I have, but libvmi doesn't fit my use case — it only works with Windows and Linux HVM guests. I will need my application to work with PV and HVM guests that are neither Windows nor Linux.
libvmi's implementation of this, `xen_get_memory()` in `libvmi/driver/xen/xen.c`, seems to assume that MFN = (addr >> page shift), which I've seen in a few places, but based on my testing as well as what's in `debug.c`, this appears not to be correct. I certainly don't end up mapping the correct pages using that formula, at least. On Wed, Oct 10, 2018 at 5:39 AM Andrew Cooper <andrew.coop...@citrix.com> wrote: > On 09/10/18 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). > > I'm using xenforeignmemory_map() to map the guest memory, but this > > function takes the MFN of the guest address to read, not the address > > itself. Xen does not seem to have an API for doing the virtual address > > --> MFN conversion. > > > > I've figured out how to do this for PV guests: map the domain's > > meminfo struct and use the PFN for the guest address (i.e. address >> > > XC_PAGE_SHIFT) as an index into the P2M table. > > > > However, I am having trouble doing the same for HVM guests. Right now > > I am trying to follow the implementation of bg_hvm_va2mfn in > > xen/arch/x86/debug.c, but this function uses so many internal Xen > > functions it seems I would have to copy tons of code out from Xen, and > > I'm wondering if there's a better way. Is there some API I'm missing > > that lets me to do the vaddr --> MFN conversion for HVM guests? If > > not, what is the simplest way to do this conversion? > > Have you come across libvmi? It seems to be exactly what you are trying > to make here. > > ~Andrew >
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