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vfio: powerpc/spapr/iommu/powernv/ioda2: Rework IOMMU ownership control

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This adds tce_iommu_take_ownership() and tce_iommu_release_ownership
which call in a loop iommu_take_ownership()/iommu_release_ownership()
for every table on the group. As there is just one now, no change in
behaviour is expected.

At the moment the iommu_table struct has a set_bypass() which enables/
disables DMA bypass on IODA2 PHB. This is exposed to POWERPC IOMMU code
which calls this callback when external IOMMU users such as VFIO are
about to get over a PHB.

The set_bypass() callback is not really an iommu_table function but
IOMMU/PE function. This introduces a iommu_table_group_ops struct and
adds take_ownership()/release_ownership() callbacks to it which are
called when an external user takes/releases control over the IOMMU.

This replaces set_bypass() with ownership callbacks as it is not
necessarily just bypass enabling, it can be something else/more
so let's give it more generic name.

The callbacks is implemented for IODA2 only. Other platforms (P5IOC2,
IODA1) will use the old iommu_take_ownership/iommu_release_ownership API.
The following patches will replace iommu_take_ownership/
iommu_release_ownership calls in IODA2 with full IOMMU table release/
create.

As we here and touching bypass control, this removes
pnv_pci_ioda2_setup_bypass_pe() as it does not do much
more compared to pnv_pci_ioda2_set_bypass. This moves tce_bypass_base
initialization to pnv_pci_ioda2_setup_dma_pe.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
[aw: for the vfio related changes]
Acked-by: Alex Williamson <alex.williamson@redhat.com>
Reviewed-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Alexey Kardashevskiy 2015-06-05 16:35:10 +10:00 committed by Michael Ellerman
parent 0eaf4defc7
commit f87a88642e
4 changed files with 104 additions and 34 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

11
arch/powerpc/include/asm/iommu.h
View file

@ -93,7 +93,6 @@ struct iommu_table {
unsigned long it_page_shift;/* table iommu page size */
struct list_head it_group_list;/* List of iommu_table_group_link */
struct iommu_table_ops *it_ops;
void (*set_bypass)(struct iommu_table *tbl, bool enable);
};
/* Pure 2^n version of get_order */
@ -126,6 +125,15 @@ extern struct iommu_table *iommu_init_table(struct iommu_table * tbl,
int nid);
#define IOMMU_TABLE_GROUP_MAX_TABLES 1
struct iommu_table_group;
struct iommu_table_group_ops {
/* Switch ownership from platform code to external user (e.g. VFIO) */
void (*take_ownership)(struct iommu_table_group *table_group);
/* Switch ownership from external user (e.g. VFIO) back to core */
void (*release_ownership)(struct iommu_table_group *table_group);
};
struct iommu_table_group_link {
struct list_head next;
struct rcu_head rcu;
@ -135,6 +143,7 @@ struct iommu_table_group_link {
struct iommu_table_group {
struct iommu_group *group;
struct iommu_table *tables[IOMMU_TABLE_GROUP_MAX_TABLES];
struct iommu_table_group_ops *ops;
};
#ifdef CONFIG_IOMMU_API

12
arch/powerpc/kernel/iommu.c
View file

@ -1047,14 +1047,6 @@ int iommu_take_ownership(struct iommu_table *tbl)
memset(tbl->it_map, 0xff, sz);
/*
* Disable iommu bypass, otherwise the user can DMA to all of
* our physical memory via the bypass window instead of just
* the pages that has been explicitly mapped into the iommu
*/
if (tbl->set_bypass)
tbl->set_bypass(tbl, false);
return 0;
}
EXPORT_SYMBOL_GPL(iommu_take_ownership);
@ -1068,10 +1060,6 @@ void iommu_release_ownership(struct iommu_table *tbl)
/* Restore bit#0 set by iommu_init_table() */
if (tbl->it_offset == 0)
set_bit(0, tbl->it_map);
/* The kernel owns the device now, we can restore the iommu bypass */
if (tbl->set_bypass)
tbl->set_bypass(tbl, true);
}
EXPORT_SYMBOL_GPL(iommu_release_ownership);

45
arch/powerpc/platforms/powernv/pci-ioda.c
View file

@ -1919,13 +1919,8 @@ static void pnv_pci_ioda_setup_dma_pe(struct pnv_phb *phb,
}
}
static void pnv_pci_ioda2_set_bypass(struct iommu_table *tbl, bool enable)
static void pnv_pci_ioda2_set_bypass(struct pnv_ioda_pe *pe, bool enable)
{
struct iommu_table_group_link *tgl = list_first_entry_or_null(
&tbl->it_group_list, struct iommu_table_group_link,
next);
struct pnv_ioda_pe *pe = container_of(tgl->table_group,
struct pnv_ioda_pe, table_group);
uint16_t window_id = (pe->pe_number << 1 ) + 1;
int64_t rc;
@ -1952,19 +1947,31 @@ static void pnv_pci_ioda2_set_bypass(struct iommu_table *tbl, bool enable)
pe->tce_bypass_enabled = enable;
}
static void pnv_pci_ioda2_setup_bypass_pe(struct pnv_phb *phb,
struct pnv_ioda_pe *pe)
#ifdef CONFIG_IOMMU_API
static void pnv_ioda2_take_ownership(struct iommu_table_group *table_group)
{
/* TVE #1 is selected by PCI address bit 59 */
pe->tce_bypass_base = 1ull << 59;
struct pnv_ioda_pe *pe = container_of(table_group, struct pnv_ioda_pe,
table_group);
/* Install set_bypass callback for VFIO */
pe->table_group.tables[0]->set_bypass = pnv_pci_ioda2_set_bypass;
/* Enable bypass by default */
pnv_pci_ioda2_set_bypass(pe->table_group.tables[0], true);
iommu_take_ownership(table_group->tables[0]);
pnv_pci_ioda2_set_bypass(pe, false);
}
static void pnv_ioda2_release_ownership(struct iommu_table_group *table_group)
{
struct pnv_ioda_pe *pe = container_of(table_group, struct pnv_ioda_pe,
table_group);
iommu_release_ownership(table_group->tables[0]);
pnv_pci_ioda2_set_bypass(pe, true);
}
static struct iommu_table_group_ops pnv_pci_ioda2_ops = {
.take_ownership = pnv_ioda2_take_ownership,
.release_ownership = pnv_ioda2_release_ownership,
};
#endif
static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
struct pnv_ioda_pe *pe)
{
@ -1979,6 +1986,9 @@ static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
if (WARN_ON(pe->tce32_seg >= 0))
return;
/* TVE #1 is selected by PCI address bit 59 */
pe->tce_bypass_base = 1ull << 59;
tbl = pnv_pci_table_alloc(phb->hose->node);
iommu_register_group(&pe->table_group, phb->hose->global_number,
pe->pe_number);
@ -2033,6 +2043,9 @@ static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
}
tbl->it_ops = &pnv_ioda2_iommu_ops;
iommu_init_table(tbl, phb->hose->node);
#ifdef CONFIG_IOMMU_API
pe->table_group.ops = &pnv_pci_ioda2_ops;
#endif
if (pe->flags & PNV_IODA_PE_DEV) {
/*
@ -2047,7 +2060,7 @@ static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
/* Also create a bypass window */
if (!pnv_iommu_bypass_disabled)
pnv_pci_ioda2_setup_bypass_pe(phb, pe);
pnv_pci_ioda2_set_bypass(pe, true);
return;
fail:

70
drivers/vfio/vfio_iommu_spapr_tce.c
View file

@ -486,6 +486,61 @@ static long tce_iommu_ioctl(void *iommu_data,
return -ENOTTY;
}
static void tce_iommu_release_ownership(struct tce_container *container,
struct iommu_table_group *table_group)
{
int i;
for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
struct iommu_table *tbl = table_group->tables[i];
if (!tbl)
continue;
tce_iommu_clear(container, tbl, tbl->it_offset, tbl->it_size);
if (tbl->it_map)
iommu_release_ownership(tbl);
}
}
static int tce_iommu_take_ownership(struct tce_container *container,
struct iommu_table_group *table_group)
{
int i, j, rc = 0;
for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
struct iommu_table *tbl = table_group->tables[i];
if (!tbl || !tbl->it_map)
continue;
rc = iommu_take_ownership(tbl);
if (rc) {
for (j = 0; j < i; ++j)
iommu_release_ownership(
table_group->tables[j]);
return rc;
}
}
return 0;
}
static void tce_iommu_release_ownership_ddw(struct tce_container *container,
struct iommu_table_group *table_group)
{
table_group->ops->release_ownership(table_group);
}
static long tce_iommu_take_ownership_ddw(struct tce_container *container,
struct iommu_table_group *table_group)
{
table_group->ops->take_ownership(table_group);
return 0;
}
static int tce_iommu_attach_group(void *iommu_data,
struct iommu_group *iommu_group)
{
@ -518,7 +573,12 @@ static int tce_iommu_attach_group(void *iommu_data,
goto unlock_exit;
}
ret = iommu_take_ownership(table_group->tables[0]);
if (!table_group->ops || !table_group->ops->take_ownership ||
!table_group->ops->release_ownership)
ret = tce_iommu_take_ownership(container, table_group);
else
ret = tce_iommu_take_ownership_ddw(container, table_group);
if (!ret)
container->grp = iommu_group;
@ -533,7 +593,6 @@ static void tce_iommu_detach_group(void *iommu_data,
{
struct tce_container *container = iommu_data;
struct iommu_table_group *table_group;
struct iommu_table *tbl;
mutex_lock(&container->lock);
if (iommu_group != container->grp) {
@ -556,9 +615,10 @@ static void tce_iommu_detach_group(void *iommu_data,
table_group = iommu_group_get_iommudata(iommu_group);
BUG_ON(!table_group);
tbl = table_group->tables[0];
tce_iommu_clear(container, tbl, tbl->it_offset, tbl->it_size);
iommu_release_ownership(tbl);
if (!table_group->ops || !table_group->ops->release_ownership)
tce_iommu_release_ownership(container, table_group);
else
tce_iommu_release_ownership_ddw(container, table_group);
unlock_exit:
mutex_unlock(&container->lock);