When we allocate/change the IRQ informations, we do not
need to use spinlocks. We can use a mutex (which is
what the generic IRQ code does for allocations/changes).
Fixes a slew of:
BUG: sleeping function called from invalid context at /linux/kernel/mutex.c:271
in_atomic(): 1, irqs_disabled(): 0, pid: 3216, name: xenstored
2 locks held by xenstored/3216:
#0: (&u->bind_mutex){......}, at: [<ffffffffa02e0920>] evtchn_ioctl+0x30/0x3a0 [xen_evtchn]
#1: (irq_mapping_update_lock){......}, at: [<ffffffff8138b274>] bind_evtchn_to_irq+0x24/0x90
Pid: 3216, comm: xenstored Not tainted 3.1.0-rc6-00021-g437a3d1 #2
Call Trace:
[<ffffffff81088d10>] __might_sleep+0x100/0x130
[<ffffffff81645c2f>] mutex_lock_nested+0x2f/0x50
[<ffffffff81627529>] __irq_alloc_descs+0x49/0x200
[<ffffffffa02e0920>] ? evtchn_ioctl+0x30/0x3a0 [xen_evtchn]
[<ffffffff8138b214>] xen_allocate_irq_dynamic+0x34/0x70
[<ffffffff8138b2ad>] bind_evtchn_to_irq+0x5d/0x90
[<ffffffffa02e03c0>] ? evtchn_bind_to_user+0x60/0x60 [xen_evtchn]
[<ffffffff8138c282>] bind_evtchn_to_irqhandler+0x32/0x80
[<ffffffffa02e03a9>] evtchn_bind_to_user+0x49/0x60 [xen_evtchn]
[<ffffffffa02e0a34>] evtchn_ioctl+0x144/0x3a0 [xen_evtchn]
[<ffffffff811b4070>] ? vfsmount_lock_local_unlock+0x50/0x80
[<ffffffff811a6a1a>] do_vfs_ioctl+0x9a/0x5e0
[<ffffffff811b476f>] ? mntput+0x1f/0x30
[<ffffffff81196259>] ? fput+0x199/0x240
[<ffffffff811a7001>] sys_ioctl+0xa1/0xb0
[<ffffffff8164ea82>] system_call_fastpath+0x16/0x1b
Reported-by: Jim Burns <jim_burn@bellsouth.net>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Fix build errors (found when CONFIG_SYSFS is not enabled):
drivers/xen/xen-selfballoon.c:446: warning: data definition has no type or storage class
drivers/xen/xen-selfballoon.c:446: warning: type defaults to 'int' in declaration of 'EXPORT_SYMBOL'
drivers/xen/xen-selfballoon.c:446: warning: parameter names (without types) in function declaration
drivers/xen/xen-selfballoon.c:485: error: expected declaration specifiers or '...' before string constant
drivers/xen/xen-selfballoon.c:485: warning: data definition has no type or storage class
drivers/xen/xen-selfballoon.c:485: warning: type defaults to 'int' in declaration of 'MODULE_LICENSE'
drivers/xen/xen-selfballoon.c:485: warning: function declaration isn't a prototype
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix build errors (found when CONFIG_SYSFS is not enabled):
drivers/xen/xen-selfballoon.c:446: warning: data definition has no type or storage class
drivers/xen/xen-selfballoon.c:446: warning: type defaults to 'int' in declaration of 'EXPORT_SYMBOL'
drivers/xen/xen-selfballoon.c:446: warning: parameter names (without types) in function declaration
drivers/xen/xen-selfballoon.c:485: error: expected declaration specifiers or '...' before string constant
drivers/xen/xen-selfballoon.c:485: warning: data definition has no type or storage class
drivers/xen/xen-selfballoon.c:485: warning: type defaults to 'int' in declaration of 'MODULE_LICENSE'
drivers/xen/xen-selfballoon.c:485: warning: function declaration isn't a prototype
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Without enabling CONFIG_XEN_TMEM we get this:
drivers/xen/xen-selfballoon.c:461: undefined reference to `tmem_enabled'
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
With a specific enough .config file compile errors show
for missing workqueue declarations.
Reported-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
With a specific enough .config file compile errors show
for missing workqueue declarations.
Reported-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Memory hotplug support for Xen balloon driver. It should be mentioned
that hotplugged memory is not onlined automatically. It should be onlined
by user through standard sysfs interface.
Memory could be hotplugged in following steps:
1) dom0: xl mem-max <domU> <maxmem>
where <maxmem> is >= requested memory size,
2) dom0: xl mem-set <domU> <memory>
where <memory> is requested memory size; alternatively memory
could be added by writing proper value to
/sys/devices/system/xen_memory/xen_memory0/target or
/sys/devices/system/xen_memory/xen_memory0/target_kb on dumU,
3) domU: for i in /sys/devices/system/memory/memory*/state; do \
[ "`cat "$i"`" = offline ] && echo online > "$i"; done
Memory could be onlined automatically on domU by adding following line to
udev rules:
SUBSYSTEM=="memory", ACTION=="add", RUN+="/bin/sh -c '[ -f /sys$devpath/state ] && echo online > /sys$devpath/state'"
In that case step 3 should be omitted.
Signed-off-by: Daniel Kiper <dkiper@net-space.pl>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
.. compile options. This way the user can decide during runtime whether they
want the default 'vpci' (virtual pci passthrough) or where the PCI devices
are passed in without any BDF renumbering. The option 'passthrough' allows
the user to toggle the it from 0 (vpci) to 1 (passthrough).
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
The latter is easily fixed - by the developer compiling the
module with -DDEBUG. And during runtime - the loglvl provides
quite a lot of useful data.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
- Remove the slot and controller controller backend as they
are not used.
- Document the find pciback_[read|write]_config_[byte|word|dword]
to make it easier to find.
- Collapse the code from conf_space_capability_msi into pciback_ops.c
- Collapse conf_space_capability_[pm|vpd].c in conf_space_capability.c
[and remove the conf_space_capability.h file]
- Rename all visible functions from pciback to xen_pcibk.
- Rename all the printk/pr_info, etc that use the "pciback" to say
"xen-pciback".
- Convert functions that are not referenced outside the code to be
static to save on name space.
- Do the same thing for structures that are internal to the driver.
- Run checkpatch.pl after the renames and fixup its warnings and
fix any compile errors caused by the variable rename
- Cleanup any structs that checkpath.pl commented about or just
look odd.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
If the verbose_request is set (and loglevel high enough), print out
the MSI/MSI-X values that are sent to the guest. This should aid in
debugging issues.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
If we try to setup an fake IRQ handler for legacy interrupts
for devices that only have MSI-X (most if not all SR-IOV cards),
we will fail with this:
pciback[0000:01:10.0]: failed to install fake IRQ handler for IRQ 0! (rc:-38)
Since those cards don't have anything in dev->irq.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
pciback is rather generic for a modular distro style kernel.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
We were using coarse spinlocks that could end up with a deadlock.
This patch fixes that and makes the spinlocks much more fine-grained.
We also drop be->watchding state spinlocks as they are already
guarded by the xenwatch_thread against multiple customers. Without
that we would trigger the BUG: scheduling while atomic.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
If the device that is to be shared with a guest is a level device and
the IRQ is shared with the initial domain we need to take actions.
Mainly we install a dummy IRQ handler that will ACK on the interrupt
line so as to not have the initial domain disable the interrupt line.
This dummy IRQ handler is not enabled when the device MSI/MSI-X lines
are set, nor for edge interrupts. And also not for level interrupts
that are not shared amongst devices. Lastly, if the user passes
to the guest all of the PCI devices on the shared line the we won't
install the dummy handler either.
There is also SysFS instrumentation to check its state and turn
IRQ ACKing on/off if necessary.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
In cases where the guest is abruptly killed and has not disabled
MSI/MSI-X interrupts we want to do it for it.
Otherwise when the guest is started up and enables MSI, we would
get a WARN() that the device already had been enabled.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
These changes are for PV guest to use Virtual Function. Because the VF's
vendor, device registers in cfg space are 0xffff, which are invalid and
ignored by PCI device scan. Values in 'struct pci_dev' are fixed up by
SR-IOV code, and using these values will present correct VID and DID to
PV guest kernel.
And command registers in the cfg space are read only 0, which means we
have to emulate MMIO enable bit (VF only uses MMIO resource) so PV
kernel can work properly.
Acked-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
When the front-end and back-end start negotiating we register
the domain that will use the PCI device. Furthermore during shutdown
of guest or unbinding of the PCI device (and unloading of module)
from pciback we unregister the domain owner.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Checkpatch found some extra warnings and errors. This mega
patch fixes them all in one big swoop. We also spruce
up the pcistub_ids to use DEFINE_PCI_DEVICE_TABLE macro
(suggested by Jan Beulich).
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This is the host side counterpart to the frontend driver in
drivers/pci/xen-pcifront.c. The PV protocol is also implemented by
frontend drivers in other OSes too, such as the BSDs.
The PV protocol is rather simple. There is page shared with the guest,
which has the 'struct xen_pci_sharedinfo' embossed in it. The backend
has a thread that is kicked every-time the structure is changed and
based on the operation field it performs specific tasks:
XEN_PCI_OP_conf_[read|write]:
Read/Write 0xCF8/0xCFC filtered data. (conf_space*.c)
Based on which field is probed, we either enable/disable the PCI
device, change power state, read VPD, etc. The major goal of this
call is to provide a Physical IRQ (PIRQ) to the guest.
The PIRQ is Xen hypervisor global IRQ value irrespective of the IRQ
is tied in to the IO-APIC, or is a vector. For GSI type
interrupts, the PIRQ==GSI holds. For MSI/MSI-X the
PIRQ value != Linux IRQ number (thought PIRQ==vector).
Please note, that with Xen, all interrupts (except those level shared ones)
are injected directly to the guest - there is no host interaction.
XEN_PCI_OP_[enable|disable]_msi[|x] (pciback_ops.c)
Enables/disables the MSI/MSI-X capability of the device. These operations
setup the MSI/MSI-X vectors for the guest and pass them to the frontend.
When the device is activated, the interrupts are directly injected in the
guest without involving the host.
XEN_PCI_OP_aer_[detected|resume|mmio|slotreset]: In case of failure,
perform the appropriate AER commands on the guest. Right now that is
a cop-out - we just kill the guest.
Besides implementing those commands, it can also
- hide a PCI device from the host. When booting up, the user can specify
xen-pciback.hide=(1:0:0)(BDF..) so that host does not try to use the
device.
The driver was lifted from linux-2.6.18.hg tree and fixed up
so that it could compile under v3.0. Per suggestion from Jesse Barnes
moved the driver to drivers/xen/xen-pciback.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
In the past (2.6.38) the 'xen_allocate_pirq_gsi' would allocate
an entry in a Linux IRQ -> {XEN_IRQ, type, event, ..} array. All
of that has been removed in 2.6.39 and the Xen IRQ subsystem uses
an linked list that is populated when the call to
'xen_allocate_irq_gsi' (universally done from any of the xen_bind_*
calls) is done. The 'xen_allocate_pirq_gsi' is a NOP and there is
no need for it anymore so lets remove it.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Since they are only called once and the rest of the pci_xen_*
functions follow the same pattern of setup.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This patch introduces two in-kernel drivers for Xen transcendent memory
("tmem") functionality that complement cleancache and frontswap. Both
use control theory to dynamically adjust and optimize memory utilization.
Selfballooning controls the in-kernel Xen balloon driver, targeting a goal
value (vm_committed_as), thus pushing less frequently used clean
page cache pages (through the cleancache code) into Xen tmem where
Xen can balance needs across all VMs residing on the physical machine.
Frontswap-selfshrinking controls the number of pages in frontswap,
driving it towards zero (effectively doing a partial swapoff) when
in-kernel memory pressure subsides, freeing up RAM for other VMs.
More detail is provided in the header comment of xen-selfballooning.c.
Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
[v8: konrad.wilk@oracle.com: set default enablement depending on frontswap]
[v7: konrad.wilk@oracle.com: fix capitalization and punctuation in comments]
[v6: fix frontswap-selfshrinking initialization]
[v6: konrad.wilk@oracle.com: fix init pr_infos; add comments about swap]
[v5: konrad.wilk@oracle.com: add NULL to attr list; move inits up to decls]
[v4: dkiper@net-space.pl: use strict_strtoul plus a few syntactic nits]
[v3: konrad.wilk@oracle.com: fix potential divides-by-zero]
[v3: konrad.wilk@oracle.com: add many more comments, fix nits]
[v2: rebased to linux-3.0-rc1]
[v2: Ian.Campbell@citrix.com: reorganize as new file (xen-selfballoon.c)]
[v2: dkiper@net-space.pl: proper access to vm_committed_as]
[v2: dkiper@net-space.pl: accounting fixes]
Cc: Jan Beulich <JBeulich@novell.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: <xen-devel@lists.xensource.com>
All the Xen backend drivers are assigned to a special bus type
xen-backend. This patch exports xen-backend:* names through modalias and
uevent to autoload them.
Signed-off-by: Bastian Blank <waldi@debian.org>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
The xenbus bus type uses device_create_file to assign all used device
attributes. However it does not remove them when the device goes away.
This patch uses the dev_attrs field of the bus type to specify default
attributes for all devices.
Signed-off-by: Bastian Blank <waldi@debian.org>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Provide the shim code for frontswap for Xen tmem even if the
frontswap patchset is not present yet. (The egg is before
the chicken.)
Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Reviewed-by: Konrad Wilk <konrad.wilk@oracle.com>
By default the io_tlb_nslabs is set to zero, and gets set to
whatever value is passed in via swiotlb_init_with_tbl function.
The default value passed in is 64MB. However, if the user provides
the 'swiotlb=<nslabs>' the default value is ignored and
the value provided by the user is used... Except when the SWIOTLB
is used under Xen - there the default value of 64MB is used and
the Xen-SWIOTLB has no mechanism to get the 'io_tlb_nslabs' filled
out by setup_io_tlb_npages functions. This patch provides a function
for the Xen-SWIOTLB to call to see if the io_tlb_nslabs is set
and if so use that value.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Do not use pirq_needs_eoi to decide which irq handler to use because Xen
always returns true if the guest does not support pirq_eoi_map.
Use the trigger information we already have from MP-tables and ACPI.
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Reported-by: Thomas Goetz <tom.goetz@virtualcomputer.com>
Tested-by: Thomas Goetz <tom.goetz@virtualcomputer.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This patch provides a shim between the kernel-internal cleancache
API (see Documentation/mm/cleancache.txt) and the Xen Transcendent
Memory ABI (see http://oss.oracle.com/projects/tmem).
Xen tmem provides "hypervisor RAM" as an ephemeral page-oriented
pseudo-RAM store for cleancache pages, shared cleancache pages,
and frontswap pages. Tmem provides enterprise-quality concurrency,
full save/restore and live migration support, compression
and deduplication.
A presentation showing up to 8% faster performance and up to 52%
reduction in sectors read on a kernel compile workload, despite
aggressive in-kernel page reclamation ("self-ballooning") can be
found at:
http://oss.oracle.com/projects/tmem/dist/documentation/presentations/TranscendentMemoryXenSummit2010.pdf
Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Reviewed-by: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Rik Van Riel <riel@redhat.com>
Cc: Jan Beulich <JBeulich@novell.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Andreas Dilger <adilger@sun.com>
Cc: Ted Ts'o <tytso@mit.edu>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <joel.becker@oracle.com>
Cc: Nitin Gupta <ngupta@vflare.org>
We only supported the M2P (and P2M) override only for the
GNTMAP_contains_pte type mappings. Meaning that we grants
operations would "contain the machine address of the PTE to update"
If the flag is unset, then the grant operation is
"contains a host virtual address". The latter case means that
the Hypervisor takes care of updating our page table
(specifically the PTE entry) with the guest's MFN. As such we should
not try to do anything with the PTE. Previous to this patch
we would try to clear the PTE which resulted in Xen hypervisor
being upset with us:
(XEN) mm.c:1066:d0 Attempt to implicitly unmap a granted PTE c0100000ccc59067
(XEN) domain_crash called from mm.c:1067
(XEN) Domain 0 (vcpu#0) crashed on cpu#3:
(XEN) ----[ Xen-4.0-110228 x86_64 debug=y Not tainted ]----
and crashing us.
This patch allows us to inhibit the PTE clearing in the PV guest
if the GNTMAP_contains_pte is not set.
On the m2p_remove_override path we provide the same parameter.
Sadly in the grant-table driver we do not have a mechanism to
tell m2p_remove_override whether to clear the PTE or not. Since
the grant-table driver is used by user-space, we can safely assume
that it operates only on PTE's. Hence the implementation for
it to work on !GNTMAP_contains_pte returns -EOPNOTSUPP. In the future
we can implement the support for this. It will require some extra
accounting structure to keep track of the page[i], and the flag.
[v1: Added documentation details, made it return -EOPNOTSUPP instead
of trying to do a half-way implementation]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Various merges over time have led to rather a mish-mash of indentation.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: xen-devel@lists.xensource.com
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Since suspend, resume and shutdown operations in struct sysdev_class
and struct sysdev_driver are not used any more, remove them. Also
drop sysdev_suspend(), sysdev_resume() and sysdev_shutdown() used
for executing those operations and modify all of their users
accordingly. This reduces kernel code size quite a bit and reduces
its complexity.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Change the irq handler of evtchns and pirqs that don't need EOI (pirqs
that correspond to physical edge interrupts) to handle_edge_irq.
Use handle_fasteoi_irq for pirqs that need eoi (they generally
correspond to level triggered irqs), no risk in loosing interrupts
because we have to EOI the irq anyway.
This change has the following benefits:
- it uses the very same handlers that Linux would use on native for the
same irqs (handle_edge_irq for edge irqs and msis, and
handle_fasteoi_irq for everything else);
- it uses these handlers in the same way native code would use them: it
let Linux mask\unmask and ack the irq when Linux want to mask\unmask
and ack the irq;
- it fixes a problem occurring when a driver calls disable_irq() in its
handler: the old code was unconditionally unmasking the evtchn even if
the irq is disabled when irq_eoi was called.
See Documentation/DocBook/genericirq.tmpl for more informations.
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
[v1: Fixed space/tab issues]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Device suspend/resume infrastructure is used not only by the suspend
and hibernate code in kernel/power, but also by APM, Xen and the
kexec jump feature. However, commit 40dc166cb5
(PM / Core: Introduce struct syscore_ops for core subsystems PM)
failed to add syscore_suspend() and syscore_resume() calls to that
code, which generally leads to breakage when the features in question
are used.
To fix this problem, add the missing syscore_suspend() and
syscore_resume() calls to arch/x86/kernel/apm_32.c, kernel/kexec.c
and drivers/xen/manage.c.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
They were used to check if the queue does not have QUEUE_FLAG_DEAD
set. That is not necessary anymore as the 'submit_io' call
ends up doing that for us.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
After the commit 0faa8cca88
(" xen/blkback: remove per-queue plugging") we forgot
to retrieve the 'struct request_queue' from the block device.
This puts the functionality back in and fixes a NULL pointer
bug.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
The commit 976222e05e
xen/blkback: Move the check for misaligned I/O higher.
moved it a bit to high. The preq->vbdev was not set, so the
check for misaligned I/O would cause a NULL pointer derefence.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
We only supported the M2P (and P2M) override only for the
GNTMAP_contains_pte type mappings. Meaning that we grants
operations would "contain the machine address of the PTE to update"
If the flag is unset, then the grant operation is
"contains a host virtual address". The latter case means that
the Hypervisor takes care of updating our page table
(specifically the PTE entry) with the guest's MFN. As such we should
not try to do anything with the PTE. Previous to this patch
we would try to clear the PTE which resulted in Xen hypervisor
being upset with us:
(XEN) mm.c:1066:d0 Attempt to implicitly unmap a granted PTE c0100000ccc59067
(XEN) domain_crash called from mm.c:1067
(XEN) Domain 0 (vcpu#0) crashed on cpu#3:
(XEN) ----[ Xen-4.0-110228 x86_64 debug=y Not tainted ]----
and crashing us.
This patch allows us to inhibit the PTE clearing in the PV guest
if the GNTMAP_contains_pte is not set.
On the m2p_remove_override path we provide the same parameter.
Sadly in the grant-table driver we do not have a mechanism to
tell m2p_remove_override whether to clear the PTE or not. Since
the grant-table driver is used by user-space, we can safely assume
that it operates only on PTE's. Hence the implementation for
it to work on !GNTMAP_contains_pte returns -EOPNOTSUPP. In the future
we can implement the support for this. It will require some extra
accounting structure to keep track of the page[i], and the flag.
[v1: Added documentation details, made it return -EOPNOTSUPP instead
of trying to do a half-way implementation]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
The previous name ('fast_flush_area') had nothing to do with what it
does right now. Changing the names so that the code dealing with
mapping pages in and out of the guest is called xen_blkbk_[map|unmap].
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
We move it up higher to be in same loop that actually computes
the sector number.
This way, all of the code that deals with verifying that the
request is correct is all done before we do any of the
page mapping, I/O submission, etc.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
We take out the chunk of code dealing with mapping to the guest
of pages into the xen_blk_map_buf code. And we also move the
vbd_translate to be done much earlier.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Moving it so that the code that 'fast_flush_area' code is
close to the code that deals with it so that the reader
won't lose focus.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
We seperate the bio allocation (bio_alloc) from the bio submission so
that the error paths are much easier, and also so that the bio
submission can be done in one tight loop. It also makes the
plug/unplug calls much much easier.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Konrad Rzeszutek Wilk