From patchwork Sun Oct 10 19:10:05 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Adam Lackorzynski X-Patchwork-Id: 1539061 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) 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 bilbo.ozlabs.org (Postfix) with ESMTPS id 4HSBNw1qgkz9sRN for ; Mon, 11 Oct 2021 06:11:26 +1100 (AEDT) Received: from localhost ([::1]:54718 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mZeEF-0007jX-6r for incoming@patchwork.ozlabs.org; Sun, 10 Oct 2021 15:11:23 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:32890) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mZeD7-0007ir-Tu for qemu-devel@nongnu.org; Sun, 10 Oct 2021 15:10:13 -0400 Received: from os.inf.tu-dresden.de ([141.76.48.99]:58414) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mZeD5-0005jY-RX for qemu-devel@nongnu.org; Sun, 10 Oct 2021 15:10:13 -0400 Received: from erwin.inf.tu-dresden.de ([141.76.48.80] helo=os.inf.tu-dresden.de) by os.inf.tu-dresden.de with esmtps (TLS1.3:TLS_AES_256_GCM_SHA384:256) (Exim 4.94.2) id 1mZeD1-0004EK-S9; Sun, 10 Oct 2021 21:10:07 +0200 Date: Sun, 10 Oct 2021 21:10:05 +0200 From: Adam Lackorzynski To: qemu-devel@nongnu.org Subject: [PATCH] multiboot: Use DMA instead port-based transfer Message-ID: MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/2.0.5 (2021-01-21) Received-SPF: none client-ip=141.76.48.99; envelope-from=adam@l4re.org; helo=os.inf.tu-dresden.de X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=0.001, SPF_NONE=0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" Use DMA transfers in the multiboot loader to copy data. This significantly lowers QEMU's startup latency by a factor of about 40, for example, going from 30sec to 0.8sec when loading modules of 120MB in size. This change has been used successfully for some time. Signed-off-by: Marcus Hähnel Signed-off-by: Adam Lackorzynski Tested-by: Stefano Garzarella Reviewed-by: Stefano Garzarella --- pc-bios/multiboot.bin | Bin 1024 -> 1536 bytes pc-bios/optionrom/multiboot.S | 10 ++--- pc-bios/optionrom/optionrom.h | 77 ++++++++++++++++++++++++++++++++++ 3 files changed, 82 insertions(+), 5 deletions(-) diff --git a/pc-bios/multiboot.bin b/pc-bios/multiboot.bin index e772713c95749bee82c20002b50ec6d05b2d4987..94dc3fc9644ad2e1c87a3ac62a60cce659ada04f 100644 GIT binary patch literal 1536 zcmds1&ubG=5S~qT?GnMHKP*K`h!WyKk>(FGWJ<31w0V@s$A79HaepfSLo_l~H>SdrOA+1nDF6ZVLMD9PF-abWu&V zWk}5eM3U%@N(GUWshU(32FHlqF=gad30cdqAhx0RreGfDM9iLm?nL-e5qFj#=F^{H z%D!tf-G^v}cmUI{E(q&GxX?QZ_SI(;?7@`$T?fP9>MiCu-Kcz7LUlg93t@lH8}q~d zTHZC76F*HToUk+QvLE8#=oAaE0QW^Ju!BH;?CT4cr5AU=(%TEz4>-aX z9c!-dD^A!$-m#k5bG uF?zB=fqgWxPiZtKI!iA9P;TTF7U^DPxqSCdu~<$m7jJ8YQb_SX+SzZT$^;(( delta 357 zcmZqRY2aW9UBz^IvLUP3L@5E5X-u=3ChA$%CorWk9!^c`lw)An&B2h`DaXRlEjNJ) z$Y5hg>z11YljdMZGd$3DU!5u;jX+Q%Q z7(hn+`J5w**TBgMOvmffcCdr>q`glASqriihWSr)9#7i=bQ;h|?9vC*b_jx8#J~WN w2U?l7Ljb=9E);1=RQnF^VA`-&`~O3R-HelOu^2FAFiqxR{XE%$wSw^v0Movl^Z)<= diff --git a/pc-bios/optionrom/multiboot.S b/pc-bios/optionrom/multiboot.S index b7efe4de34..5fe4da6486 100644 --- a/pc-bios/optionrom/multiboot.S +++ b/pc-bios/optionrom/multiboot.S @@ -68,10 +68,10 @@ run_multiboot: mov %eax, %es /* Read the bootinfo struct into RAM */ - read_fw_blob(FW_CFG_INITRD) + read_fw_blob_dma(FW_CFG_INITRD) /* FS = bootinfo_struct */ - read_fw FW_CFG_INITRD_ADDR + read_fw_dma_var32 FW_CFG_INITRD_ADDR shr $4, %eax mov %ax, %fs @@ -188,14 +188,14 @@ prot_mode: movl %eax, %gs /* Read the kernel and modules into RAM */ - read_fw_blob(FW_CFG_KERNEL) + read_fw_blob_dma(FW_CFG_KERNEL) /* Jump off to the kernel */ - read_fw FW_CFG_KERNEL_ENTRY + read_fw_dma_var32 FW_CFG_KERNEL_ENTRY mov %eax, %ecx /* EBX contains a pointer to the bootinfo struct */ - read_fw FW_CFG_INITRD_ADDR + read_fw_dma_var32 FW_CFG_INITRD_ADDR movl %eax, %ebx /* EAX has to contain the magic */ diff --git a/pc-bios/optionrom/optionrom.h b/pc-bios/optionrom/optionrom.h index a2b612f1a7..5a88c7c5a3 100644 --- a/pc-bios/optionrom/optionrom.h +++ b/pc-bios/optionrom/optionrom.h @@ -37,6 +37,17 @@ #define BIOS_CFG_IOPORT_CFG 0x510 #define BIOS_CFG_IOPORT_DATA 0x511 +#define FW_CFG_DMA_CTL_ERROR 0x01 +#define FW_CFG_DMA_CTL_READ 0x02 +#define FW_CFG_DMA_CTL_SKIP 0x04 +#define FW_CFG_DMA_CTL_SELECT 0x08 +#define FW_CFG_DMA_CTL_WRITE 0x10 + +#define FW_CFG_DMA_SIGNATURE 0x51454d5520434647ULL /* "QEMU CFG" */ + +#define BIOS_CFG_DMA_ADDR_HIGH 0x514 +#define BIOS_CFG_DMA_ADDR_LOW 0x518 + /* Break the translation block flow so -d cpu shows us values */ #define DEBUG_HERE \ jmp 1f; \ @@ -62,6 +73,72 @@ bswap %eax .endm + +/* + * Read data from the fw_cfg device using DMA. + * Clobbers: %eax, %edx, memory[%esp-16] to memory[%esp] + */ +.macro read_fw_dma VAR, SIZE, ADDR + movl $\VAR, %eax /* Control */ + shl $16, %eax + or $FW_CFG_DMA_CTL_READ, %eax + or $FW_CFG_DMA_CTL_SELECT, %eax + bswapl %eax + movl %eax, -16(%esp) + + movl \SIZE, %eax /* Length */ + bswapl %eax + mov %eax, -12(%esp) + + mov \ADDR, %eax /* Address to write to */ + bswapl %eax + mov %eax, -4(%esp) + + movl $0, %eax /* We only support 32 bit target addresses */ + mov %eax, -8(%esp) + + mov %esp, %eax /* Address of the struct we generated */ + subl $16, %eax + bswapl %eax + + mov $BIOS_CFG_DMA_ADDR_LOW, %dx + outl %eax, (%dx) /* Initiate DMA */ + + movl $FW_CFG_DMA_CTL_ERROR, %eax + not %eax + bswapl %eax + +1: mov -16(%esp), %edx /* Wait for completion */ + and %eax, %edx + jnz 1b +.endm + +/* + * Read a single 32 bit value from the fw_cfg device using DMA + * Clobbers: %edx, memory[%esp-20] to memory[%esp] + * Out: %eax + */ +.macro read_fw_dma_var32 VAR + mov %esp, %edx + subl $20, %edx + read_fw_dma \VAR, $4, %edx + mov -20(%esp), %eax +.endm + + +/* + * Read a blob from the fw_cfg device using DMA + * Requires _ADDR, _SIZE and _DATA values for the parameter. + * + * Clobbers: %eax, %edx, %es, %ecx, %edi and adresses %esp-20 to %esp + */ +#define read_fw_blob_dma(var) \ + read_fw_dma_var32 var ## _SIZE; \ + mov %eax, %ecx; \ + read_fw_dma_var32 var ## _ADDR; \ + mov %eax, %edi ;\ + read_fw_dma var ## _DATA, %ecx, %edi + #define read_fw_blob_pre(var) \ read_fw var ## _SIZE; \ mov %eax, %ecx; \