From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5A65943AB7; Wed, 8 Jan 2025 21:26:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736371618; cv=none; b=PKbrxUNfZArbCyIzWMzfEv/dIGJqBp5iyyn8KIuWb7HWUc/DCVHMeZh4pGkG/koYYMLcuu3uDJ0YFTX3RFWsXCbJ/Tvo6xZA/aCG9daxO2rEuzDKLeezi7YIjL0jxduneCHA2SYeRlT+T3R3hCY/f+FBb79N0fw0mg13HxdPv/w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736371618; c=relaxed/simple; bh=riKG7nO9RJbSoa7gdJfJX23y+iFGgRy+JO5p42yyI3Q=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References: MIME-Version:Content-Type; b=osbbTVOMpMFm8dogKCAk7KFRkoEisT6T+C0AbLY/NtJ3D2vMAqhFEZCWcjRUoMBDWz0dWKlua7OiDjAte6jV8CUveCq/83SQkgGuo4hAzHW+kgJgi2oB4edJ5UX3Wfxs6K1igA/YVLjKmgbYPX6MJ+ydXH05JhThuXfV436pElg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=rnJRgfqF; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="rnJRgfqF" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DA55AC4CED3; Wed, 8 Jan 2025 21:26:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1736371617; bh=riKG7nO9RJbSoa7gdJfJX23y+iFGgRy+JO5p42yyI3Q=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=rnJRgfqFifjraX/uM6puPSoMy7ZH54bMm538/ME5wO2e53ka3wN/5efvnJOxG08YG buX/eMsyeIzQKzBhj6qVEiFdIktPTkDcOvutjSpRxStSIVeFYjloiD49y6adVYJBNm ytE3kfDjj5vINPYxxZh3XLOBD9LyfX39XSB/Nh7XEnAukbrf3bHGKNbuisUtZjPp8x D/wHbrfP0gt5jSjHzxT9ggIq36A9Fy49uX5oA1Ne4/7oTYK6JHSa9hqTKT581lxUtg jtJaj6n1vE0Ln06cc4gLFzvlloVFLxPW72vz2tRUOINKM25g82gCuZM5JgTqQx5XOh 5PZIaRBcYoeKA== Received: from sofa.misterjones.org ([185.219.108.64] helo=wait-a-minute.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1tVdZn-00AIsV-HJ; Wed, 08 Jan 2025 21:26:55 +0000 Date: Wed, 08 Jan 2025 21:26:54 +0000 Message-ID: <87jzb5q9nl.wl-maz@kernel.org> From: Marc Zyngier To: Oliver Upton Cc: Will Deacon , kvmarm@lists.linux.dev, Joey Gouly , Suzuki K Poulose , Zenghui Yu , Mingwei Zhang , Colton Lewis , Raghavendra Rao Ananta , Catalin Marinas , Mark Rutland , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 00/18] KVM: arm64: Support FEAT_PMUv3 on Apple hardware In-Reply-To: References: <20241217212048.3709204-1-oliver.upton@linux.dev> <20250108123840.GA9197@willie-the-truck> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/29.4 (x86_64-pc-linux-gnu) MULE/6.0 (HANACHIRUSATO) Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: oliver.upton@linux.dev, will@kernel.org, kvmarm@lists.linux.dev, joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, mizhang@google.com, coltonlewis@google.com, rananta@google.com, catalin.marinas@arm.com, mark.rutland@arm.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false On Wed, 08 Jan 2025 20:14:07 +0000, Oliver Upton wrote: > > Hey Will, > > On Wed, Jan 08, 2025 at 12:38:41PM +0000, Will Deacon wrote: > > What's your plan for this series? I started looking at it and I can take > > the first four apple_m1 patches if you like? > > I plan on posting a respin of it by next week, which should look pretty > much the same besides cleaning up the build error I introduced :) > > Besides that, I think we need to decide on the KVM side of things > whether or not we want to support an event counter in addition to the > PMU cycle counter. Janne's FEX use case would certainly benefit from it. I think we should always be able to support *one* counter on top of the cycle counter. Doing more than that would result in inconsistent behaviours (some events only count on a single counter). Unless we restrict ourselves to a very small set of events that we can always schedule on any counter, but this doesn't sound very promising. Thoughts? M. -- Without deviation from the norm, progress is not possible.