Stefan Hajnoczi <stefa...@linux.vnet.ibm.com> writes: > On Thu, Mar 22, 2012 at 07:07:52PM +0000, Chris Webb wrote: > > Stefan Hajnoczi <stefa...@linux.vnet.ibm.com> writes: > > > > > Yesterday I only posted an analysis of the bug but here are some > > > thoughts on how to move forward. Throttling itself is not the problem. > > > We've known that synchronous operations in the vcpu thread are a problem > > > long before throttling. This is just another reason to convert device > > > emulation to use asynchronous interfaces. > > > > > > Here is the list of device models that perform synchronous block I/O: > > > hw/fdc.c > > > hw/ide/atapi.c > > > hw/ide/core.c > > > hw/nand.c > > > hw/onenand.c > > > hw/pflash_cfi01.c > > > hw/pflash_cfi02.c > > > hw/sd.c > > > > > > Zhi Hui Li is working on hw/fdc.c and recently sent a patch. > > > > > > I think it's too close to QEMU 1.1 to convert all the remaining devices > > > and test them properly before the soft-freeze. But it's probably > > > possible to convert IDE before the soft-freeze. > > > > IDE is the only of these that would affect us as a typical user of > > throttling. The others aren't really the kind of devices which you'd be > > using in a hosting setting in any case. > > Can you check whether your Windows guest has DMA or PIO mode enabled? > > http://msdn.microsoft.com/en-us/windows/hardware/gg463526
Hi. We were producing the IDE assert()s and deadlocks with linux kernels. Although I believe the same symptoms exist on windows, I haven't actually tested it myself. Typically they would show up in the 16-bit bootloader code, even before the 32-bit OS has started. Cheers, Chris.
