Development

[assembler-0]

virtio driver read/write

Summary by CodeRabbit

• New Features

  • Added write support to the VirtIO block driver.
  • Improved I/O handling to support multiple in-flight requests with better completion and resource cleanup.

• Documentation

  • Fixed Quickstart command path to run the configuration script from the correct directory.

• Chores

  • Updated CI to run on pull requests targeting both main and dev; removed push builds to these branches.
  • Introduced a command-line utility to mangle C function names across a project, with mapping output and progress reporting.

[coderabbitai]

Caution

Review failed

The pull request is closed.

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Reviewing files that changed from the base of the PR and between ea3bbb8 and 9fd184f.

📒 Files selected for processing (4)

• .github/workflows/main.yaml (1 hunks)
• README.md (1 hunks)
• drivers/virtio/VirtioBlk.h (1 hunks)
• scripts/mangle.py (1 hunks)

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[coderabbitai]

Actionable comments posted: 9

🧹 Nitpick comments (3)

drivers/virtio/VirtioBlk.c (3)

299-312: Make write buffer const in implementation to match the header

Keep signatures consistent and protect writes.

Apply:

-int VirtioBlkWrite(uint64_t sector, void* buffer) {
+int VirtioBlkWrite(uint64_t sector, const void* buffer) {
...
-    vq_desc_table[head_idx + 1].addr  = VIRT_TO_PHYS((uint64_t)buffer);
+    vq_desc_table[head_idx + 1].addr  = VIRT_TO_PHYS((uint64_t)buffer);

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221-229: VMemAlloc per-request is heavyweight; consider a small object cache

Allocating and mapping full pages for tiny structs/status bytes per I/O is costly and increases TLB pressure. Use a slab/pool or pre-allocated per-request structures.

I can sketch a fixed-size pool (power-of-two) with a free list and no locks under virtio_lock if helpful.

Also applies to: 289-297

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24-24: Wrap-around handling for last_used_idx

Keep last_used_idx as uint16_t (good). When comparing to vq_used_ring->idx, the loop is fine, but ensure producers can’t starve consumers. Consider reading used->idx once per outer iteration to reduce live racing.

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📥 Commits

Reviewing files that changed from the base of the PR and between 9005515 and ea3bbb8.

📒 Files selected for processing (2)

• drivers/virtio/VirtioBlk.c (3 hunks)
• drivers/virtio/VirtioBlk.h (1 hunks)

🧰 Additional context used

🧬 Code graph analysis (2)

drivers/virtio/VirtioBlk.h (1)

drivers/virtio/VirtioBlk.c (1)

• VirtioBlkWrite (280-346)

drivers/virtio/VirtioBlk.c (4)

kernel/etc/Console.c (1)

• PrintKernel (181-199)

kernel/atomic/Spinlock.h (2)

• SpinLock (26-60)
• SpinUnlock (120-122)

mm/VMem.c (2)

• VMemAlloc (243-309)
• VMemFree (311-375)

kernel/atomic/Atomics.c (1)

• AtomicInc (6-8)

🔇 Additional comments (2)

drivers/virtio/VirtioBlk.c (2)

8-8: Including Virtio.h here is correct

Localizing the dependency to the implementation file is the right call.

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171-175: Sanity-check queue_size vs descriptor allocations

After reading queue_size, consider validating it’s divisible by 3 if you only support fixed 3-desc chains, or implement wrap-aware chaining across the ring boundary to avoid unusable tail fragments.

I can provide a trivial boundary-crossing chain builder (idx, (idx+1)%vq_size, (idx+2)%vq_size) if you want to keep the simple allocator.

Also applies to: 177-193