Commit Graph

193 Commits

Author SHA1 Message Date
Izik Eidus 3da0dd433d KVM: add support for change_pte mmu notifiers
this is needed for kvm if it want ksm to directly map pages into its
shadow page tables.

[marcelo: cast pfn assignment to u64]

Signed-off-by: Izik Eidus <ieidus@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2009-10-04 17:04:53 +02:00
Alexey Dobriyan 828c09509b const: constify remaining file_operations
[akpm@linux-foundation.org: fix KVM]
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-10-01 16:11:11 -07:00
Alexey Dobriyan f0f37e2f77 const: mark struct vm_struct_operations
* mark struct vm_area_struct::vm_ops as const
* mark vm_ops in AGP code

But leave TTM code alone, something is fishy there with global vm_ops
being used.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-27 11:39:25 -07:00
Li Zefan 79f5599772 cpumask: use zalloc_cpumask_var() where possible
Remove open-coded zalloc_cpumask_var() and zalloc_cpumask_var_node().

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2009-09-24 09:34:24 +09:30
Julia Lawall 6223011fb9 KVM: correct error-handling code
This code is not executed before file has been initialized to the result of
calling eventfd_fget.  This function returns an ERR_PTR value in an error
case instead of NULL.  Thus the test that file is not NULL is always true.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@match exists@
expression x, E;
statement S1, S2;
@@

x = eventfd_fget(...)
... when != x = E
(
*  if (x == NULL || ...) S1 else S2
|
*  if (x == NULL && ...) S1 else S2
)
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 18:11:12 +03:00
Heiko Carstens 28bcb11218 KVM: fix compile warnings on s390
CC      arch/s390/kvm/../../../virt/kvm/kvm_main.o
arch/s390/kvm/../../../virt/kvm/kvm_main.c: In function '__kvm_set_memory_region':
arch/s390/kvm/../../../virt/kvm/kvm_main.c:485: warning: unused variable 'j'
arch/s390/kvm/../../../virt/kvm/kvm_main.c:484: warning: unused variable 'lpages'
arch/s390/kvm/../../../virt/kvm/kvm_main.c:483: warning: unused variable 'ugfn'

Cc: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2009-09-10 18:11:11 +03:00
Gleb Natapov 65a8221163 KVM: Fix coalesced interrupt reporting in IOAPIC
This bug was introduced by b4a2f5e723.

Cc: stable@kernel.org
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 10:46:59 +03:00
Avi Kivity 6621fbc2c6 KVM: Move #endif KVM_CAP_IRQ_ROUTING to correct place
The symbol only controls irq routing, not MSI-X.

Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 10:46:42 +03:00
Xiao Guangrong aed665f7bb KVM: fix kvm_init() error handling
Remove debugfs file if kvm_arch_init() return error

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:33:17 +03:00
Jan Kiszka e601e3be7a KVM: Drop obsolete cpu_get/put in make_all_cpus_request
spin_lock disables preemption, so we can simply read the current cpu.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2009-09-10 08:33:16 +03:00
Gleb Natapov a1b37100d9 KVM: Reduce runnability interface with arch support code
Remove kvm_cpu_has_interrupt() and kvm_arch_interrupt_allowed() from
interface between general code and arch code. kvm_arch_vcpu_runnable()
checks for interrupts instead.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:33:13 +03:00
Gregory Haskins d34e6b175e KVM: add ioeventfd support
ioeventfd is a mechanism to register PIO/MMIO regions to trigger an eventfd
signal when written to by a guest.  Host userspace can register any
arbitrary IO address with a corresponding eventfd and then pass the eventfd
to a specific end-point of interest for handling.

Normal IO requires a blocking round-trip since the operation may cause
side-effects in the emulated model or may return data to the caller.
Therefore, an IO in KVM traps from the guest to the host, causes a VMX/SVM
"heavy-weight" exit back to userspace, and is ultimately serviced by qemu's
device model synchronously before returning control back to the vcpu.

However, there is a subclass of IO which acts purely as a trigger for
other IO (such as to kick off an out-of-band DMA request, etc).  For these
patterns, the synchronous call is particularly expensive since we really
only want to simply get our notification transmitted asychronously and
return as quickly as possible.  All the sychronous infrastructure to ensure
proper data-dependencies are met in the normal IO case are just unecessary
overhead for signalling.  This adds additional computational load on the
system, as well as latency to the signalling path.

Therefore, we provide a mechanism for registration of an in-kernel trigger
point that allows the VCPU to only require a very brief, lightweight
exit just long enough to signal an eventfd.  This also means that any
clients compatible with the eventfd interface (which includes userspace
and kernelspace equally well) can now register to be notified. The end
result should be a more flexible and higher performance notification API
for the backend KVM hypervisor and perhipheral components.

To test this theory, we built a test-harness called "doorbell".  This
module has a function called "doorbell_ring()" which simply increments a
counter for each time the doorbell is signaled.  It supports signalling
from either an eventfd, or an ioctl().

We then wired up two paths to the doorbell: One via QEMU via a registered
io region and through the doorbell ioctl().  The other is direct via
ioeventfd.

You can download this test harness here:

ftp://ftp.novell.com/dev/ghaskins/doorbell.tar.bz2

The measured results are as follows:

qemu-mmio:       110000 iops, 9.09us rtt
ioeventfd-mmio: 200100 iops, 5.00us rtt
ioeventfd-pio:  367300 iops, 2.72us rtt

I didn't measure qemu-pio, because I have to figure out how to register a
PIO region with qemu's device model, and I got lazy.  However, for now we
can extrapolate based on the data from the NULLIO runs of +2.56us for MMIO,
and -350ns for HC, we get:

qemu-pio:      153139 iops, 6.53us rtt
ioeventfd-hc: 412585 iops, 2.37us rtt

these are just for fun, for now, until I can gather more data.

Here is a graph for your convenience:

http://developer.novell.com/wiki/images/7/76/Iofd-chart.png

The conclusion to draw is that we save about 4us by skipping the userspace
hop.

--------------------

Signed-off-by: Gregory Haskins <ghaskins@novell.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:33:12 +03:00
Gregory Haskins 090b7aff27 KVM: make io_bus interface more robust
Today kvm_io_bus_regsiter_dev() returns void and will internally BUG_ON
if it fails.  We want to create dynamic MMIO/PIO entries driven from
userspace later in the series, so we need to enhance the code to be more
robust with the following changes:

   1) Add a return value to the registration function
   2) Fix up all the callsites to check the return code, handle any
      failures, and percolate the error up to the caller.
   3) Add an unregister function that collapses holes in the array

Signed-off-by: Gregory Haskins <ghaskins@novell.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:33:12 +03:00
Gleb Natapov 1000ff8d89 KVM: Add trace points in irqchip code
Add tracepoint in msi/ioapic/pic set_irq() functions,
in IPI sending and in the point where IRQ is placed into
apic's IRR.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:33:11 +03:00
Michael S. Tsirkin 07fb8bb29f KVM: ignore msi request if !level
Irqfd sets level for interrupt to 1 and then to 0.
For MSI, check level so that a single message is sent.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:33:10 +03:00
Gleb Natapov 70f93dae32 KVM: Use temporary variable to shorten lines.
Cosmetic only. No logic is changed by this patch.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:33:08 +03:00
Avi Kivity ae8c1c4025 KVM: Trace irq level and source id
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:33:06 +03:00
Jiri Slaby 27c4ba6017 KVM: fix lock imbalance
There is a missing unlock on one fail path in ioapic_mmio_write,
fix that.

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:33:06 +03:00
Michael S. Tsirkin 22fc02943a KVM: document lock nesting rule
Document kvm->lock nesting within kvm->slots_lock

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:33:06 +03:00
Michael S. Tsirkin bda9020e24 KVM: remove in_range from io devices
This changes bus accesses to use high-level kvm_io_bus_read/kvm_io_bus_write
functions. in_range now becomes unused so it is removed from device ops in
favor of read/write callbacks performing range checks internally.

This allows aliasing (mostly for in-kernel virtio), as well as better error
handling by making it possible to pass errors up to userspace.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:33:05 +03:00
Michael S. Tsirkin 6c47469453 KVM: convert bus to slots_lock
Use slots_lock to protect device list on the bus.  slots_lock is already
taken for read everywhere, so we only need to take it for write when
registering devices.  This is in preparation to removing in_range and
kvm->lock around it.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:33:05 +03:00
Michael S. Tsirkin d5c2dcc36a KVM: switch coalesced mmio changes to slots_lock
switch coalesced mmio slots_lock.  slots_lock is already taken for read
everywhere, so we only need to take it for write when changing zones.
This is in preparation to removing in_range and kvm->lock around it.

[avi: fix build]

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:33:04 +03:00
Michael S. Tsirkin 69fa2d7865 KVM: document locking for kvm_io_device_ops
slots_lock is taken everywhere when device ops are called.
Document this as we will use this to rework locking for io.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:33:04 +03:00
Marcelo Tosatti 2023a29cbe KVM: remove old KVMTRACE support code
Return EOPNOTSUPP for KVM_TRACE_ENABLE/PAUSE/DISABLE ioctls.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:33:03 +03:00
Marcelo Tosatti 894a9c5543 KVM: x86: missing locking in PIT/IRQCHIP/SET_BSP_CPU ioctl paths
Correct missing locking in a few places in x86's vm_ioctl handling path.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:33:02 +03:00
Joerg Roedel ec04b2604c KVM: Prepare memslot data structures for multiple hugepage sizes
[avi: fix build on non-x86]

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:33:02 +03:00
Christian Borntraeger 3eea8437f6 KVM: s390: Fix memslot initialization for userspace_addr != 0
Since
commit 854b5338196b1175706e99d63be43a4f8d8ab607
Author: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
    KVM: s390: streamline memslot handling

s390 uses the values of the memslot instead of doing everything in the arch
ioctl handler of the KVM_SET_USER_MEMORY_REGION. Unfortunately we missed to
set the userspace_addr of our memslot due to our s390 ifdef in
__kvm_set_memory_region.
Old s390 userspace launchers did not notice, since they started the guest at
userspace address 0.
Because of CONFIG_DEFAULT_MMAP_MIN_ADDR we now put the guest at 1M userspace,
which does not work. This patch makes sure that new.userspace_addr is set
on s390.
This fix should go in quickly. Nevertheless, looking at the code we should
clean up that ifdef in the long term. Any kernel janitors?

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:33:01 +03:00
Marcelo Tosatti 229456fc34 KVM: convert custom marker based tracing to event traces
This allows use of the powerful ftrace infrastructure.

See Documentation/trace/ for usage information.

[avi, stephen: various build fixes]
[sheng: fix control register breakage]

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:32:59 +03:00
Marcelo Tosatti 54dee9933e KVM: VMX: conditionally disable 2M pages
Disable usage of 2M pages if VMX_EPT_2MB_PAGE_BIT (bit 16) is clear
in MSR_IA32_VMX_EPT_VPID_CAP and EPT is enabled.

[avi: s/largepages_disabled/largepages_enabled/ to avoid negative logic]

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:32:56 +03:00
Gleb Natapov 988a2cae6a KVM: Use macro to iterate over vcpus.
[christian: remove unused variables on s390]

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:32:52 +03:00
Gleb Natapov 73880c80aa KVM: Break dependency between vcpu index in vcpus array and vcpu_id.
Archs are free to use vcpu_id as they see fit. For x86 it is used as
vcpu's apic id. New ioctl is added to configure boot vcpu id that was
assumed to be 0 till now.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:32:52 +03:00
Gleb Natapov c5af89b68a KVM: Introduce kvm_vcpu_is_bsp() function.
Use it instead of open code "vcpu_id zero is BSP" assumption.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:32:51 +03:00
Marcelo Tosatti fa40a8214b KVM: switch irq injection/acking data structures to irq_lock
Protect irq injection/acking data structures with a separate irq_lock
mutex. This fixes the following deadlock:

CPU A                               CPU B
kvm_vm_ioctl_deassign_dev_irq()
  mutex_lock(&kvm->lock);            worker_thread()
  -> kvm_deassign_irq()                -> kvm_assigned_dev_interrupt_work_handler()
    -> deassign_host_irq()               mutex_lock(&kvm->lock);
      -> cancel_work_sync() [blocked]

[gleb: fix ia64 path]

Reported-by: Alex Williamson <alex.williamson@hp.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:32:49 +03:00
Marcelo Tosatti 60eead79ad KVM: introduce irq_lock, use it to protect ioapic
Introduce irq_lock, and use to protect ioapic data structures.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:32:49 +03:00
Marcelo Tosatti 64a2268dcf KVM: move coalesced_mmio locking to its own device
Move coalesced_mmio locking to its own device, instead of relying on
kvm->lock.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:32:49 +03:00
Avi Kivity 105f8d40a7 KVM: Calculate available entries in coalesced mmio ring
Instead of checking whether we'll wrap around, calculate how many entries
are available, and check whether we have enough (just one) for the pending
mmio.

By itself, this doesn't change anything, but it paves the way for making
this function lockless.

Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:32:47 +03:00
Gregory Haskins d76685c4a0 KVM: cleanup io_device code
We modernize the io_device code so that we use container_of() instead of
dev->private, and move the vtable to a separate ops structure
(theoretically allows better caching for multiple instances of the same
ops structure)

Signed-off-by: Gregory Haskins <ghaskins@novell.com>
Acked-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:32:45 +03:00
Gregory Haskins 787a660a4f KVM: Clean up coalesced_mmio destruction
We invoke kfree() on a data member instead of the structure.  This works today
because the kvm_io_device is the first element of the private structure, but
this could change in the future, so lets clean this up.

Signed-off-by: Gregory Haskins <ghaskins@novell.com>
Acked-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:32:45 +03:00
Sheng Yang 968a634793 KVM: No disable_irq for MSI/MSI-X interrupt on device assignment
Disable interrupt at interrupt handler and enable it when guest ack is for
the level triggered interrupt, to prevent reinjected interrupt. MSI/MSI-X don't
need it.

One possible problem is multiply same vector interrupt injected between irq
handler and scheduled work handler would be merged as one for MSI/MSI-X.
But AFAIK, the drivers handle it well.

The patch fixed the oplin card performance issue(MSI-X performance is half of
MSI/INTx).

Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:32:43 +03:00
Gregory Haskins 721eecbf4f KVM: irqfd
KVM provides a complete virtual system environment for guests, including
support for injecting interrupts modeled after the real exception/interrupt
facilities present on the native platform (such as the IDT on x86).
Virtual interrupts can come from a variety of sources (emulated devices,
pass-through devices, etc) but all must be injected to the guest via
the KVM infrastructure.  This patch adds a new mechanism to inject a specific
interrupt to a guest using a decoupled eventfd mechnanism:  Any legal signal
on the irqfd (using eventfd semantics from either userspace or kernel) will
translate into an injected interrupt in the guest at the next available
interrupt window.

Signed-off-by: Gregory Haskins <ghaskins@novell.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:32:41 +03:00
Avi Kivity 0ba12d1081 KVM: Move common KVM Kconfig items to new file virt/kvm/Kconfig
Reduce Kconfig code duplication.

Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:32:41 +03:00
Gleb Natapov b4a2f5e723 KVM: Avoid redelivery of edge interrupt before next edge
The check for an edge is broken in current ioapic code. ioapic->irr is
cleared on each edge interrupt by ioapic_service() and this makes
old_irr != ioapic->irr condition in kvm_ioapic_set_irq() to be always
true. The patch fixes the code to properly recognise edge.

Some HW emulation calls set_irq() without level change. If each such
call is propagated to an OS it may confuse a device driver. This is the
case with keyboard device emulation and Windows XP x64  installer on SMP VM.
Each keystroke produce two interrupts (down/up) one interrupt is
submitted to CPU0 and another to CPU1. This confuses Windows somehow
and it ignores keystrokes.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-08-09 11:45:49 +03:00
Michael S. Tsirkin 5116d8f6b9 KVM: fix ack not being delivered when msi present
kvm_notify_acked_irq does not check irq type, so that it sometimes
interprets msi vector as irq.  As a result, ack notifiers are not
called, which typially hangs the guest.  The fix is to track and
check irq type.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-08-05 14:03:43 +03:00
Marcelo Tosatti 84261923d3 KVM: protect concurrent make_all_cpus_request
make_all_cpus_request contains a race condition which can
trigger false request completed status, as follows:

CPU0                                              CPU1

if (test_and_set_bit(req,&vcpu->requests))
   ....                                        	   if (test_and_set_bit(req,&vcpu->requests))
   ..                                                  return
proceed to smp_call_function_many(wait=1)

Use a spinlock to serialize concurrent CPUs.

Cc: stable@kernel.org
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-28 14:10:29 +03:00
Izik Eidus e244584fe3 KVM: Fix dirty bit tracking for slots with large pages
When slot is already allocated and being asked to be tracked we need
to break the large pages.

This code flush the mmu when someone ask a slot to start dirty bit
tracking.

Cc: stable@kernel.org
Signed-off-by: Izik Eidus <ieidus@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-28 14:10:29 +03:00
Yinghai Lu aee74f3bb3 kvm: remove the duplicated cpumask_clear
zalloc_cpumask_var already cleared it.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 20:04:37 -07:00
Avi Kivity 09f8ca74ae KVM: Prevent overflow in largepages calculation
If userspace specifies a memory slot that is larger than 8 petabytes, it
could overflow the largepages variable.

Cc: stable@kernel.org
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-10 15:18:16 +03:00
Avi Kivity ac04527f79 KVM: Disable large pages on misaligned memory slots
If a slots guest physical address and host virtual address unequal (mod
large page size), then we would erronously try to back guest large pages
with host large pages.  Detect this misalignment and diable large page
support for the trouble slot.

Cc: stable@kernel.org
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-10 15:17:58 +03:00
Marcelo Tosatti b43b1901ad KVM: take mmu_lock when updating a deleted slot
kvm_handle_hva relies on mmu_lock protection to safely access
the memslot structures.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-10 11:48:54 +03:00
Marcelo Tosatti 547de29e5b KVM: protect assigned dev workqueue, int handler and irq acker
kvm_assigned_dev_ack_irq is vulnerable to a race condition with the
interrupt handler function. It does:

        if (dev->host_irq_disabled) {
                enable_irq(dev->host_irq);
                dev->host_irq_disabled = false;
        }

If an interrupt triggers before the host->dev_irq_disabled assignment,
it will disable the interrupt and set dev->host_irq_disabled to true.

On return to kvm_assigned_dev_ack_irq, dev->host_irq_disabled is set to
false, and the next kvm_assigned_dev_ack_irq call will fail to reenable
it.

Other than that, having the interrupt handler and work handlers run in
parallel sounds like asking for trouble (could not spot any obvious
problem, but better not have to, its fragile).

CC: sheng.yang@intel.com
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-10 11:48:53 +03:00