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Discovery-migration prerequisites (M19.0)

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The host bridge now carries MMIO apertures derived from the boot memory
map's gaps below 4 GiB (largest three, sort-merged; a single after-the-
last-region hole dies on OVMF's flash at the top) plus one aperture above
the described space — so a user-space device_register of PCI functions
with BAR resources can pass containment. The discovery test asserts
every PCI memory resource lies inside a bridge window and names any
escapee. device_register is idempotent on exact (parent, class, identity,
resources) match — a restarted registering bus cannot duplicate its
children; proven directly against the broker in the bus test.
ChildAdded gains device_id so a report can carry the registered kernel
id a matched driver needs as its assignment.
This commit is contained in:
Daniel Samson
2026-07-13 01:59:32 +01:00
parent 75d62660b0
commit a2a05d0b3d
8 changed files with 165 additions and 9 deletions
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system/kernel/devices-broker.zig
+20
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@@ -180,6 +180,26 @@ pub fn register(parent_id: u64, owner: u32, descriptor: *const device_abi.Device
if (!ok) return error.NotContained;
}
// Idempotent on exact match (docs/m19-m20-plan.md decision 3): a restarted
// registering bus re-registers what it rediscovers, and the table has no
// unregister — an identical (class, identity, resources) child under the
// same parent returns the existing id instead of appending a duplicate.
for (devices[0..count]) |*existing| {
if (existing.parent != parent_id) continue;
if (existing.class != descriptor.class) continue;
if (existing.pci_class != descriptor.pci_class) continue;
if (existing.hid_len != descriptor.hid_len) continue;
if (!std.mem.eql(u8, existing.hid[0..@intCast(existing.hid_len)], descriptor.hid[0..@intCast(descriptor.hid_len)])) continue;
if (existing.resource_count != descriptor.resource_count) continue;
var same = true;
for (0..@intCast(descriptor.resource_count)) |i| {
const a = existing.resources[i];
const b = descriptor.resources[i];
if (a.kind != b.kind or a.start != b.start or a.len != b.len) same = false;
}
if (same) return existing.id;
}
var d = std.mem.zeroes(device_abi.DeviceDescriptor);
d.id = count;
d.parent = parent_id;