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[54.240.197.234]) by smtp.gmail.com with ESMTPSA id je19-20020a05600c1f9300b004090798d29csm41802wmb.15.2023.11.22.09.05.23 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 22 Nov 2023 09:05:24 -0800 (PST) From: Paul Durrant X-Google-Original-From: Paul Durrant Message-ID: Date: Wed, 22 Nov 2023 17:05:23 +0000 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 1/6] hw/xen: Set XenBackendInstance in the XenDevice before realizing it Content-Language: en-US To: Volodymyr Babchuk , "qemu-devel@nongnu.org" Cc: David Woodhouse , Stefano Stabellini , Julien Grall , Anthony Perard , Kevin Wolf , Hanna Reitz , =?UTF-8?Q?Marc-Andr=C3=A9_Lureau?= , Paolo Bonzini , Jason Wang , "open list:X86 Xen CPUs" , "open list:Block layer core" References: <20231121221023.419901-1-volodymyr_babchuk@epam.com> <20231121221023.419901-2-volodymyr_babchuk@epam.com> Organization: Xen Project In-Reply-To: <20231121221023.419901-2-volodymyr_babchuk@epam.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=2a00:1450:4864:20::335; envelope-from=xadimgnik@gmail.com; helo=mail-wm1-x335.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 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, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=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: , Reply-To: paul@xen.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On 21/11/2023 22:10, Volodymyr Babchuk wrote: > From: David Woodhouse > > This allows a XenDevice implementation to know whether it was created > by QEMU, or merely discovered in XenStore after the toolstack created > it. This will allow us to create frontend/backend nodes only when we > should, rather than unconditionally attempting to overwrite them from > a driver domain which doesn't have privileges to do so. > > As an added benefit, it also means we no longer have to call the > xen_backend_set_device() function from the device models immediately > after calling qdev_realize_and_unref(). Even though we could make > the argument that it's safe to do so, and the pointer to the unreffed > device *will* actually still be valid, it still made my skin itch to > look at it. > > Signed-off-by: David Woodhouse > --- > hw/block/xen-block.c | 3 +-- > hw/char/xen_console.c | 2 +- > hw/net/xen_nic.c | 2 +- > hw/xen/xen-bus.c | 4 ++++ > include/hw/xen/xen-backend.h | 2 -- > include/hw/xen/xen-bus.h | 2 ++ > 6 files changed, 9 insertions(+), 6 deletions(-) > Actually, I think you should probably update xen_backend_try_device_destroy() in this patch too. It currently uses xen_backend_list_find() to check whether the specified XenDevice has an associated XenBackendInstance. Paul