From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=217.140.110.172 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793038343; b=W3Jhcx0OoHnJqmM+sreq763KVfvfWwl/Cfl5Abnxv6V4mWcY6dqOS8ZrJyiUomvAz4Qk 0siPfaw5FXnDdYMZXOsLvH5gfqx+piVDAzuAsh4p3lpiDUz81MEso3ppWNYqB3KRR1BxJ FrPsc5hGaNdbPxPCuB72DhTj8dEhV+pq8fLUOx9Iyc5h0vKHOp3rcI0Ur8gFdE0iIo0/Z GgP1cBt7wt91556kSAhys+t3bAEPfeC1f+JFaixL+f3rJX8LBVopSdy8jNZqvTVlGO3dX JbgdlUpen/8tQlMSlCOB6/p0eluBIShwiuJp8Gq2DnfXpyk99f+Vz44pXqrPnRgyaiQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793038343; h=DMARC-Filter:Received:Received:DKIM-Signature:From:To:Cc:Subject: Date:Message-ID:X-Mailer:In-Reply-To:References:MIME-Version: Content-Type:Content-Disposition:Content-Transfer-Encoding; bh=sS8eK21wcStxD43pokzl5l+eKhxWDBCgOyN2a4eiOW0=; b=klds9021BtUuJKJrAFqY5vZzwz2prcGWKCBrp1jaeLMRuZmawOWzFqftM89l/m7y/0um dO7C6TvxdiqcBCXHQ6kUXzqYizr8V9LI+tUGJWNpx7+WgHb041ZC3G3E9I6DpgMKTwXTv YGhsW0CEI3pQyq6b7otrID7o3VZyN+HMqYhKUVffjSojxL6s1Ot59MqE/PxWWISalD3R7 VcOu4TEjGeoSZ+ZnK2XkadYlfTRTgXvr6T4Vm7ZnJT79k/RSFUsYu+BQmwEGVng5pHurJ TwwfeRNh42oYdemv1NCqNdcL0DyQwyfXHXZvR0M73S7Hj2D7ueyxy2haGDdG0C6eh+A== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass header.d=arm.com header.i=@arm.com header.a=rsa-sha256 header.s=foss header.b=HaGbgBhG; arc=none smtp.remote-ip=217.140.110.172 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id AE38A606A31A; Mon, 26 Oct 2026 18:12:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org AE38A606A31A 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 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=arm.com header.i=@arm.com header.a=rsa-sha256 header.s=foss header.b=HaGbgBhG 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 D935819F6; Mon, 26 Oct 2026 11:12:17 -0700 (PDT) Received: from LeoBrasDK.cambridge.arm.com (LeoBrasDK.cambridge.arm.com [10.2.212.21]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 5730A3F7B4; Mon, 26 Oct 2026 11:12:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1793038341; bh=wWJzTR3+Htr+1KB+CeXE1r7KMO3Eq6qQO8tranbjgEk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HaGbgBhGvHNrCSoZMQZwE2Rf+O7xkvPrz8EmYBL5er1/HwqECfBXYRDWtWQR5/akt H29jkInDU8TVzJ/EY6x/NrfrEC5SJpx/2ZTHZlIRabLVwtJe6gjhw1nE4dvJijMwCw 1BY5t2eXAWy1WXZLn4ljoJUkMWmP5t/p13GzHy9Y= From: Leonardo Bras To: Tian Zheng Cc: Leonardo Bras , maz@kernel.org, oupton@kernel.org, catalin.marinas@arm.com, will@kernel.org, corbet@lwn.net, pbonzini@redhat.com, yuzenghui@huawei.com, wangzhou1@hisilicon.com, yangjinqian1@huawei.com, caijian11@h-partners.com, liuyonglong@huawei.com, tangchengchang@huawei.com, yezhenyu2@huawei.com, yubihong@huawei.com, linuxarm@huawei.com, joey.gouly@arm.com, kvmarm@lists.linux.dev, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, seiden@linux.ibm.com, suzuki.poulose@arm.com, fuad.tabba@linux.dev, mark.rutland@arm.com, seanjc@google.com, rdunlap@infradead.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, skhan@linuxfoundation.org Subject: Re: [PATCH v5 06/15] KVM: arm64: Add support for FEAT_HDBSS Date: Mon, 26 Oct 2026 18:12:15 +0000 Message-ID: X-Mailer: git-send-email 2.56.0 In-Reply-To: <20260929103655.85107-7-zhengtian10@huawei.com> References: <20260929103655.85107-1-zhengtian10@huawei.com> <20260929103655.85107-7-zhengtian10@huawei.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: 8bit On Tue, Sep 29, 2026 at 06:36:46PM +0800, Tian Zheng wrote: > diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c > index 32102c3912fa..12fa37328dd2 100644 > --- a/arch/arm64/kernel/cpufeature.c > +++ b/arch/arm64/kernel/cpufeature.c > @@ -2158,6 +2158,11 @@ static bool hvhe_possible(const struct arm64_cpu_capabilities *entry, > return arm64_test_sw_feature_override(ARM64_SW_FEATURE_OVERRIDE_HVHE); > } > > +static bool has_vhe_hdbss(const struct arm64_cpu_capabilities *entry, int scope) > +{ > + return is_kernel_in_hyp_mode() && has_cpuid_feature(entry, scope); > +} > + IIUC you run this on every cpu in the system, to make sure it's matching the feature. Is there any chance the kernel is in EL2 only on some of the cpus here? If not, maybe we can run it on system_supports_hdbss() instead, which would be easier for the user to understand it only runs in EL2, on top of not needing the above. Other than that, seems ok to me. Thanks! Leo