[virtio] Fix queue_sel ordering in virtio_queue_init and virtio_queue_destroy

[Copilot]

Per VirtIO spec, QueueSel must be written before reading queue-specific registers like QueueNumMax. The code was reading queue_num_max before setting queue_sel, causing failures on ARM FVP.

Changes

virtio_queue_init:

• Set queue_sel before reading queue_num_max (moved from line 131 to 105)
• Replace invalid assertion queue_num_max > queue_index with queue_index < queues_num
• Add assertion ring_size <= queue_num_max to validate against hardware limits

virtio_queue_destroy:

• Set queue_sel before reading queue_num_max (moved from line 170 to 163)
• Replace invalid assertion queue_num_max > queue_index with queue_index < queues_num

// Before: reads queue_num_max without selecting queue first
RT_ASSERT(dev->mmio_config->queue_num_max > 0);
RT_ASSERT(dev->mmio_config->queue_num_max > queue_index);  // wrong comparison
// ... later:
dev->mmio_config->queue_sel = queue_index;

// After: select queue, then read its queue_num_max
dev->mmio_config->queue_sel = queue_index;
RT_ASSERT(dev->mmio_config->queue_num_max > 0);
RT_ASSERT(ring_size <= dev->mmio_config->queue_num_max);

Original prompt

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This section details on the original issue you should resolve

<issue_title>[Bug] virtio驱动中virtio_queue_init函数中开头的queue_num_max检测有问题</issue_title>
<issue_description>### RT-Thread Version

5.3.0

Hardware Type/Architectures

arm FVP

Develop Toolchain

GCC

Describe the bug

根据virtio规范，QueueSel作用于QueueNumMax, QueueNum, QueueReady, QueueDescLow,QueueDescHigh, QueueAvailLow, QueueAvailHigh, QueueUsedLow and QueueUsedHigh。
因此virtio_queue_init函数开头处应当是先选择queue, dev->mmio_config->queue_sel = queue_index;然后去检测queue_num_max。并且queue_num_max和queue_index无关，无需检测。

实际上这个驱动在arm FVP上就会触发这个问题。

Other additional context

No response</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes [Bug] virtio驱动中virtio_queue_init函数中开头的queue_num_max检测有问题 #11106

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[github-actions]

📌 Code Review Assignment

🏷️ Tag: components

Reviewers: @Maihuanyi

Changed Files (Click to expand)

• components/drivers/virtio/virtio.c

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📊 Current Review Status (Last Updated: 2026-01-02 23:02 CST)

• ⌛ @Maihuanyi Pending Review

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