From patchwork Fri Feb 23 23:25:37 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tim Gardner X-Patchwork-Id: 1904051 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ubuntu.com (client-ip=185.125.189.65; helo=lists.ubuntu.com; envelope-from=kernel-team-bounces@lists.ubuntu.com; receiver=patchwork.ozlabs.org) Received: from lists.ubuntu.com (lists.ubuntu.com [185.125.189.65]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4TjkBF6Tqpz23cb for ; Mon, 26 Feb 2024 12:51:49 +1100 (AEDT) Received: from localhost ([127.0.0.1] helo=lists.ubuntu.com) by lists.ubuntu.com with esmtp (Exim 4.86_2) (envelope-from ) id 1reQ9V-0001xw-Bx; Mon, 26 Feb 2024 01:51:34 +0000 Received: from mail.tpi.com ([50.126.108.186]) by lists.ubuntu.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1rdevG-0000Ik-4t for kernel-team@lists.ubuntu.com; Fri, 23 Feb 2024 23:25:42 +0000 Received: from mail.tpi.om (174-045-099-030.res.spectrum.com [174.45.99.30]) (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) (Authenticated sender: timg) by mail.tpi.com (Postfix) with ESMTPSA id 9BBDC2C0ECF; Fri, 23 Feb 2024 15:25:40 -0800 (PST) From: Tim Gardner To: kernel-team@lists.ubuntu.com Subject: [PATCH] Drivers: hv: Always reserve framebuffer region for Gen1 VMs Date: Fri, 23 Feb 2024 16:25:37 -0700 Message-Id: <20240223232537.253005-2-timg@tpi.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240223232537.253005-1-timg@tpi.com> References: <20240223232537.253005-1-timg@tpi.com> MIME-Version: 1.0 X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.20 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: "kernel-team" From: Vitaly Kuznetsov BugLink: https://bugs.launchpad.net/bugs/2054855 vmbus_reserve_fb() tries reserving framebuffer region iff 'screen_info.lfb_base' is set. Gen2 VMs seem to have it set by EFI and/or by the kernel EFI FB driver (or, in some edge cases like kexec, the address where the buffer was moved, see https://lore.kernel.org/all/20201014092429.1415040-1-kasong@redhat.com/) but on Gen1 VM it depends on bootloader behavior. With grub, it depends on 'gfxpayload=' setting but in some cases it is observed to be zero. That being said, relying on 'screen_info.lfb_base' to reserve framebuffer region is risky. For Gen1 VMs, it should always be possible to get the address from the dedicated PCI device instead. Check for legacy PCI video device presence and reserve the whole region for framebuffer on Gen1 VMs. Reviewed-by: Michael Kelley Signed-off-by: Vitaly Kuznetsov Link: https://lore.kernel.org/r/20220827130345.1320254-3-vkuznets@redhat.com Signed-off-by: Wei Liu (cherry picked from commit 2a8a8afba0c3053d0ea8686182f6b2104293037e) Signed-off-by: Tim Gardner --- drivers/hv/vmbus_drv.c | 46 +++++++++++++++++++++++++++++------------- 1 file changed, 32 insertions(+), 14 deletions(-) diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index 3e6db9effd98..e47f7b48f09c 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -34,6 +34,7 @@ #include #include #include +#include #include #include "hyperv_vmbus.h" @@ -2309,26 +2310,43 @@ static int vmbus_acpi_remove(struct acpi_device *device) static void vmbus_reserve_fb(void) { - int size; + resource_size_t start = 0, size; + struct pci_dev *pdev; + + if (efi_enabled(EFI_BOOT)) { + /* Gen2 VM: get FB base from EFI framebuffer */ + start = screen_info.lfb_base; + size = max_t(__u32, screen_info.lfb_size, 0x800000); + } else { + /* Gen1 VM: get FB base from PCI */ + pdev = pci_get_device(PCI_VENDOR_ID_MICROSOFT, + PCI_DEVICE_ID_HYPERV_VIDEO, NULL); + if (!pdev) + return; + + if (pdev->resource[0].flags & IORESOURCE_MEM) { + start = pci_resource_start(pdev, 0); + size = pci_resource_len(pdev, 0); + } + + /* + * Release the PCI device so hyperv_drm or hyperv_fb driver can + * grab it later. + */ + pci_dev_put(pdev); + } + + if (!start) + return; + /* * Make a claim for the frame buffer in the resource tree under the * first node, which will be the one below 4GB. The length seems to * be underreported, particularly in a Generation 1 VM. So start out * reserving a larger area and make it smaller until it succeeds. */ - - if (screen_info.lfb_base) { - if (efi_enabled(EFI_BOOT)) - size = max_t(__u32, screen_info.lfb_size, 0x800000); - else - size = max_t(__u32, screen_info.lfb_size, 0x4000000); - - for (; !fb_mmio && (size >= 0x100000); size >>= 1) { - fb_mmio = __request_region(hyperv_mmio, - screen_info.lfb_base, size, - fb_mmio_name, 0); - } - } + for (; !fb_mmio && (size >= 0x100000); size >>= 1) + fb_mmio = __request_region(hyperv_mmio, start, size, fb_mmio_name, 0); } /**