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Fri, 09 Jan 2026 08:29:51 -0800 (PST) Received: from [192.168.1.3] ([185.48.77.170]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-47d8678cad8sm70961885e9.3.2026.01.09.08.29.50 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 09 Jan 2026 08:29:51 -0800 (PST) Message-ID: <1aaffbcd-ba0c-4371-80d7-ce59ac7f13a9@linaro.org> Date: Fri, 9 Jan 2026 16:29:50 +0000 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH v6 03/35] KVM: arm64: Add CONFIG_KVM_ARM_SPE Kconfig option To: Alexandru Elisei Cc: mark.rutland@arm.com, james.morse@arm.com, maz@kernel.org, oliver.upton@linux.dev, joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, will@kernel.org, catalin.marinas@arm.com, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev References: <20251114160717.163230-1-alexandru.elisei@arm.com> <20251114160717.163230-4-alexandru.elisei@arm.com> Content-Language: en-US From: James Clark In-Reply-To: <20251114160717.163230-4-alexandru.elisei@arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260109_082953_203422_039782CA X-CRM114-Status: GOOD ( 19.37 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 14/11/2025 4:06 pm, Alexandru Elisei wrote: > Add a new configuration option that will be used for KVM SPE emulation. > CONFIG_KVM_ARM_SPE depends on the SPE driver being builtin because: > > 1. The SPE driver maintains a cpumask of physical CPUs that support SPE, > and that will be used by KVM to emulate SPE on heterogeneous systems. > > 2. KVM will rely on the SPE driver enabling the SPE interrupt at the GIC > level. > > Signed-off-by: Alexandru Elisei > --- > arch/arm64/kvm/Kconfig | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig > index 4f803fd1c99a..31388b5b2655 100644 > --- a/arch/arm64/kvm/Kconfig > +++ b/arch/arm64/kvm/Kconfig > @@ -83,4 +83,12 @@ config PTDUMP_STAGE2_DEBUGFS > > If in doubt, say N. > > +config KVM_ARM_SPE > + bool > + depends on KVM && ARM_SPE_PMU=y I think the most common configuration is module, so requiring built-in isn't great. If there's any way of avoiding it, even if it costs a little bit of pain, it would be good for adoption. It was basically the first thing I got stuck on trying to get it to work. Or if it really can't be done, maybe some kind of debug message to say why enabling failed. > + default n > + help > + Adds support for Statistical Profiling Extension (SPE) in virtual > + machines. > + > endif # VIRTUALIZATION