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Wed, 06 May 2026 04:05:02 +0000 (GMT) Received: from smtpav02.dal12v.mail.ibm.com (smtpav02.dal12v.mail.ibm.com [10.241.53.101]) by smtprelay05.wdc07v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 646450Uv13173360 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 6 May 2026 04:05:00 GMT Received: from smtpav02.dal12v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 6F75858051; Wed, 6 May 2026 04:05:00 +0000 (GMT) Received: from smtpav02.dal12v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id B00315805A; Wed, 6 May 2026 04:04:55 +0000 (GMT) Received: from [9.124.209.5] (unknown [9.124.209.5]) by smtpav02.dal12v.mail.ibm.com (Postfix) with ESMTP; Wed, 6 May 2026 04:04:55 +0000 (GMT) Message-ID: <36506ccd-5448-4ed6-a1be-aa89d80c4d43@linux.ibm.com> Date: Wed, 6 May 2026 09:34:53 +0530 X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] powerpc/pseries/iommu: Add TCEs for 16GB pages when RAM is pre-mapped Content-Language: en-GB To: Gaurav Batra , maddy@linux.ibm.com Cc: linuxppc-dev@lists.ozlabs.org, ritesh.list@gmail.com, donettom@linux.ibm.com, vaibhav@linux.ibm.com, sbhat@linux.ibm.com References: <20260504205459.39185-1-gbatra@linux.ibm.com> <83e821e1-2a71-4d8e-a40a-59ed7b333e95@linux.ibm.com> From: Harsh Prateek Bora In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNTA2MDAzMiBTYWx0ZWRfX8RrXt4MvXbod Ujk1QFHMR/SgQpKz4vkHD9q6tYpWNWMtWQCaY+OJVel2z7RVEMfeRMi9q3j0ExYe2psrDQv4eZ5 pCcnX0Q2p70QM4EaYmUAP/E2Q7TPO4+xmN0dcJLnkHQ/u5X4g/+V89jQMwFgI5/gBERx//9WzX7 VlVP+KqddLg0qtdU8Fm7/M6hAJ8ScbrzHiNz0qA7hmcam4TyAiWYbtKjIsdVcNN2Q0WwlOBHTMh LaxEeD+WfTWW7eCS4zkKmUUCXO4++rC9EvRvbFZtw4xX3Zp5NuiDaB3ffnx4YNIoOQr6k2fpmWc MAYf63IsDDGekS0/lu0JvasdtU1189UuIg4zWxDdS/mIRfqCaO0ASxxzWqBlVdlZQn29XTRjya6 SKFGXB4ifzaTha7jtY/U/ZOXXs4SI/TjT7QQPLOSxLKWA3mGxYqtOIAVdM/PAWDi82nxtmH6i3E KeF0V1v2N2zR0nGHkCA== X-Proofpoint-GUID: XmfFKO_oAvaJOBzx8ehHy81OSR7gqTTl X-Proofpoint-ORIG-GUID: 7PzKTF7I8B135SPJnaJw0Pn84H1CYkHC X-Authority-Analysis: v=2.4 cv=eu/vCIpX c=1 sm=1 tr=0 ts=69fabdef cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=IkcTkHD0fZMA:10 a=NGcC8JguVDcA:10 a=f7IdgyKtn90A:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=iQ6ETzBq9ecOQQE5vZCe:22 a=m7yw0iWS10_1d7RJ39cA:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-05-05_02,2026-04-30_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 phishscore=0 lowpriorityscore=0 clxscore=1015 adultscore=0 suspectscore=0 malwarescore=0 bulkscore=0 impostorscore=0 spamscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2604200000 definitions=main-2605060032 On 06/05/26 2:31 am, Gaurav Batra wrote: > > On 5/5/26 1:49 PM, Harsh Prateek Bora wrote: >> >> >> On 05/05/26 2:24 am, Gaurav Batra wrote: >>> @@ -2431,7 +2437,7 @@ static int iommu_mem_notifier(struct >>> notifier_block *nb, unsigned long action, >>>           spin_lock(&dma_win_list_lock); >>>           list_for_each_entry(window, &dma_win_list, list) { >>>               if (window->direct && (arg->start_pfn << PAGE_SHIFT) < >>> -                ddw_memory_hotplug_max()) { >>> +                pseries_ddw_max_ram) { >>>                   ret |= tce_setrange_multi_pSeriesLP(arg->start_pfn, >>>                           arg->nr_pages, window->prop); >> >> I think not only start_pfn, but end_pfn also needs to be within allowed >> range, which may require clamping arg->nr_pages if crossing the limits. > The reason to only check for start_pfn is because the range given will > either be in the RAM or pmemory. It can never cross the boundary Usually as an API, we do not trust the caller, hence the check for start_pfn. However, if at all we need to go ahead with that assumption, may be document that as a code comment and/or in the commit log also? >> >>>               } >>> @@ -2444,7 +2450,7 @@ static int iommu_mem_notifier(struct >>> notifier_block *nb, unsigned long action, >>>           spin_lock(&dma_win_list_lock); >>>           list_for_each_entry(window, &dma_win_list, list) { >>>               if (window->direct && (arg->start_pfn << PAGE_SHIFT) < >>> -                ddw_memory_hotplug_max()) { >>> +                pseries_ddw_max_ram) { >>>                   ret |= tce_clearrange_multi_pSeriesLP(arg->start_pfn, >>>                           arg->nr_pages, window->prop); >>>               } >>