From nobody Fri Dec 19 14:03:08 2025 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 BE56825C82E for ; Fri, 10 Oct 2025 15:45:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760111157; cv=none; b=GIrB5F7SCh2n+bDBHOch8UC463u51DsLJhzp1rGlTN2uc4sNJPoRarTJ11XEjEXHNBmVKj898GdOVOiK4H+RltPYs73p4Kan+T1GtkNT+e7uoNBdTVUnCyxRY1EdhJHAJ6YXMtVEkbbXDB61yCBXa3g7P4MDMl5dkkzNjB1CxS0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760111157; c=relaxed/simple; bh=yA74IhlGtg4yTqbTpZM40Gs/gwwkkEGQQOBunTmQts8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=QkqKAQ2u39OsNDsQzUGdHLu0AzNLKF+pAtDy+jf/t6L4P+5Z3g6kC0YfSlBtiUPCFGAVZv3hBV4HeHX8Vp7uZLp+U8IenUAGKjCECKqZnD5FGhBwbuZ0n2CssJ7+GkrOzXTinUur08CAv2KD/gfL6RucAYuhaPVl3gqlx0W7N2s= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=Pg2zUujy; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Pg2zUujy" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1760111154; 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=uA/joIxupKiXJwORpnKdW+bHmjp4JFkmsKHil6Ud81E=; b=Pg2zUujyM+jqHLS4ku+ps6l0nDheucz6+SBf8mqPeu7wUgSEYCNxsyYXgZSX5e/15si3ZZ MPvHFxgx6WkOSKXlTxnvFUllVaoTCWb137sPS7AFlequtgwFFh1sh8EKrEBldIYoaRrZv3 7XzeSXv6F2nc7IxGF8iNx1jFTElOPGk= Received: from mx-prod-mc-05.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-275-b-Sr8LpaOGShfFTrtDDmzw-1; Fri, 10 Oct 2025 11:45:51 -0400 X-MC-Unique: b-Sr8LpaOGShfFTrtDDmzw-1 X-Mimecast-MFC-AGG-ID: b-Sr8LpaOGShfFTrtDDmzw_1760111141 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (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-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 4EA4319560BB; Fri, 10 Oct 2025 15:45:41 +0000 (UTC) Received: from vschneid-thinkpadt14sgen2i.remote.csb (unknown [10.45.224.29]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 84AAE180035E; Fri, 10 Oct 2025 15:45:26 +0000 (UTC) From: Valentin Schneider To: linux-kernel@vger.kernel.org, linux-mm@kvack.org, rcu@vger.kernel.org, x86@kernel.org, linux-arm-kernel@lists.infradead.org, loongarch@lists.linux.dev, linux-riscv@lists.infradead.org, linux-arch@vger.kernel.org, linux-trace-kernel@vger.kernel.org Cc: Josh Poimboeuf , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , Andy Lutomirski , Peter Zijlstra , Arnaldo Carvalho de Melo , Paolo Bonzini , Arnd Bergmann , Frederic Weisbecker , "Paul E. McKenney" , Jason Baron , Steven Rostedt , Ard Biesheuvel , Sami Tolvanen , "David S. Miller" , Neeraj Upadhyay , Joel Fernandes , Josh Triplett , Boqun Feng , Uladzislau Rezki , Mathieu Desnoyers , Mel Gorman , Andrew Morton , Masahiro Yamada , Han Shen , Rik van Riel , Jann Horn , Dan Carpenter , Oleg Nesterov , Juri Lelli , Clark Williams , Yair Podemsky , Marcelo Tosatti , Daniel Wagner , Petr Tesarik Subject: [PATCH v6 19/29] KVM: VMX: Mark vmx_l1d_should flush and vmx_l1d_flush_cond keys as allowed in .noinstr Date: Fri, 10 Oct 2025 17:38:29 +0200 Message-ID: <20251010153839.151763-20-vschneid@redhat.com> In-Reply-To: <20251010153839.151763-1-vschneid@redhat.com> References: <20251010153839.151763-1-vschneid@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 Content-Type: text/plain; charset="utf-8" Later commits will cause objtool to warn about static keys being used in .noinstr sections in order to safely defer instruction patching IPIs targeted at NOHZ_FULL CPUs. These keys are used in .noinstr code, and can be modified at runtime (/proc/kernel/vmx* write). However it is not expected that they will be flipped during latency-sensitive operations, and thus shouldn't be a source of interference wrt the text patching IPI. Mark it to let objtool know not to warn about it. Reported-by: Josh Poimboeuf Signed-off-by: Valentin Schneider --- arch/x86/kvm/vmx/vmx.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index aa157fe5b7b31..dce2bd7375ec8 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -204,8 +204,15 @@ module_param(pt_mode, int, S_IRUGO); =20 struct x86_pmu_lbr __ro_after_init vmx_lbr_caps; =20 -static DEFINE_STATIC_KEY_FALSE(vmx_l1d_should_flush); -static DEFINE_STATIC_KEY_FALSE(vmx_l1d_flush_cond); +/* + * Both of these static keys end up being used in .noinstr sections, howev= er + * they are only modified: + * - at init + * - from a /proc/kernel/vmx* write + * thus during latency-sensitive operations they should remain stable. + */ +static DEFINE_STATIC_KEY_FALSE_NOINSTR(vmx_l1d_should_flush); +static DEFINE_STATIC_KEY_FALSE_NOINSTR(vmx_l1d_flush_cond); static DEFINE_MUTEX(vmx_l1d_flush_mutex); =20 /* Storage for pre module init parameter parsing */ --=20 2.51.0