On 10 September 2013 17:10, Michael Moese <michael.mo...@gmail.com> wrote: > Hello dear Qemu developers, > I have some weird issues with a PCI device I have developed. > I am using shared memory to create an abstraction from the Qemu-PCI device I > developed and forward all requests to another process running a SystemC > device (this should not matter here). > > In my pci-read and write implementations I lock a mutex on the shared > memory, then write address, data and r/w-flag to the shared memory, then I > poll for a completion-flag. > > This seems to work quite fine while writing data, which happen in some kind > of posted writes, so I finish the operation as soon as possible. > When I execute a pci memory read from inside the guest the read-function > still gets executed, but Qemu gets stuck then.
This sounds suspiciously like you've introduced a deadlock somewhere (ie the other end of your system is not returning the data to QEMU because it's waiting for QEMU to respond to it for something else). > Now my question is, am I doing something I must not when just busy-waiting > for the completion flag? > > Is there another way to "stop" the simulated CPU during this transfer and > resume afterwards? No. You have to return data immediately from a read or write callback. -- PMM
