From: Marc Zyngier <maz@kernel.org>
To: linux-arm-kernel@lists.infradead.org
Cc: Will Deacon <will@kernel.org>,
kernel-team@android.com, ascull@google.com, tabba@google.com,
dbrazdil@google.com, James Morse <james.morse@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Alexandru Elisei <alexandru.elisei@arm.com>
Subject: [PATCH] KVM: arm64: Clarify vcpu reset behaviour
Date: Tue, 6 Apr 2021 13:58:41 +0100 [thread overview]
Message-ID: <20210406125841.1077079-1-maz@kernel.org> (raw)
Although the KVM_ARM_VCPU_INIT documentation mention that the
registers are reset to their "initial values", it doesn't
describe what these values are.
Describe this state explicitly.
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
Documentation/virt/kvm/api.rst | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index 38e327d4b479..e2237e4e10ba 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -3115,6 +3115,16 @@ optional features it should have. This will cause a reset of the cpu
registers to their initial values. If this is not called, KVM_RUN will
return ENOEXEC for that vcpu.
+The initial values are defined as:
+ - Processor state:
+ * AArch64: EL1h, D, A, I and F bits set
+ * Aarch32: SVC, D, A, I and F bits set
+ - General Purpose registers, including PC and SP: set to 0
+ - FPSIMD/NEON registers: set to 0
+ - SVE registers: set to 0
+ - System registers: Reset to their architecturally defined
+ values as for a warm reset to EL1 (resp. SVC)
+
Note that because some registers reflect machine topology, all vcpus
should be created before this ioctl is invoked.
--
2.29.2
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next reply other threads:[~2021-04-06 13:00 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-06 12:58 Marc Zyngier [this message]
2021-04-07 15:59 ` [PATCH] KVM: arm64: Clarify vcpu reset behaviour Alexandru Elisei
2021-04-07 16:26 ` Marc Zyngier
2021-04-07 20:35 ` Will Deacon
2021-04-08 10:36 ` Marc Zyngier
2021-04-08 10:53 ` Will Deacon
2021-04-08 13:14 ` Marc Zyngier
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=20210406125841.1077079-1-maz@kernel.org \
--to=maz@kernel.org \
--cc=alexandru.elisei@arm.com \
--cc=ascull@google.com \
--cc=dbrazdil@google.com \
--cc=james.morse@arm.com \
--cc=kernel-team@android.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=suzuki.poulose@arm.com \
--cc=tabba@google.com \
--cc=will@kernel.org \
/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;
as well as URLs for NNTP newsgroup(s).