Commit Graph

475 Commits

Author SHA1 Message Date
Linus Torvalds b9085bcbf5 Fairly small update, but there are some interesting new features.
Common: Optional support for adding a small amount of polling on each HLT
 instruction executed in the guest (or equivalent for other architectures).
 This can improve latency up to 50% on some scenarios (e.g. O_DSYNC writes
 or TCP_RR netperf tests).  This also has to be enabled manually for now,
 but the plan is to auto-tune this in the future.
 
 ARM/ARM64: the highlights are support for GICv3 emulation and dirty page
 tracking
 
 s390: several optimizations and bugfixes.  Also a first: a feature
 exposed by KVM (UUID and long guest name in /proc/sysinfo) before
 it is available in IBM's hypervisor! :)
 
 MIPS: Bugfixes.
 
 x86: Support for PML (page modification logging, a new feature in
 Broadwell Xeons that speeds up dirty page tracking), nested virtualization
 improvements (nested APICv---a nice optimization), usual round of emulation
 fixes.  There is also a new option to reduce latency of the TSC deadline
 timer in the guest; this needs to be tuned manually.
 
 Some commits are common between this pull and Catalin's; I see you
 have already included his tree.
 
 ARM has other conflicts where functions are added in the same place
 by 3.19-rc and 3.20 patches.  These are not large though, and entirely
 within KVM.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull KVM update from Paolo Bonzini:
 "Fairly small update, but there are some interesting new features.

  Common:
     Optional support for adding a small amount of polling on each HLT
     instruction executed in the guest (or equivalent for other
     architectures).  This can improve latency up to 50% on some
     scenarios (e.g. O_DSYNC writes or TCP_RR netperf tests).  This
     also has to be enabled manually for now, but the plan is to
     auto-tune this in the future.

  ARM/ARM64:
     The highlights are support for GICv3 emulation and dirty page
     tracking

  s390:
     Several optimizations and bugfixes.  Also a first: a feature
     exposed by KVM (UUID and long guest name in /proc/sysinfo) before
     it is available in IBM's hypervisor! :)

  MIPS:
     Bugfixes.

  x86:
     Support for PML (page modification logging, a new feature in
     Broadwell Xeons that speeds up dirty page tracking), nested
     virtualization improvements (nested APICv---a nice optimization),
     usual round of emulation fixes.

     There is also a new option to reduce latency of the TSC deadline
     timer in the guest; this needs to be tuned manually.

     Some commits are common between this pull and Catalin's; I see you
     have already included his tree.

  Powerpc:
     Nothing yet.

     The KVM/PPC changes will come in through the PPC maintainers,
     because I haven't received them yet and I might end up being
     offline for some part of next week"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (130 commits)
  KVM: ia64: drop kvm.h from installed user headers
  KVM: x86: fix build with !CONFIG_SMP
  KVM: x86: emulate: correct page fault error code for NoWrite instructions
  KVM: Disable compat ioctl for s390
  KVM: s390: add cpu model support
  KVM: s390: use facilities and cpu_id per KVM
  KVM: s390/CPACF: Choose crypto control block format
  s390/kernel: Update /proc/sysinfo file with Extended Name and UUID
  KVM: s390: reenable LPP facility
  KVM: s390: floating irqs: fix user triggerable endless loop
  kvm: add halt_poll_ns module parameter
  kvm: remove KVM_MMIO_SIZE
  KVM: MIPS: Don't leak FPU/DSP to guest
  KVM: MIPS: Disable HTW while in guest
  KVM: nVMX: Enable nested posted interrupt processing
  KVM: nVMX: Enable nested virtual interrupt delivery
  KVM: nVMX: Enable nested apic register virtualization
  KVM: nVMX: Make nested control MSRs per-cpu
  KVM: nVMX: Enable nested virtualize x2apic mode
  KVM: nVMX: Prepare for using hardware MSR bitmap
  ...
2015-02-13 09:55:09 -08:00
Andrea Arcangeli 0664e57ff0 mm: gup: kvm use get_user_pages_unlocked
Use the more generic get_user_pages_unlocked which has the additional
benefit of passing FAULT_FLAG_ALLOW_RETRY at the very first page fault
(which allows the first page fault in an unmapped area to be always able
to block indefinitely by being allowed to release the mmap_sem).

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: Andres Lagar-Cavilla <andreslc@google.com>
Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Peter Feiner <pfeiner@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-11 17:06:05 -08:00
Christian Borntraeger de8e5d7440 KVM: Disable compat ioctl for s390
We never had a 31bit QEMU/kuli running. We would need to review several
ioctls to check if this creates holes, bugs or whatever to make it work.
Lets just disable compat support for KVM on s390.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
2015-02-09 12:44:14 +01:00
Paolo Bonzini f781951299 kvm: add halt_poll_ns module parameter
This patch introduces a new module parameter for the KVM module; when it
is present, KVM attempts a bit of polling on every HLT before scheduling
itself out via kvm_vcpu_block.

This parameter helps a lot for latency-bound workloads---in particular
I tested it with O_DSYNC writes with a battery-backed disk in the host.
In this case, writes are fast (because the data doesn't have to go all
the way to the platters) but they cannot be merged by either the host or
the guest.  KVM's performance here is usually around 30% of bare metal,
or 50% if you use cache=directsync or cache=writethrough (these
parameters avoid that the guest sends pointless flush requests, and
at the same time they are not slow because of the battery-backed cache).
The bad performance happens because on every halt the host CPU decides
to halt itself too.  When the interrupt comes, the vCPU thread is then
migrated to a new physical CPU, and in general the latency is horrible
because the vCPU thread has to be scheduled back in.

With this patch performance reaches 60-65% of bare metal and, more
important, 99% of what you get if you use idle=poll in the guest.  This
means that the tunable gets rid of this particular bottleneck, and more
work can be done to improve performance in the kernel or QEMU.

Of course there is some price to pay; every time an otherwise idle vCPUs
is interrupted by an interrupt, it will poll unnecessarily and thus
impose a little load on the host.  The above results were obtained with
a mostly random value of the parameter (500000), and the load was around
1.5-2.5% CPU usage on one of the host's core for each idle guest vCPU.

The patch also adds a new stat, /sys/kernel/debug/kvm/halt_successful_poll,
that can be used to tune the parameter.  It counts how many HLT
instructions received an interrupt during the polling period; each
successful poll avoids that Linux schedules the VCPU thread out and back
in, and may also avoid a likely trip to C1 and back for the physical CPU.

While the VM is idle, a Linux 4 VCPU VM halts around 10 times per second.
Of these halts, almost all are failed polls.  During the benchmark,
instead, basically all halts end within the polling period, except a more
or less constant stream of 50 per second coming from vCPUs that are not
running the benchmark.  The wasted time is thus very low.  Things may
be slightly different for Windows VMs, which have a ~10 ms timer tick.

The effect is also visible on Marcelo's recently-introduced latency
test for the TSC deadline timer.  Though of course a non-RT kernel has
awful latency bounds, the latency of the timer is around 8000-10000 clock
cycles compared to 20000-120000 without setting halt_poll_ns.  For the TSC
deadline timer, thus, the effect is both a smaller average latency and
a smaller variance.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-02-06 13:08:37 +01:00
Kai Huang 3b0f1d01e5 KVM: Rename kvm_arch_mmu_write_protect_pt_masked to be more generic for log dirty
We don't have to write protect guest memory for dirty logging if architecture
supports hardware dirty logging, such as PML on VMX, so rename it to be more
generic.

Signed-off-by: Kai Huang <kai.huang@linux.intel.com>
Reviewed-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-01-29 15:30:38 +01:00
Tiejun Chen b0165f1b41 kvm: update_memslots: clean flags for invalid memslots
Indeed, any invalid memslots should be new->npages = 0,
new->base_gfn = 0 and new->flags = 0 at the same time.

Signed-off-by: Tiejun Chen <tiejun.chen@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-01-27 21:31:44 +01:00
Mario Smarduch ba0513b5b8 KVM: Add generic support for dirty page logging
kvm_get_dirty_log() provides generic handling of dirty bitmap, currently reused
by several architectures. Building on that we intrdoduce
kvm_get_dirty_log_protect() adding write protection to mark these pages dirty
for future write access, before next KVM_GET_DIRTY_LOG ioctl call from user
space.

Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Mario Smarduch <m.smarduch@samsung.com>
2015-01-16 14:40:14 +01:00
Mario Smarduch a6d5101661 KVM: Add architecture-defined TLB flush support
Allow architectures to override the generic kvm_flush_remote_tlbs()
function via HAVE_KVM_ARCH_TLB_FLUSH_ALL. ARMv7 will need this to
provide its own TLB flush interface.

Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Mario Smarduch <m.smarduch@samsung.com>
2015-01-16 14:40:14 +01:00
Wincy Van ff651cb613 KVM: nVMX: Add nested msr load/restore algorithm
Several hypervisors need MSR auto load/restore feature.
We read MSRs from VM-entry MSR load area which specified by L1,
and load them via kvm_set_msr in the nested entry.
When nested exit occurs, we get MSRs via kvm_get_msr, writing
them to L1`s MSR store area. After this, we read MSRs from VM-exit
MSR load area, and load them via kvm_set_msr.

Signed-off-by: Wincy Van <fanwenyi0529@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-01-08 22:45:14 +01:00
Paolo Bonzini dbaff30940 kvm: warn on more invariant breakage
Modifying a non-existent slot is not allowed.  Also check that the
first loop doesn't move a deleted slot beyond the used part of
the mslots array.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-12-28 10:01:25 +01:00
Paolo Bonzini efbeec7098 kvm: fix sorting of memslots with base_gfn == 0
Before commit 0e60b0799f (kvm: change memslot sorting rule from size
to GFN, 2014-12-01), the memslots' sorting key was npages, meaning
that a valid memslot couldn't have its sorting key equal to zero.
On the other hand, a valid memslot can have base_gfn == 0, and invalid
memslots are identified by base_gfn == npages == 0.

Because of this, commit 0e60b0799f broke the invariant that invalid
memslots are at the end of the mslots array.  When a memslot with
base_gfn == 0 was created, any invalid memslot before it were left
in place.

This can be fixed by changing the insertion to use a ">=" comparison
instead of "<=", but some care is needed to avoid breaking the case
of deleting a memslot; see the comment in update_memslots.

Thanks to Tiejun Chen for posting an initial patch for this bug.

Reported-by: Jamie Heilman <jamie@audible.transient.net>
Reported-by: Andy Lutomirski <luto@amacapital.net>
Tested-by: Jamie Heilman <jamie@audible.transient.net>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-12-28 10:01:17 +01:00
Paolo Bonzini 333bce5aac Second round of changes for KVM for arm/arm64 for v3.19; fixes reboot
problems, clarifies VCPU init, and fixes a regression concerning the
 VGIC init flow.
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Merge tag 'kvm-arm-for-3.19-take2' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

Second round of changes for KVM for arm/arm64 for v3.19; fixes reboot
problems, clarifies VCPU init, and fixes a regression concerning the
VGIC init flow.

Conflicts:
	arch/ia64/kvm/kvm-ia64.c [deleted in HEAD and modified in kvmarm]
2014-12-15 13:06:40 +01:00
Christian Borntraeger 7a72f7a140 KVM: track pid for VCPU only on KVM_RUN ioctl
We currently track the pid of the task that runs the VCPU in vcpu_load.
If a yield to that VCPU is triggered while the PID of the wrong thread
is active, the wrong thread might receive a yield, but this will most
likely not help the executing thread at all.  Instead, if we only track
the pid on the KVM_RUN ioctl, there are two possibilities:

1) the thread that did a non-KVM_RUN ioctl is holding a mutex that
the VCPU thread is waiting for.  In this case, the VCPU thread is not
runnable, but we also do not do a wrong yield.

2) the thread that did a non-KVM_RUN ioctl is sleeping, or doing
something that does not block the VCPU thread.  In this case, the
VCPU thread can receive the directed yield correctly.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
CC: Rik van Riel <riel@redhat.com>
CC: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
CC: Michael Mueller <mimu@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-12-04 15:29:13 +01:00
David Hildenbrand eed6e79d73 KVM: don't check for PF_VCPU when yielding
kvm_enter_guest() has to be called with preemption disabled and will
set PF_VCPU.  Current code takes PF_VCPU as a hint that the VCPU thread
is running and therefore needs no yield.

However, the check on PF_VCPU is wrong on s390, where preemption has
to stay enabled in order to correctly process page faults.  Thus,
s390 reenables preemption and starts to execute the guest.  The thread
might be scheduled out between kvm_enter_guest() and kvm_exit_guest(),
resulting in PF_VCPU being set but not being run.  When this happens,
the opportunity for directed yield is missed.

However, this check is done already in kvm_vcpu_on_spin before calling
kvm_vcpu_yield_loop:

        if (!ACCESS_ONCE(vcpu->preempted))
                continue;

so the check on PF_VCPU is superfluous in general, and this patch
removes it.

Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-12-04 15:29:12 +01:00
Igor Mammedov 9c1a5d3878 kvm: optimize GFN to memslot lookup with large slots amount
Current linear search doesn't scale well when
large amount of memslots is used and looked up slot
is not in the beginning memslots array.
Taking in account that memslots don't overlap, it's
possible to switch sorting order of memslots array from
'npages' to 'base_gfn' and use binary search for
memslot lookup by GFN.

As result of switching to binary search lookup times
are reduced with large amount of memslots.

Following is a table of search_memslot() cycles
during WS2008R2 guest boot.

                         boot,          boot + ~10 min
                         mostly same    of using it,
                         slot lookup    randomized lookup
                max      average        average
                cycles   cycles         cycles

13 slots      : 1450       28           30

13 slots      : 1400       30           40
binary search

117 slots     : 13000      30           460

117 slots     : 2000       35           180
binary search

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-12-04 15:29:11 +01:00
Igor Mammedov 0e60b0799f kvm: change memslot sorting rule from size to GFN
it will allow to use binary search for GFN -> memslot
lookups, reducing lookup cost with large slots amount.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-12-04 15:29:11 +01:00
Igor Mammedov 7f379cff11 kvm: update_memslots: drop not needed check for the same slot
UP/DOWN shift loops will shift array in needed
direction and stop at place where new slot should
be placed regardless of old slot size.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-12-04 15:29:09 +01:00
Igor Mammedov 5a38b6e6b4 kvm: update_memslots: drop not needed check for the same number of pages
if number of pages haven't changed sorting algorithm
will do nothing, so there is no need to do extra check
to avoid entering sorting logic.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-12-04 15:29:09 +01:00
Ard Biesheuvel bf4bea8e9a kvm: fix kvm_is_mmio_pfn() and rename to kvm_is_reserved_pfn()
This reverts commit 85c8555ff0 ("KVM: check for !is_zero_pfn() in
kvm_is_mmio_pfn()") and renames the function to kvm_is_reserved_pfn.

The problem being addressed by the patch above was that some ARM code
based the memory mapping attributes of a pfn on the return value of
kvm_is_mmio_pfn(), whose name indeed suggests that such pfns should
be mapped as device memory.

However, kvm_is_mmio_pfn() doesn't do quite what it says on the tin,
and the existing non-ARM users were already using it in a way which
suggests that its name should probably have been 'kvm_is_reserved_pfn'
from the beginning, e.g., whether or not to call get_page/put_page on
it etc. This means that returning false for the zero page is a mistake
and the patch above should be reverted.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2014-11-25 13:57:26 +00:00
Radim Krčmář c274e03af7 kvm: x86: move assigned-dev.c and iommu.c to arch/x86/
Now that ia64 is gone, we can hide deprecated device assignment in x86.

Notable changes:
 - kvm_vm_ioctl_assigned_device() was moved to x86/kvm_arch_vm_ioctl()

The easy parts were removed from generic kvm code, remaining
 - kvm_iommu_(un)map_pages() would require new code to be moved
 - struct kvm_assigned_dev_kernel depends on struct kvm_irq_ack_notifier

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-23 18:33:36 +01:00
Paolo Bonzini 6ef768fac9 kvm: x86: move ioapic.c and irq_comm.c back to arch/x86/
ia64 does not need them anymore.  Ack notifiers become x86-specific
too.

Suggested-by: Gleb Natapov <gleb@kernel.org>
Reviewed-by: Radim Krcmar <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-21 18:02:37 +01:00
Paolo Bonzini 5cc1502799 kvm: simplify update_memslots invocation
The update_memslots invocation is only needed in one case.  Make
the code clearer by moving it to __kvm_set_memory_region, and
removing the wrapper around insert_memslot.

Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-17 12:16:13 +01:00
Paolo Bonzini f2a8103651 kvm: commonize allocation of the new memory slots
The two kmemdup invocations can be unified.  I find that the new
placement of the comment makes it easier to see what happens.

Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-17 12:15:34 +01:00
Paolo Bonzini 8593176c67 kvm: memslots: track id_to_index changes during the insertion sort
This completes the optimization from the previous patch, by
removing the KVM_MEM_SLOTS_NUM-iteration loop from insert_memslot.

Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-14 15:40:17 +01:00
Igor Mammedov 063584d443 kvm: memslots: replace heap sort with an insertion sort pass
memslots is a sorted array.  When a slot is changed, heapsort (lib/sort.c)
would take O(n log n) time to update it; an optimized insertion sort will
only cost O(n) on an array with just one item out of order.

Replace sort() with a custom sort that takes advantage of memslots usage
pattern and the known position of the changed slot.

performance change of 128 memslots insertions with gradually increasing
size (the worst case):

      heap sort   custom sort
max:  249747      2500 cycles

with custom sort alg taking ~98% less then original
update time.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-14 10:49:04 +01:00
Dominik Dingel 02d5d55b7e KVM: trivial fix comment regarding __kvm_set_memory_region
commit 72dc67a696 ("KVM: remove the usage of the mmap_sem for the protection of the memory slots.")
changed the lock which will be taken. This should be reflected in the function
commentary.

Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-03 12:07:30 +01:00
Wanpeng Li 571ee1b685 kvm: vfio: fix unregister kvm_device_ops of vfio
After commit 80ce163 (KVM: VFIO: register kvm_device_ops dynamically),
kvm_device_ops of vfio can be registered dynamically. Commit 3c3c29fd
(kvm-vfio: do not use module_init) move the dynamic register invoked by
kvm_init in order to fix broke unloading of the kvm module. However,
kvm_device_ops of vfio is unregistered after rmmod kvm-intel module
which lead to device type collision detection warning after kvm-intel
module reinsmod.

    WARNING: CPU: 1 PID: 10358 at /root/cathy/kvm/arch/x86/kvm/../../../virt/kvm/kvm_main.c:3289 kvm_init+0x234/0x282 [kvm]()
    Modules linked in: kvm_intel(O+) kvm(O) nfsv3 nfs_acl auth_rpcgss oid_registry nfsv4 dns_resolver nfs fscache lockd sunrpc pci_stub bridge stp llc autofs4 8021q cpufreq_ondemand ipv6 joydev microcode pcspkr igb i2c_algo_bit ehci_pci ehci_hcd e1000e i2c_i801 ixgbe ptp pps_core hwmon mdio tpm_tis tpm ipmi_si ipmi_msghandler acpi_cpufreq isci libsas scsi_transport_sas button dm_mirror dm_region_hash dm_log dm_mod [last unloaded: kvm_intel]
    CPU: 1 PID: 10358 Comm: insmod Tainted: G        W  O   3.17.0-rc1 #2
    Hardware name: Intel Corporation S2600CP/S2600CP, BIOS RMLSDP.86I.00.29.D696.1311111329 11/11/2013
     0000000000000cd9 ffff880ff08cfd18 ffffffff814a61d9 0000000000000cd9
     0000000000000000 ffff880ff08cfd58 ffffffff810417b7 ffff880ff08cfd48
     ffffffffa045bcac ffffffffa049c420 0000000000000040 00000000000000ff
    Call Trace:
     [<ffffffff814a61d9>] dump_stack+0x49/0x60
     [<ffffffff810417b7>] warn_slowpath_common+0x7c/0x96
     [<ffffffffa045bcac>] ? kvm_init+0x234/0x282 [kvm]
     [<ffffffff810417e6>] warn_slowpath_null+0x15/0x17
     [<ffffffffa045bcac>] kvm_init+0x234/0x282 [kvm]
     [<ffffffffa016e995>] vmx_init+0x1bf/0x42a [kvm_intel]
     [<ffffffffa016e7d6>] ? vmx_check_processor_compat+0x64/0x64 [kvm_intel]
     [<ffffffff810002ab>] do_one_initcall+0xe3/0x170
     [<ffffffff811168a9>] ? __vunmap+0xad/0xb8
     [<ffffffff8109c58f>] do_init_module+0x2b/0x174
     [<ffffffff8109d414>] load_module+0x43e/0x569
     [<ffffffff8109c6d8>] ? do_init_module+0x174/0x174
     [<ffffffff8109c75a>] ? copy_module_from_user+0x39/0x82
     [<ffffffff8109b7dd>] ? module_sect_show+0x20/0x20
     [<ffffffff8109d65f>] SyS_init_module+0x54/0x81
     [<ffffffff814a9a12>] system_call_fastpath+0x16/0x1b
    ---[ end trace 0626f4a3ddea56f3 ]---

The bug can be reproduced by:

    rmmod kvm_intel.ko
    insmod kvm_intel.ko

without rmmod/insmod kvm.ko
This patch fixes the bug by unregistering kvm_device_ops of vfio when the
kvm-intel module is removed.

Reported-by: Liu Rongrong <rongrongx.liu@intel.com>
Fixes: 3c3c29fd0d
Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-10-24 13:30:47 +02:00
Linus Torvalds e4e65676f2 Fixes and features for 3.18.
Apart from the usual cleanups, here is the summary of new features:
 
 - s390 moves closer towards host large page support
 
 - PowerPC has improved support for debugging (both inside the guest and
   via gdbstub) and support for e6500 processors
 
 - ARM/ARM64 support read-only memory (which is necessary to put firmware
   in emulated NOR flash)
 
 - x86 has the usual emulator fixes and nested virtualization improvements
   (including improved Windows support on Intel and Jailhouse hypervisor
   support on AMD), adaptive PLE which helps overcommitting of huge guests.
   Also included are some patches that make KVM more friendly to memory
   hot-unplug, and fixes for rare caching bugs.
 
 Two patches have trivial mm/ parts that were acked by Rik and Andrew.
 
 Note: I will soon switch to a subkey for signing purposes.  To verify
 future signed pull requests from me, please update my key with
 "gpg --recv-keys 9B4D86F2".  You should see 3 new subkeys---the
 one for signing will be a 2048-bit RSA key, 4E6B09D7.
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v2.0.22 (GNU/Linux)
 
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 WpExZSUFL2+4CztpdGIsek1BeJYHmqv3+c5S+WvaWVA1aqh2R7FT1D1ErBLjgLQq
 lq23IOr+XxmC3dXQUEEk+TlD+283UzypzEG4l4UD3JYg79fE3UrXAz82SeyewJDY
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 sFo1tSPTVgRs8QFYUZ2fJUPBAmUVddsgqh2K9d0NftGTq7b8YszaCsfFrs2/Y4MU
 YxssWEhxsfszerCu12bbAJrv6JBZYQ7TwGvI9L7P0iFU6IVw/djmukU4AkM9/e91
 YS/cue/PN+9Pn2ccXzL9J7xRtZb8FsOuRsCXTCmbOwDkLmrKPDBN2t3RUbeF+Eam
 ABrpWnLKX13kZSo4LKU+/niarzmPMp7odQfHVdr8ea0fiYLp4iN8puA20WaSPIgd
 CLvm+RAvXe5Lm91L4mpFotJ2uFyK6QlIYJV4FsgeWv/0D0qppWQi0Utb/aCNHCgy
 z8MyUMD48y7EpoQrFYr/7cddXIu0/NegnM8I1coVjIPEk4NfeebGUlCJ/V3D8wMG
 BgEfS2x6jRc5zB3hjwDr
 =iEVi
 -----END PGP SIGNATURE-----

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull KVM updates from Paolo Bonzini:
 "Fixes and features for 3.18.

  Apart from the usual cleanups, here is the summary of new features:

   - s390 moves closer towards host large page support

   - PowerPC has improved support for debugging (both inside the guest
     and via gdbstub) and support for e6500 processors

   - ARM/ARM64 support read-only memory (which is necessary to put
     firmware in emulated NOR flash)

   - x86 has the usual emulator fixes and nested virtualization
     improvements (including improved Windows support on Intel and
     Jailhouse hypervisor support on AMD), adaptive PLE which helps
     overcommitting of huge guests.  Also included are some patches that
     make KVM more friendly to memory hot-unplug, and fixes for rare
     caching bugs.

  Two patches have trivial mm/ parts that were acked by Rik and Andrew.

  Note: I will soon switch to a subkey for signing purposes"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (157 commits)
  kvm: do not handle APIC access page if in-kernel irqchip is not in use
  KVM: s390: count vcpu wakeups in stat.halt_wakeup
  KVM: s390/facilities: allow TOD-CLOCK steering facility bit
  KVM: PPC: BOOK3S: HV: CMA: Reserve cma region only in hypervisor mode
  arm/arm64: KVM: Report correct FSC for unsupported fault types
  arm/arm64: KVM: Fix VTTBR_BADDR_MASK and pgd alloc
  kvm: Fix kvm_get_page_retry_io __gup retval check
  arm/arm64: KVM: Fix set_clear_sgi_pend_reg offset
  kvm: x86: Unpin and remove kvm_arch->apic_access_page
  kvm: vmx: Implement set_apic_access_page_addr
  kvm: x86: Add request bit to reload APIC access page address
  kvm: Add arch specific mmu notifier for page invalidation
  kvm: Rename make_all_cpus_request() to kvm_make_all_cpus_request() and make it non-static
  kvm: Fix page ageing bugs
  kvm/x86/mmu: Pass gfn and level to rmapp callback.
  x86: kvm: use alternatives for VMCALL vs. VMMCALL if kernel text is read-only
  kvm: x86: use macros to compute bank MSRs
  KVM: x86: Remove debug assertion of non-PAE reserved bits
  kvm: don't take vcpu mutex for obviously invalid vcpu ioctls
  kvm: Faults which trigger IO release the mmap_sem
  ...
2014-10-08 05:27:39 -04:00
Paolo Bonzini e77d99d4a4 Changes for KVM for arm/arm64 for 3.18
This includes a bunch of changes:
  - Support read-only memory slots on arm/arm64
  - Various changes to fix Sparse warnings
  - Correctly detect write vs. read Stage-2 faults
  - Various VGIC cleanups and fixes
  - Dynamic VGIC data strcuture sizing
  - Fix SGI set_clear_pend offset bug
  - Fix VTTBR_BADDR Mask
  - Correctly report the FSC on Stage-2 faults
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Merge tag 'kvm-arm-for-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into kvm-next

Changes for KVM for arm/arm64 for 3.18

This includes a bunch of changes:
 - Support read-only memory slots on arm/arm64
 - Various changes to fix Sparse warnings
 - Correctly detect write vs. read Stage-2 faults
 - Various VGIC cleanups and fixes
 - Dynamic VGIC data strcuture sizing
 - Fix SGI set_clear_pend offset bug
 - Fix VTTBR_BADDR Mask
 - Correctly report the FSC on Stage-2 faults

Conflicts:
	virt/kvm/eventfd.c
	[duplicate, different patch where the kvm-arm version broke x86.
	 The kvm tree instead has the right one]
2014-09-27 11:03:33 +02:00
Andres Lagar-Cavilla bb0ca6acd4 kvm: Fix kvm_get_page_retry_io __gup retval check
Confusion around -EBUSY and zero (inside a BUG_ON no less).

Reported-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andres Lagar-Cavilla <andreslc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-26 10:21:29 +02:00
Tang Chen fe71557afb kvm: Add arch specific mmu notifier for page invalidation
This will be used to let the guest run while the APIC access page is
not pinned.  Because subsequent patches will fill in the function
for x86, place the (still empty) x86 implementation in the x86.c file
instead of adding an inline function in kvm_host.h.

Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-24 14:07:59 +02:00
Tang Chen 445b823695 kvm: Rename make_all_cpus_request() to kvm_make_all_cpus_request() and make it non-static
Different architectures need different requests, and in fact we
will use this function in architecture-specific code later. This
will be outside kvm_main.c, so make it non-static and rename it to
kvm_make_all_cpus_request().

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-24 14:07:59 +02:00
Andres Lagar-Cavilla 5712846808 kvm: Fix page ageing bugs
1. We were calling clear_flush_young_notify in unmap_one, but we are
within an mmu notifier invalidate range scope. The spte exists no more
(due to range_start) and the accessed bit info has already been
propagated (due to kvm_pfn_set_accessed). Simply call
clear_flush_young.

2. We clear_flush_young on a primary MMU PMD, but this may be mapped
as a collection of PTEs by the secondary MMU (e.g. during log-dirty).
This required expanding the interface of the clear_flush_young mmu
notifier, so a lot of code has been trivially touched.

3. In the absence of shadow_accessed_mask (e.g. EPT A bit), we emulate
the access bit by blowing the spte. This requires proper synchronizing
with MMU notifier consumers, like every other removal of spte's does.

Signed-off-by: Andres Lagar-Cavilla <andreslc@google.com>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-24 14:07:58 +02:00
David Matlack 2ea75be321 kvm: don't take vcpu mutex for obviously invalid vcpu ioctls
vcpu ioctls can hang the calling thread if issued while a vcpu is running.
However, invalid ioctls can happen when userspace tries to probe the kind
of file descriptors (e.g. isatty() calls ioctl(TCGETS)); in that case,
we know the ioctl is going to be rejected as invalid anyway and we can
fail before trying to take the vcpu mutex.

This patch does not change functionality, it just makes invalid ioctls
fail faster.

Cc: stable@vger.kernel.org
Signed-off-by: David Matlack <dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-24 14:07:55 +02:00
Andres Lagar-Cavilla 234b239bea kvm: Faults which trigger IO release the mmap_sem
When KVM handles a tdp fault it uses FOLL_NOWAIT. If the guest memory
has been swapped out or is behind a filemap, this will trigger async
readahead and return immediately. The rationale is that KVM will kick
back the guest with an "async page fault" and allow for some other
guest process to take over.

If async PFs are enabled the fault is retried asap from an async
workqueue. If not, it's retried immediately in the same code path. In
either case the retry will not relinquish the mmap semaphore and will
block on the IO. This is a bad thing, as other mmap semaphore users
now stall as a function of swap or filemap latency.

This patch ensures both the regular and async PF path re-enter the
fault allowing for the mmap semaphore to be relinquished in the case
of IO wait.

Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Andres Lagar-Cavilla <andreslc@google.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-24 14:07:54 +02:00
Paolo Bonzini 3c3c29fd0d kvm-vfio: do not use module_init
/me got confused between the kernel and QEMU.  In the kernel, you can
only have one module_init function, and it will prevent unloading the
module unless you also have the corresponding module_exit function.

So, commit 80ce163972 (KVM: VFIO: register kvm_device_ops dynamically,
2014-09-02) broke unloading of the kvm module, by adding a module_init
function and no module_exit.

Repair it by making kvm_vfio_ops_init weak, and checking it in
kvm_init.

Cc: Will Deacon <will.deacon@arm.com>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: Alex Williamson <Alex.Williamson@redhat.com>
Fixes: 80ce163972
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-24 14:06:36 +02:00
Sam Bobroff 27fbe64bfa KVM: correct null pid check in kvm_vcpu_yield_to()
Correct a simple mistake of checking the wrong variable
before a dereference, resulting in the dereference not being
properly protected by rcu_dereference().

Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-22 13:21:29 +02:00
Christoffer Dall a875dafcf9 Merge remote-tracking branch 'kvm/next' into queue
Conflicts:
	arch/arm64/include/asm/kvm_host.h
	virt/kvm/arm/vgic.c
2014-09-18 18:15:32 -07:00
Will Deacon 80ce163972 KVM: VFIO: register kvm_device_ops dynamically
Now that we have a dynamic means to register kvm_device_ops, use that
for the VFIO kvm device, instead of relying on the static table.

This is achieved by a module_init call to register the ops with KVM.

Cc: Gleb Natapov <gleb@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Alex Williamson <Alex.Williamson@redhat.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-17 13:10:10 +02:00
Cornelia Huck 84877d9333 KVM: s390: register flic ops dynamically
Using the new kvm_register_device_ops() interface makes us get rid of
an #ifdef in common code.

Cc: Gleb Natapov <gleb@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-17 13:10:09 +02:00
Will Deacon c06a841bf3 KVM: ARM: vgic: register kvm_device_ops dynamically
Now that we have a dynamic means to register kvm_device_ops, use that
for the ARM VGIC, instead of relying on the static table.

Cc: Gleb Natapov <gleb@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-17 13:10:09 +02:00
Will Deacon d60eacb070 KVM: device: add simple registration mechanism for kvm_device_ops
kvm_ioctl_create_device currently has knowledge of all the device types
and their associated ops. This is fairly inflexible when adding support
for new in-kernel device emulations, so move what we currently have out
into a table, which can support dynamic registration of ops by new
drivers for virtual hardware.

Cc: Alex Williamson <Alex.Williamson@redhat.com>
Cc: Alex Graf <agraf@suse.de>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-17 13:10:08 +02:00
Ard Biesheuvel 85c8555ff0 KVM: check for !is_zero_pfn() in kvm_is_mmio_pfn()
Read-only memory ranges may be backed by the zero page, so avoid
misidentifying it a a MMIO pfn.

This fixes another issue I identified when testing QEMU+KVM_UEFI, where
a read to an uninitialized emulated NOR flash brought in the zero page,
but mapped as a read-write device region, because kvm_is_mmio_pfn()
misidentifies it as a MMIO pfn due to its PG_reserved bit being set.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Fixes: b88657674d ("ARM: KVM: user_mem_abort: support stage 2 MMIO page mapping")
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-14 16:26:05 +02:00
Christian Borntraeger f2a2516088 KVM: remove redundant assignments in __kvm_set_memory_region
__kvm_set_memory_region sets r to EINVAL very early.
Doing it again is not necessary. The same is true later on, where
r is assigned -ENOMEM twice.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-05 12:01:15 +02:00
Christian Borntraeger a13f533b2f KVM: remove redundant assigment of return value in kvm_dev_ioctl
The first statement of kvm_dev_ioctl is
        long r = -EINVAL;

No need to reassign the same value.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-05 12:01:15 +02:00
Christian Borntraeger 3465611318 KVM: remove redundant check of in_spin_loop
The expression `vcpu->spin_loop.in_spin_loop' is always true,
because it is evaluated only when the condition
`!vcpu->spin_loop.in_spin_loop' is false.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-05 12:01:14 +02:00
David Matlack ee3d1570b5 kvm: fix potentially corrupt mmio cache
vcpu exits and memslot mutations can run concurrently as long as the
vcpu does not aquire the slots mutex. Thus it is theoretically possible
for memslots to change underneath a vcpu that is handling an exit.

If we increment the memslot generation number again after
synchronize_srcu_expedited(), vcpus can safely cache memslot generation
without maintaining a single rcu_dereference through an entire vm exit.
And much of the x86/kvm code does not maintain a single rcu_dereference
of the current memslots during each exit.

We can prevent the following case:

   vcpu (CPU 0)                             | thread (CPU 1)
--------------------------------------------+--------------------------
1  vm exit                                  |
2  srcu_read_unlock(&kvm->srcu)             |
3  decide to cache something based on       |
     old memslots                           |
4                                           | change memslots
                                            | (increments generation)
5                                           | synchronize_srcu(&kvm->srcu);
6  retrieve generation # from new memslots  |
7  tag cache with new memslot generation    |
8  srcu_read_unlock(&kvm->srcu)             |
...                                         |
   <action based on cache occurs even       |
    though the caching decision was based   |
    on the old memslots>                    |
...                                         |
   <action *continues* to occur until next  |
    memslot generation change, which may    |
    be never>                               |
                                            |

By incrementing the generation after synchronizing with kvm->srcu readers,
we ensure that the generation retrieved in (6) will become invalid soon
after (8).

Keeping the existing increment is not strictly necessary, but we
do keep it and just move it for consistency from update_memslots to
install_new_memslots.  It invalidates old cached MMIOs immediately,
instead of having to wait for the end of synchronize_srcu_expedited,
which makes the code more clearly correct in case CPU 1 is preempted
right after synchronize_srcu() returns.

To avoid halving the generation space in SPTEs, always presume that the
low bit of the generation is zero when reconstructing a generation number
out of an SPTE.  This effectively disables MMIO caching in SPTEs during
the call to synchronize_srcu_expedited.  Using the low bit this way is
somewhat like a seqcount---where the protected thing is a cache, and
instead of retrying we can simply punt if we observe the low bit to be 1.

Cc: stable@vger.kernel.org
Signed-off-by: David Matlack <dmatlack@google.com>
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Reviewed-by: David Matlack <dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-03 10:03:41 +02:00
Paolo Bonzini 00f034a12f KVM: do not bias the generation number in kvm_current_mmio_generation
The next patch will give a meaning (a la seqcount) to the low bit of the
generation number.  Ensure that it matches between kvm->memslots->generation
and kvm_current_mmio_generation().

Cc: stable@vger.kernel.org
Reviewed-by: David Matlack <dmatlack@google.com>
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-03 10:03:35 +02:00
Radim Krčmář 13a34e067e KVM: remove garbage arg to *hardware_{en,dis}able
In the beggining was on_each_cpu(), which required an unused argument to
kvm_arch_ops.hardware_{en,dis}able, but this was soon forgotten.

Remove unnecessary arguments that stem from this.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-08-29 16:35:55 +02:00
Christoffer Dall 0f8a4de3e0 KVM: Unconditionally export KVM_CAP_READONLY_MEM
The idea between capabilities and the KVM_CHECK_EXTENSION ioctl is that
userspace can, at run-time, determine if a feature is supported or not.
This allows KVM to being supporting a new feature with a new kernel
version without any need to update user space.  Unfortunately, since the
definition of KVM_CAP_READONLY_MEM was guarded by #ifdef
__KVM_HAVE_READONLY_MEM, such discovery still required a user space
update.

Therefore, unconditionally export KVM_CAP_READONLY_MEM and change the
in-kernel conditional to rely on __KVM_HAVE_READONLY_MEM.

Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-08-29 13:47:04 +02:00