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Re: [PATCH v2 7/9] tcg: mirror mapping RWX pages for iOS optional
From: |
Richard Henderson |
Subject: |
Re: [PATCH v2 7/9] tcg: mirror mapping RWX pages for iOS optional |
Date: |
Mon, 19 Oct 2020 18:27:11 -0700 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 |
On 10/18/20 6:39 PM, Joelle van Dyne wrote:
> From: osy <osy86@users.noreply.github.com>
>
> This allows jailbroken devices with entitlements to switch the option off.
>
> Signed-off-by: Joelle van Dyne <j@getutm.app>
> ---
I can guess why this performs better: half the page table entries and thus half
the tlb entries required. Which for any non-trivially sized jit arena is going
to add up. [*]
In line with my comments re patch 6, and making this feature available
everywhere (or at least non-windows), the ifdefs would go away. I might also
suggest default on for CONFIG_DEBUG_TCG and otherwise default off (when the
host os allows).
r~
* Which makes me wonder how much we should use the "const TranslationBlock *"
version of that structure in the rx mapping, so that we're using a tlb entry
that is more likely to be present, since we've just branched from the code (or
just about to branch to the code) on the same page.
[PATCH v2 1/9] configure: option to disable host block devices, Joelle van Dyne, 2020/10/18
[PATCH v2 4/9] coroutine: add libucontext as external library, Joelle van Dyne, 2020/10/18
[PATCH v2 3/9] qemu: add support for iOS host, Joelle van Dyne, 2020/10/18
[PATCH v2 7/9] tcg: mirror mapping RWX pages for iOS optional, Joelle van Dyne, 2020/10/18
- Re: [PATCH v2 7/9] tcg: mirror mapping RWX pages for iOS optional,
Richard Henderson <=
[PATCH v2 5/9] tcg: add const hints for code pointers, Joelle van Dyne, 2020/10/18
[PATCH v2 6/9] tcg: implement mirror mapped JIT for iOS, Joelle van Dyne, 2020/10/18