From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by dpdk.org (Postfix) with ESMTP id 56B8229C6 for ; Fri, 16 Nov 2018 11:36:34 +0100 (CET) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 16 Nov 2018 02:36:33 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,239,1539673200"; d="scan'208";a="105113128" Received: from aburakov-mobl1.ger.corp.intel.com (HELO [10.237.220.124]) ([10.237.220.124]) by fmsmga002.fm.intel.com with ESMTP; 16 Nov 2018 02:36:32 -0800 To: "Tone Zhang (Arm Technology China)" , "dev@dpdk.org" Cc: "Gavin Hu (Arm Technology China)" , Honnappa Nagarahalli , Steve Capper , nd References: <1540347604-18590-1-git-send-email-tone.zhang@arm.com> <1541743077-27994-1-git-send-email-tone.zhang@arm.com> <68c31d94-3e4d-7b03-209b-1e63c564aa74@intel.com> From: "Burakov, Anatoly" Message-ID: <03d60745-ad79-c469-5c63-3a3d7eadfddd@intel.com> Date: Fri, 16 Nov 2018 10:36:31 +0000 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Subject: Re: [dpdk-dev] [PATCH v2] pci_vfio: Support 64KB kernel page_size with vfio-pci driver X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 16 Nov 2018 10:36:34 -0000 On 16-Nov-18 2:34 AM, Tone Zhang (Arm Technology China) wrote: > Hi Anatoly, > > I have some comments. > >> -----Original Message----- >> From: Tone Zhang (Arm Technology China) >> Sent: Thursday, November 15, 2018 8:49 AM >> To: Burakov, Anatoly ; dev@dpdk.org >> Cc: Gavin Hu (Arm Technology China) ; Honnappa >> Nagarahalli ; Steve Capper >> ; nd >> Subject: RE: [PATCH v2] pci_vfio: Support 64KB kernel page_size with vfio-pci >> driver >> >> Hi Anatoly, >> >> Sorry for the late response. >> >>> -----Original Message----- >>> From: Burakov, Anatoly >>> Sent: Friday, November 9, 2018 8:15 PM >>> To: Tone Zhang (Arm Technology China) ; >>> dev@dpdk.org >>> Cc: Gavin Hu (Arm Technology China) ; Honnappa >>> Nagarahalli ; Steve Capper >>> ; nd >>> Subject: Re: [PATCH v2] pci_vfio: Support 64KB kernel page_size with >>> vfio-pci driver >>> >>> On 09-Nov-18 5:57 AM, tone.zhang wrote: >>>> With a larger PAGE_SIZE it is possible for the MSI table to very >>>> close to the end of the BAR s.t. when we align the start and end of >>>> the MSI table to the PAGE_SIZE, the end offset of the MSI table is >>>> out of the PCI BAR boundary. >>>> >>>> This patch addresses the issue by comparing both the start and the >>>> end offset of the MSI table with the BAR size, and skip the mapping >>>> if it is out of Bar scope. >>>> >>>> The patch fixes the debug log as below: >>>> EAL: Skipping BAR0 >>>> >>>> Signed-off-by: tone.zhang >>>> Reviewed-by: Gavin Hu >>>> Reviewed-by: Honnappa Nagarahalli >>>> Reviewed-by: Steve Capper >>>> Reviewed-by: Burakov Anatoly >>> >>> In the future, please don't include my Reviewed tag unless i actually >>> sent one :) >> >> Thanks a lot! Will keep in mind. 😊 >> >>> >>>> --- >>>> drivers/bus/pci/linux/pci_vfio.c | 36 >>>> +++++++++++++++++++++++++++++++--- >>> -- >>>> 1 file changed, 31 insertions(+), 5 deletions(-) >>>> >>>> diff --git a/drivers/bus/pci/linux/pci_vfio.c >>>> b/drivers/bus/pci/linux/pci_vfio.c >>>> index 305cc06..9a0affe 100644 >>>> --- a/drivers/bus/pci/linux/pci_vfio.c >>>> +++ b/drivers/bus/pci/linux/pci_vfio.c >>>> @@ -445,9 +445,11 @@ pci_vfio_mmap_bar(int vfio_dev_fd, struct >>> mapped_pci_resource *vfio_res, >>>> struct pci_msix_table *msix_table = &vfio_res->msix_table; >>>> struct pci_map *bar = &vfio_res->maps[bar_index]; >>>> >>>> - if (bar->size == 0) >>>> + if (bar->size == 0) { >>>> /* Skip this BAR */ >>>> + RTE_LOG(INFO, EAL, "Skipping BAR%d\n", bar_index); >>>> return 0; >>>> + } >>>> >>>> if (msix_table->bar_index == bar_index) { >>>> /* >>>> @@ -456,8 +458,22 @@ pci_vfio_mmap_bar(int vfio_dev_fd, struct >>> mapped_pci_resource *vfio_res, >>>> */ >>>> uint32_t table_start = msix_table->offset; >>>> uint32_t table_end = table_start + msix_table->size; >>>> - table_end = (table_end + ~PAGE_MASK) & PAGE_MASK; >>>> - table_start &= PAGE_MASK; >>>> + table_end = RTE_ALIGN(table_end, PAGE_SIZE); >>>> + table_start = RTE_ALIGN(table_start, PAGE_SIZE); >>>> + /* after rounding to PAGE_SIZE, it is over the bar->size, >>>> + * fall back to the MSI-X table offset in the bar and >>>> + * align with PAGE_SIZE. >>>> + */ >>> >>> Minor nitpick - wording of comment could be better, for example: >>> >>> if page-aligned start of MSI-X table is beyond BAR size, shrink the >>> mapping size to MSI-X table start address. >>> >>> Also, probably needs newline before comment. >>> >> >> Will update the code in next version. Thanks! >> >>>> + if (table_start >= bar->size) { >>>> + table_start = RTE_ALIGN_FLOOR(msix_table->offset, >>>> + PAGE_SIZE); >>>> + /* after aligning with PAGE_SIZE, if it is less than >>>> + * the MSI-X table offset, continue falling back to >>>> + * the actual MSI-X table offset in the bar. >>>> + */ >>> >>> Same here, wording could probably be improved. Suggested rewording: >>> >>> If MSI-X table address, floor-aligned by page size, is lower than >>> actual MSI-X table offset, fall back to using MSI-X table offset as table start. >>> >>> Now that i think of it, this could really be expressed like this: >>> >>> uint32_t aligned = RTE_ALIGN_FLOOR(msix_table->offset, PAGE_SIZE); >>> table_start = RTE_MAX(aligned, msix_table_offset); >>> >>> I believe this would be much clearer. >>> >> >> Will update the patch. >> > > When enter the judgement, it implies the "msix_table->offset" is NOT page size aligned, I think we can replace the code in the judgement with one line: table_start = msix_table->offset; > It looks more simple. What's your opinion? Thanks! Agree, what was i thinking :D > >>>> + if (table_start < msix_table->offset) >>>> + table_start = msix_table->offset; >>>> + } >>>> >>>> if (table_start == 0 && table_end >= bar->size) { >>>> /* Cannot map this BAR */ >>>> @@ -469,8 +485,18 @@ pci_vfio_mmap_bar(int vfio_dev_fd, struct >>>> mapped_pci_resource *vfio_res, >>>> >>>> memreg[0].offset = bar->offset; >>>> memreg[0].size = table_start; >>>> - memreg[1].offset = bar->offset + table_end; >>>> - memreg[1].size = bar->size - table_end; >>>> + if (bar->size < table_end) { >>>> + /* >>>> + * after rounding to PAGE_SIZE we don't have any space >>>> + * left after the MSI table, so don't try and map it. >>>> + */ >>> >>> Suggested rewording: >>> >>> If MSI-X table end is beyond BAR end, don't attempt to perform second >> mapping. >>> >> >> Thanks a lot. Will update. >> >>>> + memreg[1].offset = 0; >>>> + memreg[1].size = 0; >>>> + } >>>> + else { >>>> + memreg[1].offset = bar->offset + table_end; >>>> + memreg[1].size = bar->size - table_end; >>>> + } >>>> >>>> RTE_LOG(DEBUG, EAL, >>>> "Trying to map BAR%d that contains the MSI-X " >>>> >>> >>> However, the patch can go in as is if needed, so >>> >>> Reviewed-by: Anatoly Burakov >>> >> >> Thanks! 😉 >> >>> -- >>> Thanks, >>> Anatoly >> >> Br, >> Tone > > Br, > Tone > -- Thanks, Anatoly