linux-stable.git/virt, branch v3.16.35

KVM: fix spin_lock_init order on x86

2016-04-30T22:06:03+00:00

commit e9ad4ec8379ad1ba6f68b8ca1c26b50b5ae0a327 upstream.

Moving the initialization earlier is needed in 4.6 because
kvm_arch_init_vm is now using mmu_lock, causing lockdep to
complain:

[  284.440294] INFO: trying to register non-static key.
[  284.445259] the code is fine but needs lockdep annotation.
[  284.450736] turning off the locking correctness validator.
...
[  284.528318]  [] lock_acquire+0xd3/0x240
[  284.533733]  [] ? kvm_page_track_register_notifier+0x20/0x60 [kvm]
[  284.541467]  [] _raw_spin_lock+0x41/0x80
[  284.546960]  [] ? kvm_page_track_register_notifier+0x20/0x60 [kvm]
[  284.554707]  [] kvm_page_track_register_notifier+0x20/0x60 [kvm]
[  284.562281]  [] kvm_mmu_init_vm+0x20/0x30 [kvm]
[  284.568381]  [] kvm_arch_init_vm+0x1ea/0x200 [kvm]
[  284.574740]  [] kvm_dev_ioctl+0xbf/0x4d0 [kvm]

However, it also helps fixing a preexisting problem, which is why this
patch is also good for stable kernels: kvm_create_vm was incrementing
current->mm->mm_count but not decrementing it at the out_err label (in
case kvm_init_mmu_notifier failed).  The new initialization order makes
it possible to add the required mmdrop without adding a new error label.

Reported-by: Borislav Petkov 
Signed-off-by: Paolo Bonzini 
Signed-off-by: Ben Hutchings

KVM: async_pf: do not warn on page allocation failures

2016-03-08T12:15:30+00:00

commit d7444794a02ff655eda87e3cc54e86b940e7736f upstream.

In async_pf we try to allocate with NOWAIT to get an element quickly
or fail. This code also handle failures gracefully. Lets silence
potential page allocation failures under load.

qemu-system-s39: page allocation failure: order:0,mode:0x2200000
[...]
Call Trace:
([<00000000001146b8>] show_trace+0xf8/0x148)
[<000000000011476a>] show_stack+0x62/0xe8
[<00000000004a36b8>] dump_stack+0x70/0x98
[<0000000000272c3a>] warn_alloc_failed+0xd2/0x148
[<000000000027709e>] __alloc_pages_nodemask+0x94e/0xb38
[<00000000002cd36a>] new_slab+0x382/0x400
[<00000000002cf7ac>] ___slab_alloc.constprop.30+0x2dc/0x378
[<00000000002d03d0>] kmem_cache_alloc+0x160/0x1d0
[<0000000000133db4>] kvm_setup_async_pf+0x6c/0x198
[<000000000013dee8>] kvm_arch_vcpu_ioctl_run+0xd48/0xd58
[<000000000012fcaa>] kvm_vcpu_ioctl+0x372/0x690
[<00000000002f66f6>] do_vfs_ioctl+0x3be/0x510
[<00000000002f68ec>] SyS_ioctl+0xa4/0xb8
[<0000000000781c5e>] system_call+0xd6/0x264
[<000003ffa24fa06a>] 0x3ffa24fa06a

Signed-off-by: Christian Borntraeger 
Reviewed-by: Dominik Dingel 
Signed-off-by: Paolo Bonzini 
Signed-off-by: Luis Henriques

kvm: fix zero length mmio searching

2015-10-06T10:52:28+00:00

commit 8f4216c7d28976f7ec1b2bcbfa0a9f787133c45e upstream.

Currently, if we had a zero length mmio eventfd assigned on
KVM_MMIO_BUS. It will never be found by kvm_io_bus_cmp() since it
always compares the kvm_io_range() with the length that guest
wrote. This will cause e.g for vhost, kick will be trapped by qemu
userspace instead of vhost. Fixing this by using zero length if an
iodevice is zero length.

Cc: Gleb Natapov 
Cc: Paolo Bonzini 
Signed-off-by: Jason Wang 
Reviewed-by: Cornelia Huck 
Signed-off-by: Paolo Bonzini 
Signed-off-by: Luis Henriques

kvm: fix double free for fast mmio eventfd

2015-10-06T10:52:28+00:00

commit eefd6b06b17c5478e7c24bea6f64beaa2c431ca6 upstream.

We register wildcard mmio eventfd on two buses, once for KVM_MMIO_BUS
and once on KVM_FAST_MMIO_BUS but with a single iodev
instance. This will lead to an issue: kvm_io_bus_destroy() knows
nothing about the devices on two buses pointing to a single dev. Which
will lead to double free[1] during exit. Fix this by allocating two
instances of iodevs then registering one on KVM_MMIO_BUS and another
on KVM_FAST_MMIO_BUS.

CPU: 1 PID: 2894 Comm: qemu-system-x86 Not tainted 3.19.0-26-generic #28-Ubuntu
Hardware name: LENOVO 2356BG6/2356BG6, BIOS G7ET96WW (2.56 ) 09/12/2013
task: ffff88009ae0c4b0 ti: ffff88020e7f0000 task.ti: ffff88020e7f0000
RIP: 0010:[]  [] ioeventfd_release+0x28/0x60 [kvm]
RSP: 0018:ffff88020e7f3bc8  EFLAGS: 00010292
RAX: dead000000200200 RBX: ffff8801ec19c900 RCX: 000000018200016d
RDX: ffff8801ec19cf80 RSI: ffffea0008bf1d40 RDI: ffff8801ec19c900
RBP: ffff88020e7f3bd8 R08: 000000002fc75a01 R09: 000000018200016d
R10: ffffffffc07df6ae R11: ffff88022fc75a98 R12: ffff88021e7cc000
R13: ffff88021e7cca48 R14: ffff88021e7cca50 R15: ffff8801ec19c880
FS:  00007fc1ee3e6700(0000) GS:ffff88023e240000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8f389d8000 CR3: 000000023dc13000 CR4: 00000000001427e0
Stack:
ffff88021e7cc000 0000000000000000 ffff88020e7f3be8 ffffffffc07e2622
ffff88020e7f3c38 ffffffffc07df69a ffff880232524160 ffff88020e792d80
 0000000000000000 ffff880219b78c00 0000000000000008 ffff8802321686a8
Call Trace:
[] ioeventfd_destructor+0x12/0x20 [kvm]
[] kvm_put_kvm+0xca/0x210 [kvm]
[] kvm_vcpu_release+0x18/0x20 [kvm]
[] __fput+0xe7/0x250
[] ____fput+0xe/0x10
[] task_work_run+0xd4/0xf0
[] do_exit+0x368/0xa50
[] ? recalc_sigpending+0x1f/0x60
[] do_group_exit+0x45/0xb0
[] get_signal+0x291/0x750
[] do_signal+0x28/0xab0
[] ? do_futex+0xdb/0x5d0
[] ? __wake_up_locked_key+0x18/0x20
[] ? SyS_futex+0x76/0x170
[] do_notify_resume+0x69/0xb0
[] int_signal+0x12/0x17
Code: 5d c3 90 0f 1f 44 00 00 55 48 89 e5 53 48 89 fb 48 83 ec 08 48 8b 7f 20 e8 06 d6 a5 c0 48 8b 43 08 48 8b 13 48 89 df 48 89 42 08 <48> 89 10 48 b8 00 01 10 00 00
 RIP  [] ioeventfd_release+0x28/0x60 [kvm]
 RSP 

Cc: Gleb Natapov 
Cc: Paolo Bonzini 
Signed-off-by: Jason Wang 
Reviewed-by: Cornelia Huck 
Signed-off-by: Paolo Bonzini 
Signed-off-by: Luis Henriques

kvm: factor out core eventfd assign/deassign logic

2015-10-06T10:52:28+00:00

commit 85da11ca587c8eb73993a1b503052391a73586f9 upstream.

This patch factors out core eventfd assign/deassign logic and leaves
the argument checking and bus index selection to callers.

Cc: Gleb Natapov 
Cc: Paolo Bonzini 
Signed-off-by: Jason Wang 
Reviewed-by: Cornelia Huck 
Signed-off-by: Paolo Bonzini 
Signed-off-by: Luis Henriques

kvm: don't try to register to KVM_FAST_MMIO_BUS for non mmio eventfd

2015-10-06T10:52:28+00:00

commit 8453fecbecae26edb3f278627376caab05d9a88d upstream.

We only want zero length mmio eventfd to be registered on
KVM_FAST_MMIO_BUS. So check this explicitly when arg->len is zero to
make sure this.

Cc: Gleb Natapov 
Cc: Paolo Bonzini 
Signed-off-by: Jason Wang 
Reviewed-by: Cornelia Huck 
Signed-off-by: Paolo Bonzini 
Signed-off-by: Luis Henriques

arm/arm64: KVM: Keep elrsr/aisr in sync with software model

2015-05-20T12:25:54+00:00

commit ae705930fca6322600690df9dc1c7d0516145a93 upstream.

There is an interesting bug in the vgic code, which manifests itself
when the KVM run loop has a signal pending or needs a vmid generation
rollover after having disabled interrupts but before actually switching
to the guest.

In this case, we flush the vgic as usual, but we sync back the vgic
state and exit to userspace before entering the guest.  The consequence
is that we will be syncing the list registers back to the software model
using the GICH_ELRSR and GICH_EISR from the last execution of the guest,
potentially overwriting a list register containing an interrupt.

This showed up during migration testing where we would capture a state
where the VM has masked the arch timer but there were no interrupts,
resulting in a hung test.

Cc: Marc Zyngier 
Reported-by: Alex Bennee 
Signed-off-by: Christoffer Dall 
Signed-off-by: Alex Bennée 
Acked-by: Marc Zyngier 
Signed-off-by: Christoffer Dall 
Signed-off-by: Shannon Zhao 
[ luis: backported to 3.16: used shannon's backport to 3.14 ]
Signed-off-by: Luis Henriques

arm/arm64: KVM: Require in-kernel vgic for the arch timers

2015-05-20T12:25:52+00:00

commit 05971120fca43e0357789a14b3386bb56eef2201 upstream.

It is curently possible to run a VM with architected timers support
without creating an in-kernel VGIC, which will result in interrupts from
the virtual timer going nowhere.

To address this issue, move the architected timers initialization to the
time when we run a VCPU for the first time, and then only initialize
(and enable) the architected timers if we have a properly created and
initialized in-kernel VGIC.

When injecting interrupts from the virtual timer to the vgic, the
current setup should ensure that this never calls an on-demand init of
the VGIC, which is the only call path that could return an error from
kvm_vgic_inject_irq(), so capture the return value and raise a warning
if there's an error there.

We also change the kvm_timer_init() function from returning an int to be
a void function, since the function always succeeds.

Reviewed-by: Marc Zyngier 
Signed-off-by: Christoffer Dall 
Signed-off-by: Shannon Zhao 
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques

arm/arm64: KVM: vgic: Fix error code in kvm_vgic_create()

2015-05-20T12:25:48+00:00

commit 6b50f54064a02b77a7b990032b80234fee59bcd6 upstream.

If we detect another vCPU is running we just exit and return 0 as if we
succesfully created the VGIC, but the VGIC wouldn't actual be created.

This shouldn't break in-kernel behavior because the kernel will not
observe the failed the attempt to create the VGIC, but userspace could
be rightfully confused.

Cc: Andre Przywara 
Signed-off-by: Christoffer Dall 
Signed-off-by: Marc Zyngier 
Signed-off-by: Paolo Bonzini 
Signed-off-by: Shannon Zhao 
Signed-off-by: Luis Henriques

arm/arm64: KVM: Fix set_clear_sgi_pend_reg offset

2015-05-20T12:25:45+00:00

commit 0fea6d7628ed6e25a9ee1b67edf7c859718d39e8 upstream.

The sgi values calculated in read_set_clear_sgi_pend_reg() and
write_set_clear_sgi_pend_reg() were horribly incorrectly multiplied by 4
with catastrophic results in that subfunctions ended up overwriting
memory not allocated for the expected purpose.

This showed up as bugs in kfree() and the kernel complaining a lot of
you turn on memory debugging.

This addresses: http://marc.info/?l=kvm&m=141164910007868&w=2

Reported-by: Shannon Zhao 
Signed-off-by: Christoffer Dall 
Signed-off-by: Shannon Zhao 
Signed-off-by: Luis Henriques