Commit Graph

26 Commits

Author SHA1 Message Date
Rusty Russell
42b36cc0ce virtio: Force use of power-of-two for descriptor ring sizes
The virtio descriptor rings of size N-1 were nicely set up to be
aligned to an N-byte boundary.  But as Anthony Liguori points out, the
free-running indices used by virtio require that the sizes be a power
of 2, otherwise we get problems on wrap (demonstrated with lguest).

So we replace the clever "2^n-1" scheme with a simple "align to page
boundary" scheme: this means that all virtio rings take at least two
pages, but it's safer than guessing cache alignment.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2007-11-12 13:59:40 +11:00
Anthony Liguori
1200e646ae lguest: Fix lguest virtio-blk backend size computation
This seems like an obvious typo but it's worked in the past because the virtio
blk frontend just ignores the length field on completion.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2007-11-12 13:59:26 +11:00
Rusty Russell
e1e72965ec lguest: documentation update
Went through the documentation doing typo and content fixes.  This
patch contains only comment and whitespace changes.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2007-10-25 15:02:50 +10:00
Rusty Russell
db24e8c2ef lguest: example launcher header cleanup.
Now the kernel headers are clean for userspace export, we don't need
to typedef kernel types before including them.  We also don't need
pci_ids.h (that was from an earlier virtio draft).

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2007-10-25 14:09:25 +10:00
Rusty Russell
43d33b21a0 Use "struct boot_params" in example launcher
Now that the "struct boot_params" is userspace accessible, we don't need
magic numbers.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2007-10-23 15:49:57 +10:00
Rusty Russell
5bbf89fc26 Loading bzImage directly.
Now arch/i386/boot/compressed/head.S understands the hardware_platform field,
we can directly execute bzImages.  No more horrific unpacking code.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2007-10-23 15:49:57 +10:00
Rusty Russell
814a0e5cdf Revert lguest magic and use hook in head.S
Version 2.07 of the boot protocol uses 0x23C for the hardware_subarch
field, that for lguest is "1".  This allows us to use the standard
boot entry point rather than the "GenuineLguest" string hack.

The standard entry point also clears the BSS and copies the boot parameters
and commandline for us, saving more code.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2007-10-23 15:49:57 +10:00
Chris Malley
1f5a29022a Update lguest documentation to reflect the new virtual block device name.
Signed-off-by: Chris Malley <mail@chrismalley.co.uk>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2007-10-23 15:49:57 +10:00
Rusty Russell
56ae43dfe2 Example launcher handle guests not being ready for input
We currently discard console and network input when the guest has no
input buffers.  This patch changes that, so that we simply stop
listening to that fd until the guest refills its input buffers.

This is particularly important because hvc_console without interrupts
does backoff polling and so often lose characters if we discard.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2007-10-23 15:49:56 +10:00
Rusty Russell
17cbca2ba3 Update example launcher for virtio
Implements virtio-based console, network and block servers.  The block
server uses a thread so it's async, which is an improvement over the
old synchronous implementation (but a little more complex).

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2007-10-23 15:49:56 +10:00
Rusty Russell
47436aa4ad Boot with virtual == physical to get closer to native Linux.
1) This allows us to get alot closer to booting bzImages.

2) It means we don't have to know page_offset.

3) The Guest needs to modify the boot pagetables to create the
   PAGE_OFFSET mapping before jumping to C code.

4) guest_pa() walks the page tables rather than using page_offset.

5) We don't use page_offset to figure out whether to emulate: it was
   always kinda quesationable, and won't work for instructions done
   before remapping (bzImage unpacking in particular).

6) We still want the kernel address for tlb flushing: have the initial
   hypercall give us that, too.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2007-10-23 15:49:54 +10:00
Jes Sorensen
511801dc31 Change example launcher to use unsigned long not u32
Apply Clue 2x4 to lguest userland<->kernel handling code and the
lguest launcher. Pointers are not to be passed in u32's!

Basic rule of thumb: Anything passing u32's back and forth should be
passing unsigned longs to be portable to 64 bit archs.

For those who forgotten already, I repeat: NO POINTERS IN u32!

Signed-off-by: Jes Sorensen <jes@sgi.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2007-10-23 15:49:52 +10:00
Rusty Russell
3c6b5bfa3c Introduce guest mem offset, static link example launcher
In order to avoid problematic special linking of the Launcher, we give
the Host an offset: this means we can use any memory region in the
Launcher as Guest memory rather than insisting on mmap() at 0.

The result is quite pleasing: a number of casts are replaced with
simple additions.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2007-10-23 15:49:50 +10:00
Ronald G. Minnich
6649bb7af6 Accept elf files that are valid but have sections that can not be mmap'ed for some reason.
Plan9 kernel binaries don't neatly align their ELF sections to our
page boundaries.

Signed-off-by: Ronald G. Minnich <rminnich@gmail.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2007-10-23 15:49:50 +10:00
Rusty Russell
b45d8cb054 Make lguest_launcher.h types userspace-friendly
lguest_launcher.h uses "u32" not "__u32", which sets a bad example.  Fix that,
and include <linux/types.h>.

This means we need to use -I on the Launcher build line so types.h is found.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2007-10-23 15:49:49 +10:00
Rusty Russell
9653c4aff9 lguest.txt update
o Describe the new split configurations
o Highlight code documentation in drivers/lguest/README
o Point out necessity of having a getty on /dev/hvc0
o Remove gratuitous "m" in example
o Don't discuss I/O model here, stick to user documentation.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2007-10-23 15:49:48 +10:00
Glauber de Oliveira Costa
babed5c002 turn err into errx in lguest call sites
These two callsites should really be errx instead of err, since there is
no errno associated with them in the moment they are issued.

Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Glauber de Oliveira Costa <gcosta@redhat.com>
2007-10-23 15:49:47 +10:00
Rusty Russell
ee8e7cfe9d Make asm-x86/bootparam.h includable from userspace.
To actually write a bootloader (or, say, the lguest launcher)
currently requires duplication of these structures.  Making them
includable from userspace is much nicer.

We merge the common userspace-required definitions of e820_32/64.h
into e820.h for export.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2007-10-23 15:49:47 +10:00
Thomas Gleixner
96a388de5d i386/x86_64: move headers to include/asm-x86
Move the headers to include/asm-x86 and fixup the
header install make rules

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-10-11 11:20:03 +02:00
Chris Malley
f6a592e8ab lguest example launcher truncates block device file to 0 length on problems
The function should also use ftruncate64() rather than ftruncate() to prevent
files over 4GB (not uncommon for a root filesystem) being zeroed.

Signed-off-by: Chris Malley <mail@chrismalley.co.uk>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-09-26 09:22:04 -07:00
Ronald G. Minnich
e3bcf5e278 lguest: avoid shared libraries mapped over guest memory
Some versions of ld.so mmap the shared libraries right in over guest
memory, so compile lguest statically by default.

[ FC7 maps shared libraries very low, where the launcher maps guest's
  physical memory.  Quick fix is to link Launcher static, real fix is
  for 2.6.24. ]

-static is a simple fix. I expect this problem will be more common than we
like, as different distro's make different "improvements" to ld.so

Signed-off-by: Ronald G. Minnich <rminnich@gmail.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-08-09 08:14:56 -07:00
Rusty Russell
f56a384e98 lguest: documentation VII: FIXMEs
Documentation: The FIXMEs

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-26 11:35:17 -07:00
Rusty Russell
dde797899a lguest: documentation IV: Launcher
Documentation: The Launcher

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-26 11:35:17 -07:00
Rusty Russell
f938d2c892 lguest: documentation I: Preparation
The netfilter code had very good documentation: the Netfilter Hacking HOWTO.
Noone ever read it.

So this time I'm trying something different, using a bit of Knuthiness.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-26 11:35:16 -07:00
Rusty Russell
6570c45995 link lguest example launcher non-static
S.Caglar Onur points out that many distributions don't ship a static
zlib.  Unfortunately the launcher currently maps virtual device memory
where shared libraries want to go.

The solution is to pre-scan the args to figure out how much memory we
have, then allocate devices above that, rather than down from the top
possible address.  This also turns out to be simpler.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-24 12:24:59 -07:00
Rusty Russell
8ca47e0069 lguest: the documentation, example launcher
A brief document describing how to use lguest.  Because lguest doesn't have an
ABI we also include an example launcher in the Documentation directory.

[jmorris@namei.org: Fix up nat example in documentation]
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: James Morris <jmorris@namei.org>
Cc: Matias Zabaljauregui <matias.zabaljauregui@cern.ch>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-19 10:04:53 -07:00