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 481F14207A; Fri, 12 Sep 2025 11:00:52 +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=1757674853; cv=none; b=gKCIWcgdt47ZD6DCCd0R0N6z0atPf3cXvSDG8aU3n1RO198rwbOyU/Q+Rs8AjREeupw0tHcliwrZeOcsSTIjd+Bg7uLScwkqvZk6MAXMiXMf733eEjOv3NE2FyUj3mhDzef6saAbUOA9RskGIQ6V/svW1Q80irQH0iN6sqNYIjA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757674853; c=relaxed/simple; bh=9Hig5MO2Jffefaua87KEncrMekSgvRAlciqOrU/lgR8=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References: MIME-Version:Content-Type; b=H75seW5tD+izcMwq96fSXlMbMy91kcUU0AJScQtrZnWx8gIi4Vo69O//rXcQWNlqLSZIgWtuTCTTQr19uxr/cR34OlIVuwl1yHE4Z6m59OSyZvMBHR3H9RFOhpdJbRQ4NreNuZPtsXn8mlhLsQyOKSheCjlwW9+If0/t8SX5yKE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Y9jIiJ0S; 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="Y9jIiJ0S" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CE1A1C4CEF1; Fri, 12 Sep 2025 11:00:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1757674852; bh=9Hig5MO2Jffefaua87KEncrMekSgvRAlciqOrU/lgR8=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=Y9jIiJ0SlD76AkupUHHfrxAvk88t0QaJTxlubaz7Lee2xy2D0BRqnWy9kHOd+UEyZ ucw6CFXjEg23lC4HIKq0YD3BJL7UetQbE0vKECGBR/Bq0X6LlaR/kmSB/pu1+AnrxX cbiUamOX6fsmRIK6CpkZMPRvhxzpyKtLeDtJq93aoQoHkN4MmaA3LlKMATXFOqd28O x3Kko9USQF71yCJC0lsZsB8W+T4D7IKWsudRCawlXuGZmzWDSLJyfmcr1/MaTJWn0t R4lj6LhwbLOIqKDKh49o/fHDe5jximaOFTDlE8JCRYKZ4rL5P4zYCoLAmaKXoHibiN Om0+/jjPkBRVQ== 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 1ux1WM-00000005etW-1zmH; Fri, 12 Sep 2025 11:00:50 +0000 Date: Fri, 12 Sep 2025 12:00:50 +0100 Message-ID: <867by4c4v1.wl-maz@kernel.org> From: Marc Zyngier To: Itaru Kitayama Cc: Oliver Upton , Joey Gouly , Suzuki K Poulose , Zenghui Yu , Paolo Bonzini , Shuah Khan , linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, kvm@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, Itaru Kitayama Subject: Re: [PATCH] PMCR_EL0.N is RAZ/WI. At least a build failes in Ubuntu 22.04 LTS. Remove the set function. In-Reply-To: <20250912-selftest-fix3-v1-1-256710a5ae5b@linux.dev> References: <20250912-selftest-fix3-v1-1-256710a5ae5b@linux.dev> 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: linux-kernel@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 X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: itaru.kitayama@linux.dev, oliver.upton@linux.dev, joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, pbonzini@redhat.com, shuah@kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, kvm@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, itaru.kitayama@fujitsu.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, 12 Sep 2025 09:27:40 +0100, Itaru Kitayama wrote: > > Signed-off-by: Itaru Kitayama This isn't an acceptable commit message. > --- > Seen a build failure with old Ubuntu 22.04 LTS, while the latest release > has no build issue, a write to the bit fields is RAZ/WI, remove the > function. > --- > tools/testing/selftests/kvm/arm64/vpmu_counter_access.c | 6 ------ > 1 file changed, 6 deletions(-) > > diff --git a/tools/testing/selftests/kvm/arm64/vpmu_counter_access.c b/tools/testing/selftests/kvm/arm64/vpmu_counter_access.c > index f16b3b27e32ed7ca57481f27d689d47783aa0345..56214a4430be90b3e1d840f2719b22dd44f0b49b 100644 > --- a/tools/testing/selftests/kvm/arm64/vpmu_counter_access.c > +++ b/tools/testing/selftests/kvm/arm64/vpmu_counter_access.c > @@ -45,11 +45,6 @@ static uint64_t get_pmcr_n(uint64_t pmcr) > return FIELD_GET(ARMV8_PMU_PMCR_N, pmcr); > } > > -static void set_pmcr_n(uint64_t *pmcr, uint64_t pmcr_n) > -{ > - u64p_replace_bits((__u64 *) pmcr, pmcr_n, ARMV8_PMU_PMCR_N); > -} > - > static uint64_t get_counters_mask(uint64_t n) > { > uint64_t mask = BIT(ARMV8_PMU_CYCLE_IDX); > @@ -490,7 +485,6 @@ static void test_create_vpmu_vm_with_pmcr_n(uint64_t pmcr_n, bool expect_fail) > * Setting a larger value of PMCR.N should not modify the field, and > * return a success. > */ > - set_pmcr_n(&pmcr, pmcr_n); > vcpu_set_reg(vcpu, KVM_ARM64_SYS_REG(SYS_PMCR_EL0), pmcr); > pmcr = vcpu_get_reg(vcpu, KVM_ARM64_SYS_REG(SYS_PMCR_EL0)); > > So what are you fixing here? A build failure? A semantic defect? Something else? What makes this a valid change? Frankly, I have no idea. But KVM definitely allows PMCR_EL0.N to be written from userspace, and that's not going to change. M. -- Without deviation from the norm, progress is not possible.