[Xen-devel] Xendbg: a full-featured debugger for both PV & HVM Xen guests

2019-03-28 Thread Spencer Michaels
Hello everyone, I'm Spencer Michaels, creator of Xendbg, a recently-released full-featured debugger for both HVM and PV Xen guests. I developed Xendbg under the auspices of my company, NCC Group, and released it via a post on their blog about two months ago. Andrew Cooper kindly pointed out to me

[Xen-devel] Mapping discontiguous virtual memory ranges

2018-12-03 Thread Spencer Michaels
Hello, I'm currently attempting to add guard pages to a Xen-based unikernel. These are memory regions that cannot be read, written, or executed, could be potentially ones up to 1MB in size, and would, for instance, separate the stack and the heap to prevent buffer overflows and stack clashes.

Re: [Xen-devel] Mapping HVM guest memory from Dom0

2018-10-11 Thread Spencer Michaels
PM Andrew Cooper > wrote: > > > > On 10/10/18 23:08, Spencer Michaels wrote: > > > Interesting … sorry, I had read the docs a while ago and my > > > interpretation at the time was that it didn't. I can try to get libvmi > > > working, but nonetheless I do want

Re: [Xen-devel] Mapping HVM guest memory from Dom0

2018-10-10 Thread Spencer Michaels
HVM guest is running in. If, on the other hand, any of the above sounds familiar, suggestions/hints would be very helpful. On Wed, Oct 10, 2018 at 11:25 AM Tamas K Lengyel wrote: > On Wed, Oct 10, 2018 at 8:47 AM Spencer Michaels > wrote: > > > > I have, but libvmi doesn't fit

Re: [Xen-devel] Mapping HVM guest memory from Dom0

2018-10-10 Thread Spencer Michaels
/18 20:34, Spencer Michaels wrote: > > Hello, > > > > I'm developing an application that runs in Dom0 and needs to read > > memory from a guest given a guest address (for instance, reading RIP > > from the guest CPU context and then reading the current instruction). >

[Xen-devel] Mapping HVM guest memory from Dom0

2018-10-09 Thread Spencer Michaels
Hello, I'm developing an application that runs in Dom0 and needs to read memory from a guest given a guest address (for instance, reading RIP from the guest CPU context and then reading the current instruction). I'm using xenforeignmemory_map() to map the guest memory, but this function takes the

Re: [Xen-devel] Reading guest page flags

2018-09-14 Thread Spencer Michaels
/ programs that read guest PTEs, that would be helpful to know as well. On Thu, Sep 13, 2018, 10:47 AM Razvan Cojocaru wrote: > On 9/13/18 8:29 PM, Spencer Michaels wrote: > > I'm writing an application that can read/write guest memory, and as part > > of that I need to check whether

[Xen-devel] Reading guest page flags

2018-09-13 Thread Spencer Michaels
Hello, I'm writing an application that can read/write guest memory, and as part of that I need to check whether the page being manipulated is readable/writable by the guest itself. Does Xen have an API that would allow me to read the flags of an arbitrary page on a guest, given either its address

[Xen-devel] Event monitoring support for PV guests

2018-09-02 Thread Spencer Michaels
Hello, I'm currently doing some research that involves examining the behavior of native code on paravirtualized Xen guests. gdbsx has proven somewhat limited for my use case, in large part due to the very limitations I describe below, so I have been writing my own application with some debugging