsigned long mask = ~(page_mask | TCE_PCI_WRITE | TCE_PCI_READ);
+ unsigned long gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
+ enum dma_data_direction dir = iommu_tce_direction(tce);
- if (tce & mask)
+ /* Allow userspace to poison TCE table */
+ if (dir == DMA_NONE)
+ return H_SUCCESS;
+
+ if (iommu_tce_check_tce(stt->page_shift, gpa))
return H_PARAMETER;
return H_SUCCESS;
--
2.11.0
^ permalink raw reply related [flat|nested] 21+ messages in thread
* [PATCH kernel v5 10/10] KVM: PPC: VFIO: Add in-kernel acceleration for VFIO
2017-02-22 8:21 [PATCH kernel v5 00/10] powerpc/kvm/vfio: Enable in-kernel acceleration Alexey Kardashevskiy
` (8 preceding siblings ...)
2017-02-22 8:21 ` [PATCH kernel v5 09/10] KVM: PPC: iommu: Unify TCE checking Alexey Kardashevskiy
@ 2017-02-22 8:21 ` Alexey Kardashevskiy
2017-02-24 2:14 ` David Gibson
9 siblings, 1 reply; 21+ messages in thread
From: Alexey Kardashevskiy @ 2017-02-22 8:21 UTC (permalink / raw)
To: linuxppc-dev
Cc: Alexey Kardashevskiy, Alex Williamson, David Gibson,
Paul Mackerras, kvm-ppc, kvm
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 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@ozlabs.ru>
---
Changes:
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 | 307 ++++++++++++++++++++++++++++-
arch/powerpc/kvm/book3s_64_vio_hv.c | 152 +++++++++++++-
arch/powerpc/kvm/powerpc.c | 2 +
virt/kvm/vfio.c | 60 ++++++
8 files changed, 555 insertions(+), 8 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 e59b172666cd..a827006941f8 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 e04b7fb8ccaa..b8a39dec92cf 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);
+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 a2c9bb5a0ead..cdfa01169bd2 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -1076,6 +1076,7 @@ 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,
@@ -1097,6 +1098,13 @@ 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..062407af09ee 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 +43,36 @@
#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;
+}
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;
}
+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,
@@ -132,6 +290,8 @@ 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 +341,7 @@ 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 +370,102 @@ 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 (WARN_ON(!pua))
+ return H_HARDWARE;
+
+ 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 (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 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_PARAMETER;
+
+ mem = mm_iommu_lookup(kvm->mm, ua, 1ULL << tbl->it_page_shift);
+ if (!mem)
+ return H_TOO_HARD;
+
+ if (WARN_ON(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 (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(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, gpa;
+ enum dma_data_direction dir;
/* udbg_printf("H_PUT_TCE(): liobn=0x%lx ioba=0x%lx, tce=0x%lx\n", */
/* liobn, ioba, tce); */
@@ -230,7 +482,28 @@ 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);
+ entry = ioba >> stt->page_shift;
+ gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
+ dir = iommu_tce_direction(tce);
+
+ 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, gpa, dir);
+ srcu_read_unlock(&vcpu->kvm->srcu, idx);
+ }
+
+ if (WARN_ON_ONCE(ret == H_HARDWARE))
+ kvmppc_clear_tce(stit->tbl, entry);
+ else if (ret != H_SUCCESS)
+ return ret;
+ }
+
+ kvmppc_tce_put(stt, entry, tce);
return H_SUCCESS;
}
@@ -242,9 +515,10 @@ long kvmppc_h_put_tce_indirect(struct kvm_vcpu *vcpu,
{
struct kvmppc_spapr_tce_table *stt;
long i, ret = H_SUCCESS, idx;
- unsigned long entry, ua = 0;
+ unsigned long entry, ua = 0, gpa;
u64 __user *tces;
u64 tce;
+ struct kvmppc_spapr_tce_iommu_table *stit;
stt = kvmppc_find_table(vcpu->kvm, liobn);
if (!stt)
@@ -283,6 +557,18 @@ long kvmppc_h_put_tce_indirect(struct kvm_vcpu *vcpu,
if (ret != H_SUCCESS)
goto unlock_exit;
+ gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
+
+ list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
+ ret = kvmppc_tce_iommu_map(vcpu->kvm,
+ stit->tbl, entry + i, gpa,
+ iommu_tce_direction(tce));
+ if (WARN_ON_ONCE(ret == H_HARDWARE))
+ kvmppc_clear_tce(stit->tbl, entry);
+ else if (ret != H_SUCCESS)
+ goto unlock_exit;
+ }
+
kvmppc_tce_put(stt, entry + i, tce);
}
@@ -299,6 +585,7 @@ 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 +599,20 @@ 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 (WARN_ON_ONCE(ret == H_HARDWARE))
+ kvmppc_clear_tce(stit->tbl, entry);
+ else 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 92d769f4eaea..4a1d978ebd98 100644
--- a/arch/powerpc/kvm/book3s_64_vio_hv.c
+++ b/arch/powerpc/kvm/book3s_64_vio_hv.c
@@ -161,11 +161,111 @@ 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 (WARN_ON(!pua))
+ return H_HARDWARE;
+
+ pua = (void *) vmalloc_to_phys(pua);
+ if (!pua)
+ return H_TOO_HARD;
+
+ 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))
+ return H_HARDWARE;
+
+ 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 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(kvm, gpa, &ua, NULL))
+ return H_PARAMETER;
+
+ mem = mm_iommu_lookup_rm(kvm->mm, ua, 1ULL << tbl->it_page_shift);
+ if (!mem)
+ return H_TOO_HARD;
+
+ if (WARN_ON(mm_iommu_ua_to_hpa_rm(mem, ua, &hpa)))
+ return H_HARDWARE;
+
+ pua = (void *) vmalloc_to_phys(pua);
+ if (WARN_ON(!pua))
+ return H_HARDWARE;
+
+ if (WARN_ON(mm_iommu_mapped_inc(mem)))
+ return H_CLOSED;
+
+ 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(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, gpa;
+ 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 +282,25 @@ 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);
+ entry = ioba >> stt->page_shift;
+ gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
+ dir = iommu_tce_direction(tce);
+
+ 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, gpa, dir);
+
+ if (WARN_ON_ONCE(ret == H_HARDWARE))
+ kvmppc_rm_clear_tce(stit->tbl, entry);
+ else if (ret != H_SUCCESS)
+ return ret;
+ }
+
+ kvmppc_tce_put(stt, entry, tce);
return H_SUCCESS;
}
@@ -220,9 +338,10 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu,
{
struct kvmppc_spapr_tce_table *stt;
long i, ret = H_SUCCESS;
- unsigned long tces, entry, ua = 0;
+ unsigned long tces, entry, ua = 0, tce, gpa;
unsigned long *rmap = NULL;
bool prereg = false;
+ struct kvmppc_spapr_tce_iommu_table *stit;
stt = kvmppc_find_table(vcpu->kvm, liobn);
if (!stt)
@@ -287,12 +406,24 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu,
}
for (i = 0; i < npages; ++i) {
- unsigned long tce = be64_to_cpu(((u64 *)tces)[i]);
+ tce = be64_to_cpu(((u64 *)tces)[i]);
ret = kvmppc_tce_validate(stt, tce);
if (ret != H_SUCCESS)
goto unlock_exit;
+ gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
+
+ list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
+ ret = kvmppc_rm_tce_iommu_map(vcpu->kvm,
+ stit->tbl, entry + i, gpa,
+ iommu_tce_direction(tce));
+ if (WARN_ON_ONCE(ret == H_HARDWARE))
+ kvmppc_rm_clear_tce(stit->tbl, entry);
+ else if (ret != H_SUCCESS)
+ goto unlock_exit;
+ }
+
kvmppc_tce_put(stt, entry + i, tce);
}
@@ -309,6 +440,7 @@ 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 +454,20 @@ 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 (WARN_ON_ONCE(ret == H_HARDWARE))
+ kvmppc_rm_clear_tce(stit->tbl, entry);
+ else 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 cd892dec7cb6..f3127dc87912 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_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 */
}
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);
--
2.11.0
^ permalink raw reply related [flat|nested] 21+ messages in thread
* Re: [PATCH kernel v5 03/10] powerpc/iommu/vfio_spapr_tce: Cleanup iommu_table disposal
2017-02-22 8:21 ` [PATCH kernel v5 03/10] powerpc/iommu/vfio_spapr_tce: Cleanup iommu_table disposal Alexey Kardashevskiy
@ 2017-02-23 3:31 ` David Gibson
0 siblings, 0 replies; 21+ messages in thread
From: David Gibson @ 2017-02-23 3:31 UTC (permalink / raw)
To: Alexey Kardashevskiy
Cc: linuxppc-dev, Alex Williamson, Paul Mackerras, kvm-ppc, kvm
[-- Attachment #1: Type: text/plain, Size: 4882 bytes --]
On Wed, Feb 22, 2017 at 07:21:26PM +1100, Alexey Kardashevskiy wrote:
> At the moment iommu_table can be disposed by either calling
> iommu_table_free() directly or it_ops::free(); the only implementation
> of free() is in IODA2 - pnv_ioda2_table_free() - and it calls
> iommu_table_free() anyway.
>
> As we are going to have reference counting on tables, we need an unified
> way of disposing tables.
>
> This moves it_ops::free() call into iommu_free_table() and makes use
> of the latter. The free() callback now handles only platform-specific
> data.
>
> As from now on the iommu_free_table() calls it_ops->free(), we need
> to have it_ops initialized before calling iommu_free_table() so this
> moves this initialization in pnv_pci_ioda2_create_table().
>
> This should cause no behavioral change.
>
> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
> ---
> Changes:
> v5:
> * moved "tbl->it_ops = &pnv_ioda2_iommu_ops" earlier and updated
> the commit log
> ---
> arch/powerpc/kernel/iommu.c | 4 ++++
> arch/powerpc/platforms/powernv/pci-ioda.c | 10 ++++------
> drivers/vfio/vfio_iommu_spapr_tce.c | 2 +-
> 3 files changed, 9 insertions(+), 7 deletions(-)
>
> diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
> index 9bace5df05d5..bc142d87130f 100644
> --- a/arch/powerpc/kernel/iommu.c
> +++ b/arch/powerpc/kernel/iommu.c
> @@ -719,6 +719,9 @@ void iommu_free_table(struct iommu_table *tbl, const char *node_name)
> if (!tbl)
> return;
>
> + if (tbl->it_ops->free)
> + tbl->it_ops->free(tbl);
> +
> if (!tbl->it_map) {
> kfree(tbl);
> return;
> @@ -745,6 +748,7 @@ void iommu_free_table(struct iommu_table *tbl, const char *node_name)
> /* free table */
> kfree(tbl);
> }
> +EXPORT_SYMBOL_GPL(iommu_free_table);
>
> /* Creates TCEs for a user provided buffer. The user buffer must be
> * contiguous real kernel storage (not vmalloc). The address passed here
> diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
> index 133c7f300c12..27801c61ebdb 100644
> --- a/arch/powerpc/platforms/powernv/pci-ioda.c
> +++ b/arch/powerpc/platforms/powernv/pci-ioda.c
> @@ -1423,7 +1423,6 @@ static void pnv_pci_ioda2_release_dma_pe(struct pci_dev *dev, struct pnv_ioda_pe
> iommu_group_put(pe->table_group.group);
> BUG_ON(pe->table_group.group);
> }
> - pnv_pci_ioda2_table_free_pages(tbl);
> iommu_free_table(tbl, of_node_full_name(dev->dev.of_node));
> }
>
> @@ -2040,7 +2039,6 @@ static void pnv_ioda2_tce_free(struct iommu_table *tbl, long index,
> static void pnv_ioda2_table_free(struct iommu_table *tbl)
> {
> pnv_pci_ioda2_table_free_pages(tbl);
> - iommu_free_table(tbl, "pnv");
> }
>
> static struct iommu_table_ops pnv_ioda2_iommu_ops = {
> @@ -2317,6 +2315,8 @@ static long pnv_pci_ioda2_create_table(struct iommu_table_group *table_group,
> if (!tbl)
> return -ENOMEM;
>
> + tbl->it_ops = &pnv_ioda2_iommu_ops;
> +
> ret = pnv_pci_ioda2_table_alloc_pages(nid,
> bus_offset, page_shift, window_size,
> levels, tbl);
> @@ -2325,8 +2325,6 @@ static long pnv_pci_ioda2_create_table(struct iommu_table_group *table_group,
> return ret;
> }
>
> - tbl->it_ops = &pnv_ioda2_iommu_ops;
> -
> *ptbl = tbl;
>
> return 0;
> @@ -2367,7 +2365,7 @@ static long pnv_pci_ioda2_setup_default_config(struct pnv_ioda_pe *pe)
> if (rc) {
> pe_err(pe, "Failed to configure 32-bit TCE table, err %ld\n",
> rc);
> - pnv_ioda2_table_free(tbl);
> + iommu_free_table(tbl, "");
> return rc;
> }
>
> @@ -2455,7 +2453,7 @@ static void pnv_ioda2_take_ownership(struct iommu_table_group *table_group)
> pnv_pci_ioda2_unset_window(&pe->table_group, 0);
> if (pe->pbus)
> pnv_ioda_setup_bus_dma(pe, pe->pbus, false);
> - pnv_ioda2_table_free(tbl);
> + iommu_free_table(tbl, "pnv");
> }
>
> static void pnv_ioda2_release_ownership(struct iommu_table_group *table_group)
> diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
> index 59b3f62a2d64..ffab01874a22 100644
> --- a/drivers/vfio/vfio_iommu_spapr_tce.c
> +++ b/drivers/vfio/vfio_iommu_spapr_tce.c
> @@ -677,7 +677,7 @@ static void tce_iommu_free_table(struct tce_container *container,
> unsigned long pages = tbl->it_allocated_size >> PAGE_SHIFT;
>
> tce_iommu_userspace_view_free(tbl, container->mm);
> - tbl->it_ops->free(tbl);
> + iommu_free_table(tbl, "");
> decrement_locked_vm(container->mm, pages);
> }
>
--
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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^ permalink raw reply [flat|nested] 21+ messages in thread
* Re: [PATCH kernel v5 09/10] KVM: PPC: iommu: Unify TCE checking
2017-02-22 8:21 ` [PATCH kernel v5 09/10] KVM: PPC: iommu: Unify TCE checking Alexey Kardashevskiy
@ 2017-02-23 4:40 ` David Gibson
0 siblings, 0 replies; 21+ messages in thread
From: David Gibson @ 2017-02-23 4:40 UTC (permalink / raw)
To: Alexey Kardashevskiy
Cc: linuxppc-dev, Alex Williamson, Paul Mackerras, kvm-ppc, kvm
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On Wed, Feb 22, 2017 at 07:21:32PM +1100, Alexey Kardashevskiy wrote:
> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
I like this, except for one detail
> ---
> arch/powerpc/include/asm/iommu.h | 20 +++++++++++++++-----
> arch/powerpc/include/asm/kvm_ppc.h | 6 ++++--
> arch/powerpc/kernel/iommu.c | 37 +++++++++++++------------------------
> arch/powerpc/kvm/book3s_64_vio_hv.c | 31 +++++++------------------------
> 4 files changed, 39 insertions(+), 55 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h
> index 82e77ebf85f4..d4396d1d89df 100644
> --- a/arch/powerpc/include/asm/iommu.h
> +++ b/arch/powerpc/include/asm/iommu.h
> @@ -296,11 +296,21 @@ static inline void iommu_restore(void)
> #endif
>
> /* The API to support IOMMU operations for VFIO */
> -extern int iommu_tce_clear_param_check(struct iommu_table *tbl,
> - unsigned long ioba, unsigned long tce_value,
> - unsigned long npages);
> -extern int iommu_tce_put_param_check(struct iommu_table *tbl,
> - unsigned long ioba, unsigned long tce);
> +extern int iommu_tce_check_ioba(unsigned long page_shift,
> + unsigned long offset, unsigned long size,
> + unsigned long ioba, unsigned long npages);
> +extern int iommu_tce_check_tce(unsigned long page_shift,
> + unsigned long tce);
> +
> +#define iommu_tce_clear_param_check(tbl, ioba, tce_value, npages) \
> + (iommu_tce_check_ioba((tbl)->it_page_shift, \
> + (tbl)->it_offset, (tbl)->it_size, \
> + (ioba), (npages)) || (tce_value))
> +#define iommu_tce_put_param_check(tbl, ioba, tce) \
> + (iommu_tce_check_ioba((tbl)->it_page_shift, \
> + (tbl)->it_offset, (tbl)->it_size, \
> + (ioba), 1) || \
> + iommu_tce_check_tce((tbl)->it_page_shift, (tce)))
>
> extern void iommu_flush_tce(struct iommu_table *tbl);
> extern int iommu_take_ownership(struct iommu_table *tbl);
> diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h
> index 37bc9e7e90ba..e04b7fb8ccaa 100644
> --- a/arch/powerpc/include/asm/kvm_ppc.h
> +++ b/arch/powerpc/include/asm/kvm_ppc.h
> @@ -168,8 +168,10 @@ extern long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm,
> struct kvm_create_spapr_tce_64 *args);
> extern struct kvmppc_spapr_tce_table *kvmppc_find_table(
> struct kvm *kvm, unsigned long liobn);
> -extern long kvmppc_ioba_validate(struct kvmppc_spapr_tce_table *stt,
> - unsigned long ioba, unsigned long npages);
> +#define kvmppc_ioba_validate(stt, ioba, npages) \
> + (iommu_tce_check_ioba((stt)->page_shift, (stt)->offset, \
> + (stt)->size, (ioba), (npages)) ? \
> + H_PARAMETER : H_SUCCESS)
> extern long kvmppc_tce_validate(struct kvmppc_spapr_tce_table *tt,
> unsigned long tce);
> extern long kvmppc_gpa_to_ua(struct kvm *kvm, unsigned long gpa,
> diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
> index d02b8d22fb50..a419bd3997ba 100644
> --- a/arch/powerpc/kernel/iommu.c
> +++ b/arch/powerpc/kernel/iommu.c
> @@ -960,47 +960,36 @@ void iommu_flush_tce(struct iommu_table *tbl)
> }
> EXPORT_SYMBOL_GPL(iommu_flush_tce);
>
> -int iommu_tce_clear_param_check(struct iommu_table *tbl,
> - unsigned long ioba, unsigned long tce_value,
> - unsigned long npages)
> +int iommu_tce_check_ioba(unsigned long page_shift,
> + unsigned long offset, unsigned long size,
> + unsigned long ioba, unsigned long npages)
> {
> - /* tbl->it_ops->clear() does not support any value but 0 */
> - if (tce_value)
> - return -EINVAL;
> + unsigned long mask = (1 << page_shift) - 1;
>
> - if (ioba & ~IOMMU_PAGE_MASK(tbl))
> + if (ioba & mask)
> return -EINVAL;
>
> - ioba >>= tbl->it_page_shift;
> - if (ioba < tbl->it_offset)
> + ioba >>= page_shift;
> + if (ioba < offset)
> return -EINVAL;
>
> - if ((ioba + npages) > (tbl->it_offset + tbl->it_size))
> + if ((ioba + 1) > (offset + size))
> return -EINVAL;
>
> return 0;
> }
> -EXPORT_SYMBOL_GPL(iommu_tce_clear_param_check);
> +EXPORT_SYMBOL_GPL(iommu_tce_check_ioba);
>
> -int iommu_tce_put_param_check(struct iommu_table *tbl,
> - unsigned long ioba, unsigned long tce)
> +int iommu_tce_check_tce(unsigned long page_shift, unsigned long tce)
> {
> - if (tce & ~IOMMU_PAGE_MASK(tbl))
> - return -EINVAL;
> -
> - if (ioba & ~IOMMU_PAGE_MASK(tbl))
> - return -EINVAL;
> -
> - ioba >>= tbl->it_page_shift;
> - if (ioba < tbl->it_offset)
> - return -EINVAL;
> + unsigned long mask = (1 << page_shift) - 1;
>
> - if ((ioba + 1) > (tbl->it_offset + tbl->it_size))
> + if (tce & mask)
> return -EINVAL;
This doesn't seem to be quite correctly named, since it doesn't check
a TCE (including permission bits), but rather a GPA.
> return 0;
> }
> -EXPORT_SYMBOL_GPL(iommu_tce_put_param_check);
> +EXPORT_SYMBOL_GPL(iommu_tce_check_tce);
>
> long iommu_tce_xchg(struct iommu_table *tbl, unsigned long entry,
> unsigned long *hpa, enum dma_data_direction *direction)
> diff --git a/arch/powerpc/kvm/book3s_64_vio_hv.c b/arch/powerpc/kvm/book3s_64_vio_hv.c
> index 0f145fc7a3a5..92d769f4eaea 100644
> --- a/arch/powerpc/kvm/book3s_64_vio_hv.c
> +++ b/arch/powerpc/kvm/book3s_64_vio_hv.c
> @@ -62,27 +62,6 @@ struct kvmppc_spapr_tce_table *kvmppc_find_table(struct kvm *kvm,
> EXPORT_SYMBOL_GPL(kvmppc_find_table);
>
> /*
> - * Validates IO address.
> - *
> - * WARNING: This will be called in real-mode on HV KVM and virtual
> - * mode on PR KVM
> - */
> -long kvmppc_ioba_validate(struct kvmppc_spapr_tce_table *stt,
> - unsigned long ioba, unsigned long npages)
> -{
> - unsigned long mask = (1ULL << stt->page_shift) - 1;
> - unsigned long idx = ioba >> stt->page_shift;
> -
> - if ((ioba & mask) || (idx < stt->offset) ||
> - (idx - stt->offset + npages > stt->size) ||
> - (idx + npages < idx))
> - return H_PARAMETER;
> -
> - return H_SUCCESS;
> -}
> -EXPORT_SYMBOL_GPL(kvmppc_ioba_validate);
> -
> -/*
> * Validates TCE address.
> * At the moment flags and page mask are validated.
> * As the host kernel does not access those addresses (just puts them
> @@ -95,10 +74,14 @@ EXPORT_SYMBOL_GPL(kvmppc_ioba_validate);
> */
> long kvmppc_tce_validate(struct kvmppc_spapr_tce_table *stt, unsigned long tce)
> {
> - unsigned long page_mask = ~((1ULL << stt->page_shift) - 1);
> - unsigned long mask = ~(page_mask | TCE_PCI_WRITE | TCE_PCI_READ);
> + unsigned long gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
> + enum dma_data_direction dir = iommu_tce_direction(tce);
>
> - if (tce & mask)
> + /* Allow userspace to poison TCE table */
> + if (dir == DMA_NONE)
> + return H_SUCCESS;
> +
> + if (iommu_tce_check_tce(stt->page_shift, gpa))
> return H_PARAMETER;
>
> return H_SUCCESS;
--
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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^ permalink raw reply [flat|nested] 21+ messages in thread
* Re: [PATCH kernel v5 10/10] KVM: PPC: VFIO: Add in-kernel acceleration for VFIO
2017-02-22 8:21 ` [PATCH kernel v5 10/10] KVM: PPC: VFIO: Add in-kernel acceleration for VFIO Alexey Kardashevskiy
@ 2017-02-24 2:14 ` David Gibson
2017-02-24 3:29 ` Alexey Kardashevskiy
0 siblings, 1 reply; 21+ messages in thread
From: David Gibson @ 2017-02-24 2:14 UTC (permalink / raw)
To: Alexey Kardashevskiy
Cc: linuxppc-dev, Alex Williamson, Paul Mackerras, kvm-ppc, kvm
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On Wed, Feb 22, 2017 at 07:21:33PM +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 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 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@ozlabs.ru>
I have some comments on this patch, but all the definite ones are
pretty minor and could be done as later cleanups.
I have some more serious queries, but they are just queries and
requests for clarification. If there are satisfactory answers to
them, I'll add my R-b.
---
> Changes:
> 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 | 307 ++++++++++++++++++++++++++++-
> arch/powerpc/kvm/book3s_64_vio_hv.c | 152 +++++++++++++-
> arch/powerpc/kvm/powerpc.c | 2 +
> virt/kvm/vfio.c | 60 ++++++
> 8 files changed, 555 insertions(+), 8 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 e59b172666cd..a827006941f8 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 e04b7fb8ccaa..b8a39dec92cf 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);
> +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 a2c9bb5a0ead..cdfa01169bd2 100644
> --- a/include/uapi/linux/kvm.h
> +++ b/include/uapi/linux/kvm.h
> @@ -1076,6 +1076,7 @@ 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,
> @@ -1097,6 +1098,13 @@ 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..062407af09ee 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 +43,36 @@
> #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;
> +}
>
> 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;
> }
>
> +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;
I think it would be nicer to have a function that goes directly from
vfio_group to iommu_group rather than going via id. That can be a
later cleanup, though.
> +
> + 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,
> @@ -132,6 +290,8 @@ 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 +341,7 @@ 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 +370,102 @@ 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;
Initialization is unnecessary for the variable above.
> + const unsigned long pgsize = 1ULL << tbl->it_page_shift;
> + unsigned long *pua = IOMMU_TABLE_USERSPACE_ENTRY(tbl, entry);
> +
> + if (WARN_ON(!pua))
> + return H_HARDWARE;
> +
> + 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 (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 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_PARAMETER;
> +
> + mem = mm_iommu_lookup(kvm->mm, ua, 1ULL << tbl->it_page_shift);
> + if (!mem)
> + return H_TOO_HARD;
> +
> + if (WARN_ON(mm_iommu_ua_to_hpa(mem, ua, &hpa)))
> + return H_HARDWARE;
Remind me - could a failure here be triggered by userspace failing to
preregister all the memory it should?
> + if (mm_iommu_mapped_inc(mem))
> + return H_CLOSED;
> +
> + 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(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, gpa;
> + enum dma_data_direction dir;
>
> /* udbg_printf("H_PUT_TCE(): liobn=0x%lx ioba=0x%lx, tce=0x%lx\n", */
> /* liobn, ioba, tce); */
> @@ -230,7 +482,28 @@ 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);
> + entry = ioba >> stt->page_shift;
> + gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
> + dir = iommu_tce_direction(tce);
> +
> + 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, gpa, dir);
> + srcu_read_unlock(&vcpu->kvm->srcu, idx);
> + }
> +
> + if (WARN_ON_ONCE(ret == H_HARDWARE))
> + kvmppc_clear_tce(stit->tbl, entry);
> + else if (ret != H_SUCCESS)
> + return ret;
> + }
> +
> + kvmppc_tce_put(stt, entry, tce);
>
> return H_SUCCESS;
> }
> @@ -242,9 +515,10 @@ long kvmppc_h_put_tce_indirect(struct kvm_vcpu *vcpu,
> {
> struct kvmppc_spapr_tce_table *stt;
> long i, ret = H_SUCCESS, idx;
> - unsigned long entry, ua = 0;
> + unsigned long entry, ua = 0, gpa;
> u64 __user *tces;
> u64 tce;
> + struct kvmppc_spapr_tce_iommu_table *stit;
>
> stt = kvmppc_find_table(vcpu->kvm, liobn);
> if (!stt)
> @@ -283,6 +557,18 @@ long kvmppc_h_put_tce_indirect(struct kvm_vcpu *vcpu,
> if (ret != H_SUCCESS)
> goto unlock_exit;
>
> + gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
> +
> + list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
> + ret = kvmppc_tce_iommu_map(vcpu->kvm,
> + stit->tbl, entry + i, gpa,
> + iommu_tce_direction(tce));
> + if (WARN_ON_ONCE(ret == H_HARDWARE))
> + kvmppc_clear_tce(stit->tbl, entry);
> + else if (ret != H_SUCCESS)
> + goto unlock_exit;
> + }
> +
> kvmppc_tce_put(stt, entry + i, tce);
> }
>
> @@ -299,6 +585,7 @@ 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 +599,20 @@ 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 (WARN_ON_ONCE(ret == H_HARDWARE))
> + kvmppc_clear_tce(stit->tbl, entry);
> + else 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 92d769f4eaea..4a1d978ebd98 100644
> --- a/arch/powerpc/kvm/book3s_64_vio_hv.c
> +++ b/arch/powerpc/kvm/book3s_64_vio_hv.c
> @@ -161,11 +161,111 @@ 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 (WARN_ON(!pua))
> + return H_HARDWARE;
> +
> + pua = (void *) vmalloc_to_phys(pua);
> + if (!pua)
> + return H_TOO_HARD;
> +
> + 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))
> + return H_HARDWARE;
To avoid a double WARN() (and to make the warnings easier to
understand) I'd suggest putting a WARN_ON() here, rather than in the
callers when they receieve an H_HARDWARE. IIUC this really shouldn't
ever happen, and it certainly can't be the guest's fault?
> +
> + 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 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(kvm, gpa, &ua, NULL))
> + return H_PARAMETER;
> +
> + mem = mm_iommu_lookup_rm(kvm->mm, ua, 1ULL << tbl->it_page_shift);
> + if (!mem)
> + return H_TOO_HARD;
> +
> + if (WARN_ON(mm_iommu_ua_to_hpa_rm(mem, ua, &hpa)))
> + return H_HARDWARE;
> +
> + pua = (void *) vmalloc_to_phys(pua);
> + if (WARN_ON(!pua))
> + return H_HARDWARE;
> +
> + if (WARN_ON(mm_iommu_mapped_inc(mem)))
> + return H_CLOSED;
> +
> + 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(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, gpa;
> + 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 +282,25 @@ 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);
> + entry = ioba >> stt->page_shift;
> + gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
> + dir = iommu_tce_direction(tce);
> +
> + 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, gpa, dir);
> +
> + if (WARN_ON_ONCE(ret == H_HARDWARE))
> + kvmppc_rm_clear_tce(stit->tbl, entry);
> + else if (ret != H_SUCCESS)
> + return ret;
> + }
> +
> + kvmppc_tce_put(stt, entry, tce);
>
> return H_SUCCESS;
> }
> @@ -220,9 +338,10 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu,
> {
> struct kvmppc_spapr_tce_table *stt;
> long i, ret = H_SUCCESS;
> - unsigned long tces, entry, ua = 0;
> + unsigned long tces, entry, ua = 0, tce, gpa;
> unsigned long *rmap = NULL;
> bool prereg = false;
> + struct kvmppc_spapr_tce_iommu_table *stit;
>
> stt = kvmppc_find_table(vcpu->kvm, liobn);
> if (!stt)
> @@ -287,12 +406,24 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu,
> }
>
> for (i = 0; i < npages; ++i) {
> - unsigned long tce = be64_to_cpu(((u64 *)tces)[i]);
> + tce = be64_to_cpu(((u64 *)tces)[i]);
>
> ret = kvmppc_tce_validate(stt, tce);
> if (ret != H_SUCCESS)
> goto unlock_exit;
>
> + gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
> +
> + list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
> + ret = kvmppc_rm_tce_iommu_map(vcpu->kvm,
> + stit->tbl, entry + i, gpa,
> + iommu_tce_direction(tce));
> + if (WARN_ON_ONCE(ret == H_HARDWARE))
I don't think you need the WARN() here - the only H_HARDWARE failure
path in iommu_map() already includes a WARN().
> + kvmppc_rm_clear_tce(stit->tbl, entry);
> + else if (ret != H_SUCCESS)
> + goto unlock_exit;
It's also not clear to me why the H_HARDWARE error path clears the
entry, but the other failure paths don't. Or why an H_HARDWARE will
result in continuing to set the rest of the TCEs, but other failures
won't.
> + }
> +
> kvmppc_tce_put(stt, entry + i, tce);
> }
>
> @@ -309,6 +440,7 @@ 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 +454,20 @@ 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 (WARN_ON_ONCE(ret == H_HARDWARE))
> + kvmppc_rm_clear_tce(stit->tbl, entry);
As noted earlier, I think this WARN belongs within iommu_unmap()
rather than out here.
> + else 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 cd892dec7cb6..f3127dc87912 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_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 */
> }
>
> 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
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 819 bytes --]
^ permalink raw reply [flat|nested] 21+ messages in thread
* Re: [PATCH kernel v5 10/10] KVM: PPC: VFIO: Add in-kernel acceleration for VFIO
2017-02-24 2:14 ` David Gibson
@ 2017-02-24 3:29 ` Alexey Kardashevskiy
2017-02-24 3:36 ` David Gibson
0 siblings, 1 reply; 21+ messages in thread
From: Alexey Kardashevskiy @ 2017-02-24 3:29 UTC (permalink / raw)
To: David Gibson; +Cc: linuxppc-dev, Alex Williamson, Paul Mackerras, kvm-ppc, kvm
[-- Attachment #1.1: Type: text/plain, Size: 32028 bytes --]
On 24/02/17 13:14, David Gibson wrote:
> On Wed, Feb 22, 2017 at 07:21:33PM +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 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 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@ozlabs.ru>
>
> I have some comments on this patch, but all the definite ones are
> pretty minor and could be done as later cleanups.
>
> I have some more serious queries, but they are just queries and
> requests for clarification. If there are satisfactory answers to
> them, I'll add my R-b.
>
>
> ---
>> Changes:
>> 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 | 307 ++++++++++++++++++++++++++++-
>> arch/powerpc/kvm/book3s_64_vio_hv.c | 152 +++++++++++++-
>> arch/powerpc/kvm/powerpc.c | 2 +
>> virt/kvm/vfio.c | 60 ++++++
>> 8 files changed, 555 insertions(+), 8 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 e59b172666cd..a827006941f8 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 e04b7fb8ccaa..b8a39dec92cf 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);
>> +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 a2c9bb5a0ead..cdfa01169bd2 100644
>> --- a/include/uapi/linux/kvm.h
>> +++ b/include/uapi/linux/kvm.h
>> @@ -1076,6 +1076,7 @@ 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,
>> @@ -1097,6 +1098,13 @@ 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..062407af09ee 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 +43,36 @@
>> #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;
>> +}
>>
>> 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;
>> }
>>
>> +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;
>
> I think it would be nicer to have a function that goes directly from
> vfio_group to iommu_group rather than going via id. That can be a
> later cleanup, though.
>
>> +
>> + 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,
>> @@ -132,6 +290,8 @@ 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 +341,7 @@ 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 +370,102 @@ 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;
>
> Initialization is unnecessary for the variable above.
>
>> + const unsigned long pgsize = 1ULL << tbl->it_page_shift;
>> + unsigned long *pua = IOMMU_TABLE_USERSPACE_ENTRY(tbl, entry);
>> +
>> + if (WARN_ON(!pua))
>> + return H_HARDWARE;
>> +
>> + 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 (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 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_PARAMETER;
>> +
>> + mem = mm_iommu_lookup(kvm->mm, ua, 1ULL << tbl->it_page_shift);
>> + if (!mem)
>> + return H_TOO_HARD;
>> +
>> + if (WARN_ON(mm_iommu_ua_to_hpa(mem, ua, &hpa)))
>> + return H_HARDWARE;
>
> Remind me - could a failure here be triggered by userspace failing to
> preregister all the memory it should?
mm_iommu_lookup() should fail first as the only reason for
mm_iommu_ua_to_hpa() to fail is (entry >= mem->entries) but this is checked
in mm_iommu_lookup().
>
>> + if (mm_iommu_mapped_inc(mem))
>> + return H_CLOSED;
>> +
>> + 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(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, gpa;
>> + enum dma_data_direction dir;
>>
>> /* udbg_printf("H_PUT_TCE(): liobn=0x%lx ioba=0x%lx, tce=0x%lx\n", */
>> /* liobn, ioba, tce); */
>> @@ -230,7 +482,28 @@ 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);
>> + entry = ioba >> stt->page_shift;
>> + gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
>> + dir = iommu_tce_direction(tce);
>> +
>> + 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, gpa, dir);
>> + srcu_read_unlock(&vcpu->kvm->srcu, idx);
>> + }
>> +
>> + if (WARN_ON_ONCE(ret == H_HARDWARE))
>> + kvmppc_clear_tce(stit->tbl, entry);
>> + else if (ret != H_SUCCESS)
>> + return ret;
>> + }
>> +
>> + kvmppc_tce_put(stt, entry, tce);
>>
>> return H_SUCCESS;
>> }
>> @@ -242,9 +515,10 @@ long kvmppc_h_put_tce_indirect(struct kvm_vcpu *vcpu,
>> {
>> struct kvmppc_spapr_tce_table *stt;
>> long i, ret = H_SUCCESS, idx;
>> - unsigned long entry, ua = 0;
>> + unsigned long entry, ua = 0, gpa;
>> u64 __user *tces;
>> u64 tce;
>> + struct kvmppc_spapr_tce_iommu_table *stit;
>>
>> stt = kvmppc_find_table(vcpu->kvm, liobn);
>> if (!stt)
>> @@ -283,6 +557,18 @@ long kvmppc_h_put_tce_indirect(struct kvm_vcpu *vcpu,
>> if (ret != H_SUCCESS)
>> goto unlock_exit;
>>
>> + gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
>> +
>> + list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
>> + ret = kvmppc_tce_iommu_map(vcpu->kvm,
>> + stit->tbl, entry + i, gpa,
>> + iommu_tce_direction(tce));
>> + if (WARN_ON_ONCE(ret == H_HARDWARE))
>> + kvmppc_clear_tce(stit->tbl, entry);
>> + else if (ret != H_SUCCESS)
>> + goto unlock_exit;
>> + }
>> +
>> kvmppc_tce_put(stt, entry + i, tce);
>> }
>>
>> @@ -299,6 +585,7 @@ 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 +599,20 @@ 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 (WARN_ON_ONCE(ret == H_HARDWARE))
>> + kvmppc_clear_tce(stit->tbl, entry);
>> + else 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 92d769f4eaea..4a1d978ebd98 100644
>> --- a/arch/powerpc/kvm/book3s_64_vio_hv.c
>> +++ b/arch/powerpc/kvm/book3s_64_vio_hv.c
>> @@ -161,11 +161,111 @@ 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 (WARN_ON(!pua))
>> + return H_HARDWARE;
>> +
>> + pua = (void *) vmalloc_to_phys(pua);
>> + if (!pua)
>> + return H_TOO_HARD;
>> +
>> + 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))
>> + return H_HARDWARE;
>
> To avoid a double WARN() (and to make the warnings easier to
> understand) I'd suggest putting a WARN_ON() here, rather than in the
> callers when they receieve an H_HARDWARE. IIUC this really shouldn't
> ever happen, and it certainly can't be the guest's fault?
Makes sense.
>> +
>> + 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 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(kvm, gpa, &ua, NULL))
>> + return H_PARAMETER;
Referred below as [1]
>> +
>> + mem = mm_iommu_lookup_rm(kvm->mm, ua, 1ULL << tbl->it_page_shift);
>> + if (!mem)
>> + return H_TOO_HARD;
>> +
>> + if (WARN_ON(mm_iommu_ua_to_hpa_rm(mem, ua, &hpa)))
>> + return H_HARDWARE;
>> +
>> + pua = (void *) vmalloc_to_phys(pua);
>> + if (WARN_ON(!pua))
>> + return H_HARDWARE;
>> +
>> + if (WARN_ON(mm_iommu_mapped_inc(mem)))
>> + return H_CLOSED;
>> +
>> + 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(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, gpa;
>> + 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 +282,25 @@ 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);
>> + entry = ioba >> stt->page_shift;
>> + gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
>> + dir = iommu_tce_direction(tce);
>> +
>> + 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, gpa, dir);
>> +
>> + if (WARN_ON_ONCE(ret == H_HARDWARE))
>> + kvmppc_rm_clear_tce(stit->tbl, entry);
>> + else if (ret != H_SUCCESS)
>> + return ret;
>> + }
>> +
>> + kvmppc_tce_put(stt, entry, tce);
>>
>> return H_SUCCESS;
>> }
>> @@ -220,9 +338,10 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu,
>> {
>> struct kvmppc_spapr_tce_table *stt;
>> long i, ret = H_SUCCESS;
>> - unsigned long tces, entry, ua = 0;
>> + unsigned long tces, entry, ua = 0, tce, gpa;
>> unsigned long *rmap = NULL;
>> bool prereg = false;
>> + struct kvmppc_spapr_tce_iommu_table *stit;
>>
>> stt = kvmppc_find_table(vcpu->kvm, liobn);
>> if (!stt)
>> @@ -287,12 +406,24 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu,
>> }
>>
>> for (i = 0; i < npages; ++i) {
>> - unsigned long tce = be64_to_cpu(((u64 *)tces)[i]);
>> + tce = be64_to_cpu(((u64 *)tces)[i]);
>>
>> ret = kvmppc_tce_validate(stt, tce);
>> if (ret != H_SUCCESS)
>> goto unlock_exit;
>>
>> + gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
>> +
>> + list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
>> + ret = kvmppc_rm_tce_iommu_map(vcpu->kvm,
>> + stit->tbl, entry + i, gpa,
>> + iommu_tce_direction(tce));
>> + if (WARN_ON_ONCE(ret == H_HARDWARE))
>
> I don't think you need the WARN() here - the only H_HARDWARE failure
> path in iommu_map() already includes a WARN().
True, I can drop it here.
>
>> + kvmppc_rm_clear_tce(stit->tbl, entry);
>> + else if (ret != H_SUCCESS)
>> + goto unlock_exit;
>
> It's also not clear to me why the H_HARDWARE error path clears the
> entry, but the other failure paths don't. Or why an H_HARDWARE will
> result in continuing to set the rest of the TCEs, but other failures
> won't.
The idea was that other failures still have some chance that handling may
succeed in virtual mode or via QEMU, H_HARDWARE is fatal.
I am just not sure if H_PARAMETER is what I want to return at [1], to make
the calling code simplier, I could return H_HARDWARE there as well (instead
of H_PARAMETER).
>
>> + }
>> +
>> kvmppc_tce_put(stt, entry + i, tce);
>> }
>>
>> @@ -309,6 +440,7 @@ 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 +454,20 @@ 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 (WARN_ON_ONCE(ret == H_HARDWARE))
>> + kvmppc_rm_clear_tce(stit->tbl, entry);
>
> As noted earlier, I think this WARN belongs within iommu_unmap()
> rather than out here.
>
>> + else 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 cd892dec7cb6..f3127dc87912 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_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 */
>> }
>>
>> 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);
>
--
Alexey
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^ permalink raw reply [flat|nested] 21+ messages in thread
* Re: [PATCH kernel v5 10/10] KVM: PPC: VFIO: Add in-kernel acceleration for VFIO
2017-02-24 3:29 ` Alexey Kardashevskiy
@ 2017-02-24 3:36 ` David Gibson
2017-02-24 3:43 ` Alexey Kardashevskiy
0 siblings, 1 reply; 21+ messages in thread
From: David Gibson @ 2017-02-24 3:36 UTC (permalink / raw)
To: Alexey Kardashevskiy
Cc: linuxppc-dev, Alex Williamson, Paul Mackerras, kvm-ppc, kvm
[-- Attachment #1: Type: text/plain, Size: 34787 bytes --]
On Fri, Feb 24, 2017 at 02:29:14PM +1100, Alexey Kardashevskiy wrote:
> On 24/02/17 13:14, David Gibson wrote:
> > On Wed, Feb 22, 2017 at 07:21:33PM +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 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 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@ozlabs.ru>
> >
> > I have some comments on this patch, but all the definite ones are
> > pretty minor and could be done as later cleanups.
> >
> > I have some more serious queries, but they are just queries and
> > requests for clarification. If there are satisfactory answers to
> > them, I'll add my R-b.
> >
> >
> > ---
> >> Changes:
> >> 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 | 307 ++++++++++++++++++++++++++++-
> >> arch/powerpc/kvm/book3s_64_vio_hv.c | 152 +++++++++++++-
> >> arch/powerpc/kvm/powerpc.c | 2 +
> >> virt/kvm/vfio.c | 60 ++++++
> >> 8 files changed, 555 insertions(+), 8 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 e59b172666cd..a827006941f8 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 e04b7fb8ccaa..b8a39dec92cf 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);
> >> +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 a2c9bb5a0ead..cdfa01169bd2 100644
> >> --- a/include/uapi/linux/kvm.h
> >> +++ b/include/uapi/linux/kvm.h
> >> @@ -1076,6 +1076,7 @@ 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,
> >> @@ -1097,6 +1098,13 @@ 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..062407af09ee 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 +43,36 @@
> >> #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;
> >> +}
> >>
> >> 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;
> >> }
> >>
> >> +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;
> >
> > I think it would be nicer to have a function that goes directly from
> > vfio_group to iommu_group rather than going via id. That can be a
> > later cleanup, though.
> >
> >> +
> >> + 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,
> >> @@ -132,6 +290,8 @@ 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 +341,7 @@ 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 +370,102 @@ 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;
> >
> > Initialization is unnecessary for the variable above.
> >
> >> + const unsigned long pgsize = 1ULL << tbl->it_page_shift;
> >> + unsigned long *pua = IOMMU_TABLE_USERSPACE_ENTRY(tbl, entry);
> >> +
> >> + if (WARN_ON(!pua))
> >> + return H_HARDWARE;
> >> +
> >> + 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 (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 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_PARAMETER;
> >> +
> >> + mem = mm_iommu_lookup(kvm->mm, ua, 1ULL << tbl->it_page_shift);
> >> + if (!mem)
> >> + return H_TOO_HARD;
> >> +
> >> + if (WARN_ON(mm_iommu_ua_to_hpa(mem, ua, &hpa)))
> >> + return H_HARDWARE;
> >
> > Remind me - could a failure here be triggered by userspace failing to
> > preregister all the memory it should?
>
>
> mm_iommu_lookup() should fail first as the only reason for
> mm_iommu_ua_to_hpa() to fail is (entry >= mem->entries) but this is checked
> in mm_iommu_lookup().
Ah, yes of course, I forgot. Ok, that should be fine.
> >
> >> + if (mm_iommu_mapped_inc(mem))
> >> + return H_CLOSED;
> >> +
> >> + 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(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, gpa;
> >> + enum dma_data_direction dir;
> >>
> >> /* udbg_printf("H_PUT_TCE(): liobn=0x%lx ioba=0x%lx, tce=0x%lx\n", */
> >> /* liobn, ioba, tce); */
> >> @@ -230,7 +482,28 @@ 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);
> >> + entry = ioba >> stt->page_shift;
> >> + gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
> >> + dir = iommu_tce_direction(tce);
> >> +
> >> + 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, gpa, dir);
> >> + srcu_read_unlock(&vcpu->kvm->srcu, idx);
> >> + }
> >> +
> >> + if (WARN_ON_ONCE(ret == H_HARDWARE))
> >> + kvmppc_clear_tce(stit->tbl, entry);
> >> + else if (ret != H_SUCCESS)
> >> + return ret;
> >> + }
> >> +
> >> + kvmppc_tce_put(stt, entry, tce);
> >>
> >> return H_SUCCESS;
> >> }
> >> @@ -242,9 +515,10 @@ long kvmppc_h_put_tce_indirect(struct kvm_vcpu *vcpu,
> >> {
> >> struct kvmppc_spapr_tce_table *stt;
> >> long i, ret = H_SUCCESS, idx;
> >> - unsigned long entry, ua = 0;
> >> + unsigned long entry, ua = 0, gpa;
> >> u64 __user *tces;
> >> u64 tce;
> >> + struct kvmppc_spapr_tce_iommu_table *stit;
> >>
> >> stt = kvmppc_find_table(vcpu->kvm, liobn);
> >> if (!stt)
> >> @@ -283,6 +557,18 @@ long kvmppc_h_put_tce_indirect(struct kvm_vcpu *vcpu,
> >> if (ret != H_SUCCESS)
> >> goto unlock_exit;
> >>
> >> + gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
> >> +
> >> + list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
> >> + ret = kvmppc_tce_iommu_map(vcpu->kvm,
> >> + stit->tbl, entry + i, gpa,
> >> + iommu_tce_direction(tce));
> >> + if (WARN_ON_ONCE(ret == H_HARDWARE))
> >> + kvmppc_clear_tce(stit->tbl, entry);
> >> + else if (ret != H_SUCCESS)
> >> + goto unlock_exit;
> >> + }
> >> +
> >> kvmppc_tce_put(stt, entry + i, tce);
> >> }
> >>
> >> @@ -299,6 +585,7 @@ 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 +599,20 @@ 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 (WARN_ON_ONCE(ret == H_HARDWARE))
> >> + kvmppc_clear_tce(stit->tbl, entry);
> >> + else 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 92d769f4eaea..4a1d978ebd98 100644
> >> --- a/arch/powerpc/kvm/book3s_64_vio_hv.c
> >> +++ b/arch/powerpc/kvm/book3s_64_vio_hv.c
> >> @@ -161,11 +161,111 @@ 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 (WARN_ON(!pua))
> >> + return H_HARDWARE;
> >> +
> >> + pua = (void *) vmalloc_to_phys(pua);
> >> + if (!pua)
> >> + return H_TOO_HARD;
> >> +
> >> + 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))
> >> + return H_HARDWARE;
> >
> > To avoid a double WARN() (and to make the warnings easier to
> > understand) I'd suggest putting a WARN_ON() here, rather than in the
> > callers when they receieve an H_HARDWARE. IIUC this really shouldn't
> > ever happen, and it certainly can't be the guest's fault?
>
>
> Makes sense.
I guess it might want WARN_ON_ONCE() to avoid spamming the user with
errors for every TCE, though.
> >> +
> >> + 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 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(kvm, gpa, &ua, NULL))
> >> + return H_PARAMETER;
>
>
> Referred below as [1]
>
>
> >> +
> >> + mem = mm_iommu_lookup_rm(kvm->mm, ua, 1ULL << tbl->it_page_shift);
> >> + if (!mem)
> >> + return H_TOO_HARD;
> >> +
> >> + if (WARN_ON(mm_iommu_ua_to_hpa_rm(mem, ua, &hpa)))
> >> + return H_HARDWARE;
> >> +
> >> + pua = (void *) vmalloc_to_phys(pua);
> >> + if (WARN_ON(!pua))
> >> + return H_HARDWARE;
> >> +
> >> + if (WARN_ON(mm_iommu_mapped_inc(mem)))
> >> + return H_CLOSED;
> >> +
> >> + 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(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, gpa;
> >> + 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 +282,25 @@ 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);
> >> + entry = ioba >> stt->page_shift;
> >> + gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
> >> + dir = iommu_tce_direction(tce);
> >> +
> >> + 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, gpa, dir);
> >> +
> >> + if (WARN_ON_ONCE(ret == H_HARDWARE))
> >> + kvmppc_rm_clear_tce(stit->tbl, entry);
> >> + else if (ret != H_SUCCESS)
> >> + return ret;
> >> + }
> >> +
> >> + kvmppc_tce_put(stt, entry, tce);
> >>
> >> return H_SUCCESS;
> >> }
> >> @@ -220,9 +338,10 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu,
> >> {
> >> struct kvmppc_spapr_tce_table *stt;
> >> long i, ret = H_SUCCESS;
> >> - unsigned long tces, entry, ua = 0;
> >> + unsigned long tces, entry, ua = 0, tce, gpa;
> >> unsigned long *rmap = NULL;
> >> bool prereg = false;
> >> + struct kvmppc_spapr_tce_iommu_table *stit;
> >>
> >> stt = kvmppc_find_table(vcpu->kvm, liobn);
> >> if (!stt)
> >> @@ -287,12 +406,24 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu,
> >> }
> >>
> >> for (i = 0; i < npages; ++i) {
> >> - unsigned long tce = be64_to_cpu(((u64 *)tces)[i]);
> >> + tce = be64_to_cpu(((u64 *)tces)[i]);
> >>
> >> ret = kvmppc_tce_validate(stt, tce);
> >> if (ret != H_SUCCESS)
> >> goto unlock_exit;
> >>
> >> + gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
> >> +
> >> + list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
> >> + ret = kvmppc_rm_tce_iommu_map(vcpu->kvm,
> >> + stit->tbl, entry + i, gpa,
> >> + iommu_tce_direction(tce));
> >> + if (WARN_ON_ONCE(ret == H_HARDWARE))
> >
> > I don't think you need the WARN() here - the only H_HARDWARE failure
> > path in iommu_map() already includes a WARN().
>
>
> True, I can drop it here.
>
>
> >
> >> + kvmppc_rm_clear_tce(stit->tbl, entry);
> >> + else if (ret != H_SUCCESS)
> >> + goto unlock_exit;
> >
> > It's also not clear to me why the H_HARDWARE error path clears the
> > entry, but the other failure paths don't. Or why an H_HARDWARE will
> > result in continuing to set the rest of the TCEs, but other failures
> > won't.
>
>
> The idea was that other failures still have some chance that handling may
> succeed in virtual mode or via QEMU, H_HARDWARE is fatal.
Um... yes.. but the logic seems to be backwards for that: on
H_HARDWARE you warn and keep going, on other errors you bail out
entirely.
> I am just not sure if H_PARAMETER is what I want to return at [1], to make
> the calling code simplier, I could return H_HARDWARE there as well (instead
> of H_PARAMETER).
That sounds right, IIUC the gpa to ua translation shouldn't ever
fail because of something the guest did. So I'd expect either
H_HARDWARE, or H_TOO_HARD (if there's some hope that virtual mode can
make the translation when real mode couldn't).
> >> + }
> >> +
> >> kvmppc_tce_put(stt, entry + i, tce);
> >> }
> >>
> >> @@ -309,6 +440,7 @@ 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 +454,20 @@ 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 (WARN_ON_ONCE(ret == H_HARDWARE))
> >> + kvmppc_rm_clear_tce(stit->tbl, entry);
> >
> > As noted earlier, I think this WARN belongs within iommu_unmap()
> > rather than out here.
> >
> >> + else 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 cd892dec7cb6..f3127dc87912 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_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 */
> >> }
> >>
> >> 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
[-- Attachment #2: signature.asc --]
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^ permalink raw reply [flat|nested] 21+ messages in thread
* Re: [PATCH kernel v5 10/10] KVM: PPC: VFIO: Add in-kernel acceleration for VFIO
2017-02-24 3:36 ` David Gibson
@ 2017-02-24 3:43 ` Alexey Kardashevskiy
2017-02-24 3:46 ` Alexey Kardashevskiy
2017-02-27 1:53 ` David Gibson
0 siblings, 2 replies; 21+ messages in thread
From: Alexey Kardashevskiy @ 2017-02-24 3:43 UTC (permalink / raw)
To: David Gibson; +Cc: linuxppc-dev, Alex Williamson, Paul Mackerras, kvm-ppc, kvm
[-- Attachment #1.1: Type: text/plain, Size: 35147 bytes --]
On 24/02/17 14:36, David Gibson wrote:
> On Fri, Feb 24, 2017 at 02:29:14PM +1100, Alexey Kardashevskiy wrote:
>> On 24/02/17 13:14, David Gibson wrote:
>>> On Wed, Feb 22, 2017 at 07:21:33PM +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 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 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@ozlabs.ru>
>>>
>>> I have some comments on this patch, but all the definite ones are
>>> pretty minor and could be done as later cleanups.
>>>
>>> I have some more serious queries, but they are just queries and
>>> requests for clarification. If there are satisfactory answers to
>>> them, I'll add my R-b.
>>>
>>>
>>> ---
>>>> Changes:
>>>> 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 | 307 ++++++++++++++++++++++++++++-
>>>> arch/powerpc/kvm/book3s_64_vio_hv.c | 152 +++++++++++++-
>>>> arch/powerpc/kvm/powerpc.c | 2 +
>>>> virt/kvm/vfio.c | 60 ++++++
>>>> 8 files changed, 555 insertions(+), 8 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 e59b172666cd..a827006941f8 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 e04b7fb8ccaa..b8a39dec92cf 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);
>>>> +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 a2c9bb5a0ead..cdfa01169bd2 100644
>>>> --- a/include/uapi/linux/kvm.h
>>>> +++ b/include/uapi/linux/kvm.h
>>>> @@ -1076,6 +1076,7 @@ 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,
>>>> @@ -1097,6 +1098,13 @@ 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..062407af09ee 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 +43,36 @@
>>>> #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;
>>>> +}
>>>>
>>>> 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;
>>>> }
>>>>
>>>> +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;
>>>
>>> I think it would be nicer to have a function that goes directly from
>>> vfio_group to iommu_group rather than going via id. That can be a
>>> later cleanup, though.
>>>
>>>> +
>>>> + 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,
>>>> @@ -132,6 +290,8 @@ 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 +341,7 @@ 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 +370,102 @@ 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;
>>>
>>> Initialization is unnecessary for the variable above.
>>>
>>>> + const unsigned long pgsize = 1ULL << tbl->it_page_shift;
>>>> + unsigned long *pua = IOMMU_TABLE_USERSPACE_ENTRY(tbl, entry);
>>>> +
>>>> + if (WARN_ON(!pua))
>>>> + return H_HARDWARE;
>>>> +
>>>> + 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 (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 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_PARAMETER;
>>>> +
>>>> + mem = mm_iommu_lookup(kvm->mm, ua, 1ULL << tbl->it_page_shift);
>>>> + if (!mem)
>>>> + return H_TOO_HARD;
>>>> +
>>>> + if (WARN_ON(mm_iommu_ua_to_hpa(mem, ua, &hpa)))
>>>> + return H_HARDWARE;
>>>
>>> Remind me - could a failure here be triggered by userspace failing to
>>> preregister all the memory it should?
>>
>>
>> mm_iommu_lookup() should fail first as the only reason for
>> mm_iommu_ua_to_hpa() to fail is (entry >= mem->entries) but this is checked
>> in mm_iommu_lookup().
>
> Ah, yes of course, I forgot. Ok, that should be fine.
>
>
>>>
>>>> + if (mm_iommu_mapped_inc(mem))
>>>> + return H_CLOSED;
>>>> +
>>>> + 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(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, gpa;
>>>> + enum dma_data_direction dir;
>>>>
>>>> /* udbg_printf("H_PUT_TCE(): liobn=0x%lx ioba=0x%lx, tce=0x%lx\n", */
>>>> /* liobn, ioba, tce); */
>>>> @@ -230,7 +482,28 @@ 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);
>>>> + entry = ioba >> stt->page_shift;
>>>> + gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
>>>> + dir = iommu_tce_direction(tce);
>>>> +
>>>> + 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, gpa, dir);
>>>> + srcu_read_unlock(&vcpu->kvm->srcu, idx);
>>>> + }
>>>> +
>>>> + if (WARN_ON_ONCE(ret == H_HARDWARE))
>>>> + kvmppc_clear_tce(stit->tbl, entry);
>>>> + else if (ret != H_SUCCESS)
>>>> + return ret;
>>>> + }
>>>> +
>>>> + kvmppc_tce_put(stt, entry, tce);
>>>>
>>>> return H_SUCCESS;
>>>> }
>>>> @@ -242,9 +515,10 @@ long kvmppc_h_put_tce_indirect(struct kvm_vcpu *vcpu,
>>>> {
>>>> struct kvmppc_spapr_tce_table *stt;
>>>> long i, ret = H_SUCCESS, idx;
>>>> - unsigned long entry, ua = 0;
>>>> + unsigned long entry, ua = 0, gpa;
>>>> u64 __user *tces;
>>>> u64 tce;
>>>> + struct kvmppc_spapr_tce_iommu_table *stit;
>>>>
>>>> stt = kvmppc_find_table(vcpu->kvm, liobn);
>>>> if (!stt)
>>>> @@ -283,6 +557,18 @@ long kvmppc_h_put_tce_indirect(struct kvm_vcpu *vcpu,
>>>> if (ret != H_SUCCESS)
>>>> goto unlock_exit;
>>>>
>>>> + gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
>>>> +
>>>> + list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
>>>> + ret = kvmppc_tce_iommu_map(vcpu->kvm,
>>>> + stit->tbl, entry + i, gpa,
>>>> + iommu_tce_direction(tce));
>>>> + if (WARN_ON_ONCE(ret == H_HARDWARE))
>>>> + kvmppc_clear_tce(stit->tbl, entry);
>>>> + else if (ret != H_SUCCESS)
>>>> + goto unlock_exit;
>>>> + }
>>>> +
>>>> kvmppc_tce_put(stt, entry + i, tce);
>>>> }
>>>>
>>>> @@ -299,6 +585,7 @@ 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 +599,20 @@ 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 (WARN_ON_ONCE(ret == H_HARDWARE))
>>>> + kvmppc_clear_tce(stit->tbl, entry);
>>>> + else 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 92d769f4eaea..4a1d978ebd98 100644
>>>> --- a/arch/powerpc/kvm/book3s_64_vio_hv.c
>>>> +++ b/arch/powerpc/kvm/book3s_64_vio_hv.c
>>>> @@ -161,11 +161,111 @@ 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 (WARN_ON(!pua))
>>>> + return H_HARDWARE;
>>>> +
>>>> + pua = (void *) vmalloc_to_phys(pua);
>>>> + if (!pua)
>>>> + return H_TOO_HARD;
>>>> +
>>>> + 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))
>>>> + return H_HARDWARE;
>>>
>>> To avoid a double WARN() (and to make the warnings easier to
>>> understand) I'd suggest putting a WARN_ON() here, rather than in the
>>> callers when they receieve an H_HARDWARE. IIUC this really shouldn't
>>> ever happen, and it certainly can't be the guest's fault?
>>
>>
>> Makes sense.
>
> I guess it might want WARN_ON_ONCE() to avoid spamming the user with
> errors for every TCE, though.
We do not expect this to happen at all :) I can convert all of them to
_ONCE really as the purpose of WARN_ON is mostly to document what we do not
expect.
>>>> +
>>>> + 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 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(kvm, gpa, &ua, NULL))
>>>> + return H_PARAMETER;
>>
>>
>> Referred below as [1]
>>
>>
>>>> +
>>>> + mem = mm_iommu_lookup_rm(kvm->mm, ua, 1ULL << tbl->it_page_shift);
>>>> + if (!mem)
>>>> + return H_TOO_HARD;
>>>> +
>>>> + if (WARN_ON(mm_iommu_ua_to_hpa_rm(mem, ua, &hpa)))
>>>> + return H_HARDWARE;
>>>> +
>>>> + pua = (void *) vmalloc_to_phys(pua);
>>>> + if (WARN_ON(!pua))
>>>> + return H_HARDWARE;
>>>> +
>>>> + if (WARN_ON(mm_iommu_mapped_inc(mem)))
>>>> + return H_CLOSED;
>>>> +
>>>> + 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(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, gpa;
>>>> + 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 +282,25 @@ 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);
>>>> + entry = ioba >> stt->page_shift;
>>>> + gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
>>>> + dir = iommu_tce_direction(tce);
>>>> +
>>>> + 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, gpa, dir);
>>>> +
>>>> + if (WARN_ON_ONCE(ret == H_HARDWARE))
>>>> + kvmppc_rm_clear_tce(stit->tbl, entry);
>>>> + else if (ret != H_SUCCESS)
>>>> + return ret;
>>>> + }
>>>> +
>>>> + kvmppc_tce_put(stt, entry, tce);
>>>>
>>>> return H_SUCCESS;
>>>> }
>>>> @@ -220,9 +338,10 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu,
>>>> {
>>>> struct kvmppc_spapr_tce_table *stt;
>>>> long i, ret = H_SUCCESS;
>>>> - unsigned long tces, entry, ua = 0;
>>>> + unsigned long tces, entry, ua = 0, tce, gpa;
>>>> unsigned long *rmap = NULL;
>>>> bool prereg = false;
>>>> + struct kvmppc_spapr_tce_iommu_table *stit;
>>>>
>>>> stt = kvmppc_find_table(vcpu->kvm, liobn);
>>>> if (!stt)
>>>> @@ -287,12 +406,24 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu,
>>>> }
>>>>
>>>> for (i = 0; i < npages; ++i) {
>>>> - unsigned long tce = be64_to_cpu(((u64 *)tces)[i]);
>>>> + tce = be64_to_cpu(((u64 *)tces)[i]);
>>>>
>>>> ret = kvmppc_tce_validate(stt, tce);
>>>> if (ret != H_SUCCESS)
>>>> goto unlock_exit;
>>>>
>>>> + gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
>>>> +
>>>> + list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
>>>> + ret = kvmppc_rm_tce_iommu_map(vcpu->kvm,
>>>> + stit->tbl, entry + i, gpa,
>>>> + iommu_tce_direction(tce));
>>>> + if (WARN_ON_ONCE(ret == H_HARDWARE))
>>>
>>> I don't think you need the WARN() here - the only H_HARDWARE failure
>>> path in iommu_map() already includes a WARN().
>>
>>
>> True, I can drop it here.
>>
>>
>>>
>>>> + kvmppc_rm_clear_tce(stit->tbl, entry);
>>>> + else if (ret != H_SUCCESS)
>>>> + goto unlock_exit;
>>>
>>> It's also not clear to me why the H_HARDWARE error path clears the
>>> entry, but the other failure paths don't. Or why an H_HARDWARE will
>>> result in continuing to set the rest of the TCEs, but other failures
>>> won't.
>>
>>
>> The idea was that other failures still have some chance that handling may
>> succeed in virtual mode or via QEMU, H_HARDWARE is fatal.
>
> Um... yes.. but the logic seems to be backwards for that: on
> H_HARDWARE you warn and keep going, on other errors you bail out
> entirely.
By "fatal" I means fatal for this particular hardware TCE(s), no hope in
trying this particular TCE in virtual mode.
>
>> I am just not sure if H_PARAMETER is what I want to return at [1], to make
>> the calling code simplier, I could return H_HARDWARE there as well (instead
>> of H_PARAMETER).
>
> That sounds right, IIUC the gpa to ua translation shouldn't ever
> fail because of something the guest did.
The guest can easily pass bad TCE/GPA which is not in any registered slot.
So it is rather H_PARAMETER.
> So I'd expect either
> H_HARDWARE, or H_TOO_HARD (if there's some hope that virtual mode can
> make the translation when real mode couldn't).
No, virtual mode uses the exact same helper.
>>>> + }
>>>> +
>>>> kvmppc_tce_put(stt, entry + i, tce);
>>>> }
>>>>
>>>> @@ -309,6 +440,7 @@ 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 +454,20 @@ 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 (WARN_ON_ONCE(ret == H_HARDWARE))
>>>> + kvmppc_rm_clear_tce(stit->tbl, entry);
>>>
>>> As noted earlier, I think this WARN belongs within iommu_unmap()
>>> rather than out here.
>>>
>>>> + else 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 cd892dec7cb6..f3127dc87912 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_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 */
>>>> }
>>>>
>>>> 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);
>>>
>>
>>
>
>
>
>
--
Alexey
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^ permalink raw reply [flat|nested] 21+ messages in thread
* Re: [PATCH kernel v5 10/10] KVM: PPC: VFIO: Add in-kernel acceleration for VFIO
2017-02-24 3:43 ` Alexey Kardashevskiy
@ 2017-02-24 3:46 ` Alexey Kardashevskiy
2017-02-27 1:53 ` David Gibson
1 sibling, 0 replies; 21+ messages in thread
From: Alexey Kardashevskiy @ 2017-02-24 3:46 UTC (permalink / raw)
To: David Gibson; +Cc: linuxppc-dev, Alex Williamson, Paul Mackerras, kvm-ppc, kvm
[-- Attachment #1.1: Type: text/plain, Size: 72587 bytes --]
On 24/02/17 14:43, Alexey Kardashevskiy wrote:
> On 24/02/17 14:36, David Gibson wrote:
>> On Fri, Feb 24, 2017 at 02:29:14PM +1100, Alexey Kardashevskiy wrote:
>>> On 24/02/17 13:14, David Gibson wrote:
>>>> On Wed, Feb 22, 2017 at 07:21:33PM +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 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 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@ozlabs.ru>
>>>>
>>>> I have some comments on this patch, but all the definite ones are
>>>> pretty minor and could be done as later cleanups.
>>>>
>>>> I have some more serious queries, but they are just queries and
>>>> requests for clarification. If there are satisfactory answers to
>>>> them, I'll add my R-b.
>>>>
>>>>
>>>> ---
>>>>> Changes:
>>>>> 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 | 307 ++++++++++++++++++++++++++++-
>>>>> arch/powerpc/kvm/book3s_64_vio_hv.c | 152 +++++++++++++-
>>>>> arch/powerpc/kvm/powerpc.c | 2 +
>>>>> virt/kvm/vfio.c | 60 ++++++
>>>>> 8 files changed, 555 insertions(+), 8 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 e59b172666cd..a827006941f8 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 e04b7fb8ccaa..b8a39dec92cf 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);
>>>>> +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 a2c9bb5a0ead..cdfa01169bd2 100644
>>>>> --- a/include/uapi/linux/kvm.h
>>>>> +++ b/include/uapi/linux/kvm.h
>>>>> @@ -1076,6 +1076,7 @@ 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,
>>>>> @@ -1097,6 +1098,13 @@ 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..062407af09ee 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 +43,36 @@
>>>>> #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;
>>>>> +}
>>>>>
>>>>> 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;
>>>>> }
>>>>>
>>>>> +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;
>>>>
>>>> I think it would be nicer to have a function that goes directly from
>>>> vfio_group to iommu_group rather than going via id. That can be a
>>>> later cleanup, though.
>>>>
>>>>> +
>>>>> + 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,
>>>>> @@ -132,6 +290,8 @@ 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 +341,7 @@ 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 +370,102 @@ 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;
>>>>
>>>> Initialization is unnecessary for the variable above.
>>>>
>>>>> + const unsigned long pgsize = 1ULL << tbl->it_page_shift;
>>>>> + unsigned long *pua = IOMMU_TABLE_USERSPACE_ENTRY(tbl, entry);
>>>>> +
>>>>> + if (WARN_ON(!pua))
>>>>> + return H_HARDWARE;
>>>>> +
>>>>> + 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 (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 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_PARAMETER;
>>>>> +
>>>>> + mem = mm_iommu_lookup(kvm->mm, ua, 1ULL << tbl->it_page_shift);
>>>>> + if (!mem)
>>>>> + return H_TOO_HARD;
>>>>> +
>>>>> + if (WARN_ON(mm_iommu_ua_to_hpa(mem, ua, &hpa)))
>>>>> + return H_HARDWARE;
>>>>
>>>> Remind me - could a failure here be triggered by userspace failing to
>>>> preregister all the memory it should?
>>>
>>>
>>> mm_iommu_lookup() should fail first as the only reason for
>>> mm_iommu_ua_to_hpa() to fail is (entry >= mem->entries) but this is checked
>>> in mm_iommu_lookup().
>>
>> Ah, yes of course, I forgot. Ok, that should be fine.
>>
>>
>>>>
>>>>> + if (mm_iommu_mapped_inc(mem))
>>>>> + return H_CLOSED;
>>>>> +
>>>>> + 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(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, gpa;
>>>>> + enum dma_data_direction dir;
>>>>>
>>>>> /* udbg_printf("H_PUT_TCE(): liobn=0x%lx ioba=0x%lx, tce=0x%lx\n", */
>>>>> /* liobn, ioba, tce); */
>>>>> @@ -230,7 +482,28 @@ 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);
>>>>> + entry = ioba >> stt->page_shift;
>>>>> + gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
>>>>> + dir = iommu_tce_direction(tce);
>>>>> +
>>>>> + 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, gpa, dir);
>>>>> + srcu_read_unlock(&vcpu->kvm->srcu, idx);
>>>>> + }
>>>>> +
>>>>> + if (WARN_ON_ONCE(ret == H_HARDWARE))
>>>>> + kvmppc_clear_tce(stit->tbl, entry);
>>>>> + else if (ret != H_SUCCESS)
>>>>> + return ret;
>>>>> + }
>>>>> +
>>>>> + kvmppc_tce_put(stt, entry, tce);
>>>>>
>>>>> return H_SUCCESS;
>>>>> }
>>>>> @@ -242,9 +515,10 @@ long kvmppc_h_put_tce_indirect(struct kvm_vcpu *vcpu,
>>>>> {
>>>>> struct kvmppc_spapr_tce_table *stt;
>>>>> long i, ret = H_SUCCESS, idx;
>>>>> - unsigned long entry, ua = 0;
>>>>> + unsigned long entry, ua = 0, gpa;
>>>>> u64 __user *tces;
>>>>> u64 tce;
>>>>> + struct kvmppc_spapr_tce_iommu_table *stit;
>>>>>
>>>>> stt = kvmppc_find_table(vcpu->kvm, liobn);
>>>>> if (!stt)
>>>>> @@ -283,6 +557,18 @@ long kvmppc_h_put_tce_indirect(struct kvm_vcpu *vcpu,
>>>>> if (ret != H_SUCCESS)
>>>>> goto unlock_exit;
>>>>>
>>>>> + gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
>>>>> +
>>>>> + list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
>>>>> + ret = kvmppc_tce_iommu_map(vcpu->kvm,
>>>>> + stit->tbl, entry + i, gpa,
>>>>> + iommu_tce_direction(tce));
>>>>> + if (WARN_ON_ONCE(ret == H_HARDWARE))
>>>>> + kvmppc_clear_tce(stit->tbl, entry);
>>>>> + else if (ret != H_SUCCESS)
>>>>> + goto unlock_exit;
>>>>> + }
>>>>> +
>>>>> kvmppc_tce_put(stt, entry + i, tce);
>>>>> }
>>>>>
>>>>> @@ -299,6 +585,7 @@ 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 +599,20 @@ 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 (WARN_ON_ONCE(ret == H_HARDWARE))
>>>>> + kvmppc_clear_tce(stit->tbl, entry);
>>>>> + else 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 92d769f4eaea..4a1d978ebd98 100644
>>>>> --- a/arch/powerpc/kvm/book3s_64_vio_hv.c
>>>>> +++ b/arch/powerpc/kvm/book3s_64_vio_hv.c
>>>>> @@ -161,11 +161,111 @@ 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 (WARN_ON(!pua))
>>>>> + return H_HARDWARE;
>>>>> +
>>>>> + pua = (void *) vmalloc_to_phys(pua);
>>>>> + if (!pua)
>>>>> + return H_TOO_HARD;
>>>>> +
>>>>> + 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))
>>>>> + return H_HARDWARE;
>>>>
>>>> To avoid a double WARN() (and to make the warnings easier to
>>>> understand) I'd suggest putting a WARN_ON() here, rather than in the
>>>> callers when they receieve an H_HARDWARE. IIUC this really shouldn't
>>>> ever happen, and it certainly can't be the guest's fault?
>>>
>>>
>>> Makes sense.
>>
>> I guess it might want WARN_ON_ONCE() to avoid spamming the user with
>> errors for every TCE, though.
>
>
> We do not expect this to happen at all :) I can convert all of them to
> _ONCE really as the purpose of WARN_ON is mostly to document what we do not
> expect.
>
>
>
>>>>> +
>>>>> + 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 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(kvm, gpa, &ua, NULL))
>>>>> + return H_PARAMETER;
>>>
>>>
>>> Referred below as [1]
>>>
>>>
>>>>> +
>>>>> + mem = mm_iommu_lookup_rm(kvm->mm, ua, 1ULL << tbl->it_page_shift);
>>>>> + if (!mem)
>>>>> + return H_TOO_HARD;
>>>>> +
>>>>> + if (WARN_ON(mm_iommu_ua_to_hpa_rm(mem, ua, &hpa)))
>>>>> + return H_HARDWARE;
>>>>> +
>>>>> + pua = (void *) vmalloc_to_phys(pua);
>>>>> + if (WARN_ON(!pua))
>>>>> + return H_HARDWARE;
>>>>> +
>>>>> + if (WARN_ON(mm_iommu_mapped_inc(mem)))
>>>>> + return H_CLOSED;
>>>>> +
>>>>> + 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(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, gpa;
>>>>> + 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 +282,25 @@ 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);
>>>>> + entry = ioba >> stt->page_shift;
>>>>> + gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
>>>>> + dir = iommu_tce_direction(tce);
>>>>> +
>>>>> + 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, gpa, dir);
>>>>> +
>>>>> + if (WARN_ON_ONCE(ret == H_HARDWARE))
>>>>> + kvmppc_rm_clear_tce(stit->tbl, entry);
>>>>> + else if (ret != H_SUCCESS)
>>>>> + return ret;
>>>>> + }
>>>>> +
>>>>> + kvmppc_tce_put(stt, entry, tce);
>>>>>
>>>>> return H_SUCCESS;
>>>>> }
>>>>> @@ -220,9 +338,10 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu,
>>>>> {
>>>>> struct kvmppc_spapr_tce_table *stt;
>>>>> long i, ret = H_SUCCESS;
>>>>> - unsigned long tces, entry, ua = 0;
>>>>> + unsigned long tces, entry, ua = 0, tce, gpa;
>>>>> unsigned long *rmap = NULL;
>>>>> bool prereg = false;
>>>>> + struct kvmppc_spapr_tce_iommu_table *stit;
>>>>>
>>>>> stt = kvmppc_find_table(vcpu->kvm, liobn);
>>>>> if (!stt)
>>>>> @@ -287,12 +406,24 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu,
>>>>> }
>>>>>
>>>>> for (i = 0; i < npages; ++i) {
>>>>> - unsigned long tce = be64_to_cpu(((u64 *)tces)[i]);
>>>>> + tce = be64_to_cpu(((u64 *)tces)[i]);
>>>>>
>>>>> ret = kvmppc_tce_validate(stt, tce);
>>>>> if (ret != H_SUCCESS)
>>>>> goto unlock_exit;
>>>>>
>>>>> + gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
>>>>> +
>>>>> + list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
>>>>> + ret = kvmppc_rm_tce_iommu_map(vcpu->kvm,
>>>>> + stit->tbl, entry + i, gpa,
>>>>> + iommu_tce_direction(tce));
>>>>> + if (WARN_ON_ONCE(ret == H_HARDWARE))
>>>>
>>>> I don't think you need the WARN() here - the only H_HARDWARE failure
>>>> path in iommu_map() already includes a WARN().
>>>
>>>
>>> True, I can drop it here.
>>>
>>>
>>>>
>>>>> + kvmppc_rm_clear_tce(stit->tbl, entry);
>>>>> + else if (ret != H_SUCCESS)
>>>>> + goto unlock_exit;
>>>>
>>>> It's also not clear to me why the H_HARDWARE error path clears the
>>>> entry, but the other failure paths don't. Or why an H_HARDWARE will
>>>> result in continuing to set the rest of the TCEs, but other failures
>>>> won't.
>>>
>>>
>>> The idea was that other failures still have some chance that handling may
>>> succeed in virtual mode or via QEMU, H_HARDWARE is fatal.
>>
>> Um... yes.. but the logic seems to be backwards for that: on
>> H_HARDWARE you warn and keep going, on other errors you bail out
>> entirely.
>
> By "fatal" I means fatal for this particular hardware TCE(s), no hope in
> trying this particular TCE in virtual mode.
>
>
>>
>>> I am just not sure if H_PARAMETER is what I want to return at [1], to make
>>> the calling code simplier, I could return H_HARDWARE there as well (instead
>>> of H_PARAMETER).
>>
>> That sounds right, IIUC the gpa to ua translation shouldn't ever
>> fail because of something the guest did.
>
>
> The guest can easily pass bad TCE/GPA which is not in any registered slot.
> So it is rather H_PARAMETER.
>
>> So I'd expect either
>> H_HARDWARE, or H_TOO_HARD (if there's some hope that virtual mode can
>> make the translation when real mode couldn't).
>
> No, virtual mode uses the exact same helper.
I just realized that kvmppc_gpa_to_ua() could be a part of
kvmppc_tce_validate() and kvmppc_rm_tce_iommu_map() could just receive the
userspace address rather than guest physical.
>
>
>>>>> + }
>>>>> +
>>>>> kvmppc_tce_put(stt, entry + i, tce);
>>>>> }
>>>>>
>>>>> @@ -309,6 +440,7 @@ 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 +454,20 @@ 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 (WARN_ON_ONCE(ret == H_HARDWARE))
>>>>> + kvmppc_rm_clear_tce(stit->tbl, entry);
>>>>
>>>> As noted earlier, I think this WARN belongs within iommu_unmap()
>>>> rather than out here.
>>>>
>>>>> + else 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 cd892dec7cb6..f3127dc87912 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_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 */
>>>>> }
>>>>>
>>>>> 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);
>>>>
>>>
>>>
>>
>>
>>
>>
>
>
--
Alexey
On 24/02/17 14:43, Alexey Kardashevskiy wrote:
> On 24/02/17 14:36, David Gibson wrote:
>> On Fri, Feb 24, 2017 at 02:29:14PM +1100, Alexey Kardashevskiy wrote:
>>> On 24/02/17 13:14, David Gibson wrote:
>>>> On Wed, Feb 22, 2017 at 07:21:33PM +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 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 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@ozlabs.ru>
>>>>
>>>> I have some comments on this patch, but all the definite ones are
>>>> pretty minor and could be done as later cleanups.
>>>>
>>>> I have some more serious queries, but they are just queries and
>>>> requests for clarification. If there are satisfactory answers to
>>>> them, I'll add my R-b.
>>>>
>>>>
>>>> ---
>>>>> Changes:
>>>>> 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 | 307
++++++++++++++++++++++++++++-
>>>>> arch/powerpc/kvm/book3s_64_vio_hv.c | 152 +++++++++++++-
>>>>> arch/powerpc/kvm/powerpc.c | 2 +
>>>>> virt/kvm/vfio.c | 60 ++++++
>>>>> 8 files changed, 555 insertions(+), 8 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 e59b172666cd..a827006941f8 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 e04b7fb8ccaa..b8a39dec92cf 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);
>>>>> +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 a2c9bb5a0ead..cdfa01169bd2 100644
>>>>> --- a/include/uapi/linux/kvm.h
>>>>> +++ b/include/uapi/linux/kvm.h
>>>>> @@ -1076,6 +1076,7 @@ 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,
>>>>> @@ -1097,6 +1098,13 @@ 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..062407af09ee 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 +43,36 @@
>>>>> #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;
>>>>> +}
>>>>>
>>>>> 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;
>>>>> }
>>>>>
>>>>> +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;
>>>>
>>>> I think it would be nicer to have a function that goes directly from
>>>> vfio_group to iommu_group rather than going via id. That can be a
>>>> later cleanup, though.
>>>>
>>>>> +
>>>>> + 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,
>>>>> @@ -132,6 +290,8 @@ 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 +341,7 @@ 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 +370,102 @@ 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;
>>>>
>>>> Initialization is unnecessary for the variable above.
>>>>
>>>>> + const unsigned long pgsize = 1ULL << tbl->it_page_shift;
>>>>> + unsigned long *pua = IOMMU_TABLE_USERSPACE_ENTRY(tbl, entry);
>>>>> +
>>>>> + if (WARN_ON(!pua))
>>>>> + return H_HARDWARE;
>>>>> +
>>>>> + 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 (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 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_PARAMETER;
>>>>> +
>>>>> + mem = mm_iommu_lookup(kvm->mm, ua, 1ULL << tbl->it_page_shift);
>>>>> + if (!mem)
>>>>> + return H_TOO_HARD;
>>>>> +
>>>>> + if (WARN_ON(mm_iommu_ua_to_hpa(mem, ua, &hpa)))
>>>>> + return H_HARDWARE;
>>>>
>>>> Remind me - could a failure here be triggered by userspace failing to
>>>> preregister all the memory it should?
>>>
>>>
>>> mm_iommu_lookup() should fail first as the only reason for
>>> mm_iommu_ua_to_hpa() to fail is (entry >= mem->entries) but this is checked
>>> in mm_iommu_lookup().
>>
>> Ah, yes of course, I forgot. Ok, that should be fine.
>>
>>
>>>>
>>>>> + if (mm_iommu_mapped_inc(mem))
>>>>> + return H_CLOSED;
>>>>> +
>>>>> + 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(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, gpa;
>>>>> + enum dma_data_direction dir;
>>>>>
>>>>> /* udbg_printf("H_PUT_TCE(): liobn=0x%lx ioba=0x%lx, tce=0x%lx\n", */
>>>>> /* liobn, ioba, tce); */
>>>>> @@ -230,7 +482,28 @@ 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);
>>>>> + entry = ioba >> stt->page_shift;
>>>>> + gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
>>>>> + dir = iommu_tce_direction(tce);
>>>>> +
>>>>> + 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, gpa, dir);
>>>>> + srcu_read_unlock(&vcpu->kvm->srcu, idx);
>>>>> + }
>>>>> +
>>>>> + if (WARN_ON_ONCE(ret == H_HARDWARE))
>>>>> + kvmppc_clear_tce(stit->tbl, entry);
>>>>> + else if (ret != H_SUCCESS)
>>>>> + return ret;
>>>>> + }
>>>>> +
>>>>> + kvmppc_tce_put(stt, entry, tce);
>>>>>
>>>>> return H_SUCCESS;
>>>>> }
>>>>> @@ -242,9 +515,10 @@ long kvmppc_h_put_tce_indirect(struct kvm_vcpu
*vcpu,
>>>>> {
>>>>> struct kvmppc_spapr_tce_table *stt;
>>>>> long i, ret = H_SUCCESS, idx;
>>>>> - unsigned long entry, ua = 0;
>>>>> + unsigned long entry, ua = 0, gpa;
>>>>> u64 __user *tces;
>>>>> u64 tce;
>>>>> + struct kvmppc_spapr_tce_iommu_table *stit;
>>>>>
>>>>> stt = kvmppc_find_table(vcpu->kvm, liobn);
>>>>> if (!stt)
>>>>> @@ -283,6 +557,18 @@ long kvmppc_h_put_tce_indirect(struct kvm_vcpu
*vcpu,
>>>>> if (ret != H_SUCCESS)
>>>>> goto unlock_exit;
>>>>>
>>>>> + gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
>>>>> +
>>>>> + list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
>>>>> + ret = kvmppc_tce_iommu_map(vcpu->kvm,
>>>>> + stit->tbl, entry + i, gpa,
>>>>> + iommu_tce_direction(tce));
>>>>> + if (WARN_ON_ONCE(ret == H_HARDWARE))
>>>>> + kvmppc_clear_tce(stit->tbl, entry);
>>>>> + else if (ret != H_SUCCESS)
>>>>> + goto unlock_exit;
>>>>> + }
>>>>> +
>>>>> kvmppc_tce_put(stt, entry + i, tce);
>>>>> }
>>>>>
>>>>> @@ -299,6 +585,7 @@ 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 +599,20 @@ 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 (WARN_ON_ONCE(ret == H_HARDWARE))
>>>>> + kvmppc_clear_tce(stit->tbl, entry);
>>>>> + else 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 92d769f4eaea..4a1d978ebd98 100644
>>>>> --- a/arch/powerpc/kvm/book3s_64_vio_hv.c
>>>>> +++ b/arch/powerpc/kvm/book3s_64_vio_hv.c
>>>>> @@ -161,11 +161,111 @@ 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 (WARN_ON(!pua))
>>>>> + return H_HARDWARE;
>>>>> +
>>>>> + pua = (void *) vmalloc_to_phys(pua);
>>>>> + if (!pua)
>>>>> + return H_TOO_HARD;
>>>>> +
>>>>> + 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))
>>>>> + return H_HARDWARE;
>>>>
>>>> To avoid a double WARN() (and to make the warnings easier to
>>>> understand) I'd suggest putting a WARN_ON() here, rather than in the
>>>> callers when they receieve an H_HARDWARE. IIUC this really shouldn't
>>>> ever happen, and it certainly can't be the guest's fault?
>>>
>>>
>>> Makes sense.
>>
>> I guess it might want WARN_ON_ONCE() to avoid spamming the user with
>> errors for every TCE, though.
>
>
> We do not expect this to happen at all :) I can convert all of them to
> _ONCE really as the purpose of WARN_ON is mostly to document what we do not
> expect.
>
>
>
>>>>> +
>>>>> + 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 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(kvm, gpa, &ua, NULL))
>>>>> + return H_PARAMETER;
>>>
>>>
>>> Referred below as [1]
>>>
>>>
>>>>> +
>>>>> + mem = mm_iommu_lookup_rm(kvm->mm, ua, 1ULL << tbl->it_page_shift);
>>>>> + if (!mem)
>>>>> + return H_TOO_HARD;
>>>>> +
>>>>> + if (WARN_ON(mm_iommu_ua_to_hpa_rm(mem, ua, &hpa)))
>>>>> + return H_HARDWARE;
>>>>> +
>>>>> + pua = (void *) vmalloc_to_phys(pua);
>>>>> + if (WARN_ON(!pua))
>>>>> + return H_HARDWARE;
>>>>> +
>>>>> + if (WARN_ON(mm_iommu_mapped_inc(mem)))
>>>>> + return H_CLOSED;
>>>>> +
>>>>> + 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(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, gpa;
>>>>> + 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 +282,25 @@ 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);
>>>>> + entry = ioba >> stt->page_shift;
>>>>> + gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
>>>>> + dir = iommu_tce_direction(tce);
>>>>> +
>>>>> + 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, gpa, dir);
>>>>> +
>>>>> + if (WARN_ON_ONCE(ret == H_HARDWARE))
>>>>> + kvmppc_rm_clear_tce(stit->tbl, entry);
>>>>> + else if (ret != H_SUCCESS)
>>>>> + return ret;
>>>>> + }
>>>>> +
>>>>> + kvmppc_tce_put(stt, entry, tce);
>>>>>
>>>>> return H_SUCCESS;
>>>>> }
>>>>> @@ -220,9 +338,10 @@ long kvmppc_rm_h_put_tce_indirect(struct
kvm_vcpu *vcpu,
>>>>> {
>>>>> struct kvmppc_spapr_tce_table *stt;
>>>>> long i, ret = H_SUCCESS;
>>>>> - unsigned long tces, entry, ua = 0;
>>>>> + unsigned long tces, entry, ua = 0, tce, gpa;
>>>>> unsigned long *rmap = NULL;
>>>>> bool prereg = false;
>>>>> + struct kvmppc_spapr_tce_iommu_table *stit;
>>>>>
>>>>> stt = kvmppc_find_table(vcpu->kvm, liobn);
>>>>> if (!stt)
>>>>> @@ -287,12 +406,24 @@ long kvmppc_rm_h_put_tce_indirect(struct
kvm_vcpu *vcpu,
>>>>> }
>>>>>
>>>>> for (i = 0; i < npages; ++i) {
>>>>> - unsigned long tce = be64_to_cpu(((u64 *)tces)[i]);
>>>>> + tce = be64_to_cpu(((u64 *)tces)[i]);
>>>>>
>>>>> ret = kvmppc_tce_validate(stt, tce);
>>>>> if (ret != H_SUCCESS)
>>>>> goto unlock_exit;
>>>>>
>>>>> + gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
>>>>> +
>>>>> + list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
>>>>> + ret = kvmppc_rm_tce_iommu_map(vcpu->kvm,
>>>>> + stit->tbl, entry + i, gpa,
>>>>> + iommu_tce_direction(tce));
>>>>> + if (WARN_ON_ONCE(ret == H_HARDWARE))
>>>>
>>>> I don't think you need the WARN() here - the only H_HARDWARE failure
>>>> path in iommu_map() already includes a WARN().
>>>
>>>
>>> True, I can drop it here.
>>>
>>>
>>>>
>>>>> + kvmppc_rm_clear_tce(stit->tbl, entry);
>>>>> + else if (ret != H_SUCCESS)
>>>>> + goto unlock_exit;
>>>>
>>>> It's also not clear to me why the H_HARDWARE error path clears the
>>>> entry, but the other failure paths don't. Or why an H_HARDWARE will
>>>> result in continuing to set the rest of the TCEs, but other failures
>>>> won't.
>>>
>>>
>>> The idea was that other failures still have some chance that handling may
>>> succeed in virtual mode or via QEMU, H_HARDWARE is fatal.
>>
>> Um... yes.. but the logic seems to be backwards for that: on
>> H_HARDWARE you warn and keep going, on other errors you bail out
>> entirely.
>
> By "fatal" I means fatal for this particular hardware TCE(s), no hope in
> trying this particular TCE in virtual mode.
>
>
>>
>>> I am just not sure if H_PARAMETER is what I want to return at [1], to make
>>> the calling code simplier, I could return H_HARDWARE there as well (instead
>>> of H_PARAMETER).
>>
>> That sounds right, IIUC the gpa to ua translation shouldn't ever
>> fail because of something the guest did.
>
>
> The guest can easily pass bad TCE/GPA which is not in any registered slot.
> So it is rather H_PARAMETER.
>
>> So I'd expect either
>> H_HARDWARE, or H_TOO_HARD (if there's some hope that virtual mode can
>> make the translation when real mode couldn't).
>
> No, virtual mode uses the exact same helper.
>
>
>>>>> + }
>>>>> +
>>>>> kvmppc_tce_put(stt, entry + i, tce);
>>>>> }
>>>>>
>>>>> @@ -309,6 +440,7 @@ 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 +454,20 @@ 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 (WARN_ON_ONCE(ret == H_HARDWARE))
>>>>> + kvmppc_rm_clear_tce(stit->tbl, entry);
>>>>
>>>> As noted earlier, I think this WARN belongs within iommu_unmap()
>>>> rather than out here.
>>>>
>>>>> + else 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 cd892dec7cb6..f3127dc87912 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_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 */
>>>>> }
>>>>>
>>>>> 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);
>>>>
>>>
>>>
>>
>>
>>
>>
>
>
--
Alexey
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^ permalink raw reply [flat|nested] 21+ messages in thread
* Re: [PATCH kernel v5 10/10] KVM: PPC: VFIO: Add in-kernel acceleration for VFIO
2017-02-24 3:43 ` Alexey Kardashevskiy
2017-02-24 3:46 ` Alexey Kardashevskiy
@ 2017-02-27 1:53 ` David Gibson
2017-02-27 3:20 ` Alexey Kardashevskiy
1 sibling, 1 reply; 21+ messages in thread
From: David Gibson @ 2017-02-27 1:53 UTC (permalink / raw)
To: Alexey Kardashevskiy
Cc: linuxppc-dev, Alex Williamson, Paul Mackerras, kvm-ppc, kvm
[-- Attachment #1: Type: text/plain, Size: 4659 bytes --]
On Fri, Feb 24, 2017 at 02:43:05PM +1100, Alexey Kardashevskiy wrote:
> On 24/02/17 14:36, David Gibson wrote:
> > On Fri, Feb 24, 2017 at 02:29:14PM +1100, Alexey Kardashevskiy wrote:
> >> On 24/02/17 13:14, David Gibson wrote:
> >>> On Wed, Feb 22, 2017 at 07:21:33PM +1100, Alexey Kardashevskiy
> wrote:
[snip]
> >>>> +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))
> >>>> + return H_HARDWARE;
> >>>
> >>> To avoid a double WARN() (and to make the warnings easier to
> >>> understand) I'd suggest putting a WARN_ON() here, rather than in the
> >>> callers when they receieve an H_HARDWARE. IIUC this really shouldn't
> >>> ever happen, and it certainly can't be the guest's fault?
> >>
> >>
> >> Makes sense.
> >
> > I guess it might want WARN_ON_ONCE() to avoid spamming the user with
> > errors for every TCE, though.
>
>
> We do not expect this to happen at all :) I can convert all of them to
> _ONCE really as the purpose of WARN_ON is mostly to document what we do not
> expect.
Sure, seems reasonable.
[snip]
> >>>> @@ -220,9 +338,10 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu,
> >>>> {
> >>>> struct kvmppc_spapr_tce_table *stt;
> >>>> long i, ret = H_SUCCESS;
> >>>> - unsigned long tces, entry, ua = 0;
> >>>> + unsigned long tces, entry, ua = 0, tce, gpa;
> >>>> unsigned long *rmap = NULL;
> >>>> bool prereg = false;
> >>>> + struct kvmppc_spapr_tce_iommu_table *stit;
> >>>>
> >>>> stt = kvmppc_find_table(vcpu->kvm, liobn);
> >>>> if (!stt)
> >>>> @@ -287,12 +406,24 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu,
> >>>> }
> >>>>
> >>>> for (i = 0; i < npages; ++i) {
> >>>> - unsigned long tce = be64_to_cpu(((u64 *)tces)[i]);
> >>>> + tce = be64_to_cpu(((u64 *)tces)[i]);
> >>>>
> >>>> ret = kvmppc_tce_validate(stt, tce);
> >>>> if (ret != H_SUCCESS)
> >>>> goto unlock_exit;
> >>>>
> >>>> + gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
> >>>> +
> >>>> + list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
> >>>> + ret = kvmppc_rm_tce_iommu_map(vcpu->kvm,
> >>>> + stit->tbl, entry + i, gpa,
> >>>> + iommu_tce_direction(tce));
> >>>> + if (WARN_ON_ONCE(ret == H_HARDWARE))
> >>>
> >>> I don't think you need the WARN() here - the only H_HARDWARE failure
> >>> path in iommu_map() already includes a WARN().
> >>
> >>
> >> True, I can drop it here.
> >>
> >>
> >>>
> >>>> + kvmppc_rm_clear_tce(stit->tbl, entry);
> >>>> + else if (ret != H_SUCCESS)
> >>>> + goto unlock_exit;
> >>>
> >>> It's also not clear to me why the H_HARDWARE error path clears the
> >>> entry, but the other failure paths don't. Or why an H_HARDWARE will
> >>> result in continuing to set the rest of the TCEs, but other failures
> >>> won't.
> >>
> >>
> >> The idea was that other failures still have some chance that handling may
> >> succeed in virtual mode or via QEMU, H_HARDWARE is fatal.
> >
> > Um... yes.. but the logic seems to be backwards for that: on
> > H_HARDWARE you warn and keep going, on other errors you bail out
> > entirely.
>
> By "fatal" I means fatal for this particular hardware TCE(s), no hope in
> trying this particular TCE in virtual mode.
Ok... still not following why that means the "fatal" error results in
continuing to attempt for the rest of the updated TCEs, whereas the
"non fatal" one bails out. Especially since the bail out will only go
to virtual mode if ret == H_TOO_HARD, which it isn't clear is the only
possibility.
> >> I am just not sure if H_PARAMETER is what I want to return at [1], to make
> >> the calling code simplier, I could return H_HARDWARE there as well (instead
> >> of H_PARAMETER).
> >
> > That sounds right, IIUC the gpa to ua translation shouldn't ever
> > fail because of something the guest did.
>
>
> The guest can easily pass bad TCE/GPA which is not in any registered slot.
> So it is rather H_PARAMETER.
Ah, yes.
> > So I'd expect either
> > H_HARDWARE, or H_TOO_HARD (if there's some hope that virtual mode can
> > make the translation when real mode couldn't).
>
> No, virtual mode uses the exact same helper.
Ok.
--
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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^ permalink raw reply [flat|nested] 21+ messages in thread
* Re: [PATCH kernel v5 10/10] KVM: PPC: VFIO: Add in-kernel acceleration for VFIO
2017-02-27 1:53 ` David Gibson
@ 2017-02-27 3:20 ` Alexey Kardashevskiy
2017-02-28 0:54 ` David Gibson
0 siblings, 1 reply; 21+ messages in thread
From: Alexey Kardashevskiy @ 2017-02-27 3:20 UTC (permalink / raw)
To: David Gibson; +Cc: linuxppc-dev, Alex Williamson, Paul Mackerras, kvm-ppc, kvm
[-- Attachment #1.1: Type: text/plain, Size: 4930 bytes --]
On 27/02/17 12:53, David Gibson wrote:
> On Fri, Feb 24, 2017 at 02:43:05PM +1100, Alexey Kardashevskiy wrote:
>> On 24/02/17 14:36, David Gibson wrote:
>>> On Fri, Feb 24, 2017 at 02:29:14PM +1100, Alexey Kardashevskiy wrote:
>>>> On 24/02/17 13:14, David Gibson wrote:
>>>>> On Wed, Feb 22, 2017 at 07:21:33PM +1100, Alexey Kardashevskiy
>> wrote:
> [snip]
>>>>>> +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))
>>>>>> + return H_HARDWARE;
>>>>>
>>>>> To avoid a double WARN() (and to make the warnings easier to
>>>>> understand) I'd suggest putting a WARN_ON() here, rather than in the
>>>>> callers when they receieve an H_HARDWARE. IIUC this really shouldn't
>>>>> ever happen, and it certainly can't be the guest's fault?
>>>>
>>>>
>>>> Makes sense.
>>>
>>> I guess it might want WARN_ON_ONCE() to avoid spamming the user with
>>> errors for every TCE, though.
>>
>>
>> We do not expect this to happen at all :) I can convert all of them to
>> _ONCE really as the purpose of WARN_ON is mostly to document what we do not
>> expect.
>
> Sure, seems reasonable.
>
> [snip]
>>>>>> @@ -220,9 +338,10 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu,
>>>>>> {
>>>>>> struct kvmppc_spapr_tce_table *stt;
>>>>>> long i, ret = H_SUCCESS;
>>>>>> - unsigned long tces, entry, ua = 0;
>>>>>> + unsigned long tces, entry, ua = 0, tce, gpa;
>>>>>> unsigned long *rmap = NULL;
>>>>>> bool prereg = false;
>>>>>> + struct kvmppc_spapr_tce_iommu_table *stit;
>>>>>>
>>>>>> stt = kvmppc_find_table(vcpu->kvm, liobn);
>>>>>> if (!stt)
>>>>>> @@ -287,12 +406,24 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu,
>>>>>> }
>>>>>>
>>>>>> for (i = 0; i < npages; ++i) {
>>>>>> - unsigned long tce = be64_to_cpu(((u64 *)tces)[i]);
>>>>>> + tce = be64_to_cpu(((u64 *)tces)[i]);
>>>>>>
>>>>>> ret = kvmppc_tce_validate(stt, tce);
>>>>>> if (ret != H_SUCCESS)
>>>>>> goto unlock_exit;
>>>>>>
>>>>>> + gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
>>>>>> +
>>>>>> + list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
>>>>>> + ret = kvmppc_rm_tce_iommu_map(vcpu->kvm,
>>>>>> + stit->tbl, entry + i, gpa,
>>>>>> + iommu_tce_direction(tce));
>>>>>> + if (WARN_ON_ONCE(ret == H_HARDWARE))
>>>>>
>>>>> I don't think you need the WARN() here - the only H_HARDWARE failure
>>>>> path in iommu_map() already includes a WARN().
>>>>
>>>>
>>>> True, I can drop it here.
>>>>
>>>>
>>>>>
>>>>>> + kvmppc_rm_clear_tce(stit->tbl, entry);
>>>>>> + else if (ret != H_SUCCESS)
>>>>>> + goto unlock_exit;
>>>>>
>>>>> It's also not clear to me why the H_HARDWARE error path clears the
>>>>> entry, but the other failure paths don't. Or why an H_HARDWARE will
>>>>> result in continuing to set the rest of the TCEs, but other failures
>>>>> won't.
>>>>
>>>>
>>>> The idea was that other failures still have some chance that handling may
>>>> succeed in virtual mode or via QEMU, H_HARDWARE is fatal.
>>>
>>> Um... yes.. but the logic seems to be backwards for that: on
>>> H_HARDWARE you warn and keep going, on other errors you bail out
>>> entirely.
>>
>> By "fatal" I means fatal for this particular hardware TCE(s), no hope in
>> trying this particular TCE in virtual mode.
>
> Ok... still not following why that means the "fatal" error results in
> continuing to attempt for the rest of the updated TCEs, whereas the
> "non fatal" one bails out.
I was applying the principle that if after all checks done we still cannot
update the hardware table, then just clear the TCE and move on. Or I
misunderstood the idea?
> Especially since the bail out will only go
> to virtual mode if ret == H_TOO_HARD, which it isn't clear is the only
> possibility.
H_TOO_HARD goes to virtual mode, H_TOO_HARD in virtual goes to the
userspace (QEMU).
Will "if (WARN_ON_ONCE(ret != H_SUCCESS && ret != H_TOO_HARD))" make more
sense?
>
>>>> I am just not sure if H_PARAMETER is what I want to return at [1], to make
>>>> the calling code simplier, I could return H_HARDWARE there as well (instead
>>>> of H_PARAMETER).
>>>
>>> That sounds right, IIUC the gpa to ua translation shouldn't ever
>>> fail because of something the guest did.
>>
>>
>> The guest can easily pass bad TCE/GPA which is not in any registered slot.
>> So it is rather H_PARAMETER.
>
> Ah, yes.
>
>>> So I'd expect either
>>> H_HARDWARE, or H_TOO_HARD (if there's some hope that virtual mode can
>>> make the translation when real mode couldn't).
>>
>> No, virtual mode uses the exact same helper.
>
> Ok.
>
--
Alexey
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^ permalink raw reply [flat|nested] 21+ messages in thread
* Re: [PATCH kernel v5 10/10] KVM: PPC: VFIO: Add in-kernel acceleration for VFIO
2017-02-27 3:20 ` Alexey Kardashevskiy
@ 2017-02-28 0:54 ` David Gibson
0 siblings, 0 replies; 21+ messages in thread
From: David Gibson @ 2017-02-28 0:54 UTC (permalink / raw)
To: Alexey Kardashevskiy
Cc: linuxppc-dev, Alex Williamson, Paul Mackerras, kvm-ppc, kvm
[-- Attachment #1: Type: text/plain, Size: 5642 bytes --]
On Mon, Feb 27, 2017 at 02:20:13PM +1100, Alexey Kardashevskiy wrote:
> On 27/02/17 12:53, David Gibson wrote:
> > On Fri, Feb 24, 2017 at 02:43:05PM +1100, Alexey Kardashevskiy wrote:
> >> On 24/02/17 14:36, David Gibson wrote:
> >>> On Fri, Feb 24, 2017 at 02:29:14PM +1100, Alexey Kardashevskiy wrote:
> >>>> On 24/02/17 13:14, David Gibson wrote:
> >>>>> On Wed, Feb 22, 2017 at 07:21:33PM +1100, Alexey Kardashevskiy
> >> wrote:
> > [snip]
> >>>>>> +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))
> >>>>>> + return H_HARDWARE;
> >>>>>
> >>>>> To avoid a double WARN() (and to make the warnings easier to
> >>>>> understand) I'd suggest putting a WARN_ON() here, rather than in the
> >>>>> callers when they receieve an H_HARDWARE. IIUC this really shouldn't
> >>>>> ever happen, and it certainly can't be the guest's fault?
> >>>>
> >>>>
> >>>> Makes sense.
> >>>
> >>> I guess it might want WARN_ON_ONCE() to avoid spamming the user with
> >>> errors for every TCE, though.
> >>
> >>
> >> We do not expect this to happen at all :) I can convert all of them to
> >> _ONCE really as the purpose of WARN_ON is mostly to document what we do not
> >> expect.
> >
> > Sure, seems reasonable.
> >
> > [snip]
> >>>>>> @@ -220,9 +338,10 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu,
> >>>>>> {
> >>>>>> struct kvmppc_spapr_tce_table *stt;
> >>>>>> long i, ret = H_SUCCESS;
> >>>>>> - unsigned long tces, entry, ua = 0;
> >>>>>> + unsigned long tces, entry, ua = 0, tce, gpa;
> >>>>>> unsigned long *rmap = NULL;
> >>>>>> bool prereg = false;
> >>>>>> + struct kvmppc_spapr_tce_iommu_table *stit;
> >>>>>>
> >>>>>> stt = kvmppc_find_table(vcpu->kvm, liobn);
> >>>>>> if (!stt)
> >>>>>> @@ -287,12 +406,24 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu,
> >>>>>> }
> >>>>>>
> >>>>>> for (i = 0; i < npages; ++i) {
> >>>>>> - unsigned long tce = be64_to_cpu(((u64 *)tces)[i]);
> >>>>>> + tce = be64_to_cpu(((u64 *)tces)[i]);
> >>>>>>
> >>>>>> ret = kvmppc_tce_validate(stt, tce);
> >>>>>> if (ret != H_SUCCESS)
> >>>>>> goto unlock_exit;
> >>>>>>
> >>>>>> + gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
> >>>>>> +
> >>>>>> + list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
> >>>>>> + ret = kvmppc_rm_tce_iommu_map(vcpu->kvm,
> >>>>>> + stit->tbl, entry + i, gpa,
> >>>>>> + iommu_tce_direction(tce));
> >>>>>> + if (WARN_ON_ONCE(ret == H_HARDWARE))
> >>>>>
> >>>>> I don't think you need the WARN() here - the only H_HARDWARE failure
> >>>>> path in iommu_map() already includes a WARN().
> >>>>
> >>>>
> >>>> True, I can drop it here.
> >>>>
> >>>>
> >>>>>
> >>>>>> + kvmppc_rm_clear_tce(stit->tbl, entry);
> >>>>>> + else if (ret != H_SUCCESS)
> >>>>>> + goto unlock_exit;
> >>>>>
> >>>>> It's also not clear to me why the H_HARDWARE error path clears the
> >>>>> entry, but the other failure paths don't. Or why an H_HARDWARE will
> >>>>> result in continuing to set the rest of the TCEs, but other failures
> >>>>> won't.
> >>>>
> >>>>
> >>>> The idea was that other failures still have some chance that handling may
> >>>> succeed in virtual mode or via QEMU, H_HARDWARE is fatal.
> >>>
> >>> Um... yes.. but the logic seems to be backwards for that: on
> >>> H_HARDWARE you warn and keep going, on other errors you bail out
> >>> entirely.
> >>
> >> By "fatal" I means fatal for this particular hardware TCE(s), no hope in
> >> trying this particular TCE in virtual mode.
> >
> > Ok... still not following why that means the "fatal" error results in
> > continuing to attempt for the rest of the updated TCEs, whereas the
> > "non fatal" one bails out.
>
> I was applying the principle that if after all checks done we still cannot
> update the hardware table, then just clear the TCE and move on. Or I
> misunderstood the idea?
*Still* not seeing why if we cannot update the hardware table we keep
trying with the rest of the entries, but on other failures we don't.
> > Especially since the bail out will only go
> > to virtual mode if ret == H_TOO_HARD, which it isn't clear is the only
> > possibility.
>
>
> H_TOO_HARD goes to virtual mode, H_TOO_HARD in virtual goes to the
> userspace (QEMU).
>
> Will "if (WARN_ON_ONCE(ret != H_SUCCESS && ret != H_TOO_HARD))" make more
> sense?
Probably, but depends what's in the if.
> >
> >>>> I am just not sure if H_PARAMETER is what I want to return at [1], to make
> >>>> the calling code simplier, I could return H_HARDWARE there as well (instead
> >>>> of H_PARAMETER).
> >>>
> >>> That sounds right, IIUC the gpa to ua translation shouldn't ever
> >>> fail because of something the guest did.
> >>
> >>
> >> The guest can easily pass bad TCE/GPA which is not in any registered slot.
> >> So it is rather H_PARAMETER.
> >
> > Ah, yes.
> >
> >>> So I'd expect either
> >>> H_HARDWARE, or H_TOO_HARD (if there's some hope that virtual mode can
> >>> make the translation when real mode couldn't).
> >>
> >> No, virtual mode uses the exact same helper.
> >
> > Ok.
> >
>
>
--
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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^ permalink raw reply [flat|nested] 21+ messages in thread
end of thread, other threads:[~2017-02-28 1:19 UTC | newest]
Thread overview: 21+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-02-22 8:21 [PATCH kernel v5 00/10] powerpc/kvm/vfio: Enable in-kernel acceleration Alexey Kardashevskiy
2017-02-22 8:21 ` [PATCH kernel v5 01/10] powerpc/mmu: Add real mode support for IOMMU preregistered memory Alexey Kardashevskiy
2017-02-22 8:21 ` [PATCH kernel v5 02/10] powerpc/powernv/iommu: Add real mode version of iommu_table_ops::exchange() Alexey Kardashevskiy
2017-02-22 8:21 ` [PATCH kernel v5 03/10] powerpc/iommu/vfio_spapr_tce: Cleanup iommu_table disposal Alexey Kardashevskiy
2017-02-23 3:31 ` David Gibson
2017-02-22 8:21 ` [PATCH kernel v5 04/10] powerpc/vfio_spapr_tce: Add reference counting to iommu_table Alexey Kardashevskiy
2017-02-22 8:21 ` [PATCH kernel v5 05/10] KVM: PPC: Reserve KVM_CAP_SPAPR_TCE_VFIO capability number Alexey Kardashevskiy
2017-02-22 8:21 ` [PATCH kernel v5 06/10] KVM: PPC: Enable IOMMU_API for KVM_BOOK3S_64 permanently Alexey Kardashevskiy
2017-02-22 8:21 ` [PATCH kernel v5 07/10] KVM: PPC: Pass kvm* to kvmppc_find_table() Alexey Kardashevskiy
2017-02-22 8:21 ` [PATCH kernel v5 08/10] KVM: PPC: Use preregistered memory API to access TCE list Alexey Kardashevskiy
2017-02-22 8:21 ` [PATCH kernel v5 09/10] KVM: PPC: iommu: Unify TCE checking Alexey Kardashevskiy
2017-02-23 4:40 ` David Gibson
2017-02-22 8:21 ` [PATCH kernel v5 10/10] KVM: PPC: VFIO: Add in-kernel acceleration for VFIO Alexey Kardashevskiy
2017-02-24 2:14 ` David Gibson
2017-02-24 3:29 ` Alexey Kardashevskiy
2017-02-24 3:36 ` David Gibson
2017-02-24 3:43 ` Alexey Kardashevskiy
2017-02-24 3:46 ` Alexey Kardashevskiy
2017-02-27 1:53 ` David Gibson
2017-02-27 3:20 ` Alexey Kardashevskiy
2017-02-28 0:54 ` David Gibson
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