[PATCH kernel v2 6/7] powerpc/powernv/phb4: Add 4GB IOMMU bypass mode
Alexey Kardashevskiy
aik at ozlabs.ru
Mon Mar 23 18:53:53 AEDT 2020
IODA2 systems (POWER8/9) allow DMA windows at 2 fixed locations - 0 and
0x800.0000.0000.0000==1<<59, stored in TVT as TVE0/1. PHB4 on POWER9 has
a "TVT Select 'GTE4GB' Option" which allows mapping both windows at 0 and
selecting one based on IOBA address - accesses below 4GB go via TVE0 and
above 4GB - via TVE1. Note that the TVE1's window still has to allocate
TCEs for below 4GB.
This changes iommu=iommy_bypass mode to move the second window at 4GB
if possible. When TVE1_4GB enabled, this creates a small (2GB typically)
32 bit window as there is no need to cover as much of lower DMA space -
the 4GB+ window does it better anyway.
As the physical TCE table from TVE1 maps PCI space from 0 and we want it
look like a 1:1 mapping with a fixed 4GB offset, this adds
a iommu_table::it_tceoff field which is a number of reserved TCEs covering
first 4GB of DMA space.
This keeps the existing behavior by default as the TVE1_4GB flag is set
per PHB by device assignment is done on PE basis and managing both modes
dynamically might get nasty.
Signed-off-by: Alexey Kardashevskiy <aik at ozlabs.ru>
---
arch/powerpc/include/asm/iommu.h | 1 +
arch/powerpc/include/asm/opal-api.h | 9 ++-
arch/powerpc/include/asm/opal.h | 2 +
arch/powerpc/platforms/powernv/opal-call.c | 2 +
arch/powerpc/platforms/powernv/pci-ioda.c | 66 +++++++++++++++++++---
5 files changed, 70 insertions(+), 10 deletions(-)
diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h
index acf64a73ead1..b9c4af9f129c 100644
--- a/arch/powerpc/include/asm/iommu.h
+++ b/arch/powerpc/include/asm/iommu.h
@@ -97,6 +97,7 @@ struct iommu_table {
unsigned long it_level_size;
unsigned long it_allocated_size;
unsigned long it_offset; /* Offset into global table */
+ unsigned long it_tceoff;
unsigned long it_base; /* mapped address of tce table */
unsigned long it_index; /* which iommu table this is */
unsigned long it_type; /* type: PCI or Virtual Bus */
diff --git a/arch/powerpc/include/asm/opal-api.h b/arch/powerpc/include/asm/opal-api.h
index c1f25a760eb1..7873754f5ea6 100644
--- a/arch/powerpc/include/asm/opal-api.h
+++ b/arch/powerpc/include/asm/opal-api.h
@@ -214,7 +214,9 @@
#define OPAL_SECVAR_GET 176
#define OPAL_SECVAR_GET_NEXT 177
#define OPAL_SECVAR_ENQUEUE_UPDATE 178
-#define OPAL_LAST 178
+#define OPAL_PHB_SET_OPTION 179
+#define OPAL_PHB_GET_OPTION 180
+#define OPAL_LAST 180
#define QUIESCE_HOLD 1 /* Spin all calls at entry */
#define QUIESCE_REJECT 2 /* Fail all calls with OPAL_BUSY */
@@ -437,6 +439,11 @@ enum OpalSlotLedState {
OPAL_SLOT_LED_STATE_ON = 1 /* LED is ON */
};
+enum OpalPhbOption {
+ OPAL_PHB_OPTION_TVE1_4GB = 0x1,
+ OPAL_PHB_OPTION_MMIO_EEH_DISABLE = 0x2,
+};
+
/*
* Address cycle types for LPC accesses. These also correspond
* to the content of the first cell of the "reg" property for
diff --git a/arch/powerpc/include/asm/opal.h b/arch/powerpc/include/asm/opal.h
index 9986ac34b8e2..89b712288cdd 100644
--- a/arch/powerpc/include/asm/opal.h
+++ b/arch/powerpc/include/asm/opal.h
@@ -142,6 +142,8 @@ int64_t opal_pci_map_pe_dma_window(uint64_t phb_id, uint16_t pe_number, uint16_t
int64_t opal_pci_map_pe_dma_window_real(uint64_t phb_id, uint16_t pe_number,
uint16_t dma_window_number, uint64_t pci_start_addr,
uint64_t pci_mem_size);
+int64_t opal_phb_set_option(uint64_t phb_id, uint64_t opt, uint64_t setting);
+int64_t opal_phb_get_option(uint64_t phb_id, uint64_t opt, uint64_t *setting);
int64_t opal_pci_reset(uint64_t id, uint8_t reset_scope, uint8_t assert_state);
int64_t opal_pci_get_hub_diag_data(uint64_t hub_id, void *diag_buffer,
diff --git a/arch/powerpc/platforms/powernv/opal-call.c b/arch/powerpc/platforms/powernv/opal-call.c
index 5cd0f52d258f..3130d5a41570 100644
--- a/arch/powerpc/platforms/powernv/opal-call.c
+++ b/arch/powerpc/platforms/powernv/opal-call.c
@@ -293,3 +293,5 @@ OPAL_CALL(opal_mpipl_query_tag, OPAL_MPIPL_QUERY_TAG);
OPAL_CALL(opal_secvar_get, OPAL_SECVAR_GET);
OPAL_CALL(opal_secvar_get_next, OPAL_SECVAR_GET_NEXT);
OPAL_CALL(opal_secvar_enqueue_update, OPAL_SECVAR_ENQUEUE_UPDATE);
+OPAL_CALL(opal_phb_set_option, OPAL_PHB_SET_OPTION);
+OPAL_CALL(opal_phb_get_option, OPAL_PHB_GET_OPTION);
diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index 27a505a5edb4..cba2cb2e1119 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -2367,7 +2367,7 @@ static long pnv_pci_ioda2_set_window(struct iommu_table_group *table_group,
}
static long pnv_pci_ioda2_set_bypass_iommu(struct pnv_ioda_pe *pe,
- unsigned long bus_offset)
+ unsigned long bus_offset, unsigned long tbl_offset)
{
struct pnv_phb *phb = pe->phb;
long rc;
@@ -2376,6 +2376,8 @@ static long pnv_pci_ioda2_set_bypass_iommu(struct pnv_ioda_pe *pe,
pgsizes = pnv_ioda_parse_tce_sizes(phb);
+ /* Filter sizes to have round number of TCEs to cover 0..tbl_offset */
+ pgsizes &= tbl_offset | (tbl_offset - 1);
if (!pgsizes)
return -1;
@@ -2386,17 +2388,19 @@ static long pnv_pci_ioda2_set_bypass_iommu(struct pnv_ioda_pe *pe,
1 /* window number */,
bus_offset,
__fls(pgsizes),
- roundup_pow_of_two(memory_hotplug_max()),
+ roundup_pow_of_two(memory_hotplug_max() +
+ tbl_offset),
2 /* levels */,
false /* userspace cache */,
&tbl);
if (rc)
return -1;
+ tbl->it_tceoff = tbl_offset >> tbl->it_page_shift;
for_each_memblock(memory, r)
pnv_ioda2_tce_build(tbl,
(r->base >> tbl->it_page_shift) +
- tbl->it_offset,
+ tbl->it_offset + tbl->it_tceoff,
r->size >> tbl->it_page_shift,
(unsigned long) __va(r->base),
DMA_BIDIRECTIONAL,
@@ -2438,8 +2442,22 @@ static void pnv_pci_ioda2_set_bypass(struct pnv_ioda_pe *pe, bool enable)
}
if (pnv_iommu_bypass_mode == PNV_IOMMU_TCE_BYPASS) {
+ if (!opal_phb_set_option(phb->opal_id,
+ OPAL_PHB_OPTION_TVE1_4GB, 1)) {
+ pe->table_group.tce64_start = SZ_4G;
+ if (!pnv_pci_ioda2_set_bypass_iommu(pe,
+ pe->table_group.tce64_start, SZ_4G)) {
+ pe->tce_bypass_enabled = true;
+ pe_info(pe, "Enabled 64-bit IOMMU bypass at %llx\n",
+ pe->table_group.tce64_start);
+ return;
+ }
+ pe_err(pe, "Enabled TVE1_4GB but failed to configure TCE table");
+ opal_phb_set_option(phb->opal_id,
+ OPAL_PHB_OPTION_TVE1_4GB, 0);
+ }
if (!pnv_pci_ioda2_set_bypass_iommu(pe,
- pe->table_group.tce64_start)) {
+ pe->table_group.tce64_start, 0)) {
pe->tce_bypass_enabled = true;
pe_info(pe, "Enabled 64-bit IOMMU bypass at %llx\n",
pe->table_group.tce64_start);
@@ -2450,6 +2468,10 @@ static void pnv_pci_ioda2_set_bypass(struct pnv_ioda_pe *pe, bool enable)
}
if (pnv_iommu_bypass_mode == PNV_IOMMU_NO_TRANSLATE) {
+ /*
+ * FIXME: if we enable dynamic switch, here we need to disable
+ * OPAL_PCI_PHB_FLAG_TVE1_4GB
+ */
top = roundup_pow_of_two(memblock_end_of_DRAM());
if (!opal_pci_map_pe_dma_window_real(phb->opal_id,
pe->pe_number, window_id,
@@ -2521,6 +2543,15 @@ static long pnv_pci_ioda2_setup_default_config(struct pnv_ioda_pe *pe)
*/
/* iommu_table::it_map uses 1 bit per IOMMU page, hence 8 */
window_size = min((maxblock * 8) << tceshift, max_memory);
+
+ /*
+ * If we get TVE#1_4GB on, there is no point in having a huge default
+ * DMA window.
+ */
+ if (pnv_iommu_bypass_mode == PNV_IOMMU_TCE_BYPASS)
+ window_size = min_t(u64, pe->table_group.tce32_size,
+ window_size);
+
/* Each TCE level cannot exceed maxblock so go multilevel if needed */
tces_order = ilog2(window_size >> tceshift);
tcelevel_order = ilog2(maxblock >> 3);
@@ -2611,6 +2642,9 @@ unsigned long pnv_pci_ioda2_get_table_size(int num, __u32 page_shift,
!is_power_of_2(window_size))
return 0;
+ if (pnv_iommu_bypass_mode == PNV_IOMMU_TCE_BYPASS && num == 1)
+ window_size = roundup_pow_of_two(window_size + SZ_4G);
+
/* Calculate a direct table size from window_size and levels */
entries_shift = (entries_shift + levels - 1) / levels;
table_shift = entries_shift + 3;
@@ -2636,15 +2670,29 @@ static long pnv_pci_ioda2_create_table_userspace(
{
struct pnv_ioda_pe *pe = container_of(table_group, struct pnv_ioda_pe,
table_group);
- __u64 bus_offset = num ?
- pe->table_group.tce64_start : table_group->tce32_start;
- long ret = pnv_pci_ioda2_create_table(pe->phb->hose->node,
- num, bus_offset, page_shift, window_size, levels, true,
+ __u64 bus_offset, tce_offset = 0, win_size = window_size;
+ long ret;
+
+ if (num == 0) {
+ bus_offset = table_group->tce32_start;
+ } else if (table_group->tce64_start == SZ_4G) {
+ bus_offset = table_group->tce32_start;
+ tce_offset = SZ_4G;
+ win_size = roundup_pow_of_two(window_size + tce_offset);
+ } else {
+ bus_offset = table_group->tce64_start;
+ }
+
+ ret = pnv_pci_ioda2_create_table(pe->phb->hose->node,
+ num, bus_offset, page_shift, win_size, levels, true,
ptbl);
- if (!ret)
+ if (!ret) {
(*ptbl)->it_allocated_size = pnv_pci_ioda2_get_table_size(
num, page_shift, window_size, levels);
+ (*ptbl)->it_tceoff = tce_offset >> page_shift;
+ }
+
return ret;
}
--
2.17.1
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