All of lore.kernel.org
 help / color / mirror / Atom feed
From: Beata Michalska <beata.michalska@linaro.org>
To: qemu-devel@nongnu.org
Cc: peter.maydell@linaro.org, qemu-arm@nongnu.org,
	Christoffer.Dall@arm.com, pbonzini@redhat.com
Subject: [RFC PATCH 0/1] target/arm: kvm: Support for KVM DABT without valid ISS
Date: Fri, 20 Dec 2019 20:27:06 +0000	[thread overview]
Message-ID: <20191220202707.30641-1-beata.michalska@linaro.org> (raw)

Some of the ARMv7 & ARMv8 load/store instructions might trigger a data abort
exception with no valid ISS info to be decoded. The lack of decode info
makes it at least tricky to emulate the instruction which is one of the
(many) reasons why KVM will not even try to do so.

So far, if a guest made an attempt to access memory outside the memory slot,
KVM reported vague ENOSYS. As a result QEMU exited with no useful information
being provided or even a clue on what has just happened.

Recently ARM KVM introduced support for notifying guest of an attempt to
execute an instruction that resulted in dabt with no valid ISS decoding info.
This still leaves QEMU to handle the case, but at least now, it can enable
further debugging of the encountered issue by being more verbose
in a (hopefully) useful way.



Beata Michalska (1):
  target/arm: kvm: Handle DABT with no valid ISS

 accel/kvm/kvm-all.c    | 15 +++++++
 accel/stubs/kvm-stub.c |  4 ++
 include/sysemu/kvm.h   |  1 +
 target/arm/cpu.h       |  3 +-
 target/arm/kvm.c       | 95 ++++++++++++++++++++++++++++++++++++++++++
 target/arm/kvm32.c     |  3 ++
 target/arm/kvm64.c     |  3 ++
 target/arm/kvm_arm.h   | 19 +++++++++
 8 files changed, 142 insertions(+), 1 deletion(-)

-- 
2.17.1



             reply	other threads:[~2019-12-20 20:28 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-20 20:27 Beata Michalska [this message]
2019-12-20 20:27 ` [RFC PATCH 1/1] target/arm: kvm: Handle DABT with no valid ISS Beata Michalska
2020-01-06 17:14   ` Peter Maydell
2020-01-07 11:38     ` Beata Michalska
2020-01-07 14:28   ` Peter Maydell
2020-01-07 21:37     ` Beata Michalska
2020-01-08 10:55       ` Peter Maydell

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=20191220202707.30641-1-beata.michalska@linaro.org \
    --to=beata.michalska@linaro.org \
    --cc=Christoffer.Dall@arm.com \
    --cc=pbonzini@redhat.com \
    --cc=peter.maydell@linaro.org \
    --cc=qemu-arm@nongnu.org \
    --cc=qemu-devel@nongnu.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.