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b=nNwRceMisP7FZE2pLX4Ok5VI2ZG0MFEJVQDx9pAeUqAqFhKUvALGY0in194T/V8tW myrgquqQb7sQBHx+gKbEBgbJpmNSk57VGsscgBLNXEf7cib57KQB0QAG7TYsotU1Er n3AqvVrVRYAFtmD1HTkOPXh8oUSkHw0i9dJCLl4L3Q5LXH04uQHpGd1eFv7Go2iBrd 8qeAahF170WS74aduSY45aVUojSa1BBnZBeZNdiEjGkYym5eClNtOPZEQqt6ZGkAw2 GwB5D9jZ45JdX6jAzuYCDEhgdizZohPw89gW2GdOglfe2QO31+HbAjSxsCUgiwoVvx Lw9xrp32KclNw== MIME-Version: 1.0 Date: Wed, 30 Jul 2025 12:46:52 +0200 From: Nicola Vetrini To: Jan Beulich Cc: Jiqian Chen , Huang Rui , =?UTF-8?Q?Roger_Pau_Monn=C3=A9?= , Andrew Cooper , Anthony PERARD , Michal Orzel , Julien Grall , Stefano Stabellini , xen-devel@lists.xenproject.org, consulting@bugseng.com Subject: Re: [PATCH v9 4/8] vpci: Hide extended capability when it fails to initialize In-Reply-To: <562265e2a66b4eae06c4703a836e7d21@bugseng.com> References: <20250728050401.329510-1-Jiqian.Chen@amd.com> <20250728050401.329510-5-Jiqian.Chen@amd.com> <8051d388-48f9-4878-8924-8e645f313238@suse.com> <562265e2a66b4eae06c4703a836e7d21@bugseng.com> Message-ID: X-Sender: nicola.vetrini@bugseng.com Organization: BUGSENG s.r.l. Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit On 2025-07-30 12:42, Nicola Vetrini wrote: > On 2025-07-30 11:50, Jan Beulich wrote: >> On 28.07.2025 07:03, Jiqian Chen wrote: >>> +static int vpci_ext_capability_hide( >>> + const struct pci_dev *pdev, unsigned int cap) >>> +{ >>> + const unsigned int offset = pci_find_ext_capability(pdev->sbdf, >>> cap); >>> + struct vpci_register *r, *prev_r; >>> + struct vpci *vpci = pdev->vpci; >>> + uint32_t header, pre_header; >>> + >>> + if ( offset < PCI_CFG_SPACE_SIZE ) >>> + { >>> + ASSERT_UNREACHABLE(); >>> + return 0; >>> + } >>> + >>> + spin_lock(&vpci->lock); >>> + r = vpci_get_register(vpci, offset, 4); >>> + if ( !r ) >>> + { >>> + spin_unlock(&vpci->lock); >>> + return -ENODEV; >>> + } >>> + >>> + header = (uint32_t)(uintptr_t)r->private; >>> + if ( offset == PCI_CFG_SPACE_SIZE ) >>> + { >>> + if ( PCI_EXT_CAP_NEXT(header) <= PCI_CFG_SPACE_SIZE ) >>> + r->private = (void *)(uintptr_t)0; >> >> Eclair regards this a Misra rule 11.9 violation. Elsewhere we use >> (void *)0, >> which I then would conclude is "fine". But I can't say why that is. >> Cc-ing >> Bugseng for a possible explanation. >> > > Hi Jan, > > I only see > > 0|$ git grep "(void\*)0" > xen/include/xen/types.h:#define NULL ((void*)0) > > which is fine for R11.9 of course. As Andrew noted, I don't see the > need for the use of uintptr_t either. Oh, I missed forms using a space before the pointer. In any case, from the rule's Amplification: "Note: a null pointer constant of the form (void *)0 is permitted, whether or not it was expanded from NULL." -- Nicola Vetrini, B.Sc. Software Engineer BUGSENG (https://bugseng.com) LinkedIn: https://www.linkedin.com/in/nicola-vetrini-a42471253