On Mon, Mar 01, 2010 at 07:10:30PM +0100, Jan Kiszka wrote: > This grand cleanup drops all reset and vmsave/load related > synchronization points in favor of four(!) generic hooks: > > - cpu_synchronize_all_states in qemu_savevm_state_complete > (initial sync from kernel before vmsave) > - cpu_synchronize_all_post_init in qemu_loadvm_state > (writeback after vmload) > - cpu_synchronize_all_post_init in main after machine init > - cpu_synchronize_all_post_reset in qemu_system_reset > (writeback after system reset) > > These writeback points + the existing one of VCPU exec after > cpu_synchronize_state map on three levels of writeback: > > - KVM_PUT_RUNTIME_STATE (during runtime, other VCPUs continue to run) > - KVM_PUT_RESET_STATE (on synchronous system reset, all VCPUs stopped) > - KVM_PUT_FULL_STATE (on init or vmload, all VCPUs stopped as well) > > This level is passed to the arch-specific VCPU state writing function > that will decide which concrete substates need to be written. That way, > no writer of load, save or reset functions that interact with in-kernel > KVM states will ever have to worry about synchronization again. That > also means that a lot of reasons for races, segfaults and deadlocks are > eliminated. > > cpu_synchronize_state remains untouched, just as Anthony suggested. We > continue to need it before reading or writing of VCPU states that are > also tracked by in-kernel KVM subsystems. > > Consequently, this patch removes many cpu_synchronize_state calls that > are now redundant, just like remaining explicit register syncs. > > Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx> Jan, This patch breaks system reset of WinXP.32 install (more easily reproducible without iothread enabled). Screenshot attached.
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