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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [RFC PATCH 2/3] xen/arm: Add handling of extended regions for Dom0
From: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
The extended region (safe range) is a region of guest physical
address space which is unused and could be safely used to create
grant/foreign mappings instead of wasting real RAM pages from
the domain memory for establishing these mappings.
The extended regions are chosen at the domain creation time and
advertised to it via "reg" property under hypervisor node in
the guest device-tree. As region 0 is reserved for grant table
space, introduce new "extended-region" property to inform
domain about the presence of additional regions (1...N).
If extended regions could not be allocated for some reason,
Xen doesn't fail and behaves as usual, so only inserts region 0.
Please note the following limitations:
- The extended region feature is only supported for 64-bit domain.
- The ACPI case is not covered.
***
As Dom0 is direct mapped domain on Arm (e.g. MFN == GFN)
the algorithm to choose extended regions for it is different
in comparison with the algorithm for non-direct mapped DomU.
What is more, that extended regions should be chosen differently
whether IOMMU is enabled or not.
Provide RAM not assigned to Dom0 if IOMMU is disabled or memory
holes found in host device-tree if otherwise. Make sure that
extended regions are 2MB-aligned and located within maximum possible
addressable physical memory range. The maximum number of extended
regions is 128.
Suggested-by: Julien Grall <jgrall@xxxxxxxxxx>
Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
---
xen/arch/arm/domain_build.c | 233 +++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 231 insertions(+), 2 deletions(-)
diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 206038d..f9453de 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -724,6 +724,196 @@ static int __init make_memory_node(const struct domain *d,
return res;
}
+static int __init add_ext_regions(unsigned long s, unsigned long e, void *data)
+{
+ struct meminfo *ext_regions = data;
+ paddr_t start, size;
+
+ if ( ext_regions->nr_banks >= ARRAY_SIZE(ext_regions->bank) )
+ return 0;
+
+ /* Both start and size of the extended region should be 2MB aligned */
+ start = (s + SZ_2M - 1) & ~(SZ_2M - 1);
+ if ( start > e )
+ return 0;
+
+ size = (e - start + 1) & ~(SZ_2M - 1);
+ if ( !size )
+ return 0;
+
+ ext_regions->bank[ext_regions->nr_banks].start = start;
+ ext_regions->bank[ext_regions->nr_banks].size = size;
+ ext_regions->nr_banks ++;
+
+ return 0;
+}
+
+/*
+ * The extended regions will be prevalidated by the memory hotplug path
+ * in Linux which requires for any added address range to be within maximum
+ * possible addressable physical memory range for which the linear mapping
+ * could be created.
+ * For 48-bit VA space size the maximum addressable range are:
+ * 0x40000000 - 0x80003fffffff
+ */
+#define EXT_REGION_START 0x40000000ULL
+#define EXT_REGION_END 0x80003fffffffULL
+
+static int __init find_unallocated_memory(const struct kernel_info *kinfo,
+ struct meminfo *ext_regions)
+{
+ const struct meminfo *assign_mem = &kinfo->mem;
+ struct rangeset *unalloc_mem;
+ paddr_t start, end;
+ unsigned int i;
+ int res;
+
+ dt_dprintk("Find unallocated memory for extended regions\n");
+
+ unalloc_mem = rangeset_new(NULL, NULL, 0);
+ if ( !unalloc_mem )
+ return -ENOMEM;
+
+ /* Start with all available RAM */
+ for ( i = 0; i < bootinfo.mem.nr_banks; i++ )
+ {
+ start = bootinfo.mem.bank[i].start;
+ end = bootinfo.mem.bank[i].start + bootinfo.mem.bank[i].size - 1;
+ res = rangeset_add_range(unalloc_mem, start, end);
+ if ( res )
+ {
+ printk(XENLOG_ERR "Failed to add: %#"PRIx64"->%#"PRIx64"\n",
+ start, end);
+ goto out;
+ }
+ }
+
+ /* Remove RAM assigned to Dom0 */
+ for ( i = 0; i < assign_mem->nr_banks; i++ )
+ {
+ start = assign_mem->bank[i].start;
+ end = assign_mem->bank[i].start + assign_mem->bank[i].size - 1;
+ res = rangeset_remove_range(unalloc_mem, start, end);
+ if ( res )
+ {
+ printk(XENLOG_ERR "Failed to remove: %#"PRIx64"->%#"PRIx64"\n",
+ start, end);
+ goto out;
+ }
+ }
+
+ /* Remove reserved-memory regions */
+ for ( i = 0; i < bootinfo.reserved_mem.nr_banks; i++ )
+ {
+ start = bootinfo.reserved_mem.bank[i].start;
+ end = bootinfo.reserved_mem.bank[i].start +
+ bootinfo.reserved_mem.bank[i].size - 1;
+ res = rangeset_remove_range(unalloc_mem, start, end);
+ if ( res )
+ {
+ printk(XENLOG_ERR "Failed to remove: %#"PRIx64"->%#"PRIx64"\n",
+ start, end);
+ goto out;
+ }
+ }
+
+ /* Remove grant table region */
+ start = kinfo->gnttab_start;
+ end = kinfo->gnttab_start + kinfo->gnttab_size - 1;
+ res = rangeset_remove_range(unalloc_mem, start, end);
+ if ( res )
+ {
+ printk(XENLOG_ERR "Failed to remove: %#"PRIx64"->%#"PRIx64"\n",
+ start, end);
+ goto out;
+ }
+
+ start = EXT_REGION_START;
+ end = min((1ULL << p2m_ipa_bits) - 1, EXT_REGION_END);
+ res = rangeset_report_ranges(unalloc_mem, start, end,
+ add_ext_regions, ext_regions);
+ if ( res )
+ ext_regions->nr_banks = 0;
+ else if ( !ext_regions->nr_banks )
+ res = -ENOENT;
+
+out:
+ rangeset_destroy(unalloc_mem);
+
+ return res;
+}
+
+static int __init find_memory_holes(const struct kernel_info *kinfo,
+ struct meminfo *ext_regions)
+{
+ struct dt_device_node *np;
+ struct rangeset *mem_holes;
+ paddr_t start, end;
+ unsigned int i;
+ int res;
+
+ dt_dprintk("Find memory holes for extended regions\n");
+
+ mem_holes = rangeset_new(NULL, NULL, 0);
+ if ( !mem_holes )
+ return -ENOMEM;
+
+ /* Start with maximum possible addressable physical memory range */
+ start = EXT_REGION_START;
+ end = min((1ULL << p2m_ipa_bits) - 1, EXT_REGION_END);
+ res = rangeset_add_range(mem_holes, start, end);
+ if ( res )
+ {
+ printk(XENLOG_ERR "Failed to add: %#"PRIx64"->%#"PRIx64"\n",
+ start, end);
+ goto out;
+ }
+
+ /* Remove all regions described by "reg" property (MMIO, RAM, etc) */
+ dt_for_each_device_node( dt_host, np )
+ {
+ unsigned int naddr;
+ u64 addr, size;
+
+ naddr = dt_number_of_address(np);
+
+ for ( i = 0; i < naddr; i++ )
+ {
+ res = dt_device_get_address(np, i, &addr, &size);
+ if ( res )
+ {
+ printk(XENLOG_ERR "Unable to retrieve address %u for %s\n",
+ i, dt_node_full_name(np));
+ goto out;
+ }
+
+ start = addr & PAGE_MASK;
+ end = PAGE_ALIGN(addr + size) - 1;
+ res = rangeset_remove_range(mem_holes, start, end);
+ if ( res )
+ {
+ printk(XENLOG_ERR "Failed to remove: %#"PRIx64"->%#"PRIx64"\n",
+ start, end);
+ goto out;
+ }
+ }
+ }
+
+ start = EXT_REGION_START;
+ end = min((1ULL << p2m_ipa_bits) - 1, EXT_REGION_END);
+ res = rangeset_report_ranges(mem_holes, start, end,
+ add_ext_regions, ext_regions);
+ if ( res )
+ ext_regions->nr_banks = 0;
+ else if ( !ext_regions->nr_banks )
+ res = -ENOENT;
+
+out:
+ rangeset_destroy(mem_holes);
+
+ return res;
+}
+
static int __init make_hypervisor_node(struct domain *d,
const struct kernel_info *kinfo,
int addrcells, int sizecells)
@@ -731,11 +921,13 @@ static int __init make_hypervisor_node(struct domain *d,
const char compat[] =
"xen,xen-"__stringify(XEN_VERSION)"."__stringify(XEN_SUBVERSION)"\0"
"xen,xen";
- __be32 reg[4];
+ __be32 reg[(NR_MEM_BANKS + 1) * 4];
gic_interrupt_t intr;
__be32 *cells;
int res;
void *fdt = kinfo->fdt;
+ struct meminfo *ext_regions;
+ unsigned int i;
dt_dprintk("Create hypervisor node\n");
@@ -757,15 +949,52 @@ static int __init make_hypervisor_node(struct domain *d,
if ( res )
return res;
+ ext_regions = xzalloc(struct meminfo);
+ if ( !ext_regions )
+ return -ENOMEM;
+
+ if ( is_32bit_domain(d) )
+ printk(XENLOG_WARNING "The extended region is only supported for
64-bit guest\n");
+ else
+ {
+ if ( !is_iommu_enabled(d) )
+ res = find_unallocated_memory(kinfo, ext_regions);
+ else
+ res = find_memory_holes(kinfo, ext_regions);
+
+ if ( res )
+ printk(XENLOG_WARNING "Failed to allocate extended regions\n");
+ }
+
/* reg 0 is grant table space */
cells = ®[0];
dt_child_set_range(&cells, addrcells, sizecells,
kinfo->gnttab_start, kinfo->gnttab_size);
+ /* reg 1...N are extended regions */
+ for ( i = 0; i < ext_regions->nr_banks; i++ )
+ {
+ u64 start = ext_regions->bank[i].start;
+ u64 size = ext_regions->bank[i].size;
+
+ dt_dprintk("Extended region %d: %#"PRIx64"->%#"PRIx64"\n",
+ i, start, start + size);
+
+ dt_child_set_range(&cells, addrcells, sizecells, start, size);
+ }
+ xfree(ext_regions);
+
res = fdt_property(fdt, "reg", reg,
- dt_cells_to_size(addrcells + sizecells));
+ dt_cells_to_size(addrcells + sizecells) * (i + 1));
if ( res )
return res;
+ if ( i > 0 )
+ {
+ res = fdt_property(fdt, "extended-region", NULL, 0);
+ if ( res )
+ return res;
+ }
+
BUG_ON(d->arch.evtchn_irq == 0);
/*
--
2.7.4
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