Anthony Liguori wrote: > On Mon, 2007-08-27 at 18:45 +0300, Avi Kivity wrote: > >> Anthony Liguori wrote: >> >>> Since a hypercall may span two pages and is a gva, we need a function to >>> write >>> to a gva that may span multiple pages. emulator_write_phys() seems like the >>> logical choice for this. >>> >>> @@ -962,8 +962,35 @@ static int emulator_write_std(unsigned long addr, >>> unsigned int bytes, >>> struct kvm_vcpu *vcpu >>> >> I think that emulator_write_emulated(), except for being awkwardly >> named, should do the job. We have enough APIs. >> >> But! We may not overwrite the hypercall instruction while a vcpu may be >> executing, since there's no atomicity guarantee for code fetch. We have >> to to be out of guest mode while writing that insn. >> > > > Hrm, good catch. > > How can we get out of guest mode given SMP guest support? > >
kvm_flush_remote_tlbs() is something that can be generalized. Basically, you set a bit in each vcpu and send an IPI to take them out. But that's deadlock prone and complex. Maybe you can just take kvm->lock, zap the mmu and the flush tlbs, and patch the instruction at your leisure, as no vcpu will be able to map memory until the lock is released. -- Any sufficiently difficult bug is indistinguishable from a feature. ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
