In a798f09111 ("x86/entry/32: Change INT80 to be an interrupt gate")
Andy broke lguest. This is because lguest had special code to allow
the 0x80 trap gate go straight into the guest itself; interrupts gates
(without more work, as mentioned in the file's comments) bounce via
the hypervisor.
His change made them go via the hypervisor, but as it's in the range of
normal hardware interrupts, they were not directed through to the guest
at all. Turns out the guest userspace isn't very effective if syscalls
are all noops.
I haven't ripped out all the now-useless trap-direct-to-guest-kernel
code yet, since it will still be needed if someone decides to update
this optimization.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Weisbecker <fweisbec@gmail.com>
Cc: x86\@kernel.org
Link: http://lkml.kernel.org/r/87fuv685kl.fsf@rustcorp.com.au
Signed-off-by: Ingo Molnar <mingo@kernel.org>
There are a number of FPU internal function prototypes and an inline function
in fpu/api.h, mostly placed so historically as the code grew over the years.
Move them over into fpu/internal.h where they belong. (Add sched.h include
to stackprotector.h which incorrectly relied on getting it from fpu/api.h.)
fpu/api.h is now a pure file that only contains FPU APIs intended for driver
use.
Reviewed-by: Borislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull virtio updates from Rusty Russell:
"OK, this has the big virtio 1.0 implementation, as specified by OASIS.
On top of tht is the major rework of lguest, to use PCI and virtio
1.0, to double-check the implementation.
Then comes the inevitable fixes and cleanups from that work"
* tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: (80 commits)
virtio: don't set VIRTIO_CONFIG_S_DRIVER_OK twice.
virtio_net: unconditionally define struct virtio_net_hdr_v1.
tools/lguest: don't use legacy definitions for net device in example launcher.
virtio: Don't expose legacy net features when VIRTIO_NET_NO_LEGACY defined.
tools/lguest: use common error macros in the example launcher.
tools/lguest: give virtqueues names for better error messages
tools/lguest: more documentation and checking of virtio 1.0 compliance.
lguest: don't look in console features to find emerg_wr.
tools/lguest: don't start devices until DRIVER_OK status set.
tools/lguest: handle indirect partway through chain.
tools/lguest: insert driver references from the 1.0 spec (4.1 Virtio Over PCI)
tools/lguest: insert device references from the 1.0 spec (4.1 Virtio Over PCI)
tools/lguest: rename virtio_pci_cfg_cap field to match spec.
tools/lguest: fix features_accepted logic in example launcher.
tools/lguest: handle device reset correctly in example launcher.
virtual: Documentation: simplify and generalize paravirt_ops.txt
lguest: remove NOTIFY call and eventfd facility.
lguest: remove NOTIFY facility from demonstration launcher.
lguest: use the PCI console device's emerg_wr for early boot messages.
lguest: always put console in PCI slot #1.
...
We copy 7 bytes at eip for userspace's instruction decode; we have to
carefully handle the case where eip is at the end of a page. We can't
leave this to userspace since kernel has all the page table decode
logic.
The decode logic moves to userspace, basically unchanged.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
We use the ptrace API struct, and we currently don't let them set
anything but the normal registers (we'd have to filter the others).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Tell the compiler that the inline assembler statement
references lguest_entry.
This fixes compile problems with LTO where the variable
and the assembler code may end up in different files.
Cc: x86@kernel.org
Cc: rusty@rustcorp.com.au
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
ie. SHARED_SWITCHER_PAGES == 1. It is well under a page, and it's a
minor simplification: it's nice to have *one* simplification in a
patch series!
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
We currently use the whole top PGD entry for the switcher, but that's
hitting the fixmap in some configurations (mainly, large NR_CPUS).
Introduce a variable, currently set to the constant.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
The x86_64 kernel pushes the fake kernel stack in
arch/x86/kernel/entry_64.S:FAKE_STACK_FRAME, and
rflags register in it does not conform to the specification.
Although Intel's manual[1] says bit 1 of it shall be set to 1,
this bit is cleared to 0 on pushing the fake stack.
[1] Intel(R) 64 and IA-32 Architectures Software Developer's Manual
Vol.1 3-21 Figure 3-8. EFLAGS Register
If it is not on purpose, it is better to be fixed, because
it can lead some tools misunderstanding the stack frame. For example,
"crash" utility[2] actually detects it and warns you like
below:
RIP: ffffffff8005dfa2 RSP: ffff8104ce0c7f58 RFLAGS: 00000200
[...]
bt: WARNING: possibly bogus exception frame
Signed-off-by: Seiichi Ikarashi <s.ikarashi@jp.fujitsu.com>
Tested-by: Masayoshi MIZUMA <m.mizuma@jp.fujitsu.com>
Cc: Jan Beulich <JBeulich@suse.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
We were blatting too much of the register. Linux didn't care, but in
theory it might.
Reported-by: Jonas Maebe <jonas.maebe@elis.ugent.be>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
arch/x86/lguest/boot.c: In function ‘lguest_init_IRQ’:
arch/x86/lguest/boot.c:824: error: macro "__this_cpu_write" requires 2 arguments, but only 1 given
arch/x86/lguest/boot.c:824: error: ‘__this_cpu_write’ undeclared (first use in this function)
arch/x86/lguest/boot.c:824: error: (Each undeclared identifier is reported only once
arch/x86/lguest/boot.c:824: error: for each function it appears in.)
drivers/lguest/x86/core.c: In function ‘copy_in_guest_info’:
drivers/lguest/x86/core.c:94: error: lvalue required as left operand of assignment
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
It's only used by cmpxchg8b_emu (see db677ffa5f for the gory
details), and fixing that to be paravirt aware would be more work than
simply ignoring it (and AFAICT only help lguest). This makes lguest
work on machines which have cmpxchg8b, for kernels compiled for older
processors.
(We can't emulate it properly: the popf which expects to restore interrupts
does not trap).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: virtualization@lists.osdl.org
This patch updates misc percpu related symbols such that percpu
symbols are unique and don't clash with local symbols. This serves
two purposes of decreasing the possibility of global percpu symbol
collision and allowing dropping per_cpu__ prefix from percpu symbols.
* drivers/crypto/padlock-aes.c: s/last_cword/paes_last_cword/
* drivers/lguest/x86/core.c: s/last_cpu/lg_last_cpu/
* drivers/s390/net/netiucv.c: rename the variable used in a macro to
avoid clashing with percpu symbol
* arch/mn10300/kernel/kprobes.c: replace current_ prefix with cur_ for
static variables. Please note that percpu symbol current_kprobe
can't be changed as it's used by generic code.
Partly based on Rusty Russell's "alloc_percpu: rename percpu vars
which cause name clashes" patch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Chuck Ebbert <cebbert@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux390@de.ibm.com
Every so often, after code shuffles, I need to go through and unbitrot
the Lguest Journey (see drivers/lguest/README). Since we now use RCU in
a simple form in one place I took the opportunity to expand that explanation.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Rusty Russell
Ingo Molnar
Linus Torvalds
Andy Lutomirski
Andi Kleen
H. Peter Anvin
Suresh Siddha
Seiichi Ikarashi
Christoph Lameter
Tejun Heo