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Re: [PATCH V2 2/3] xen/arm: Add handling of extended regions for Dom0
On 18.09.21 00:56, Stefano Stabellini wrote:
Hi Stefano
On Fri, 17 Sep 2021, Oleksandr wrote:
+
+ 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) */
Well... The loop below is not going to handle all the regions described in
the property "reg". Instead, it will cover a subset of "reg" where the
memory is addressable.
As I understand, we are only interested in subset of "reg" where the memory is
addressable.
You will also need to cover "ranges" that will describe the BARs for the PCI
devices.
Good point.
Yes, very good point!
Could you please clarify how to recognize whether it is a PCI
device as long as PCI support is not merged? Or just to find any device nodes
with non-empty "ranges" property
and retrieve addresses?
Normally any bus can have a ranges property with the aperture and
possible address translations, including /amba (compatible =
"simple-bus"). However, in these cases dt_device_get_address already
takes care of it, see xen/common/device_tree.c:dt_device_get_address.
The PCI bus is special for 2 reasons:
- the ranges property has a different format
- the bus is hot-pluggable
So I think the only one that we need to treat specially is PCI.
As far as I am aware PCI is the only bus (or maybe just the only bus
that we support?) where ranges means the aperture.
Thank you for the clarification. I need to find device node with
non-empty ranges property
(and make sure that device_type property is "pci"), after that I need to
read the context of ranges property and translate it.
--
Regards,
Oleksandr Tyshchenko
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