Date: Fri, 17 Feb 2017 18:34:37 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-virtualization@FreeBSD.org Subject: [Bug 211746] [Hyper-V] UEFI VM can't boot from the iso installation disk Message-ID: <bug-211746-27103-oVISkbLJIh@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-211746-27103@https.bugs.freebsd.org/bugzilla/> References: <bug-211746-27103@https.bugs.freebsd.org/bugzilla/>
next in thread | previous in thread | raw e-mail | index | archive | help
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D211746 --- Comment #17 from Marcel Moolenaar <marcel@FreeBSD.org> --- I think the complexity of having the kernel at any other physical address is what has us do the staging/copying. It was a quick-n-dirty mechanism that avoided a lot of work and complexity -- which is ok if you don't know it's worth/needed to go through all that hassle. And I guess it looks like we now hit a case that warrants us to start looking at a real solution. As an example (for inspiration): For Itanium I had the kernel link against a fixed virtual address. The load= er built the VA-to-PA mapping based on where EFI allocated blobs of memory. The mapping was loaded/activated prior to booting the kernel and the loader gave the kernel all the information it needed to work with the mapping. This mak= es it possible to allocate memory before the VM system is up and running. Ultimately the mapping needs to be incorporated into the VM system and this= is where different CPU architectures have different challenges and solutions. Note that there are advantages to having the kernel link against a virtual address. In general it makes it easier to load or relocate the kernel anywh= ere and this enables a few capabilities that other OSes already have and then s= ome. There are also downsides. You may need to support a large VA range if you w= ant to support pre-loading CD-ROM images or run entirely form a memory disk tha= t's preloaded. A few GB of address space would be good to have. Anyway: It's probably time that to you restate this bug into an architectur= al (x86-specific for now) problem and have a discussion on the arch@ mailing l= ist. We need a more people involved to bring this to a closure. Good luck --=20 You are receiving this mail because: You are the assignee for the bug.=
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?bug-211746-27103-oVISkbLJIh>