I wonder - would be a record using rr of any help? I can create record for QEMU 1.2.0 where it works and on current QEMU.
Also, I did a bit of debugging myself around the DMA code as per comment #3 it was introduced in a commit that changed some of the DMA. What I did was that I added some debug printfs [1] to dma_memory_rw() to QEMU 1.2.0 and to QEMU 2.11.1. I noticed on thing - there is a big difference between writes between the two versions. Because this stuff is completely outside my knowledge, I don't know whether this is important or not, but better more information that not enough. For recent versions of QEMU I see a few 16 B writes from address 0x6d10 and addresses close to it which contain some data. Immediately after that there is a ton of 8B writes from addresses starting at 0x102004 which contain zeros only. On the other hand, the QEMU 1.2.0 is missing the initial 16B writes, but then there's even more 8B writes from addresses around 0x102004 which contain some data instead of zeros like in the current version. [1] the printf looks like this: printf("DEBUG: DMA %s at address %lx %lu bytes: ", ((dir == DMA_DIRECTION_FROM_DEVICE) ? "read" : "write"), addr, len); -- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1191326 Title: QNX 4 doesn't boot on qemu >= 1.3 Status in QEMU: Confirmed Bug description: I am using virtual machine with QNX4 operating system installed on it. I updated my qemu from version to newer and QNX4 doesn't start any more. All is ok on version 1.2 but when I try to use any newer version (1.3, 1.4, 1.5) QNX4 doesn't boot. I tried on windows and linux ubuntu hosts - effects are the same. When virtual machine boots qnx bootloader loads and starts operating system. In the next step qnx starts its ide driver, which detects qemu harddisk and cdrom. Problem starts when operating system tries mount partition - an error occur and qnx stop booting procedure: mount -p "No bios signature in partition sector on /dev/hd0" I have tried install qnx from cdrom but it seems that there is the same problem. QNX installer boot from cdrom, detects hard disk and cdrom, but cdrom can't be mounted in the next step of installation procedure. To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1191326/+subscriptions