From mboxrd@z Thu Jan 1 00:00:00 1970 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 6C662E7DF19 for ; Mon, 2 Feb 2026 18:43:58 +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=6DvRpEaDiHMFUmW/zttKhrt6yXUWKvAPVtN/Nr4F0Wc=; b=gXMn532/bs6YBg5vlYdHTj67o4 ybp8xFIrPepowg4pnTsjdFGpWh5NlWnrI+a0mlrq5bxJYJoMr+lWHMD5FGMF2nSBGmyx02BzsjBWD NjMWp256HFA9G1081WHfx6VutRnrLKlmWYhUVkdBRm4CGHSxjkNMWx6sQ00LD+YMNzoGbHLEJLFS5 djL6MDAF9H5bY+O8p3zwLumqc+5rSvcnUgNpytaPwOmFSAe3MsY6RpRyMan52M+6qGfhTv4Dj24Uc exSqIgYhIIx/CNInDfmdc85//v+9ncNB0r66XTtg6J9uZGgaB36tARSLw27GCBVY5wGZY96CHXMmh //bxhqIA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vmytq-00000005R7k-0taT; Mon, 02 Feb 2026 18:43:50 +0000 Received: from sea.source.kernel.org ([172.234.252.31]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vmyti-00000005Qxo-1M0P for linux-arm-kernel@lists.infradead.org; Mon, 02 Feb 2026 18:43:44 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id A588D4443F; Mon, 2 Feb 2026 18:43:41 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 75EBEC4AF09; Mon, 2 Feb 2026 18:43:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1770057821; bh=cUnL9eI2TSfY3RnxpVHdkNXGQe+TOBMqJnePql0UexQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VO78txqjV6lePEwq8COso/WXxK2jYKEMnsM87fTD+kYoIzL0fw/eiy3TbF4rKyrFK RU2nJnDL7GBIn7YNn3YEmOn2d9kHcgFyhM6Z9Uwy50w7a3QLq4zotaGLA3d8u1qMQE 2TItg7sn3ki1Fk6Pf8F2et2J0EE503gV4VJdMIBGgsuBFtyDrCi+XekiyzT0opPhcQ GLXqnxjU88Zxv5UFD/Q4OvyQdwQhRuxNQ6LpqdNFtbh440Z1s4HeAn6bTQXC1xYPS4 4vaHhf9Rt09MY4k5DvpECR8DzlzmEg35/bX9pNMKxai7VmEsR/XqTuZsRhh5n5CwH/ xclZx5fb0Hxpw== 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 1vmytf-00000007sAy-1e3n; Mon, 02 Feb 2026 18:43:39 +0000 From: Marc Zyngier To: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org Cc: Joey Gouly , Suzuki K Poulose , Oliver Upton , Zenghui Yu , Fuad Tabba , Will Deacon , Catalin Marinas Subject: [PATCH v2 03/20] KVM: arm64: Introduce standalone FGU computing primitive Date: Mon, 2 Feb 2026 18:43:12 +0000 Message-ID: <20260202184329.2724080-4-maz@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260202184329.2724080-1-maz@kernel.org> References: <20260202184329.2724080-1-maz@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org, joey.gouly@arm.com, suzuki.poulose@arm.com, oupton@kernel.org, yuzenghui@huawei.com, tabba@google.com, will@kernel.org, catalin.marinas@arm.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260202_104342_424842_A663D14A X-CRM114-Status: GOOD ( 13.53 ) 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 Computing the FGU bits is made oddly complicated, as we use the RES0 helper instead of using a specific abstraction. Introduce such an abstraction, which is going to make things significantly simpler in the future. Reviewed-by: Fuad Tabba Signed-off-by: Marc Zyngier --- arch/arm64/kvm/config.c | 57 ++++++++++++++++++----------------------- 1 file changed, 25 insertions(+), 32 deletions(-) diff --git a/arch/arm64/kvm/config.c b/arch/arm64/kvm/config.c index 0bcdb39885734..2122599f7cbbd 100644 --- a/arch/arm64/kvm/config.c +++ b/arch/arm64/kvm/config.c @@ -1335,26 +1335,30 @@ static u64 compute_res0_bits(struct kvm *kvm, static u64 compute_reg_res0_bits(struct kvm *kvm, const struct reg_feat_map_desc *r, unsigned long require, unsigned long exclude) - { u64 res0; res0 = compute_res0_bits(kvm, r->bit_feat_map, r->bit_feat_map_sz, require, exclude); - /* - * If computing FGUs, don't take RES0 or register existence - * into account -- we're not computing bits for the register - * itself. - */ - if (!(exclude & NEVER_FGU)) { - res0 |= compute_res0_bits(kvm, &r->feat_map, 1, require, exclude); - res0 |= ~reg_feat_map_bits(&r->feat_map); - } + res0 |= compute_res0_bits(kvm, &r->feat_map, 1, require, exclude); + res0 |= ~reg_feat_map_bits(&r->feat_map); return res0; } +static u64 compute_fgu_bits(struct kvm *kvm, const struct reg_feat_map_desc *r) +{ + /* + * If computing FGUs, we collect the unsupported feature bits as + * RES0 bits, but don't take the actual RES0 bits or register + * existence into account -- we're not computing bits for the + * register itself. + */ + return compute_res0_bits(kvm, r->bit_feat_map, r->bit_feat_map_sz, + 0, NEVER_FGU); +} + static u64 compute_reg_fixed_bits(struct kvm *kvm, const struct reg_feat_map_desc *r, u64 *fixed_bits, unsigned long require, @@ -1370,40 +1374,29 @@ void compute_fgu(struct kvm *kvm, enum fgt_group_id fgt) switch (fgt) { case HFGRTR_GROUP: - val |= compute_reg_res0_bits(kvm, &hfgrtr_desc, - 0, NEVER_FGU); - val |= compute_reg_res0_bits(kvm, &hfgwtr_desc, - 0, NEVER_FGU); + val |= compute_fgu_bits(kvm, &hfgrtr_desc); + val |= compute_fgu_bits(kvm, &hfgwtr_desc); break; case HFGITR_GROUP: - val |= compute_reg_res0_bits(kvm, &hfgitr_desc, - 0, NEVER_FGU); + val |= compute_fgu_bits(kvm, &hfgitr_desc); break; case HDFGRTR_GROUP: - val |= compute_reg_res0_bits(kvm, &hdfgrtr_desc, - 0, NEVER_FGU); - val |= compute_reg_res0_bits(kvm, &hdfgwtr_desc, - 0, NEVER_FGU); + val |= compute_fgu_bits(kvm, &hdfgrtr_desc); + val |= compute_fgu_bits(kvm, &hdfgwtr_desc); break; case HAFGRTR_GROUP: - val |= compute_reg_res0_bits(kvm, &hafgrtr_desc, - 0, NEVER_FGU); + val |= compute_fgu_bits(kvm, &hafgrtr_desc); break; case HFGRTR2_GROUP: - val |= compute_reg_res0_bits(kvm, &hfgrtr2_desc, - 0, NEVER_FGU); - val |= compute_reg_res0_bits(kvm, &hfgwtr2_desc, - 0, NEVER_FGU); + val |= compute_fgu_bits(kvm, &hfgrtr2_desc); + val |= compute_fgu_bits(kvm, &hfgwtr2_desc); break; case HFGITR2_GROUP: - val |= compute_reg_res0_bits(kvm, &hfgitr2_desc, - 0, NEVER_FGU); + val |= compute_fgu_bits(kvm, &hfgitr2_desc); break; case HDFGRTR2_GROUP: - val |= compute_reg_res0_bits(kvm, &hdfgrtr2_desc, - 0, NEVER_FGU); - val |= compute_reg_res0_bits(kvm, &hdfgwtr2_desc, - 0, NEVER_FGU); + val |= compute_fgu_bits(kvm, &hdfgrtr2_desc); + val |= compute_fgu_bits(kvm, &hdfgwtr2_desc); break; default: BUG(); -- 2.47.3