On Mon, May 5, 2014 at 8:56 AM, Alexandru Duţu <alex.dutu@xxxxxxxxx> wrote: > Dear all, > > It seems that currently, on UD interception KVM does not exit > completely. Virtualized execution finishes, KVM executes > ud_intercept() after which it enters virtualized execution again. Maybe you might want to take a look at the VMX side (to port it to SVM). The MOVBE emulation, for example, should be helpful. > > I am working on accelerating with virtualized execution a simulator > that emulates system calls. Essentially doing virtualized execution > without a OS kernel. In order to make this work, I had to modify my > the KVM kernel module such that ud_intercept() return 0 and not 1 > which break KVM __vcpu_run loop. This is necessary as I need to trap > syscall instructions, exit virtualized execution with UD exception, > emulate the system call in the simulator and after the system call is > done enter back in virtualized mode and start execution with the help > of KVM. > > So by modifying ud_intercept() to return 0, I got all this to work. Is > it possible to achieve the same effect (exit on undefined opcode) > without modifying ud_intercept()? > > It seems that re-entering virtualized execution on UD interception > gives the user the flexibility of running binaries with newer > instructions on older hardware, if kvm is able to emulate the newer > instructions. I do not fully understand the details of this scenario, > is there such a scenario or is it likely that ud_interception() will > change? > > Thank you in advance! > > Best regards, > Alex > -- -- Jun Intel Open Source Technology Center -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
