From patchwork Wed Aug 28 12:39:58 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Corvin_K=C3=B6hne?= X-Patchwork-Id: 13781252 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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (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 66233C54FA6 for ; Wed, 28 Aug 2024 12:40:57 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1sjHy8-0006qP-VX; Wed, 28 Aug 2024 08:40:13 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sjHy7-0006lS-OA for qemu-devel@nongnu.org; Wed, 28 Aug 2024 08:40:11 -0400 Received: from netsrv01.beckhoff.com ([62.159.14.10]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sjHy5-0003sx-QQ for qemu-devel@nongnu.org; Wed, 28 Aug 2024 08:40:11 -0400 Received: from 172.17.5.170 by netsrv01.beckhoff.com (Tls12, Aes256, Sha384, DiffieHellmanEllipticKey384); Wed, 28 Aug 2024 12:40:07 GMT DKIM-Signature: v=1; c=relaxed/relaxed; d=beckhoff.com; s=mail2022e; t=1724848807; bh=TYi5/nGWW/hOxupHZ9KtWIC+hZbNErkP6Qj9Uv6SzgM=; h= Subject:Subject:From:From:Date:Date:ReplyTo:ReplyTo:Cc:Cc:Message-Id:Message-Id; a=ed25519-sha256; b= u0oEDV9YwiZpMYnaFB1h2M6V5ulm6D4+LZNZs0z4+iNh4UVDqenyjHIR5lVqUluQm6LTuig7eNyxbexoIfR6DQ== DKIM-Signature: v=1; c=relaxed/relaxed; d=beckhoff.com; s=mail2022r; t=1724848807; bh=TYi5/nGWW/hOxupHZ9KtWIC+hZbNErkP6Qj9Uv6SzgM=; h= Subject:Subject:From:From:Date:Date:ReplyTo:ReplyTo:Cc:Cc:Message-Id:Message-Id; a=rsa-sha256; b= jOPi0gF+a9Xh5FEGEhlcMawvuJhtdmP5dgHD5WNr4ikBDbSkjBSBoyQ22Ae5Nps6Q9TWctWQo3BPxbtqFDE728GIyhTS4rZrQ2K5kJok2XH7CvYqAgWKWgYogMt2yc+ud1EP2DYksZIFdXib+YbaS1YSkTJcdvChfGh8dELLWlV0jedkt3ij2sPxepbyouQ1+A288s72UzXrRQEOU8vInN+e6sIip+cuuHm0n2kXODfHcMoBhEUrTglH2+E51jD1DYIHaWyWcGYLBkRAg1DU7vjs/psEyPDCQkkj+SSwnENUCFtZdArs0syhMUOPl5dnuXcdklr4K6Pc6g8JdQxbiA== Received: from corvink-nb.beckhoff.com (172.17.128.201) by ex04.beckhoff.com (172.17.5.170) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.39; Wed, 28 Aug 2024 14:40:04 +0200 From: =?utf-8?q?Corvin_K=C3=B6hne?= To: , CC: =?utf-8?q?C=C3=A9dric_Le_Goater?= , Alex Williamson Subject: [PATCH v2 6/7] vfio/igd: don't set stolen memory size to zero Date: Wed, 28 Aug 2024 14:39:58 +0200 Message-ID: <20240828123959.84400-2-c.koehne@beckhoff.com> X-Mailer: git-send-email 2.46.0 In-Reply-To: <20240828123959.84400-1-c.koehne@beckhoff.com> References: <20240828123549.83293-1-c.koehne@beckhoff.com> <20240828123959.84400-1-c.koehne@beckhoff.com> MIME-Version: 1.0 X-Originating-IP: [172.17.128.201] X-ClientProxiedBy: ex07.beckhoff.com (172.17.5.172) To ex04.beckhoff.com (172.17.5.170) X-OLX-Disclaimer: EX04.BECKHOFF.COM Received-SPF: pass client-ip=62.159.14.10; envelope-from=C.Koehne@beckhoff.com; helo=netsrv01.beckhoff.com X-Spam_score_int: -43 X-Spam_score: -4.4 X-Spam_bar: ---- X-Spam_report: (-4.4 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org The stolen memory is required for the GOP (EFI) driver and the Windows driver. While the GOP driver seems to work with any stolen memory size, the Windows driver will crash if the size doesn't match the size allocated by the host BIOS. For that reason, it doesn't make sense to overwrite the stolen memory size. It's true that this wastes some VM memory. In the worst case, the stolen memory can take up more than a GB. However, that's uncommon. Additionally, it's likely that a bunch of RAM is assigned to VMs making use of GPU passthrough. Signed-off-by: Corvin Köhne --- hw/vfio/igd.c | 35 ++++++++++++++++++----------------- 1 file changed, 18 insertions(+), 17 deletions(-) diff --git a/hw/vfio/igd.c b/hw/vfio/igd.c index 8a41b16421..0751c43eae 100644 --- a/hw/vfio/igd.c +++ b/hw/vfio/igd.c @@ -478,6 +478,23 @@ void vfio_probe_igd_bar0_quirk(VFIOPCIDevice *vdev, int nr) QLIST_INSERT_HEAD(&vdev->bars[nr].quirks, quirk, next); } +static int igd_get_stolen_mb(int gen, uint32_t gmch) +{ + int gms; + + if (gen < 8) { + gms = (gmch >> 3) & 0x1f; + } else { + gms = (gmch >> 8) & 0xff; + } + + if (gms > 0x10) { + error_report("Unsupported IGD GMS value 0x%x", gms); + return 0; + } + return gms * 32; +} + void vfio_probe_igd_bar4_quirk(VFIOPCIDevice *vdev, int nr) { g_autofree struct vfio_region_info *rom = NULL; @@ -655,23 +672,7 @@ void vfio_probe_igd_bar4_quirk(VFIOPCIDevice *vdev, int nr) ggms_mb = 1 << ggms_mb; } - /* - * Assume we have no GMS memory, but allow it to be overridden by device - * option (experimental). The spec doesn't actually allow zero GMS when - * when IVD (IGD VGA Disable) is clear, but the claim is that it's unused, - * so let's not waste VM memory for it. - */ - gmch &= ~((gen < 8 ? 0x1f : 0xff) << (gen < 8 ? 3 : 8)); - - if (vdev->igd_gms) { - if (vdev->igd_gms <= 0x10) { - gms_mb = vdev->igd_gms * 32; - gmch |= vdev->igd_gms << (gen < 8 ? 3 : 8); - } else { - error_report("Unsupported IGD GMS value 0x%x", vdev->igd_gms); - vdev->igd_gms = 0; - } - } + gms_mb = igd_get_stolen_mb(gen, gmch); /* * Request reserved memory for stolen memory via fw_cfg. VM firmware