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Tue, 26 Jul 2022 03:41:52 -0400 (EDT) Date: Tue, 26 Jul 2022 09:41:51 +0200 From: Klaus Jensen To: Jinhao Fan Cc: qemu-devel@nongnu.org, kbusch@kernel.org Subject: Re: [PATCH v4] hw/nvme: Use ioeventfd to handle doorbell updates Message-ID: References: <20220705142403.101539-1-fanjinhao21s@ict.ac.cn> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="eHnarp13lzhLnYHG" Content-Disposition: inline In-Reply-To: Received-SPF: pass client-ip=64.147.123.20; envelope-from=its@irrelevant.dk; helo=wout4-smtp.messagingengine.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" --eHnarp13lzhLnYHG Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Jul 26 15:35, Jinhao Fan wrote: > at 4:55 AM, Klaus Jensen wrote: >=20 > >=20 > > We have a regression following this patch that we need to address. > >=20 > > With this patch, issuing a reset on the device (`nvme reset /dev/nvme0` > > will do the trick) causes QEMU to hog my host cpu at 100%. > >=20 > > I'm still not sure what causes this. The trace output is a bit > > inconclusive still. > >=20 > > I'll keep looking into it. >=20 > I cannot reproduce this bug. I just start the VM and used `nvme reset > /dev/nvme0`. Did you do anything before the reset? >=20 Interesting and thanks for checking! Looks like a kernel issue then! I remember that I'm using a dev branch (nvme-v5.20) of the kernel and reverting to a stock OS kernel did not produce the bug. --eHnarp13lzhLnYHG Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEUigzqnXi3OaiR2bATeGvMW1PDekFAmLfmq8ACgkQTeGvMW1P DekFawgAxSSzsKr6tTfsynS7+Vsvff7nxxkLoRqXIJiwR/OvSQKXqUrvggct9nu3 otRA/yGZXAeNgp5sL3awCMlxajCZ8UNwtZWe3Cd2XQL7JzudgirPhjPlQ0L2MARl yUWCZtllgJlamkXCkGpQHmnWluNPeG514rxBIQmISoyZD4dmScyprKT1/tGLZhGE xIyMho9FvDQLLOn4uRKIYUca5hugYTbkynM3yh4PGyQ8JRrFp+otp1WXZnttAQ0H AfPyJY+18yPqYGGYcqtvtojdimuF9Usd+oIiGFIYl57TTLAyF8bdRUPKRGnBuX7a XWqH3dx1MKlUDF9jdVUKG3IpeT7paw== =DONi -----END PGP SIGNATURE----- --eHnarp13lzhLnYHG--