Anthony Liguori points out that three different transports use the virtio code,
but each one keeps its own counter to set the virtio_device's index field. In
theory (though not in current practice) this means that names could be
duplicated, and that risk grows as more transports are created.
So we move the selection of the unique virtio_device.index into the common code
in virtio.c, which has the side-benefit of removing duplicate code.
The only complexity is that lguest and S/390 use the index to uniquely identify
the device in case of catastrophic failure before register_virtio_device() is
called: now we use the offset within the descriptor page as a unique identifier
for the printks.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Carsten Otte <cotte@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Chris Lalancette <clalance@redhat.com>
Cc: Anthony Liguori <anthony@codemonkey.ws>
Thanks to Jon Corbet & LWN. Only took me a day to join the dots.
Host->Guest netcat before (with unnecessily large receive buffers):
1073741824 bytes (1.1 GB) copied, 24.7528 seconds, 43.4 MB/s
After:
1073741824 bytes (1.1 GB) copied, 17.6369 seconds, 60.9 MB/s
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This brings us closer to Real Life, where we'd examine the device
features once it's set the DRIVER_OK status bit.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
NR_CPUS (being a host number) is an arbitrary limit for the Guest.
Using the array size directly (which currently happes to be NR_CPUS)
is more futureproof.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
A recent proposed feature addition to the virtio block driver revealed
some flaws in the API: in particular, we assume that feature
negotiation is complete once a driver's probe function returns.
There is nothing in the API to require this, however, and even I
didn't notice when it was violated.
So instead, we require the driver to specify what features it supports
in a table, we can then move the feature negotiation into the virtio
core. The intersection of device and driver features are presented in
a new 'features' bitmap in the struct virtio_device.
Note that this highlights the difference between Linux unsigned-long
bitmaps where each unsigned long is in native endian, and a
straight-forward little-endian array of bytes.
Drivers can still remove feature bits in their probe routine if they
really have to.
API changes:
- dev->config->feature() no longer gets and acks a feature.
- drivers should advertise their features in the 'feature_table' field
- use virtio_has_feature() for extra sanity when checking feature bits
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
None of these files use any of the functionality promised by
asm/semaphore.h. It's possible that they rely on it dragging in some
unrelated header file, but I can't build all these files, so we'll have
fix any build failures as they come up.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Took some cycles to re-read the Lguest Journey end-to-end, fix some
rot and tighten some phrases.
Only comments change. No new jokes, but a couple of recycled old jokes.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Ahmed managed to crash the Host in release_pgd(), which cannot be a Guest
bug, and indeed it wasn't.
The bug was that handing a 0 as the address of the toplevel page table
being manipulated can cause the lookup code in find_pgdir() to return
an uninitialized cache entry (we shadow up to 4 top level page tables
for each Guest).
Commit 37cc8d7f96 introduced this
behaviour in the Guest, uncovering the bug.
The patch which he submitted (which removed the /4 from the index
calculation) simply ensured that these high-indexed entries hit the
early exit path of guest_set_pmd(). But you get lots of segfaults in
guest userspace as the PMDs aren't being updated.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Robert Bragg's 5dc3318528 tightened
(ie. fixed) the checking in __get_vm_area, and it broke lguest.
lguest should pass the exact "end" it wants, not some random constant
(it was possible previously that it would actually get an address
different from SWITCHER_ADDR).
Also, Fabio Checconi pointed out that we should make sure we're not
hitting the fixmap area.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Robert Bragg <robert@sixbynine.org>
If req is LHREQ_INITIALIZE, and the guest has been initialized before
(unlikely), it will attempt to access cpu->tsk even though cpu is not yet
initialized.
Signed-off-by: Eugene Teo <eugeneteo@kernel.sg>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Beginning from commit 4138cc3418, ioremap_nocache() sets the _PAGE_PWT
flag.
Lguest doesn't accept a guest pte with a _PWT flag and reports a "bad
page table entry" in that case.
Accept guest _PAGE_PWT page table entries.
Signed-off-by: Ahmed S. Darwish <darwish.07@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
A reset function solves three problems:
1) It allows us to renegotiate features, eg. if we want to upgrade a
guest driver without rebooting the guest.
2) It gives us a clean way of shutting down virtqueues: after a reset,
we know that the buffers won't be used by the host, and
3) It helps the guest recover from messed-up drivers.
So we remove the ->shutdown hook, and the only way we now remove
feature bits is via reset.
We leave it to the driver to do the reset before it deletes queues:
the balloon driver, for example, needs to chat to the host in its
remove function.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
It seems that virtio_net wants to disable callbacks (interrupts) before
calling netif_rx_schedule(), so we can't use the return value to do so.
Rename "restart" to "cb_enable" and introduce "cb_disable" hook: callback
now returns void, rather than a boolean.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Previously we used a type/len pair within the config space, but this
seems overkill. We now simply define a structure which represents the
layout in the config space: the config space can now only be extended
at the end.
The main driver-visible changes:
1) We indicate what fields are present with an explicit feature bit.
2) Virtqueues are explicitly numbered, and not in the config space.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
drivers/lguest/x86/core.c: In function ‘copy_in_guest_info’:
drivers/lguest/x86/core.c:97: error: ‘struct x86_hw_tss’ has no member named ‘esp1’
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus: (27 commits)
lguest: use __PAGE_KERNEL instead of _PAGE_KERNEL
lguest: Use explicit includes rateher than indirect
lguest: get rid of lg variable assignments
lguest: change gpte_addr header
lguest: move changed bitmap to lg_cpu
lguest: move last_pages to lg_cpu
lguest: change last_guest to last_cpu
lguest: change spte_addr header
lguest: per-vcpu lguest pgdir management
lguest: make pending notifications per-vcpu
lguest: makes special fields be per-vcpu
lguest: per-vcpu lguest task management
lguest: replace lguest_arch with lg_cpu_arch.
lguest: make registers per-vcpu
lguest: make emulate_insn receive a vcpu struct.
lguest: map_switcher_in_guest() per-vcpu
lguest: per-vcpu interrupt processing.
lguest: per-vcpu lguest timers
lguest: make hypercalls use the vcpu struct
lguest: make write() operation smp aware
...
Manual conflict resolved (maybe even correctly, who knows) in
drivers/lguest/x86/core.c
This changes size-specific register names (eip/rip, esp/rsp, etc.) to
generic names in the thread and tss structures.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
x86_64 don't expose the intermediate representation with one underline,
_PAGE_KERNEL, just the double-underlined one.
Use it, to get a common ground between 32 and 64-bit
Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
explicitly use ktime.h include
explicitly use hrtimer.h include
explicitly use sched.h include
This patch adds headers explicitly to lguest sources file,
to avoid depending on them being included somewhere else.
Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
We can save some lines of code by getting rid of
*lg = cpu... lines of code spread everywhere by now.
Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
gpte_addr() does not depend on any guest information. So we wipe out
the lg parameter from it completely.
Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
