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mx.microsoft.com 1; spf=none; dmarc=none; dkim=none; arc=none Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=suse.com; Message-ID: <1bc9c545-5af7-8665-4830-e8aa3836101b@suse.com> Date: Tue, 8 Feb 2022 10:16:59 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.5.0 Subject: Re: [PATCH v6 06/13] vpci/header: implement guest BAR register handlers Content-Language: en-US To: Oleksandr Andrushchenko Cc: "julien@xen.org" , "sstabellini@kernel.org" , Oleksandr Tyshchenko , Volodymyr Babchuk , Artem Mygaiev , "roger.pau@citrix.com" , "andrew.cooper3@citrix.com" , "george.dunlap@citrix.com" , "paul@xen.org" , Bertrand Marquis , Rahul Singh , "xen-devel@lists.xenproject.org" References: <20220204063459.680961-1-andr2000@gmail.com> <20220204063459.680961-7-andr2000@gmail.com> <61d85343-9a37-6409-449d-a662ae5258c5@suse.com> <66992013-f438-246b-451d-d96f6eea22c0@epam.com> From: Jan Beulich In-Reply-To: <66992013-f438-246b-451d-d96f6eea22c0@epam.com> Content-Type: text/plain; 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>>> +} >>> + >>> +static int bar_ignore_access(const struct pci_dev *pdev, unsigned int reg, >>> + struct vpci_bar *bar) >>> +{ >>> + if ( is_hardware_domain(pdev->domain) ) >>> + return 0; >>> + >>> + return vpci_add_register(pdev->vpci, guest_bar_ignore_read, NULL, >>> + reg, 4, bar); >>> +} >> For these two functions: I'm not sure "ignore" is an appropriate >> term here. unused_bar_read() and unused_bar() maybe? Or, >> considering we already have VPCI_BAR_EMPTY, s/unused/empty/ ? I'm >> also not sure we really need the is_hardware_domain() check here: >> Returning 0 for Dom0 is going to be fine as well; there's no need >> to fetch the value from actual hardware. The one exception might >> be for devices with buggy BAR behavior ... > Well, I think this should be ok, so then > - s/guest_bar_ignore_read/empty_bar_read > - s/bar_ignore_access/empty_bar Hmm, seeing it, I don't think empty_bar() is a good function name. setup_empty_bar() or empty_bar_setup() would make more clear what the function's purpose is. > - no is_hardware_domain check Please wait a little to see whether Roger has any input on this aspect. Jan