Re: [PATCH kernel v9 27/32] powerpc/iommu/ioda2: Add get_table_size() to calculate the size of future table
From: Alexey Kardashevskiy
Date: Fri May 01 2015 - 00:11:23 EST
On 04/29/2015 04:40 PM, David Gibson wrote:
On Sat, Apr 25, 2015 at 10:14:51PM +1000, Alexey Kardashevskiy wrote:
This adds a way for the IOMMU user to know how much a new table will
use so it can be accounted in the locked_vm limit before allocation
happens.
This stores the allocated table size in pnv_pci_create_table()
so the locked_vm counter can be updated correctly when a table is
being disposed.
This defines an iommu_table_group_ops callback to let VFIO know
how much memory will be locked if a table is created.
Signed-off-by: Alexey Kardashevskiy <aik@xxxxxxxxx>
---
Changes:
v9:
* reimplemented the whole patch
---
arch/powerpc/include/asm/iommu.h | 5 +++++
arch/powerpc/platforms/powernv/pci-ioda.c | 14 ++++++++++++
arch/powerpc/platforms/powernv/pci.c | 36 +++++++++++++++++++++++++++++++
arch/powerpc/platforms/powernv/pci.h | 2 ++
4 files changed, 57 insertions(+)
diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h
index 1472de3..9844c106 100644
--- a/arch/powerpc/include/asm/iommu.h
+++ b/arch/powerpc/include/asm/iommu.h
@@ -99,6 +99,7 @@ struct iommu_table {
unsigned long it_size; /* Size of iommu table in entries */
unsigned long it_indirect_levels;
unsigned long it_level_size;
+ unsigned long it_allocated_size;
unsigned long it_offset; /* Offset into global table */
unsigned long it_base; /* mapped address of tce table */
unsigned long it_index; /* which iommu table this is */
@@ -155,6 +156,10 @@ extern struct iommu_table *iommu_init_table(struct iommu_table * tbl,
struct iommu_table_group;
struct iommu_table_group_ops {
+ unsigned long (*get_table_size)(
+ __u32 page_shift,
+ __u64 window_size,
+ __u32 levels);
long (*create_table)(struct iommu_table_group *table_group,
int num,
__u32 page_shift,
diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index e0be556..7f548b4 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -2062,6 +2062,18 @@ static void pnv_pci_ioda2_setup_bypass_pe(struct pnv_phb *phb,
}
#ifdef CONFIG_IOMMU_API
+static unsigned long pnv_pci_ioda2_get_table_size(__u32 page_shift,
+ __u64 window_size, __u32 levels)
+{
+ unsigned long ret = pnv_get_table_size(page_shift, window_size, levels);
+
+ if (!ret)
+ return ret;
+
+ /* Add size of it_userspace */
+ return ret + (window_size >> page_shift) * sizeof(unsigned long);
This doesn't make much sense. The userspace view can't possibly be a
property of the specific low-level IOMMU model.
This it_userspace thing is all about memory preregistration.
I need some way to track how many actual mappings the
mm_iommu_table_group_mem_t has in order to decide whether to allow
unregistering or not.
When I clear TCE, I can read the old value which is host physical address
which I cannot use to find the preregistered region and adjust the mappings
counter; I can only use userspace addresses for this (not even guest
physical addresses as it is VFIO and probably no KVM).
So I have to keep userspace addresses somewhere, one per IOMMU page, and
the iommu_table seems a natural place for this.
+}
+
static long pnv_pci_ioda2_create_table(struct iommu_table_group *table_group,
int num, __u32 page_shift, __u64 window_size, __u32 levels,
struct iommu_table *tbl)
@@ -2086,6 +2098,7 @@ static long pnv_pci_ioda2_create_table(struct iommu_table_group *table_group,
BUG_ON(tbl->it_userspace);
tbl->it_userspace = uas;
+ tbl->it_allocated_size += uas_cb;
tbl->it_ops = &pnv_ioda2_iommu_ops;
if (pe->tce_inval_reg)
tbl->it_type |= (TCE_PCI_SWINV_CREATE | TCE_PCI_SWINV_FREE);
@@ -2160,6 +2173,7 @@ static void pnv_ioda2_release_ownership(struct iommu_table_group *table_group)
}
static struct iommu_table_group_ops pnv_pci_ioda2_ops = {
+ .get_table_size = pnv_pci_ioda2_get_table_size,
.create_table = pnv_pci_ioda2_create_table,
.set_window = pnv_pci_ioda2_set_window,
.unset_window = pnv_pci_ioda2_unset_window,
diff --git a/arch/powerpc/platforms/powernv/pci.c b/arch/powerpc/platforms/powernv/pci.c
index fc129c4..1b5b48a 100644
--- a/arch/powerpc/platforms/powernv/pci.c
+++ b/arch/powerpc/platforms/powernv/pci.c
@@ -662,6 +662,38 @@ void pnv_pci_setup_iommu_table(struct iommu_table *tbl,
tbl->it_type = TCE_PCI;
}
+unsigned long pnv_get_table_size(__u32 page_shift,
+ __u64 window_size, __u32 levels)
+{
+ unsigned long bytes = 0;
+ const unsigned window_shift = ilog2(window_size);
+ unsigned entries_shift = window_shift - page_shift;
+ unsigned table_shift = entries_shift + 3;
+ unsigned long tce_table_size = max(0x1000UL, 1UL << table_shift);
+ unsigned long direct_table_size;
+
+ if (!levels || (levels > POWERNV_IOMMU_MAX_LEVELS) ||
+ (window_size > memory_hotplug_max()) ||
+ !is_power_of_2(window_size))
+ return 0;
+
+ /* Calculate a direct table size from window_size and levels */
+ entries_shift = ROUND_UP(entries_shift, levels) / levels;
+ table_shift = entries_shift + 3;
+ table_shift = max_t(unsigned, table_shift, PAGE_SHIFT);
+ direct_table_size = 1UL << table_shift;
+
+ for ( ; levels; --levels) {
+ bytes += ROUND_UP(tce_table_size, direct_table_size);
+
+ tce_table_size /= direct_table_size;
+ tce_table_size <<= 3;
+ tce_table_size = ROUND_UP(tce_table_size, direct_table_size);
+ }
+
+ return bytes;
+}
+
static __be64 *pnv_alloc_tce_table_pages(int nid, unsigned shift,
unsigned levels, unsigned long limit,
unsigned long *tce_table_allocated)
@@ -741,6 +773,10 @@ long pnv_pci_create_table(struct iommu_table_group *table_group, int nid,
return -ENOMEM;
}
+ tbl->it_allocated_size = pnv_get_table_size(page_shift, window_size,
+ levels);
+ WARN_ON(!tbl->it_allocated_size);
+
/* Setup linux iommu table */
pnv_pci_setup_iommu_table(tbl, addr, tce_table_size, bus_offset,
page_shift);
diff --git a/arch/powerpc/platforms/powernv/pci.h b/arch/powerpc/platforms/powernv/pci.h
index 3d1ff584..ce4bc3c 100644
--- a/arch/powerpc/platforms/powernv/pci.h
+++ b/arch/powerpc/platforms/powernv/pci.h
@@ -224,6 +224,8 @@ extern long pnv_pci_create_table(struct iommu_table_group *table_group, int nid,
__u64 bus_offset, __u32 page_shift, __u64 window_size,
__u32 levels, struct iommu_table *tbl);
extern void pnv_pci_free_table(struct iommu_table *tbl);
+extern unsigned long pnv_get_table_size(__u32 page_shift,
+ __u64 window_size, __u32 levels);
extern void pnv_pci_init_p5ioc2_hub(struct device_node *np);
extern void pnv_pci_init_ioda_hub(struct device_node *np);
extern void pnv_pci_init_ioda2_phb(struct device_node *np);
--
Alexey
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