John McDermott CIV
2012-Mar-22 14:51 UTC
Question: PV ops Fedora 16 Initialises Hypercall Page Twice?
Xen Developers, I noticed that my PV ops guests cause the hypervisor to invoke hypercall_page_initialise twice from traps.c (i.e. through wrmsr_hypervisor_regs), for different hypercall_page addresses. Looking at the code, I see hvmloader.c causing one of those, in its main. I read the HVM Loader Xen wiki page, Googled, spelunked the source, etc. but cannot find where / why the other hypercall page is being requested. Is the other hypercall page being initialized by qemu-dm and the hvmloader page is discarded? Sincerely, John McDermott ---- What is the formal meaning of the one-line program #include "/dev/tty" J.P. McDermott building 12 Code 5542 john.mcdermott@nrl.navy.mil Naval Research Laboratory voice: +1 202.404.8301 Washington, DC 20375, US fax: +1 202.404.7942
Ian Campbell
2012-Mar-22 14:56 UTC
Re: Question: PV ops Fedora 16 Initialises Hypercall Page Twice?
On Thu, 2012-03-22 at 14:51 +0000, John McDermott CIV wrote:> Xen Developers, > > I noticed that my PV ops guests cause the hypervisor to invoke > hypercall_page_initialise twice from traps.c (i.e. through > wrmsr_hypervisor_regs), for different hypercall_page addresses. > Looking at the code, I see hvmloader.c causing one of those, in its > main. I read the HVM Loader Xen wiki page, Googled, spelunked the > source, etc. but cannot find where / why the other hypercall page is > being requested. Is the other hypercall page being initialized by > qemu-dm and the hvmloader page is discarded?The second one will be your guest Linux kernel, which I guess has PVHVM enabled, setting up its hypercall page. Ian.