从内存加载寄存器时是否有可能“中止”而不是触发页面错误？ [英] Is it possible to “abort” when loading a register from memory rather the triggering a page fault?

问题描述

我正在考虑'最小化页面错误（和TLB错误），同时遍历大图'

'如何知道指针是否在物理内存中或它将触发Page Fault？'是从另一个角度看问题的一个相关问题，但没有解决方案。

'How to know whether a pointer is in physical memory or it will trigger a Page Fault?' is a related question looking at the problem from the other side, but does not have a solution.

我希望能够将内存中的某些数据加载到寄存器中，但是如果当前内存已被调出，则将中止加载而不是发生页面错误。我需要代码可以在Windows和Linux上的用户空间中工作，而无需任何标准权限。

I wish to be able to load some data from memory into a register, but have the load abort rather than getting a page fault, if the memory is currently paged out. I need the code to work in user space on both Windows and Linux without needing any none standard permission.

（理想上，我也想可以在TLB错误时中止。）

(Ideally, I would also like to abort on a TLB fault.)

推荐答案

TXT-NI功能的RTM（受限事务存储）部分可以禁止例外：

The RTM (Restricted Transactional Memory) part of the TXT-NI feature allows to suppress exceptions:

在交易区域中必须暴露给软件的任何错误或陷阱将被抑制。 事务性
执行将中止，并且执行将转换为非事务性执行，就好像错误或陷阱从未发生过
一样。

[。 。]

同步异常事件（＃DE，＃OF，＃NP，＃SS，＃GP，＃BR，＃UD，＃AC，＃XM，＃PF，＃NM，＃TS，＃在事务执行期间发生的MF，＃DB，＃BP / INT3）可能会导致执行无法通过事务提交，并且
需要进行非事务执行。这些事件好像从未发生过一样被抑制。

Any fault or trap in a transactional region that must be exposed to software will be suppressed. Transactional execution will abort and execution will transition to a non-transactional execution, as if the fault or trap had never occurred.
[...]
Synchronous exception events (#DE, #OF, #NP, #SS, #GP, #BR, #UD, #AC, #XM, #PF, #NM, #TS, #MF, #DB, #BP/INT3) that occur during transactional execution may cause an execution not to commit transactionally, and require a non-transactional execution. These events are suppressed as if they had never occurred.

我从没使用过RTM，但是它应该像这样工作：

I've never used RTM but it should work something like this:

xbegin fallback

  ; Don't fault here

xend

; Somewhere else
fallback:
  ; Retry non-transactionally

请注意，由于多种原因可以中止交易，请参见第16.8.3.2章。英特尔手册第1卷。
另请注意，RTM并非无处不在。

Note that a transaction can be aborted for many reasons, see chapter 16.8.3.2 of the Intel manual volume 1. Also note that RTM is not ubiquitous.

除了RTM之外，我无法想出另一种抑制负载的方法，因为它必须返回一个值或最终发出中止状态的信号（与#PF相同） 。

Besides RTM I cannot think of another way to suppress a load since it must return a value or eventually signal an abort condition (which would be the same as a #PF).

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