From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.20]) (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 21D8646AF2B; Thu, 30 Apr 2026 16:33:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.20 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777566834; cv=none; b=GkE0t9AIvha+A8xgYeBSHasiqy8qy3nOEzo1YHj5d53y/xIcmJdkkWUDELbpNlB8meZwARrEtM6Y08aA77fJ5+Ylw+rK1AXslk9ukL8G2zRXSVnBzA9BxAObDkxkm244VftWW/VeEugRpQaUBH8na3tI2SrbbzYmqVbX9Qpbavc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777566834; c=relaxed/simple; bh=cfENCjc1fzzR6KbL+6+PAAkvtumH6My77uGSdh60sFg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=CqusAnQKoLFsqRUgzwrxmy43R7Kn6fF8DH6P/5tKdZPHDN3Mz9ntCpNtn6hfSci10uzw6XQCXYl5ig9uRLOQwkYoUzEZrMzneoCoQd8YkCCVJI2JRoK0F90mg+5QqFxbKWfHCnJ25DkWOpvNjjBHHz/6uKwI8WCKMIXXK2vAQSU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=dz5o9OOH; arc=none smtp.client-ip=198.175.65.20 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="dz5o9OOH" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1777566832; x=1809102832; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=cfENCjc1fzzR6KbL+6+PAAkvtumH6My77uGSdh60sFg=; b=dz5o9OOHBRiOVjwahPWla7r/T4wsp3a7wa/1Y2Mcs+063ooj9/Q2Ol3x hI1TnQ2Uzgc0BZj/FWredUq6WGboSgQG+IsCqYj3DLprE4jOgkfu1yH35 YsV604jwIyE2DQT6lKYZFk7GcLaHFX42kUtXfHKGHQh1pows9Q4C96YgZ eetTINU0UHVyEwSiTHHqFV6jBglyh0+tOSJ+z9fEbWuG3F5gZUsZYRaVD Io2pAqEJdQV65y5vZPZE5UcPnpQc4TJ86th/onrYTKwPAkmfIa7mLGqN/ eaSXBljGCthN9iqUXGVSCGaMTGJtxUBvC9r/7iww5bh6uFGmNaX1seY1K Q==; X-CSE-ConnectionGUID: du4+MePWQEu5cx9OCmfPYw== X-CSE-MsgGUID: MChYPw37QhqohImxjdUOiQ== X-IronPort-AV: E=McAfee;i="6800,10657,11772"; a="78236273" X-IronPort-AV: E=Sophos;i="6.23,208,1770624000"; d="scan'208";a="78236273" Received: from fmviesa010.fm.intel.com ([10.60.135.150]) by orvoesa112.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Apr 2026 09:33:52 -0700 X-CSE-ConnectionGUID: eQNDi5mTSUy9Qg9nksZGIw== X-CSE-MsgGUID: gnxf2RtZQkewiLYuAZR9QA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.23,208,1770624000"; d="scan'208";a="230278698" Received: from lkp-server01.sh.intel.com (HELO aa799cca880d) ([10.239.97.150]) by fmviesa010.fm.intel.com with ESMTP; 30 Apr 2026 09:33:48 -0700 Received: from kbuild by aa799cca880d with local (Exim 4.98.2) (envelope-from ) id 1wIUKf-00000000CeW-2GTG; Thu, 30 Apr 2026 16:33:45 +0000 Date: Fri, 1 May 2026 00:33:18 +0800 From: kernel test robot To: Dexuan Cui , kys@microsoft.com, haiyangz@microsoft.com, wei.liu@kernel.org, longli@microsoft.com, linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, mhklinux@outlook.com, matthew.ruffell@canonical.com, johansen@templeofstupid.com Cc: llvm@lists.linux.dev, oe-kbuild-all@lists.linux.dev, stable@vger.kernel.org Subject: Re: [PATCH] Drivers: hv: vmbus: Improve the logc of reserving fb_mmio on Gen2 VMs Message-ID: <202605010002.dnnxVZFF-lkp@intel.com> References: <20260416183529.838321-1-decui@microsoft.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260416183529.838321-1-decui@microsoft.com> Hi Dexuan, kernel test robot noticed the following build warnings: [auto build test WARNING on linus/master] [also build test WARNING on v7.1-rc1 next-20260429] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch#_base_tree_information] url: https://github.com/intel-lab-lkp/linux/commits/Dexuan-Cui/Drivers-hv-vmbus-Improve-the-logc-of-reserving-fb_mmio-on-Gen2-VMs/20260424-033622 base: linus/master patch link: https://lore.kernel.org/r/20260416183529.838321-1-decui%40microsoft.com patch subject: [PATCH] Drivers: hv: vmbus: Improve the logc of reserving fb_mmio on Gen2 VMs config: i386-buildonly-randconfig-002-20260430 (https://download.01.org/0day-ci/archive/20260501/202605010002.dnnxVZFF-lkp@intel.com/config) compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261) reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260501/202605010002.dnnxVZFF-lkp@intel.com/reproduce) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot | Closes: https://lore.kernel.org/oe-kbuild-all/202605010002.dnnxVZFF-lkp@intel.com/ All warnings (new ones prefixed by >>): >> drivers/hv/vmbus_drv.c:2403:40: warning: result of comparison of constant 4294967296 with expression of type 'resource_size_t' (aka 'unsigned int') is always false [-Wtautological-constant-out-of-range-compare] 2403 | if (!low_mmio_base || low_mmio_base >= SZ_4G || | ~~~~~~~~~~~~~ ^ ~~~~~ 1 warning generated. vim +2403 drivers/hv/vmbus_drv.c 2385 2386 static void __maybe_unused vmbus_reserve_fb(void) 2387 { 2388 resource_size_t start = 0, size; 2389 resource_size_t low_mmio_base; 2390 struct pci_dev *pdev; 2391 2392 /* Hyper-V CoCo guests do not have a framebuffer device. */ 2393 if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)) 2394 return; 2395 2396 if (efi_enabled(EFI_BOOT)) { 2397 /* Gen2 VM: get FB base from EFI framebuffer */ 2398 if (IS_ENABLED(CONFIG_SYSFB)) { 2399 start = sysfb_primary_display.screen.lfb_base; 2400 size = max_t(__u32, sysfb_primary_display.screen.lfb_size, 0x800000); 2401 2402 low_mmio_base = hyperv_mmio->start; > 2403 if (!low_mmio_base || low_mmio_base >= SZ_4G || 2404 (start && start < low_mmio_base)) { 2405 pr_warn("Unexpected low mmio base 0x%pa\n", &low_mmio_base); 2406 } else { 2407 /* 2408 * If the kdump kernel's lfb_base is 0, 2409 * fall back to the low mmio base. 2410 */ 2411 if (!start) 2412 start = low_mmio_base; 2413 /* 2414 * Reserve half of the space below 4GB for high 2415 * resolutions, but cap the reservation to 128MB. 2416 */ 2417 size = min((SZ_4G - start) / 2, SZ_128M); 2418 } 2419 } 2420 } else { 2421 /* Gen1 VM: get FB base from PCI */ 2422 pdev = pci_get_device(PCI_VENDOR_ID_MICROSOFT, 2423 PCI_DEVICE_ID_HYPERV_VIDEO, NULL); 2424 if (!pdev) 2425 return; 2426 2427 if (pdev->resource[0].flags & IORESOURCE_MEM) { 2428 start = pci_resource_start(pdev, 0); 2429 size = pci_resource_len(pdev, 0); 2430 } 2431 2432 /* 2433 * Release the PCI device so hyperv_drm driver can grab it 2434 * later. 2435 */ 2436 pci_dev_put(pdev); 2437 } 2438 2439 if (!start) 2440 return; 2441 2442 /* 2443 * Make a claim for the frame buffer in the resource tree under the 2444 * first node, which will be the one below 4GB. The length seems to 2445 * be underreported, particularly in a Generation 1 VM. So start out 2446 * reserving a larger area and make it smaller until it succeeds. 2447 */ 2448 for (; !fb_mmio && (size >= 0x100000); size >>= 1) 2449 fb_mmio = __request_region(hyperv_mmio, start, size, fb_mmio_name, 0); 2450 2451 pr_info("hv_mmio=%pR,%pR fb=%pR\n", hyperv_mmio, hyperv_mmio->sibling, fb_mmio); 2452 } 2453 -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki