In multiple functions the vcpu_id is used as an offset into a bitfield.  Ag
malicious user could specify a vcpu_id greater than 255 in order to set or
clear bits in kernel memory.  This could be used to elevate priveges in the
kernel.  This patch verifies that the vcpu_id provided is less than 255.
The api documentation already specifies that the vcpu_id must be less than
max_vcpus, but this is currently not checked.
Reported-by: NAndrew Honig <ahonig@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: NAndrew Honig <ahonig@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Using the address of 'empty_zero_page' as source address in order to
clear a page is wrong. On some architectures empty_zero_page is only the
pointer to the struct page of the empty_zero_page.  Therefore the clear
page operation would copy the contents of a couple of struct pages instead
of clearing a page.  For kvm only arm/arm64 are affected by this bug.

To fix this use the ZERO_PAGE macro instead which will return the struct
page address of the empty_zero_page on all architectures.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

It was used in conjunction with KVM_SET_MEMORY_REGION ioctl which was
removed by b74a07be in 2010, QEMU stopped using it in 2008, so
it is time to remove the code finally.
Signed-off-by: NGleb Natapov <gleb@redhat.com>

So far we've succeeded at making KVM and VFIO mostly unaware of each
other, but areas are cropping up where a connection beyond eventfds
and irqfds needs to be made.  This patch introduces a KVM-VFIO device
that is meant to be a gateway for such interaction.  The user creates
the device and can add and remove VFIO groups to it via file
descriptors.  When a group is added, KVM verifies the group is valid
and gets a reference to it via the VFIO external user interface.
Signed-off-by: NAlex Williamson <alex.williamson@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

I don't know if this was due to cut and paste, or somebody was really
using a D20 to pick the error code for kvm_init_debugfs as suggested by
Linus (EFAULT is 14, so the possibility cannot be entirely ruled out).

In any case, this patch fixes it.
Reported-by: NTim Gardner <tim.gardner@canonical.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

In kvm_iommu_map_pages(), we need to know the page size via call
kvm_host_page_size(). And it will check whether the target slot
is valid before return the right page size.
Currently, we will map the iommu pages when creating a new slot.
But we call kvm_iommu_map_pages() during preparing the new slot.
At that time, the new slot is not visible by domain(still in preparing).
So we cannot get the right page size from kvm_host_page_size() and
this will break the IOMMU super page logic.
The solution is to map the iommu pages after we insert the new slot
into domain.
Signed-off-by: NYang Zhang <yang.z.zhang@Intel.com>
Tested-by: NPatrick Lu <patrick.lu@intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

We will use that in the later patch to find the kvm ops handler
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NAlexander Graf <agraf@suse.de>

Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
[agraf: squash in compile fix]
Signed-off-by: NAlexander Graf <agraf@suse.de>

gfn_to_memslot() can return NULL or invalid slot. We need to check slot
validity before accessing it.
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

In commit e935b837 ("KVM: Convert kvm_lock to raw_spinlock"),
the kvm_lock was made a raw lock.  However, the kvm mmu_shrink()
function tries to grab the (non-raw) mmu_lock within the scope of
the raw locked kvm_lock being held.  This leads to the following:

BUG: sleeping function called from invalid context at kernel/rtmutex.c:659
in_atomic(): 1, irqs_disabled(): 0, pid: 55, name: kswapd0
Preemption disabled at:[<ffffffffa0376eac>] mmu_shrink+0x5c/0x1b0 [kvm]

Pid: 55, comm: kswapd0 Not tainted 3.4.34_preempt-rt
Call Trace:
 [<ffffffff8106f2ad>] __might_sleep+0xfd/0x160
 [<ffffffff817d8d64>] rt_spin_lock+0x24/0x50
 [<ffffffffa0376f3c>] mmu_shrink+0xec/0x1b0 [kvm]
 [<ffffffff8111455d>] shrink_slab+0x17d/0x3a0
 [<ffffffff81151f00>] ? mem_cgroup_iter+0x130/0x260
 [<ffffffff8111824a>] balance_pgdat+0x54a/0x730
 [<ffffffff8111fe47>] ? set_pgdat_percpu_threshold+0xa7/0xd0
 [<ffffffff811185bf>] kswapd+0x18f/0x490
 [<ffffffff81070961>] ? get_parent_ip+0x11/0x50
 [<ffffffff81061970>] ? __init_waitqueue_head+0x50/0x50
 [<ffffffff81118430>] ? balance_pgdat+0x730/0x730
 [<ffffffff81060d2b>] kthread+0xdb/0xe0
 [<ffffffff8106e122>] ? finish_task_switch+0x52/0x100
 [<ffffffff817e1e94>] kernel_thread_helper+0x4/0x10
 [<ffffffff81060c50>] ? __init_kthread_worker+0x

After the previous patch, kvm_lock need not be a raw spinlock anymore,
so change it back.
Reported-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
Cc: kvm@vger.kernel.org
Cc: gleb@redhat.com
Cc: jan.kiszka@siemens.com
Reviewed-by: NGleb Natapov <gleb@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The VM list need not be protected by a raw spinlock.  Separate the
two so that kvm_lock can be made non-raw.

Cc: kvm@vger.kernel.org
Cc: gleb@redhat.com
Cc: jan.kiszka@siemens.com
Reviewed-by: NGleb Natapov <gleb@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Remove the useless argument, and do not do anything if there are no
VMs running at the time of the hotplug.

Cc: kvm@vger.kernel.org
Cc: gleb@redhat.com
Cc: jan.kiszka@siemens.com
Reviewed-by: NGleb Natapov <gleb@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Page tables in a read-only memory slot will currently cause a triple
fault because the page walker uses gfn_to_hva and it fails on such a slot.

OVMF uses such a page table; however, real hardware seems to be fine with
that as long as the accessed/dirty bits are set.  Save whether the slot
is readonly, and later check it when updating the accessed and dirty bits.
Reviewed-by: NXiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Reviewed-by: NGleb Natapov <gleb@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

This is the type-safe comparison function, so the double-underscore is
not related.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

The checks on PG_reserved in the page structure on head and tail pages
aren't necessary because split_huge_page wouldn't transfer the
PG_reserved bit from head to tail anyway.

This was a forward-thinking check done in the case PageReserved was
set by a driver-owned page mapped in userland with something like
remap_pfn_range in a VM_PFNMAP region, but using hugepmds (not
possible right now). It was meant to be very safe, but it's overkill
as it's unlikely split_huge_page could ever run without the driver
noticing and tearing down the hugepage itself.

And if a driver in the future will really want to map a reserved
hugepage in userland using an huge pmd it should simply take care of
marking all subpages reserved too to keep KVM safe. This of course
would require such a hypothetical driver to tear down the huge pmd
itself and splitting the hugepage itself, instead of relaying on
split_huge_page, but that sounds very reasonable, especially
considering split_huge_page wouldn't currently transfer the reserved
bit anyway.
Signed-off-by: NAndrea Arcangeli <aarcange@redhat.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

KVM uses anon_inode_get() to allocate file descriptors as part
of some of its ioctls. But those ioctls are lacking a flag argument
allowing userspace to choose options for the newly opened file descriptor.

In such case it's advised to use O_CLOEXEC by default so that
userspace is allowed to choose, without race, if the file descriptor
is going to be inherited across exec().

This patch set O_CLOEXEC flag on all file descriptors created
with anon_inode_getfd() to not leak file descriptors across exec().
Signed-off-by: NYann Droneaud <ydroneaud@opteya.com>
Link: http://lkml.kernel.org/r/cover.1377372576.git.ydroneaud@opteya.comReviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

kvm_io_bus_sort_cmp is used also directly, not just as a callback for
sort and bsearch.  In these cases, it is handy to have a type-safe
variant.  This patch introduces such a variant, __kvm_io_bus_sort_cmp,
and uses it throughout kvm_main.c.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

This is called right after the memslots is updated, i.e. when the result
of update_memslots() gets installed in install_new_memslots().  Since
the memslots needs to be updated twice when we delete or move a memslot,
kvm_arch_commit_memory_region() does not correspond to this exactly.

In the following patch, x86 will use this new API to check if the mmio
generation has reached its maximum value, in which case mmio sptes need
to be flushed out.
Signed-off-by: NTakuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Acked-by: NAlexander Graf <agraf@suse.de>
Reviewed-by: NXiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Add new functions kvm_io_bus_{read,write}_cookie() that allows users of
the kvm io infrastructure to use a cookie value to speed up lookup of a
device on an io bus.
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

We can easily reach the 1000 limit by start VM with a couple
hundred I/O devices (multifunction=on). The hardcode limit
already been adjusted 3 times (6 ~ 200 ~ 300 ~ 1000).

In userspace, we already have maximum file descriptor to
limit ioeventfd count. But kvm_io_bus devices also are used
for pit, pic, ioapic, coalesced_mmio. They couldn't be limited
by maximum file descriptor.

Currently only ioeventfds take too much kvm_io_bus devices,
so just exclude it from counting kvm_io_range limit.

Also fixed one indent issue in kvm_host.h
Signed-off-by: NAmos Kong <akong@redhat.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

Add the missing misc_deregister() before return from kvm_init()
in the debugfs init error handling case.
Signed-off-by: NWei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

Signed-off-by: NSanjay Lal <sanjayl@kymasys.com>
Cc: kvm@vger.kernel.org
Cc: linux-mips@linux-mips.org
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

In commit a0f155e9 'KVM: Initialize irqfd from kvm_init()', when
kvm_init() is called the second time (e.g kvm-amd.ko and kvm-intel.ko),
kvm_arch_init() will fail with -EEXIST, then kvm_irqfd_exit() will be
called on the error handling path. This way, the kvm_irqfd system will
not be ready.

This patch fix the following:

BUG: unable to handle kernel NULL pointer dereference at           (null)
IP: [<ffffffff81c0721e>] _raw_spin_lock+0xe/0x30
PGD 0
Oops: 0002 [#1] SMP
Modules linked in: vhost_net
CPU 6
Pid: 4257, comm: qemu-system-x86 Not tainted 3.9.0-rc3+ #757 Dell Inc. OptiPlex 790/0V5HMK
RIP: 0010:[<ffffffff81c0721e>]  [<ffffffff81c0721e>] _raw_spin_lock+0xe/0x30
RSP: 0018:ffff880221721cc8  EFLAGS: 00010046
RAX: 0000000000000100 RBX: ffff88022dcc003f RCX: ffff880221734950
RDX: ffff8802208f6ca8 RSI: 000000007fffffff RDI: 0000000000000000
RBP: ffff880221721cc8 R08: 0000000000000002 R09: 0000000000000002
R10: 00007f7fd01087e0 R11: 0000000000000246 R12: ffff8802208f6ca8
R13: 0000000000000080 R14: ffff880223e2a900 R15: 0000000000000000
FS:  00007f7fd38488e0(0000) GS:ffff88022dcc0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000022309f000 CR4: 00000000000427e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process qemu-system-x86 (pid: 4257, threadinfo ffff880221720000, task ffff880222bd5640)
Stack:
 ffff880221721d08 ffffffff810ac5c5 ffff88022431dc00 0000000000000086
 0000000000000080 ffff880223e2a900 ffff8802208f6ca8 0000000000000000
 ffff880221721d48 ffffffff810ac8fe 0000000000000000 ffff880221734000
Call Trace:
 [<ffffffff810ac5c5>] __queue_work+0x45/0x2d0
 [<ffffffff810ac8fe>] queue_work_on+0x8e/0xa0
 [<ffffffff810ac949>] queue_work+0x19/0x20
 [<ffffffff81009b6b>] irqfd_deactivate+0x4b/0x60
 [<ffffffff8100a69d>] kvm_irqfd+0x39d/0x580
 [<ffffffff81007a27>] kvm_vm_ioctl+0x207/0x5b0
 [<ffffffff810c9545>] ? update_curr+0xf5/0x180
 [<ffffffff811b66e8>] do_vfs_ioctl+0x98/0x550
 [<ffffffff810c1f5e>] ? finish_task_switch+0x4e/0xe0
 [<ffffffff81c054aa>] ? __schedule+0x2ea/0x710
 [<ffffffff811b6bf7>] sys_ioctl+0x57/0x90
 [<ffffffff8140ae9e>] ? trace_hardirqs_on_thunk+0x3a/0x3c
 [<ffffffff81c0f602>] system_call_fastpath+0x16/0x1b
Code: c1 ea 08 38 c2 74 0f 66 0f 1f 44 00 00 f3 90 0f b6 03 38 c2 75 f7 48 83 c4 08 5b c9 c3 55 48 89 e5 66 66 66 66 90 b8 00 01 00 00 <f0> 66 0f c1 07 89 c2 66 c1 ea 08 38 c2 74 0c 0f 1f 00 f3 90 0f
RIP  [<ffffffff81c0721e>] _raw_spin_lock+0xe/0x30
RSP <ffff880221721cc8>
CR2: 0000000000000000
---[ end trace 13fb1e4b6e5ab21f ]---
Signed-off-by: NAsias He <asias@redhat.com>
Acked-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

This API shouldn't have 32/64-bit issues, but VFS assumes it does
unless told otherwise.
Signed-off-by: NScott Wood <scottwood@freescale.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

This adds the API for userspace to instantiate an XICS device in a VM
and connect VCPUs to it.  The API consists of a new device type for
the KVM_CREATE_DEVICE ioctl, a new capability KVM_CAP_IRQ_XICS, which
functions similarly to KVM_CAP_IRQ_MPIC, and the KVM_IRQ_LINE ioctl,
which is used to assert and deassert interrupt inputs of the XICS.

The XICS device has one attribute group, KVM_DEV_XICS_GRP_SOURCES.
Each attribute within this group corresponds to the state of one
interrupt source.  The attribute number is the same as the interrupt
source number.

This does not support irq routing or irqfd yet.
Signed-off-by: NPaul Mackerras <paulus@samba.org>
Acked-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NAlexander Graf <agraf@suse.de>

The hassle of getting refcounting right was greater than the hassle
of keeping a list of devices to destroy on VM exit.
Signed-off-by: NScott Wood <scottwood@freescale.com>
Signed-off-by: NAlexander Graf <agraf@suse.de>

Hook the MPIC code up to the KVM interfaces, add locking, etc.
Signed-off-by: NScott Wood <scottwood@freescale.com>
[agraf: add stub function for kvmppc_mpic_set_epr, non-booke, 64bit]
Signed-off-by: NAlexander Graf <agraf@suse.de>

Currently, devices that are emulated inside KVM are configured in a
hardcoded manner based on an assumption that any given architecture
only has one way to do it.  If there's any need to access device state,
it is done through inflexible one-purpose-only IOCTLs (e.g.
KVM_GET/SET_LAPIC).  Defining new IOCTLs for every little thing is
cumbersome and depletes a limited numberspace.

This API provides a mechanism to instantiate a device of a certain
type, returning an ID that can be used to set/get attributes of the
device.  Attributes may include configuration parameters (e.g.
register base address), device state, operational commands, etc.  It
is similar to the ONE_REG API, except that it acts on devices rather
than vcpus.

Both device types and individual attributes can be tested without having
to create the device or get/set the attribute, without the need for
separately managing enumerated capabilities.
Signed-off-by: NScott Wood <scottwood@freescale.com>
Signed-off-by: NAlexander Graf <agraf@suse.de>

Now that we have most irqfd code completely platform agnostic, let's move
irqfd's resample capability return to generic code as well.
Signed-off-by: NAlexander Graf <agraf@suse.de>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>

The IRQ routing set ioctl lives in the hacky device assignment code inside
of KVM today. This is definitely the wrong place for it. Move it to the much
more natural kvm_main.c.
Signed-off-by: NAlexander Graf <agraf@suse.de>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>

Quite a bit of code in KVM has been conditionalized on availability of
IOAPIC emulation. However, most of it is generically applicable to
platforms that don't have an IOPIC, but a different type of irq chip.

Make code that only relies on IRQ routing, not an APIC itself, on
CONFIG_HAVE_KVM_IRQ_ROUTING, so that we can reuse it later.
Signed-off-by: NAlexander Graf <agraf@suse.de>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>

Only deliver the posted interrupt when target vcpu is running
and there is no previous interrupt pending in pir.
Signed-off-by: NYang Zhang <yang.z.zhang@Intel.com>
Reviewed-by: NGleb Natapov <gleb@redhat.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

Both TMR and EOI exit bitmap need to be updated when ioapic changed
or vcpu's id/ldr/dfr changed. So use common function instead eoi exit
bitmap specific function.
Signed-off-by: NYang Zhang <yang.z.zhang@Intel.com>
Reviewed-by: NGleb Natapov <gleb@redhat.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

Userspace may deliver RTC interrupt without query the status. So we
want to track RTC EOI for this case.
Signed-off-by: NYang Zhang <yang.z.zhang@Intel.com>
Reviewed-by: NGleb Natapov <gleb@redhat.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

The routine kvm_spurious_fault() is an x86 specific routine, so
move it from virt/kvm/kvm_main.c to arch/x86/kvm/x86.c.

Fixes this sparse warning when building on arm64:

  virt/kvm/kvm_main.c:warning: symbol 'kvm_spurious_fault' was not declared. Should it be static?
Signed-off-by: NGeoff Levand <geoff@infradead.org>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

The routines get_user_page_nowait(), kvm_io_bus_sort_cmp(), kvm_io_bus_insert_dev()
and kvm_io_bus_get_first_dev() are only referenced within kvm_main.c, so give them
static linkage.

Fixes sparse warnings like these:

  virt/kvm/kvm_main.c: warning: symbol 'get_user_page_nowait' was not declared. Should it be static?
Signed-off-by: NGeoff Levand <geoff@infradead.org>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

This patch adds support for kvm_gfn_to_hva_cache_init functions for
reads and writes that will cross a page.  If the range falls within
the same memslot, then this will be a fast operation.  If the range
is split between two memslots, then the slower kvm_read_guest and
kvm_write_guest are used.

Tested: Test against kvm_clock unit tests.
Signed-off-by: NAndrew Honig <ahonig@google.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

This helps in filtering out the eligible candidates further and
thus potentially helps in quickly allowing preempted lockholders to run.
Note that if a vcpu was spinning during preemption we filter them
by checking whether they are preempted due to pause loop exit.
Reviewed-by: NChegu Vinod <chegu_vinod@hp.com>
Reviewed-by: NMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: NRaghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

Note that we mark as preempted only when vcpu's task state was
Running during preemption.

Thanks Jiannan, Avi for preemption notifier ideas. Thanks Gleb, PeterZ
for their precious suggestions. Thanks Srikar for an idea on avoiding
rcu lock while checking task state that improved overcommit numbers.
Reviewed-by: NChegu Vinod <chegu_vinod@hp.com>
Reviewed-by: NMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: NRaghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

Currently, eventfd introduces module_init/module_exit functions
to initialize/cleanup the irqfd workqueue. This only works, however,
if no other module_init/module_exit functions are built into the
same module.

Let's just move the initialization and cleanup to kvm_init and kvm_exit.
This way, it is also clearer where kvm startup may fail.
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>