---
Please note, we need to decide which approach to use in
find_unallocated_memory(),
you can find details at:
https://lore.kernel.org/xen-devel/[email protected]/
Changes RFC -> V2:
- update patch description
- drop uneeded "extended-region" DT property
Changes V2 -> V3:
- update patch description
- add comment for "size" calculation in add_ext_regions()
- clarify "end" calculation in find_unallocated_memory() and
find_memory_holes()
- only pick up regions with size >= 64MB
- allocate reg dynamically instead of keeping on the stack in
make_hypervisor_node()
- do not show warning for 32-bit domain
- drop Linux specific limits EXT_REGION_*
- also cover "ranges" property in find_memory_holes()
- add command line arg to enable/disable extended region support
Changes V3 -> V4:
- update opt_ext_regions purpose and comment in code
- reorganize make_hypervisor_node() to move allocations after initial
checks, allocate only required amount of elements instead of maximum
possible
---
docs/misc/xen-command-line.pandoc | 11 ++
xen/arch/arm/domain_build.c | 286 +++++++++++++++++++++++++++++++++++++-
2 files changed, 294 insertions(+), 3 deletions(-)
diff --git a/docs/misc/xen-command-line.pandoc
b/docs/misc/xen-command-line.pandoc
index 177e656..5cae4ad 100644
--- a/docs/misc/xen-command-line.pandoc
+++ b/docs/misc/xen-command-line.pandoc
@@ -1081,6 +1081,17 @@ hardware domain is architecture dependent.
Note that specifying zero as domU value means zero, while for dom0 it means
to use the default.
+### ext_regions (Arm)
+> `= <boolean>`
+
+> Default : `true`
+
+Flag to enable or disable support for extended regions for Dom0.
+
+Extended regions are ranges of unused address space exposed to Dom0 as
+"safe to use" for special memory mappings. Disable if your board device
+tree is incomplete.
+
### flask
> `= permissive | enforcing | late | disabled`
diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index d233d63..c5afbe2 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -34,6 +34,10 @@
static unsigned int __initdata opt_dom0_max_vcpus;
integer_param("dom0_max_vcpus", opt_dom0_max_vcpus);
+/* If true, the extended regions support is enabled for dom0 */
+static bool __initdata opt_ext_regions = true;
+boolean_param("ext_regions", opt_ext_regions);
+
static u64 __initdata dom0_mem;
static bool __initdata dom0_mem_set;
@@ -886,6 +890,232 @@ 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;
+
+ /*
+ * e is actually "end-1" because it is called by rangeset functions
+ * which are inclusive of the last address.
+ */
+ e += 1;
+ size = (e - start) & ~(SZ_2M - 1);
+ if ( size < MB(64) )
+ 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;
+}
+
+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;
+ res = rangeset_add_range(unalloc_mem, start, end - 1);
+ 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;
+ res = rangeset_remove_range(unalloc_mem, start, end - 1);
+ 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;
+ res = rangeset_remove_range(unalloc_mem, start, end - 1);
+ 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;
+ res = rangeset_remove_range(unalloc_mem, start, end - 1);
+ if ( res )
+ {
+ printk(XENLOG_ERR "Failed to remove: %#"PRIx64"->%#"PRIx64"\n",
+ start, end);
+ goto out;
+ }
+
+ start = 0;
+ end = (1ULL << p2m_ipa_bits) - 1;
+ 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 = 0;
+ end = (1ULL << p2m_ipa_bits) - 1;
+ res = rangeset_add_range(mem_holes, start, end);
+ if ( res )
+ {
+ printk(XENLOG_ERR "Failed to add: %#"PRIx64"->%#"PRIx64"\n",
+ start, end);
+ goto out;
+ }
+
+ /*
+ * Remove regions described by "reg" and "ranges" properties where
+ * the memory is addressable (MMIO, RAM, PCI BAR, 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);
+ res = rangeset_remove_range(mem_holes, start, end - 1);
+ if ( res )
+ {
+ printk(XENLOG_ERR "Failed to remove: %#"PRIx64"->%#"PRIx64"\n",
+ start, end);
+ goto out;
+ }
+ }
+
+ if ( dt_device_type_is_equal(np, "pci" ) )
+ {
+ unsigned int range_size, nr_ranges;
+ int na, ns, pna;
+ const __be32 *ranges;
+ u32 len;
+
+ /*
+ * Looking for non-empty ranges property which in this context
+ * describes the PCI host bridge aperture.
+ */
+ ranges = dt_get_property(np, "ranges", &len);
+ if ( !ranges || !len )
+ continue;
+
+ pna = dt_n_addr_cells(np);
+ na = dt_child_n_addr_cells(np);
+ ns = dt_child_n_size_cells(np);
+ range_size = pna + na + ns;
+ nr_ranges = len / sizeof(__be32) / range_size;
+
+ for ( i = 0; i < nr_ranges; i++, ranges += range_size )
+ {
+ /* Skip the child address and get the parent (CPU) address */
+ addr = dt_read_number(ranges + na, pna);
+ size = dt_read_number(ranges + na + pna, ns);
+
+ start = addr & PAGE_MASK;
+ end = PAGE_ALIGN(addr + size);
+ res = rangeset_remove_range(mem_holes, start, end - 1);
+ if ( res )
+ {
+ printk(XENLOG_ERR "Failed to remove:
%#"PRIx64"->%#"PRIx64"\n",
+ start, end);
+ goto out;
+ }
+ }
+ }
+ }
+
+ start = 0;
+ end = (1ULL << p2m_ipa_bits) - 1;
+ 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)
@@ -893,11 +1123,12 @@ 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, *cells;
gic_interrupt_t intr;
- __be32 *cells;
int res;
void *fdt = kinfo->fdt;
+ struct meminfo *ext_regions = NULL;
+ unsigned int i, nr_ext_regions;
dt_dprintk("Create hypervisor node\n");
@@ -919,12 +1150,61 @@ static int __init make_hypervisor_node(struct domain *d,
if ( res )
return res;
+ if ( !opt_ext_regions )
+ {
+ printk(XENLOG_DEBUG "The extended regions support is disabled\n");
+ nr_ext_regions = 0;
+ }
+ else if ( is_32bit_domain(d) )
+ {
+ printk(XENLOG_DEBUG "The extended regions are only supported for 64-bit
guest currently\n");
+ nr_ext_regions = 0;
+ }
+ else
+ {
+ ext_regions = xzalloc(struct meminfo);
+ if ( !ext_regions )
+ return -ENOMEM;
+
+ 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");
+ nr_ext_regions = ext_regions->nr_banks;
+ }
+
+ reg = xzalloc_array(__be32, (nr_ext_regions + 1) * (addrcells +
sizecells));
+ if ( !reg )
+ {
+ xfree(ext_regions);
+ return -ENOMEM;
+ }
+
/* 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 < nr_ext_regions; 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);
+ }
+
res = fdt_property(fdt, "reg", reg,
- dt_cells_to_size(addrcells + sizecells));
+ dt_cells_to_size(addrcells + sizecells) *
+ (nr_ext_regions + 1));
+ xfree(ext_regions);
+ xfree(reg);
+
if ( res )
return res;
--
2.7.4
