daniel/danos
1
0
Fork 0
Code Issues 4 Pull Requests Actions Packages Projects 1 Releases Wiki Activity

kernel: the IOMMU backends move behind the architecture boundary

Browse Source 
VT-d and AMD-Vi are x86 hardware, but lived in the architecture-neutral
kernel tree and leaked further: the core's public Kind enum named both
vendors, and the ACPI parser read the VT-d version/capability registers
(raw volatile MMIO inside table discovery). Now the vendor backends
live in architecture/x86_64/ behind architecture.iommu — the core hands
over the discovery facts plus an injected environment (frame allocation
+ the log sink, the same pattern enablePaging uses) and receives the
hardware vtable back, so the backends never import kernel internals and
an ARM port supplies its SMMU with no core change. Discovery keeps
table facts only; the live-unit register check moved into VT-d detect
(version reading zero now stays fail-open). The unused kindOf() is
gone. Log shapes the harness pins (iommu online, DANOS-IOMMU-FAULT)
are unchanged; all five IOMMU QEMU cases pass.
This commit is contained in:
Daniel Samson
2026-07-30 07:16:08 +01:00
parent e53d6ebafb
commit fa8203cdba
7 changed files with 197 additions and 153 deletions
Download Patch File Download Diff File Expand all files Collapse all files
system/kernel/tests.zig
+4 -5
View File
@@ -1253,11 +1253,10 @@ fn iommuTest() void {
const pinfo = platform.platformInformation();
check("IOMMU found in the firmware tables", pinfo.iommu_present);
check("IOMMU unit has a register base", pinfo.iommu_base != 0);
// The VT-d version register is a live-unit sanity check; AMD-Vi (from IVRS) records
// no version, so gate it on the vendor.
if (!pinfo.iommu_is_amd)
check("VT-d version register reads back nonzero (real, mappable unit)", pinfo.iommu_version != 0);
log("DANOS-IOMMU: base=0x{x} version=0x{x} capabilities=0x{x}\n", .{ pinfo.iommu_base, pinfo.iommu_version, pinfo.iommu_capabilities });
// The live-unit sanity (the version register reading back nonzero) now
// gates detect itself: an unusable unit stays fail-open, so `enabled()`
// below subsumes the old vendor-gated register check.
log("DANOS-IOMMU: base=0x{x}\n", .{pinfo.iommu_base});
// Translation was enabled at boot (kernel.zig: iommu.init before any driver claims
// a device). The blanket domain keeps every device identity-mapped, so DMA still