From mboxrd@z Thu Jan 1 00:00:00 1970 From: "=?gb2312?B?wfXP/r2o?=" Subject: [PATCH 1/3] KVM: pci passthrough un-page-aligned mmio device on machines w/o VT-d Date: Mon, 15 Dec 2008 22:57:42 +0800 Message-ID: <429353062.11415@nudt.edu.cn> Reply-To: "=?gb2312?B?wfXP/r2o?=" Content-Type: text/plain To: kvm@vger.kernel.org Return-path: Received: from [61.187.54.12] ([61.187.54.12]:42731 "HELO nudt.edu.cn" rhost-flags-FAIL-FAIL-OK-OK) by vger.kernel.org with SMTP id S1753788AbYLOPFP (ORCPT ); Mon, 15 Dec 2008 10:05:15 -0500 Sender: kvm-owner@vger.kernel.org List-ID: the following patches apply to KVM-79. however, just now I viewed the code in KVM-81, and saw the problem remains. when assigning a pci device to guest os, the qemu can not guarantee the device's virtual iomem address has the same page offset with the real one. for example: in native linux, the the starting iomem address for my via-rhine nic is 0x00000000df9fff00, which is not page aligned. But QEMU will emulate this nic has a page aligned mmio address. This difference will make guest os access the wrong address when it tries to do mmio. It seems Han Weidong has disabled QEMU assign this kinds of devices to guest os. The following patch will remove this constraint. --- diff -uNr kvm-79/bios/rombios32.c kvm-79-fixed/bios/rombios32.c --- kvm-79/bios/rombios32.c 2008-11-12 19:48:01.000000000 +0800 +++ kvm-79-fixed/bios/rombios32.c 2008-12-12 11:38:41.000000000 +0800 @@ -931,7 +931,9 @@ paddr = &pci_bios_bigmem_addr; else paddr = &pci_bios_mem_addr; - *paddr = (*paddr + size - 1) & ~(size - 1); + + /* To preserve the iomem page offset. --Xiaojian Liu */ + *paddr = ((*paddr + size - 1) & ~(size - 1)) | (val & 0x0fff); pci_set_io_region_addr(d, i, *paddr); *paddr += size; } Xiaojian Liu