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[34.77.69.137]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-47f464a96cfsm17087436f8f.20.2026.07.15.07.34.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 Jul 2026 07:34:13 -0700 (PDT) Date: Wed, 15 Jul 2026 15:34:09 +0100 From: Vincent Donnefort To: Mostafa Saleh Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kvmarm@lists.linux.dev, iommu@lists.linux.dev, catalin.marinas@arm.com, will@kernel.org, maz@kernel.org, oliver.upton@linux.dev, joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, joro@8bytes.org, jgg@ziepe.ca, mark.rutland@arm.com, qperret@google.com, tabba@google.com, sebastianene@google.com, keirf@google.com Subject: Re: [PATCH v7 01/24] KVM: arm64: Add a generic clock Message-ID: References: <20260715115906.2664882-1-smostafa@google.com> <20260715115906.2664882-2-smostafa@google.com> Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: [...] > > #define smmu_wait() { > > static u32 window = arch_timer_get_cntfrq() / ARM_SMMU_EL2_POLL_TIMEOUT_US > > u64 timeout = __arch_counter_get_cntvct() + window; > > u64 cur; > > > > ... > > > > while (!(__cond)) { > > ... > > > > cur = __arch_counter_get_cntvct(); > > if (cur >= timeout) > > __ret = -ETIMEOUT; > > > > > > No risk of overflowing u64 > > No init necessary > > It believe init will be needed as caching arch_timer_get_cntfrq() > is much better that re-reading everytime. But I can make all of this > contained in the SMMUv3 driver and remove this patch. That's why I have made window static :) (well of course it is per callsite...) > > Thanks, > Mostafa >