>>> On 23.11.12 at 11:37, Daniel Kiper <daniel.kiper at oracle.com> wrote: > On Fri, Nov 23, 2012 at 09:53:37AM +0000, Jan Beulich wrote: >> >>> On 23.11.12 at 02:56, Andrew Cooper <andrew.cooper3 at citrix.com> wrote: >> > On 23/11/2012 01:38, H. Peter Anvin wrote: >> >> I still don't really get why it can't be isolated from dom0, which would >> > make more sense to me, even for a Xen crash. >> >> >> > >> > The crash region (as specified by crashkernel= on the Xen command line) >> > is isolated from dom0. >> > >> > dom0 (using the kexec utility etc) has the task of locating the Xen >> > crash notes (using the kexec hypercall interface), constructing a binary >> > blob containing kernel, initram and gubbins, and asking Xen to put this >> > blob in the crash region (again, using the kexec hypercall interface). >> > >> > I do not see how this is very much different from the native case >> > currently (although please correct me if I am misinformed). Linux has >> > extra work to do by populating /proc/iomem with the Xen crash regions >> > boot (so the kexec utility can reference their physical addresses when >> > constructing the blob), and should just act as a conduit between the >> > kexec system call and the kexec hypercall to load the blob. >> >> But all of this _could_ be done completely independent of the >> Dom0 kernel's kexec infrastructure (i.e. fully from user space, >> invoking the necessary hypercalls through the privcmd driver). > > No, this is impossible. kexec/kdump image lives in dom0 kernel memory > until execution. That is why privcmd driver itself is not a solution > in this case. Even if so, there's no fundamental reason why that kernel image can't be put into Xen controlled space instead. Jan
