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[34.124.129.10]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2ca37a70a21sm5627295ad.7.2026.06.29.22.01.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 29 Jun 2026 22:01:36 -0700 (PDT) Date: Tue, 30 Jun 2026 05:01:31 +0000 From: Pranjal Shrivastava To: Nicolin Chen Cc: will@kernel.org, robin.murphy@arm.com, jgg@nvidia.com, joro@8bytes.org, kees@kernel.org, baolu.lu@linux.intel.com, kevin.tian@intel.com, miko.lenczewski@arm.com, smostafa@google.com, linux-arm-kernel@lists.infradead.org, iommu@lists.linux.dev, linux-kernel@vger.kernel.org, stable@vger.kernel.org, jamien@nvidia.com Subject: Re: [PATCH rc v6 4/7] iommu/arm-smmu-v3: Skip EVTQ/PRIQ setup in kdump kernel Message-ID: References: <1280ac4fdb37f998fd6dcb2bf8f4437283279395.1779265413.git.nicolinc@nvidia.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Mon, Jun 29, 2026 at 09:17:40PM -0700, Nicolin Chen wrote: > On Mon, Jun 29, 2026 at 03:15:21PM +0000, Pranjal Shrivastava wrote: > > On Wed, May 20, 2026 at 10:03:21AM -0700, Nicolin Chen wrote: > > > + if (!is_kdump_kernel()) { > > > + writeq_relaxed(smmu->evtq.q.q_base, > > > + smmu->base + ARM_SMMU_EVTQ_BASE); > > > + writel_relaxed(smmu->evtq.q.llq.prod, > > > + smmu->page1 + ARM_SMMU_EVTQ_PROD); > > > + writel_relaxed(smmu->evtq.q.llq.cons, > > > + smmu->page1 + ARM_SMMU_EVTQ_CONS); > > > + > > > + enables |= CR0_EVTQEN; > > > + ret = arm_smmu_write_reg_sync(smmu, enables, ARM_SMMU_CR0, > > > + ARM_SMMU_CR0ACK); > > > > Nit: > > I believe only the write_reg_sync(CR0) should be under this if condition > > do we see any weird behavior if we perform the reg writes in > > kdump_kernel? > > Since CR0_EVTQEN isn't set, the other three writes are dead code. > > So, I skipped them. Ack, Praan