Re: [PATCH kernel v9 20/32] powerpc/powernv/ioda2: Introduce pnv_pci_create_table/pnv_pci_free_table
From: Alexey Kardashevskiy
Date: Fri May 01 2015 - 06:13:17 EST
On 04/29/2015 02:39 PM, David Gibson wrote:
On Sat, Apr 25, 2015 at 10:14:44PM +1000, Alexey Kardashevskiy wrote:
This is a part of moving TCE table allocation into an iommu_ops
callback to support multiple IOMMU groups per one VFIO container.
This moves a table creation window to the file with common powernv-pci
helpers as it does not do anything IODA2-specific.
This adds pnv_pci_free_table() helper to release the actual TCE table.
This enforces window size to be a power of two.
This should cause no behavioural change.
Signed-off-by: Alexey Kardashevskiy <aik@xxxxxxxxx>
Reviewed-by: David Gibson <david@xxxxxxxxxxxxxxxxxxxxx>
---
Changes:
v9:
* moved helpers to the common powernv pci.c file from pci-ioda.c
* moved bits from pnv_pci_create_table() to pnv_alloc_tce_table_pages()
---
arch/powerpc/platforms/powernv/pci-ioda.c | 36 ++++++------------
arch/powerpc/platforms/powernv/pci.c | 61 +++++++++++++++++++++++++++++++
arch/powerpc/platforms/powernv/pci.h | 4 ++
3 files changed, 76 insertions(+), 25 deletions(-)
diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index a80be34..b9b3773 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -1307,8 +1307,7 @@ static void pnv_pci_ioda2_release_dma_pe(struct pci_dev *dev, struct pnv_ioda_pe
if (rc)
pe_warn(pe, "OPAL error %ld release DMA window\n", rc);
- iommu_reset_table(tbl, of_node_full_name(dev->dev.of_node));
- free_pages(addr, get_order(TCE32_TABLE_SIZE));
+ pnv_pci_free_table(tbl);
}
static void pnv_ioda_release_vf_PE(struct pci_dev *pdev, u16 num_vfs)
@@ -2039,10 +2038,7 @@ static struct iommu_table_group_ops pnv_pci_ioda2_ops = {
static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
struct pnv_ioda_pe *pe)
{
- struct page *tce_mem = NULL;
- void *addr;
struct iommu_table *tbl = &pe->table_group.tables[0];
- unsigned int tce_table_size, end;
int64_t rc;
/* We shouldn't already have a 32-bit DMA associated */
@@ -2053,29 +2049,20 @@ static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
/* The PE will reserve all possible 32-bits space */
pe->tce32_seg = 0;
- end = (1 << ilog2(phb->ioda.m32_pci_base));
- tce_table_size = (end / 0x1000) * 8;
pe_info(pe, "Setting up 32-bit TCE table at 0..%08x\n",
- end);
+ phb->ioda.m32_pci_base);
- /* Allocate TCE table */
- tce_mem = alloc_pages_node(phb->hose->node, GFP_KERNEL,
- get_order(tce_table_size));
- if (!tce_mem) {
- pe_err(pe, "Failed to allocate a 32-bit TCE memory\n");
- goto fail;
+ rc = pnv_pci_create_table(&pe->table_group, pe->phb->hose->node,
+ 0, IOMMU_PAGE_SHIFT_4K, phb->ioda.m32_pci_base, tbl);
+ if (rc) {
+ pe_err(pe, "Failed to create 32-bit TCE table, err %ld", rc);
+ return;
}
- addr = page_address(tce_mem);
- memset(addr, 0, tce_table_size);
-
- /* Setup iommu */
- tbl->it_table_group = &pe->table_group;
-
- /* Setup linux iommu table */
- pnv_pci_setup_iommu_table(tbl, addr, tce_table_size, 0,
- IOMMU_PAGE_SHIFT_4K);
tbl->it_ops = &pnv_ioda2_iommu_ops;
+
+ /* Setup iommu */
+ tbl->it_table_group = &pe->table_group;
iommu_init_table(tbl, phb->hose->node);
#ifdef CONFIG_IOMMU_API
pe->table_group.ops = &pnv_pci_ioda2_ops;
@@ -2121,8 +2108,7 @@ static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
fail:
if (pe->tce32_seg >= 0)
pe->tce32_seg = -1;
- if (tce_mem)
- __free_pages(tce_mem, get_order(tce_table_size));
+ pnv_pci_free_table(tbl);
}
static void pnv_ioda_setup_dma(struct pnv_phb *phb)
diff --git a/arch/powerpc/platforms/powernv/pci.c b/arch/powerpc/platforms/powernv/pci.c
index e8802ac..6bcfad5 100644
--- a/arch/powerpc/platforms/powernv/pci.c
+++ b/arch/powerpc/platforms/powernv/pci.c
@@ -20,7 +20,9 @@
#include <linux/io.h>
#include <linux/msi.h>
#include <linux/iommu.h>
+#include <linux/memblock.h>
+#include <asm/mmzone.h>
#include <asm/sections.h>
#include <asm/io.h>
#include <asm/prom.h>
@@ -645,6 +647,65 @@ void pnv_pci_setup_iommu_table(struct iommu_table *tbl,
tbl->it_type = TCE_PCI;
}
+static __be64 *pnv_alloc_tce_table_pages(int nid, unsigned shift,
+ unsigned long *tce_table_allocated)
I'm a bit confused by the tce_table_allocated parameter. What's the
circumstance where more memory is requested than required, and why
does it matter to the caller?
+{
+ struct page *tce_mem = NULL;
+ __be64 *addr;
+ unsigned order = max_t(unsigned, shift, PAGE_SHIFT) - PAGE_SHIFT;
+ unsigned long local_allocated = 1UL << (order + PAGE_SHIFT);
+
+ tce_mem = alloc_pages_node(nid, GFP_KERNEL, order);
+ if (!tce_mem) {
+ pr_err("Failed to allocate a TCE memory, order=%d\n", order);
+ return NULL;
+ }
+ addr = page_address(tce_mem);
+ memset(addr, 0, local_allocated);
+ *tce_table_allocated = local_allocated;
+
+ return addr;
+}
+
+long pnv_pci_create_table(struct iommu_table_group *table_group, int nid,
+ __u64 bus_offset, __u32 page_shift, __u64 window_size,
+ struct iommu_table *tbl)
The table_group parameter is redundant, isn't it? It must be equal to
tbl->table_group, yes?
Or would it make more sense for this function to set
tbl->table_group?
I removed table_group from here.
And for that matter wouldn't it make more sense for
this to set it_size as well?
Missed this comment. It does set it_size by calling
pnv_pci_setup_iommu_table().
+{
+ void *addr;
+ unsigned long tce_table_allocated = 0;
+ const unsigned window_shift = ilog2(window_size);
+ unsigned entries_shift = window_shift - page_shift;
+ unsigned table_shift = entries_shift + 3;
+ const unsigned long tce_table_size = max(0x1000UL, 1UL << table_shift);
So, here you round up to 4k, the in the alloc function you round up to
PAGE_SIZE (which may or may not be the same). It's not clear to me why
there are two rounds of rounding up.
@tce_table_size will be programmed later into IODA2 via OPAL and OPAL will
reject a window if it is less than 4K. I'll rework the whole thing just to
align it to PAGE_SIZE as this is what it really is anyway.
--
Alexey
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