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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 579A5C6FA8E for ; Wed, 21 Sep 2022 16:10:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232365AbiIUQJ6 (ORCPT ); Wed, 21 Sep 2022 12:09:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51680 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232701AbiIUQI5 (ORCPT ); Wed, 21 Sep 2022 12:08:57 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4B098A5703; Wed, 21 Sep 2022 08:56:22 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id C0CF463185; Wed, 21 Sep 2022 15:54:45 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0512BC433C1; Wed, 21 Sep 2022 15:54:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1663775685; bh=Xl9DQuwvvXNb/6SB5ZGg1HtsmmbR8/7Nu6p+aHx3wMs=; h=From:To:Cc:Subject:Date:From; b=vQlCMiqQ9hQRn6XWnh/v/Ga5vQXobxapTwRiTvDKmbisjKWhVqu2NIQojwN3/Fd9C 4FJNsdnQbqC2UOj0hEGYQU29Jur0pH+Um26tCLYAMlYZ4OySjzZo9quKY11jPKxdtx SOkxBgjtkdLSgyc6vchVe06QL23cHY+fGBjC/69/Dj+/2bM87jklIiZMPOTUk9XUac oL+nzYG2Fu2DTRnbKE2yjJHobsYgk6lUA67KWWSdxIlJW2XNeIBSSA+SS0SmBxLq88 IvZlJcpbZcL4PqYWfgJeZ7K8thyRIXiKOtLVtYPmwSeEH48V2dFhfset2+Pze7nWd3 RP2CzFLS30rTA== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Vitaly Kuznetsov , Michael Kelley , Wei Liu , Sasha Levin , kys@microsoft.com, haiyangz@microsoft.com, sthemmin@microsoft.com, decui@microsoft.com, linux-hyperv@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 1/3] Drivers: hv: Never allocate anything besides framebuffer from framebuffer memory region Date: Wed, 21 Sep 2022 11:54:41 -0400 Message-Id: <20220921155444.235446-1-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-hyperv@vger.kernel.org From: Vitaly Kuznetsov [ Upstream commit f0880e2cb7e1f8039a048fdd01ce45ab77247221 ] Passed through PCI device sometimes misbehave on Gen1 VMs when Hyper-V DRM driver is also loaded. Looking at IOMEM assignment, we can see e.g. $ cat /proc/iomem ... f8000000-fffbffff : PCI Bus 0000:00 f8000000-fbffffff : 0000:00:08.0 f8000000-f8001fff : bb8c4f33-2ba2-4808-9f7f-02f3b4da22fe ... fe0000000-fffffffff : PCI Bus 0000:00 fe0000000-fe07fffff : bb8c4f33-2ba2-4808-9f7f-02f3b4da22fe fe0000000-fe07fffff : 2ba2:00:02.0 fe0000000-fe07fffff : mlx4_core the interesting part is the 'f8000000' region as it is actually the VM's framebuffer: $ lspci -v ... 0000:00:08.0 VGA compatible controller: Microsoft Corporation Hyper-V virtual VGA (prog-if 00 [VGA controller]) Flags: bus master, fast devsel, latency 0, IRQ 11 Memory at f8000000 (32-bit, non-prefetchable) [size=64M] ... hv_vmbus: registering driver hyperv_drm hyperv_drm 5620e0c7-8062-4dce-aeb7-520c7ef76171: [drm] Synthvid Version major 3, minor 5 hyperv_drm 0000:00:08.0: vgaarb: deactivate vga console hyperv_drm 0000:00:08.0: BAR 0: can't reserve [mem 0xf8000000-0xfbffffff] hyperv_drm 5620e0c7-8062-4dce-aeb7-520c7ef76171: [drm] Cannot request framebuffer, boot fb still active? Note: "Cannot request framebuffer" is not a fatal error in hyperv_setup_gen1() as the code assumes there's some other framebuffer device there but we actually have some other PCI device (mlx4 in this case) config space there! The problem appears to be that vmbus_allocate_mmio() can use dedicated framebuffer region to serve any MMIO request from any device. The semantics one might assume of a parameter named "fb_overlap_ok" aren't implemented because !fb_overlap_ok essentially has no effect. The existing semantics are really "prefer_fb_overlap". This patch implements the expected and needed semantics, which is to not allocate from the frame buffer space when !fb_overlap_ok. Note, Gen2 VMs are usually unaffected by the issue because framebuffer region is already taken by EFI fb (in case kernel supports it) but Gen1 VMs may have this region unclaimed by the time Hyper-V PCI pass-through driver tries allocating MMIO space if Hyper-V DRM/FB drivers load after it. Devices can be brought up in any sequence so let's resolve the issue by always ignoring 'fb_mmio' region for non-FB requests, even if the region is unclaimed. Reviewed-by: Michael Kelley Signed-off-by: Vitaly Kuznetsov Link: https://lore.kernel.org/r/20220827130345.1320254-4-vkuznets@redhat.com Signed-off-by: Wei Liu Signed-off-by: Sasha Levin --- drivers/hv/vmbus_drv.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index fca092cfe200..9cbe0b00ebf7 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -1846,7 +1846,7 @@ int vmbus_allocate_mmio(struct resource **new, struct hv_device *device_obj, bool fb_overlap_ok) { struct resource *iter, *shadow; - resource_size_t range_min, range_max, start; + resource_size_t range_min, range_max, start, end; const char *dev_n = dev_name(&device_obj->device); int retval; @@ -1881,6 +1881,14 @@ int vmbus_allocate_mmio(struct resource **new, struct hv_device *device_obj, range_max = iter->end; start = (range_min + align - 1) & ~(align - 1); for (; start + size - 1 <= range_max; start += align) { + end = start + size - 1; + + /* Skip the whole fb_mmio region if not fb_overlap_ok */ + if (!fb_overlap_ok && fb_mmio && + (((start >= fb_mmio->start) && (start <= fb_mmio->end)) || + ((end >= fb_mmio->start) && (end <= fb_mmio->end)))) + continue; + shadow = __request_region(iter, start, size, NULL, IORESOURCE_BUSY); if (!shadow) -- 2.35.1