commit aa0f655e2104b000a61b53b6df3290f2c14f600d
author Pierre-Clément Tosi <ptosi@google.com> Wed Jul 12 14:49:35 2023 +0000
committer Pierre-Clément Tosi <ptosi@google.com> Wed Jul 12 15:29:13 2023 +0000
tree 5432bdc9489908871c6a600ff8a973488993d7e6
parent b7e26b3f2eb4bb7dbd2e2852b43693f8ec27e53d

pvmfw: Detect and log large number of PCI devices

Currently, pvmfw silently truncates the list of PCI devices
(effectively) if the VMM passes more than it can hold in the template
DT. Instead, report it to the user and abort the boot, which will help
with debugging issues such as b/290694451, aosp/2499577, or b/238371182.

Test: Manual with extra virtio devices
Change-Id: Ibf1204cd0a398f28a03704babd03559881fec917

pvmfw/src/fdt.rs

diff --git a/pvmfw/src/fdt.rs b/pvmfw/src/fdt.rs
index 2382b50..38db7aa 100644
--- a/pvmfw/src/fdt.rs
+++ b/pvmfw/src/fdt.rs
@@ -248,14 +248,22 @@
     let range1 = ranges.next().ok_or(FdtError::NotFound)?;
 
     let irq_masks = node.getprop_cells(cstr!("interrupt-map-mask"))?.ok_or(FdtError::NotFound)?;
-    let irq_masks = CellChunkIterator::<{ PciInfo::IRQ_MASK_CELLS }>::new(irq_masks);
-    let irq_masks: ArrayVec<[PciIrqMask; PciInfo::MAX_IRQS]> =
-        irq_masks.take(PciInfo::MAX_IRQS).collect();
+    let mut chunks = CellChunkIterator::<{ PciInfo::IRQ_MASK_CELLS }>::new(irq_masks);
+    let irq_masks = (&mut chunks).take(PciInfo::MAX_IRQS).collect();
+
+    if chunks.next().is_some() {
+        warn!("Input DT has more than {} PCI entries!", PciInfo::MAX_IRQS);
+        return Err(FdtError::NoSpace);
+    }
 
     let irq_maps = node.getprop_cells(cstr!("interrupt-map"))?.ok_or(FdtError::NotFound)?;
-    let irq_maps = CellChunkIterator::<{ PciInfo::IRQ_MAP_CELLS }>::new(irq_maps);
-    let irq_maps: ArrayVec<[PciIrqMap; PciInfo::MAX_IRQS]> =
-        irq_maps.take(PciInfo::MAX_IRQS).collect();
+    let mut chunks = CellChunkIterator::<{ PciInfo::IRQ_MAP_CELLS }>::new(irq_maps);
+    let irq_maps = (&mut chunks).take(PciInfo::MAX_IRQS).collect();
+
+    if chunks.next().is_some() {
+        warn!("Input DT has more than {} PCI entries!", PciInfo::MAX_IRQS);
+        return Err(FdtError::NoSpace);
+    }
 
     Ok(PciInfo { ranges: [range0, range1], irq_masks, irq_maps })
 }