Re: [PATCH v2 2/5] KVM: arm64: Support set the DBM attr during memory abort
From: Tian Zheng
Date: Thu Nov 27 2025 - 07:19:39 EST
On 2025/11/22 20:54, Marc Zyngier wrote:
On Fri, 21 Nov 2025 09:23:39 +0000,I will remove this statement in v3.
Tian Zheng <zhengtian10@xxxxxxxxxx> wrote:
From: eillon <yezhenyu2@xxxxxxxxxx>
Add DBM support to automatically promote write-clean pages to
write-dirty, preventing users from being trapped in EL2 due to
missing write permissions.
Since the DBM attribute was introduced in ARMv8.1 and remains
optional in later architecture revisions, including ARMv9.5.
What is the relevance of this statement?
Yes, this patch only adds support to set the DBM attr in the S2 PTE
Support set the DBM attr during user_mem_abort().
I don't think this commit message accurately describes what the code
does. This merely adds support to the page table code to set the DBM
bit in the S2 PTE, and nothing else.
during user_mem_abort(), and does not implement automatic promote
write-clean pages to write-dirty.
I will reward commit message of this patch like:
This patch adds support to set the DBM attr in S2 PTE during
user_mem_abort(). As long as add the DBM bit, it enable hardware
automatically promote write-clean pages to write-dirty, preventing
users from being trapped in EL2 due to missing write permissions.
M.