From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 778741DF731; Tue, 28 Jan 2025 09:11:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738055486; cv=none; b=FirJQEwDGbniTNDW+5arf4pXK93CArnX9YqaBSahBuLZEyzzGpOz6IUVix44ZBljyxAUTYOx64J45c/TAzz18ZCriTAQkrMszvSBq3+kQy6KSSJ5LK8K6RVmUXKW1Gy1jLJR1nuafSdeYPfdVarIHTx5HNUxrzAIGZ4wigygMvQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738055486; c=relaxed/simple; bh=FltoNwx1CJICDVmBGovb3tzHU01UgL7Ot70tmwww9PY=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=ozXl8OL9cTvM04JXVaR3VekVR593A69aRFUv7HkePoVomtYx76eDmytA2fHiHesQ5SFEyIBO9W3kn8VISJBH51kj6fcTmSa7p4IanBSYnJkPJUg7N6dx7UXw3ULroK2fYAjbQDT94p3gDio8jd3CMdvB/109+rnqQ6Bqims26DE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 4EE0F497; Tue, 28 Jan 2025 01:11:50 -0800 (PST) Received: from [10.162.16.94] (a077893.blr.arm.com [10.162.16.94]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 6BC663F528; Tue, 28 Jan 2025 01:11:20 -0800 (PST) Message-ID: <7f5c68c7-8036-4d18-950f-80e55ac8ea11@arm.com> Date: Tue, 28 Jan 2025 14:41:17 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 0/7] arm64/boot: Enable EL2 requirements for FEAT_PMUv3p9 To: Rob Herring , Catalin Marinas Cc: Marc Zyngier , linux-arm-kernel@lists.infradead.org, Will Deacon , Ryan Roberts , Mark Rutland , Oliver Upton , Jonathan Corbet , Eric Auger , kvmarm@lists.linux.dev, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org References: <20241220072240.1003352-1-anshuman.khandual@arm.com> <20250102160402.GB3990035-robh@kernel.org> <86wmf5wo8u.wl-maz@kernel.org> Content-Language: en-US From: Anshuman Khandual In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 1/18/25 03:37, Rob Herring wrote: > On Thu, Jan 16, 2025 at 9:32 AM Catalin Marinas wrote: >> >> On Wed, Jan 08, 2025 at 07:47:16AM -0600, Rob Herring wrote: >>> On Wed, Jan 8, 2025 at 5:15 AM Marc Zyngier wrote: >>>> On Tue, 07 Jan 2025 22:13:47 +0000, >>>> Rob Herring wrote: >>>>> On Tue, Jan 7, 2025 at 6:13 AM Catalin Marinas wrote: >>>>>> But does KVM actually expose the feature to EL1 in ID_AA64DFR1_EL1 and >>>>>> than traps it at EL2? >>>>> >>>>> As Marc pointed out KVM only advertises PMUv3.8. Regardless, guest >>>>> accesses to these registers are trapped with or without this series. >>>> >>>> And most probably generates a nice splat in the kernel log, as nobody >>>> updated KVM to handle *correctly* PMICNTR_EL0 traps, let alone deal >>>> with the FGT2 registers. >>> >>> Isn't that this series[1]? Should that have come first, I guess I know >>> that *now*. >> [...] >>> [1] https://lore.kernel.org/all/20241210055311.780688-1-anshuman.khandual@arm.com/ >> >> It's not any clearer to me. Does this series depend on the 46-patch one? >> Or, if we had the other, is this no longer needed? Or none of these, >> they are independent. > > They are independent. I think ideally we'd want everything landing at > the same time, but we're past ideal at this point. Without this > series, if someone uses PMU on v8.9 and firmware enabled FGT2, then > the kernel will crash. Without the above series, KVM will have > warnings in the kernel log, but otherwise function. Right, they are independent. Just that Rob had observed this PMU v3.8 boot requirement while reviewing the HW breakpoint series earlier. I should just respin this series after the upcoming v6.14-rc1 release is out ?