From patchwork Mon Jun 17 07:51:30 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Shaoqin Huang X-Patchwork-Id: 13700295 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5DB84C27C6E for ; Mon, 17 Jun 2024 07:52:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=KPXmcpazuVrMqUJPORzGFpRReNsdKA0hgm49aNQmAl8=; b=zuWo8SXGoPZqcybHwZBOYBcAew WlDc0J4Kg3MhF3DRArW0OyrOuUwrun3FDtIwaRIxWicJJvRdwv0+cpDWdjFYEcK2l3T5GrwxdcMKR N4c4dQdwpmYntL/KEYiUh0pQ1tThJXr0pNuczkFon/ejPN7zIgeEoXFfoKnhDZqX5OgrwA1k1huY1 n6PlhAV6w6Lpxy1DPW3zLwFai8N490eVYxru9UwS5WN83G2vQNBx+3J/plRrdexmB0a4CVu2P1/IW /Muw/IegamxL98r/tEyfe/HNYewx4cLfDMlWJTEhSvEEFqLy2tHH4Kfm9lorIlO2i5AYltDnKeppJ IIU3G5Sw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sJ79j-00000009jyg-0Iz8; Mon, 17 Jun 2024 07:51:59 +0000 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1sJ79Z-00000009jtF-2hk0 for linux-arm-kernel@lists.infradead.org; Mon, 17 Jun 2024 07:51:51 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1718610708; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=KPXmcpazuVrMqUJPORzGFpRReNsdKA0hgm49aNQmAl8=; b=Hg0Mc5tr1EJq3SNyd7dtJbjjtatj4QuD49JDzC6qgRJE5yf+E0N+tooPKHScN4/LRzkENq opb7k+0r4I8i+btx1iBs0LuGHdg5vkJUGlal5mHvlLnYeRpp8Mx9eZ+GNCx3FMO2qCTAf4 0ONqWqNKKKDFvhd6Eez6YQeaDwosZ80= Received: from mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-653-R6eXFVDiPGqWuOClDLqc0Q-1; Mon, 17 Jun 2024 03:51:45 -0400 X-MC-Unique: R6eXFVDiPGqWuOClDLqc0Q-1 Received: from mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.40]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 50E0F19560A1; Mon, 17 Jun 2024 07:51:43 +0000 (UTC) Received: from virt-mtcollins-01.lab.eng.rdu2.redhat.com (virt-mtcollins-01.lab.eng.rdu2.redhat.com [10.8.1.196]) by mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 5F72919560AB; Mon, 17 Jun 2024 07:51:41 +0000 (UTC) From: Shaoqin Huang To: Oliver Upton , Marc Zyngier , kvmarm@lists.linux.dev Cc: Shaoqin Huang , James Morse , Suzuki K Poulose , Zenghui Yu , Catalin Marinas , Will Deacon , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH v1 1/2] KVM: arm64: Allow BT field in ID_AA64PFR1_EL1 writable Date: Mon, 17 Jun 2024 03:51:30 -0400 Message-Id: <20240617075131.1006173-2-shahuang@redhat.com> In-Reply-To: <20240617075131.1006173-1-shahuang@redhat.com> References: <20240617075131.1006173-1-shahuang@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.40 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240617_005149_838150_27014F6E X-CRM114-Status: GOOD ( 14.24 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org When migrating between some of the ARM machines, the BT field value in ID_AA64PFR1_EL1 register is different and not writable. This causes migration failed. The BT field means Branch Target Identification mechanism support in AArch64 state. The value 0 means BT is not implemented, the value 1 means BT is implemented. Here is an example of the migration if the BT value is different: * On Migration Src, the BT value is 0. * On Migration Dst, the BT value is 1. As it defined in the ftr_id_aa64dfr0, the samller value is safe. So if we make the BT field writable, on the Migration Dst the BT field will be overrided with value 0. --- arch/arm64/kvm/sys_regs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index c9f4f387155f..958e4d251535 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -2292,7 +2292,7 @@ static const struct sys_reg_desc sys_reg_descs[] = { ID_AA64PFR0_EL1_GIC | ID_AA64PFR0_EL1_AdvSIMD | ID_AA64PFR0_EL1_FP), }, - ID_SANITISED(ID_AA64PFR1_EL1), + ID_WRITABLE(ID_AA64PFR1_EL1, ID_AA64PFR1_EL1_BT), ID_UNALLOCATED(4,2), ID_UNALLOCATED(4,3), ID_WRITABLE(ID_AA64ZFR0_EL1, ~ID_AA64ZFR0_EL1_RES0),