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 E329D2F6578; Fri, 17 Oct 2025 17:06:28 +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=1760720789; cv=none; b=LxJ1T648jUUjnfQJKcN17pcbtyxN9e9xa32rvTtynwE/Ru8NnfsRwiR/5z8pwcZWHSXPK54EpBy5PyZfY4nG3aZrq92wKX97kGg16beKKb8TbcZp4S3TBDldjvbJY6MSG7Ucb0LCslC6T1ayxfpYPyzSBMxZ0Yygoty18OJhuaM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760720789; c=relaxed/simple; bh=owdsvpGuqtfJqt1yeEm2ukThStXdCZDt3cCbZJE06hA=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References: MIME-Version:Content-Type; b=LmavhAfe9GNa9+pjX6ZwssUCrNTwnfFWAw463sojdnA5PDYnDU0cboDOI40C12oukwhF3tsJIf9SLz7x2SlGgfM/5bzRlFqFgL9Ivf9Ge5rW4fhnafQEkbIedYGxMghw/B2eIYurPM7SeIcTxweShnuQlWGz6CgHDJXFO6cOBTU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=srsVk+Ex; 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="srsVk+Ex" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 81C9AC4CEE7; Fri, 17 Oct 2025 17:06:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1760720788; bh=owdsvpGuqtfJqt1yeEm2ukThStXdCZDt3cCbZJE06hA=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=srsVk+ExIl6UoFr8jbNWtHjqaCU7kGEh/aCI+er06jBrVykq/oX5SoRKZDVgAsPCz 8jvZOTgIBP32o+Sw089bTZtPRh3qE5gY/+AB/C28STdV+PkV3yLAX+hERh0SWW1d5F qedQ3ePupiOP5b3OYDQXUw+xWfUoGNgQuGMmFAAOzEeSK/u54xP9gbucnPJ3WC6ZDp csMWGlgltGih3ceEXKN8oWrecFvo7mOif1VLT2q3iC6dltwQr/7Y74PLiMX14P2BXW 23XEvGzrauJBcx7c6gfUWod0B3WH/bA3Ea0Eb2OSUB33EpclLdiM2eO/rqkMOpMPf7 m1Wwx3LaVAVMw== Received: from sofa.misterjones.org ([185.219.108.64] helo=goblin-girl.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.98.2) (envelope-from ) id 1v9nuM-0000000EwrQ-0JKC; Fri, 17 Oct 2025 17:06:26 +0000 Date: Fri, 17 Oct 2025 18:06:25 +0100 Message-ID: <86v7kdwj8u.wl-maz@kernel.org> From: Marc Zyngier To: Maximilian Dittgen Cc: , , , , , , , , , Maximilian Dittgen Subject: Re: [PATCH] KVM: selftests: fix ITS collection target addresses in vgic_lpi_stress In-Reply-To: <20251017161918.40711-1-mdittgen@amazon.de> References: <20251017161918.40711-1-mdittgen@amazon.de> 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/30.1 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) Precedence: bulk X-Mailing-List: kvm@vger.kernel.org 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 Content-Transfer-Encoding: quoted-printable X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: mdittgen@amazon.de, oliver.upton@linux.dev, pbonzini@redhat.com, shuah@kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kselftest@vger.kernel.org, kvm@vger.kernel.org, epetron@amazon.de, nh-open-source@amazon.com, mdittgen@amazon.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false On Fri, 17 Oct 2025 17:19:18 +0100, Maximilian Dittgen wrote: >=20 > When mapping guest ITS collections, vgic_lpi_stress iterates over > integers in the range [0, nr_cpus), passing them as the target_addr > parameter to its_send_mapc_cmd(). These integers correspond to the > selftest userspace vCPU IDs that we intend to map each ITS collection > to. >=20 > However, its_encode_target() within its_send_mapc_cmd() expects a > vCPU's redistributor address--not the vCPU ID--as the target_addr > parameter. This is evident from how its_encode_target() encodes the > target_addr parameter as: >=20 > its_mask_encode(&cmd->raw_cmd[2], target_addr >> 16, 51, 16) >=20 > This shows that we right-shift the input target_addr parameter by 16 > bits before encoding it. This makes sense when the parameter refers to > redistributor addresses (e.g., 0x20000, 0x30000) but not vCPU IDs > (e.g., 0x2, 0x3). =46rom the KVM ITS emulation code: * We use linear CPU numbers for redistributor addressing, * so GITS_TYPER.PTA is 0. It is not an address. M. --=20 Without deviation from the norm, progress is not possible.