From nobody Sun Dec 14 13:49:51 2025 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id A60477082F; Thu, 16 Jan 2025 06:12:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=13.77.154.182 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737007952; cv=none; b=iocfOL5dw3UHkUzYvdAqVVBEHXxhi+rjaRogvxzncsavpxQ2OsOZJcP0uNodtadpbJiZWS9yrcBe+w4yjE5yRr6zAEM4gDL5rG/OfdBdeVbBUK6BcqUwnzLeC97GQLb9CKzh/Cf72LGBdP48qHhu9xODnEmwEHPs6yBpC9FQvS0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737007952; c=relaxed/simple; bh=wx0L0s5lw2Ue27/s5MAk7zurF3XpZSNpnVARgUq4z5o=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=Fh0TmTMOyFpymkOnrdVMLMjA9V6ByCHleCB11+A7A7yuve6uoZVKsJ0yGVmh2K/C14IbwiZWsYaQWIg1bjXvHOiui0MP/dXQvQWt/AVpx9c/gR+mXMLlKrj4grlP7xNdzrAL8eu4umR/2dNuHr7ovJtEFQer0zw7zTrqiNx85Ek= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com; spf=pass smtp.mailfrom=linux.microsoft.com; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b=N+2qUiwg; arc=none smtp.client-ip=13.77.154.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="N+2qUiwg" Received: from namjain-hibernation.4uyjgaamrtuunfhsycmekme4ua.xx.internal.cloudapp.net (unknown [20.94.232.156]) by linux.microsoft.com (Postfix) with ESMTPSA id 222B7203D608; Wed, 15 Jan 2025 22:12:30 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 222B7203D608 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1737007950; bh=QukWsI7AClV1k83KOW///qMqhXC/yY5t0dJRKNVQKEs=; h=From:To:Cc:Subject:Date:From; b=N+2qUiwgs3URnS1HAGj3lC5OYU9a7S1LXmpHfYaUELPRyyndhD5JeuOimRGHctwy4 TvwrmBjewvzJ8vaS+Mw2z538OtHLtrtBXqeh7YcdHBRykbu83+2fTYH3yASnf8GqFo xSeivfDy4AlkmlmxdeG+q51o7wcOvFPT819d+kaQ= From: Naman Jain To: "K . Y . Srinivasan" , Haiyang Zhang , Wei Liu , Dexuan Cui , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org Cc: linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, Saurabh Sengar Subject: [PATCH] x86/hyperv/vtl: Stop kernel from probing VTL0 low memory Date: Thu, 16 Jan 2025 06:12:24 +0000 Message-ID: <20250116061224.1701-1-namjain@linux.microsoft.com> X-Mailer: git-send-email 2.43.0 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 Content-Type: text/plain; charset="utf-8" For Linux, running in Hyper-V VTL (Virtual Trust Level), kernel in VTL2 tries to access VTL0 low memory in probe_roms. This memory is not described in the e820 map. Initialize probe_roms call to no-ops during boot for VTL2 kernel to avoid this. The issue got identified in OpenVMM which detects invalid accesses initiated from kernel running in VTL2. Co-developed-by: Saurabh Sengar Signed-off-by: Saurabh Sengar Signed-off-by: Naman Jain Reviewed-by: Roman Kisel Tested-by: Roman Kisel --- arch/x86/hyperv/hv_vtl.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/hyperv/hv_vtl.c b/arch/x86/hyperv/hv_vtl.c index 4e1b1e3b5658..3f4e20d7b724 100644 --- a/arch/x86/hyperv/hv_vtl.c +++ b/arch/x86/hyperv/hv_vtl.c @@ -30,6 +30,7 @@ void __init hv_vtl_init_platform(void) x86_platform.realmode_init =3D x86_init_noop; x86_init.irqs.pre_vector_init =3D x86_init_noop; x86_init.timers.timer_init =3D x86_init_noop; + x86_init.resources.probe_roms =3D x86_init_noop; =20 /* Avoid searching for BIOS MP tables */ x86_init.mpparse.find_mptable =3D x86_init_noop; base-commit: 37136bf5c3a6f6b686d74f41837a6406bec6b7bc --=20 2.43.0