From: Marc Zyngier <maz@kernel.org>
To: oliver.upton@linux.dev, yuzenghui@huawei.com,
Jinqian Yang <yangjinqian1@huawei.com>
Cc: linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev,
linux-kernel@vger.kernel.org, liuyonglong@huawei.com,
wangzhou1@hisilicon.com
Subject: Re: [PATCH v3 0/2] KVM: arm64: make EL2 feature fields writable in ID_AA64MMFR1_EL1
Date: Fri, 19 Sep 2025 14:15:15 +0100 [thread overview]
Message-ID: <175828771292.1762581.13961318453079156132.b4-ty@kernel.org> (raw)
In-Reply-To: <20250911114621.3724469-1-yangjinqian1@huawei.com>
On Thu, 11 Sep 2025 19:46:19 +0800, Jinqian Yang wrote:
> Allow userspace to downgrade EL2 features (TWED, HCX) to ensure VM live
> migration compatibility between hosts with varying feature support.
>
> Although ID_AA64MMFR1_EL1.VH is an EL2 feature, it is still kept as non-
> writable in userspace. When FEAT_E2H0 is not implemented, HCR_EL2.E2H is
> res1. When E2H=1, EL2 operates in VHE mode. In this case, if userspace
> modifies the VH bit to 0, the Guest's kernel will still run in vEL2, leading
> to inconsistency.
>
> [...]
Applied to next, thanks!
[1/2] KVM: arm64: Make ID_AA64MMFR1_EL1.{HCX, TWED} writable from userspace
commit: 1a0b2bf6ff11d2e0438f3a7d1d299339edab96e8
[2/2] KVM: arm64: selftests: Test writes to ID_AA64MMFR1_EL1.{HCX, TWED}
commit: be8c9192eaeee21fdaacd72ad4ba992b9e42377b
Cheers,
M.
--
Without deviation from the norm, progress is not possible.
prev parent reply other threads:[~2025-09-19 13:15 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-11 11:46 Jinqian Yang
2025-09-11 11:46 ` [PATCH v3 1/2] KVM: arm64: Make ID_AA64MMFR1_EL1.{HCX, TWED} writable from userspace Jinqian Yang
2025-09-12 21:51 ` Oliver Upton
2025-09-14 20:27 ` Marc Zyngier
2025-09-11 11:46 ` [PATCH v3 2/2] KVM: arm64: selftests: Test writes to ID_AA64MMFR1_EL1.{HCX, TWED} Jinqian Yang
2025-09-19 13:15 ` Marc Zyngier [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=175828771292.1762581.13961318453079156132.b4-ty@kernel.org \
--to=maz@kernel.org \
--cc=kvmarm@lists.linux.dev \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=liuyonglong@huawei.com \
--cc=oliver.upton@linux.dev \
--cc=wangzhou1@hisilicon.com \
--cc=yangjinqian1@huawei.com \
--cc=yuzenghui@huawei.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®