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Synchronize satp & SPT #1

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KuangjuX opened this issue Jan 29, 2023 · 2 comments
Closed

Synchronize satp & SPT #1

KuangjuX opened this issue Jan 29, 2023 · 2 comments
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@KuangjuX
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由于此时 satp 是作为 SPT(shadow page table) 的唯一标识，因此，有一种情况是：当操作系统的某进程被释放后，当前的 satp 所使用的根页表被释放，并在之后被其他进程所使用，但是此时 VMM 并不知道此时 satp 已经被替换，因此会造成错。所以，当 OS 请求向 VMM 写入 satp 时也需检查是否 satp 已经被替换。
@KuangjuX KuangjuX added the bug Something isn't working label Jan 29, 2023
@KuangjuX
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具体情况是当进程被 drop 掉后，该根目录地址是在 Guest OS 被分配到其他进程，由于在 Guest OS 中并没有将其他进程的用户页表设置为只读，因此 VMM 实际上并没有办法发现用户进程的页表已经被替换并且被重写了，造成了影子页表和用户页表的不一致。

@KuangjuX
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KuangjuX commented Feb 6, 2023

See issue: #2 fix this bug

@KuangjuX KuangjuX closed this as completed Feb 6, 2023
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