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 4013B1E98FF for ; Mon, 2 Mar 2026 11:57:15 +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=1772452635; cv=none; b=IDKTnLw0xkazfNbCemPH5/h6Y//if4Ht96h7orV1heysAzZEqldzYbK6vjymq5exO9HODhhwejhK5W1QT+0kvQ2v0SdJllffkfZpm3NzlPHvBq6ffuE/+xIOEBP247iZlWUnxrb+YFe3UiGxgTwgzqn9M/5oS76zdztYlosv+qs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772452635; c=relaxed/simple; bh=XYv2uFoCScsWY4QYL23fib7a+k78PtSH2Bqah2U4qNs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=rcnhmI/i697l9SJZYummd9UKwfKzKIcbYWQPqgn1BRPcP1CRVAj159Z+pY79WRID/IwvllIpyvf1kgbeEo915uOOKXW/e5fZEgfGWRVd6tn1wVGn82hnWh5nBPmiBHHUvWmJAq/lBwF4P4KPzT1KGDQLwmckuEzEw7w/ROrw6k0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=s+oRTm/3; 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="s+oRTm/3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EEFA4C2BC86; Mon, 2 Mar 2026 11:57:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772452635; bh=XYv2uFoCScsWY4QYL23fib7a+k78PtSH2Bqah2U4qNs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=s+oRTm/38BZES5QNRLH3fG9evg+VNxa5AvoUru8iuxu2hhxUFF6AWHo0x1LmMpel7 I5lQ4sQs5Veyh+uSJVkOW4vdnpKuytDq7NoZwH+FBiT46IYv32SDyEEPGsJ1+AP/24 FooeLWS5Mu2X9ZaJf5oG/+boZt32AT87z0TbWogRe18lwKRihnE5Lsk+GSmuVB3Dat h/3AQ2AQiPN2oEj1BAUg0liT/cf5g2ElDse/w7cbXAr8ZUfZHlOV0e+6eRHTVOieRP riJ+K+d48O9FQi/+GWGgGoKcndRRyQzwu/+s28KXHuxRP8yCR+VsLQ07XLcKFlJ1K6 gwoSsD38w5vbQ== Received: from sofa.misterjones.org ([185.219.108.64] helo=valley-girl.lan) 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 1vx1th-0000000FDFJ-0OkR; Mon, 02 Mar 2026 11:57:13 +0000 From: Marc Zyngier To: linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev Cc: Fuad Tabba , Will Deacon , Catalin Marinas , Mark Rutland , Joey Gouly , Suzuki K Poulose , Oliver Upton , Zenghui Yu Subject: [PATCH v2 01/11] arm64: Skip update of an idreg field affected by an override Date: Mon, 2 Mar 2026 11:56:42 +0000 Message-ID: <20260302115653.1517326-2-maz@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260302115653.1517326-1-maz@kernel.org> References: <20260302115653.1517326-1-maz@kernel.org> Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, tabba@google.com, will@kernel.org, catalin.marinas@arm.com, mark.rutland@arm.com, joey.gouly@arm.com, suzuki.poulose@arm.com, oupton@kernel.org, yuzenghui@huawei.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false When computing the new value od an idreg that contains a field affected by an override, do not update that particular field. The value computed at init-time must be kept as-is, as that's what the user has asked for, for better or worse. Signed-off-by: Marc Zyngier --- arch/arm64/kernel/cpufeature.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index c31f8e17732a3..28fc77443ccd3 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -1224,6 +1224,13 @@ static void update_cpu_ftr_reg(struct arm64_ftr_reg *reg, u64 new) s64 ftr_cur = arm64_ftr_value(ftrp, reg->sys_val); s64 ftr_new = arm64_ftr_value(ftrp, new); + /* + * Don't alter the initial value that has been forced + * by an override. + */ + if ((reg->override->mask & arm64_ftr_mask(ftrp)) == arm64_ftr_mask(ftrp)) + continue; + if (ftr_cur == ftr_new) continue; /* Find a safe value */ -- 2.47.3