Граф коммитов

92 Коммитов

Автор SHA1 Сообщение Дата
Wanpeng Li e332b55fe7 KVM: eventfd: Fix false positive RCU usage warning
The splat below can be seen when running kvm-unit-test:

     =============================
     WARNING: suspicious RCU usage
     5.18.0-rc7 #5 Tainted: G          IOE
     -----------------------------
     /home/kernel/linux/arch/x86/kvm/../../../virt/kvm/eventfd.c:80 RCU-list traversed in non-reader section!!

     other info that might help us debug this:

     rcu_scheduler_active = 2, debug_locks = 1
     4 locks held by qemu-system-x86/35124:
      #0: ffff9725391d80b8 (&vcpu->mutex){+.+.}-{4:4}, at: kvm_vcpu_ioctl+0x77/0x710 [kvm]
      #1: ffffbd25cfb2a0b8 (&kvm->srcu){....}-{0:0}, at: vcpu_enter_guest+0xdeb/0x1900 [kvm]
      #2: ffffbd25cfb2b920 (&kvm->irq_srcu){....}-{0:0}, at: kvm_hv_notify_acked_sint+0x79/0x1e0 [kvm]
      #3: ffffbd25cfb2b920 (&kvm->irq_srcu){....}-{0:0}, at: irqfd_resampler_ack+0x5/0x110 [kvm]

     stack backtrace:
     CPU: 2 PID: 35124 Comm: qemu-system-x86 Tainted: G          IOE     5.18.0-rc7 #5
     Call Trace:
      <TASK>
      dump_stack_lvl+0x6c/0x9b
      irqfd_resampler_ack+0xfd/0x110 [kvm]
      kvm_notify_acked_gsi+0x32/0x90 [kvm]
      kvm_hv_notify_acked_sint+0xc5/0x1e0 [kvm]
      kvm_hv_set_msr_common+0xec1/0x1160 [kvm]
      kvm_set_msr_common+0x7c3/0xf60 [kvm]
      vmx_set_msr+0x394/0x1240 [kvm_intel]
      kvm_set_msr_ignored_check+0x86/0x200 [kvm]
      kvm_emulate_wrmsr+0x4f/0x1f0 [kvm]
      vmx_handle_exit+0x6fb/0x7e0 [kvm_intel]
      vcpu_enter_guest+0xe5a/0x1900 [kvm]
      kvm_arch_vcpu_ioctl_run+0x16e/0xac0 [kvm]
      kvm_vcpu_ioctl+0x279/0x710 [kvm]
      __x64_sys_ioctl+0x83/0xb0
      do_syscall_64+0x3b/0x90
      entry_SYSCALL_64_after_hwframe+0x44/0xae

resampler-list is protected by irq_srcu (see kvm_irqfd_assign), so fix
the false positive by using list_for_each_entry_srcu().

Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Message-Id: <1652950153-12489-1-git-send-email-wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-05-20 09:10:33 -04:00
Hou Wenlong 6a0c61703e KVM: eventfd: Fix false positive RCU usage warning
Fix the following false positive warning:
 =============================
 WARNING: suspicious RCU usage
 5.16.0-rc4+ #57 Not tainted
 -----------------------------
 arch/x86/kvm/../../../virt/kvm/eventfd.c:484 RCU-list traversed in non-reader section!!

 other info that might help us debug this:

 rcu_scheduler_active = 2, debug_locks = 1
 3 locks held by fc_vcpu 0/330:
  #0: ffff8884835fc0b0 (&vcpu->mutex){+.+.}-{3:3}, at: kvm_vcpu_ioctl+0x88/0x6f0 [kvm]
  #1: ffffc90004c0bb68 (&kvm->srcu){....}-{0:0}, at: vcpu_enter_guest+0x600/0x1860 [kvm]
  #2: ffffc90004c0c1d0 (&kvm->irq_srcu){....}-{0:0}, at: kvm_notify_acked_irq+0x36/0x180 [kvm]

 stack backtrace:
 CPU: 26 PID: 330 Comm: fc_vcpu 0 Not tainted 5.16.0-rc4+
 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
 Call Trace:
  <TASK>
  dump_stack_lvl+0x44/0x57
  kvm_notify_acked_gsi+0x6b/0x70 [kvm]
  kvm_notify_acked_irq+0x8d/0x180 [kvm]
  kvm_ioapic_update_eoi+0x92/0x240 [kvm]
  kvm_apic_set_eoi_accelerated+0x2a/0xe0 [kvm]
  handle_apic_eoi_induced+0x3d/0x60 [kvm_intel]
  vmx_handle_exit+0x19c/0x6a0 [kvm_intel]
  vcpu_enter_guest+0x66e/0x1860 [kvm]
  kvm_arch_vcpu_ioctl_run+0x438/0x7f0 [kvm]
  kvm_vcpu_ioctl+0x38a/0x6f0 [kvm]
  __x64_sys_ioctl+0x89/0xc0
  do_syscall_64+0x3a/0x90
  entry_SYSCALL_64_after_hwframe+0x44/0xae

Since kvm_unregister_irq_ack_notifier() does synchronize_srcu(&kvm->irq_srcu),
kvm->irq_ack_notifier_list is protected by kvm->irq_srcu. In fact,
kvm->irq_srcu SRCU read lock is held in kvm_notify_acked_irq(), making it
a false positive warning. So use hlist_for_each_entry_srcu() instead of
hlist_for_each_entry_rcu().

Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Hou Wenlong <houwenlong93@linux.alibaba.com>
Message-Id: <f98bac4f5052bad2c26df9ad50f7019e40434512.1643265976.git.houwenlong.hwl@antgroup.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-01-28 07:38:27 -05:00
Longpeng(Mike) 515a0c79e7 kvm: irqfd: avoid update unmodified entries of the routing
All of the irqfds would to be updated when update the irq
routing, it's too expensive if there're too many irqfds.

However we can reduce the cost by avoid some unnecessary
updates. For irqs of MSI type on X86, the update can be
saved if the msi values are not change.

The vfio migration could receives benefit from this optimi-
zaiton. The test VM has 128 vcpus and 8 VF (with 65 vectors
enabled), so the VM has more than 520 irqfds. We mesure the
cost of the vfio_msix_enable (in QEMU, it would set routing
for each irqfd) for each VF, and we can see the total cost
can be significantly reduced.

                Origin         Apply this Patch
1st             8              4
2nd             15             5
3rd             22             6
4th             24             6
5th             36             7
6th             44             7
7th             51             8
8th             58             8
Total           258ms          51ms

We're also tring to optimize the QEMU part [1], but it's still
worth to optimize the KVM to gain more benefits.

[1] https://lists.gnu.org/archive/html/qemu-devel/2021-08/msg04215.html

Signed-off-by: Longpeng(Mike) <longpeng2@huawei.com>
Message-Id: <20210827080003.2689-1-longpeng2@huawei.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-09-30 04:27:10 -04:00
David Woodhouse b59e00dd8c kvm/eventfd: Drain events from eventfd in irqfd_wakeup()
Don't allow the events to accumulate in the eventfd counter, drain them
as they are handled.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <20201027135523.646811-4-dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-11-15 09:49:11 -05:00
David Woodhouse e8dbf19508 kvm/eventfd: Use priority waitqueue to catch events before userspace
As far as I can tell, when we use posted interrupts we silently cut off
the events from userspace, if it's listening on the same eventfd that
feeds the irqfd.

I like that behaviour. Let's do it all the time, even without posted
interrupts. It makes it much easier to handle IRQ remapping invalidation
without having to constantly add/remove the fd from the userspace poll
set. We can just leave userspace polling on it, and the bypass will...
well... bypass it.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <20201026175325.585623-2-dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-11-15 09:49:10 -05:00
Yi Li 2fc4f15dac kvm/eventfd: move wildcard calculation outside loop
There is no need to calculate wildcard in each iteration
since wildcard is not changed.

Signed-off-by: Yi Li <yili@winhong.com>
Message-Id: <20200911055652.3041762-1-yili@winhong.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-09-28 07:57:08 -04:00
Ahmed S. Darwish 5c73b9a2b1 kvm/eventfd: Use sequence counter with associated spinlock
A sequence counter write side critical section must be protected by some
form of locking to serialize writers. A plain seqcount_t does not
contain the information of which lock must be held when entering a write
side critical section.

Use the new seqcount_spinlock_t data type, which allows to associate a
spinlock with the sequence counter. This enables lockdep to verify that
the spinlock used for writer serialization is held when the write side
critical section is entered.

If lockdep is disabled this lock association is compiled out and has
neither storage size nor runtime overhead.

Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Link: https://lkml.kernel.org/r/20200720155530.1173732-24-a.darwish@linutronix.de
2020-07-29 16:14:29 +02:00
Paolo Bonzini 380609445c KVM/arm64 updates for Linux 5.8:
- Move the arch-specific code into arch/arm64/kvm
 - Start the post-32bit cleanup
 - Cherry-pick a few non-invasive pre-NV patches
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Merge tag 'kvmarm-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm64 updates for Linux 5.8:

- Move the arch-specific code into arch/arm64/kvm
- Start the post-32bit cleanup
- Cherry-pick a few non-invasive pre-NV patches
2020-06-01 04:26:27 -04:00
Fuad Tabba 656012c731 KVM: Fix spelling in code comments
Fix spelling and typos (e.g., repeated words) in comments.

Signed-off-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200401140310.29701-1-tabba@google.com
2020-05-16 15:05:01 +01:00
Jason Yan c4e115f08c kvm/eventfd: remove unneeded conversion to bool
The '==' expression itself is bool, no need to convert it to bool again.
This fixes the following coccicheck warning:

virt/kvm/eventfd.c:724:38-43: WARNING: conversion to bool not needed
here

Signed-off-by: Jason Yan <yanaijie@huawei.com>
Message-Id: <20200420123805.4494-1-yanaijie@huawei.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-05-13 12:14:58 -04:00
Thomas Gleixner 775c8a3d71 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 504
Based on 1 normalized pattern(s):

  this file is free software you can redistribute it and or modify it
  under the terms of version 2 of the gnu general public license as
  published by the free software foundation this program is
  distributed in the hope that it will be useful but without any
  warranty without even the implied warranty of merchantability or
  fitness for a particular purpose see the gnu general public license
  for more details you should have received a copy of the gnu general
  public license along with this program if not write to the free
  software foundation inc 51 franklin st fifth floor boston ma 02110
  1301 usa

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 8 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081207.443595178@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-19 17:09:56 +02:00
Peter Xu 654f1f13ea kvm: Check irqchip mode before assign irqfd
When assigning kvm irqfd we didn't check the irqchip mode but we allow
KVM_IRQFD to succeed with all the irqchip modes.  However it does not
make much sense to create irqfd even without the kernel chips.  Let's
provide a arch-dependent helper to check whether a specific irqfd is
allowed by the arch.  At least for x86, it should make sense to check:

- when irqchip mode is NONE, all irqfds should be disallowed, and,

- when irqchip mode is SPLIT, irqfds that are with resamplefd should
  be disallowed.

For either of the case, previously we'll silently ignore the irq or
the irq ack event if the irqchip mode is incorrect.  However that can
cause misterious guest behaviors and it can be hard to triage.  Let's
fail KVM_IRQFD even earlier to detect these incorrect configurations.

CC: Paolo Bonzini <pbonzini@redhat.com>
CC: Radim Krčmář <rkrcmar@redhat.com>
CC: Alex Williamson <alex.williamson@redhat.com>
CC: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-05-24 21:27:12 +02:00
Sebastian Andrzej Siewior ca0488aadd kvm: don't redefine flags as something else
The function irqfd_wakeup() has flags defined as __poll_t and then it
has additional flags which is used for irqflags.

Redefine the inner flags variable as iflags so it does not shadow the
outer flags.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: kvm@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-03-28 17:28:59 +01:00
Ben Gardon b12ce36a43 kvm: Add memcg accounting to KVM allocations
There are many KVM kernel memory allocations which are tied to the life of
the VM process and should be charged to the VM process's cgroup. If the
allocations aren't tied to the process, the OOM killer will not know
that killing the process will free the associated kernel memory.
Add __GFP_ACCOUNT flags to many of the allocations which are not yet being
charged to the VM process's cgroup.

Tested:
	Ran all kvm-unit-tests on a 64 bit Haswell machine, the patch
	introduced no new failures.
	Ran a kernel memory accounting test which creates a VM to touch
	memory and then checks that the kernel memory allocated for the
	process is within certain bounds.
	With this patch we account for much more of the vmalloc and slab memory
	allocated for the VM.

There remain a few allocations which should be charged to the VM's
cgroup but are not. In they include:
        vcpu->run
        kvm->coalesced_mmio_ring
There allocations are unaccounted in this patch because they are mapped
to userspace, and accounting them to a cgroup causes problems. This
should be addressed in a future patch.

Signed-off-by: Ben Gardon <bgardon@google.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-02-20 22:48:29 +01:00
Linus Torvalds 47f7dc4b84 Miscellaneous bugfixes, plus a small patchlet related to Spectre v2.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull kvm fixes from Paolo Bonzini:
 "Miscellaneous bugfixes, plus a small patchlet related to Spectre v2"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  kvmclock: fix TSC calibration for nested guests
  KVM: VMX: Mark VMXArea with revision_id of physical CPU even when eVMCS enabled
  KVM: irqfd: fix race between EPOLLHUP and irq_bypass_register_consumer
  KVM/Eventfd: Avoid crash when assign and deassign specific eventfd in parallel.
  x86/kvmclock: set pvti_cpu0_va after enabling kvmclock
  x86/kvm/Kconfig: Ensure CRYPTO_DEV_CCP_DD state at minimum matches KVM_AMD
  kvm: nVMX: Restore exit qual for VM-entry failure due to MSR loading
  x86/kvm/vmx: don't read current->thread.{fs,gs}base of legacy tasks
  KVM: VMX: support MSR_IA32_ARCH_CAPABILITIES as a feature MSR
2018-07-18 11:08:44 -07:00
Paolo Bonzini 9432a31757 KVM: irqfd: fix race between EPOLLHUP and irq_bypass_register_consumer
A comment warning against this bug is there, but the code is not doing what
the comment says.  Therefore it is possible that an EPOLLHUP races against
irq_bypass_register_consumer.  The EPOLLHUP handler schedules irqfd_shutdown,
and if that runs soon enough, you get a use-after-free.

Reported-by: syzbot <syzkaller@googlegroups.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
2018-07-18 11:31:27 +02:00
Lan Tianyu b5020a8e6b KVM/Eventfd: Avoid crash when assign and deassign specific eventfd in parallel.
Syzbot reports crashes in kvm_irqfd_assign(), caused by use-after-free
when kvm_irqfd_assign() and kvm_irqfd_deassign() run in parallel
for one specific eventfd. When the assign path hasn't finished but irqfd
has been added to kvm->irqfds.items list, another thead may deassign the
eventfd and free struct kvm_kernel_irqfd(). The assign path then uses
the struct kvm_kernel_irqfd that has been freed by deassign path. To avoid
such issue, keep irqfd under kvm->irq_srcu protection after the irqfd
has been added to kvm->irqfds.items list, and call synchronize_srcu()
in irq_shutdown() to make sure that irqfd has been fully initialized in
the assign path.

Reported-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Tianyu Lan <tianyu.lan@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-07-18 11:31:27 +02:00
Christoph Hellwig 9965ed174e fs: add new vfs_poll and file_can_poll helpers
These abstract out calls to the poll method in preparation for changes
in how we poll.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-05-26 09:16:44 +02:00
Linus Torvalds a9a08845e9 vfs: do bulk POLL* -> EPOLL* replacement
This is the mindless scripted replacement of kernel use of POLL*
variables as described by Al, done by this script:

    for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do
        L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'`
        for f in $L; do sed -i "-es/^\([^\"]*\)\(\<POLL$V\>\)/\\1E\\2/" $f; done
    done

with de-mangling cleanups yet to come.

NOTE! On almost all architectures, the EPOLL* constants have the same
values as the POLL* constants do.  But they keyword here is "almost".
For various bad reasons they aren't the same, and epoll() doesn't
actually work quite correctly in some cases due to this on Sparc et al.

The next patch from Al will sort out the final differences, and we
should be all done.

Scripted-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-02-11 14:34:03 -08:00
Al Viro 3ad6f93e98 annotate poll-related wait keys
__poll_t is also used as wait key in some waitqueues.
Verify that wait_..._poll() gets __poll_t as key and
provide a helper for wakeup functions to get back to
that __poll_t value.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-11-27 16:19:54 -05:00
Al Viro e6c8adca20 anntotate the places where ->poll() return values go
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-11-27 16:19:53 -05:00
Jan H. Schönherr 95e2a3b3ef Revert "KVM: Don't accept obviously wrong gsi values via KVM_IRQFD"
This reverts commit 36ae3c0a36.

The commit broke compilation on !CONFIG_HAVE_KVM_IRQ_ROUTING. Also,
there may be cases with CONFIG_HAVE_KVM_IRQ_ROUTING, where larger
gsi values make sense.

As the commit was meant as an early indicator to user space that
something is wrong, reverting just restores the previous behavior
where overly large values are ignored when encountered (without
any direct feedback).

Reported-by: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
Signed-off-by: Jan H. Schönherr <jschoenh@amazon.de>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2017-09-19 08:37:17 +02:00
Jan H. Schönherr 36ae3c0a36 KVM: Don't accept obviously wrong gsi values via KVM_IRQFD
We cannot add routes for gsi values >= KVM_MAX_IRQ_ROUTES -- see
kvm_set_irq_routing(). Hence, there is no sense in accepting them
via KVM_IRQFD. Prevent them from entering the system in the first
place.

Signed-off-by: Jan H. Schönherr <jschoenh@amazon.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-09-15 16:55:28 +02:00
Paolo Bonzini 8c61af9ebc Merge branch 'annotations' of git://git.kernel.org/pub/scm/linux/kernel/git/borntraeger/linux into kvm-master 2017-07-10 14:44:24 +02:00
Christian Borntraeger 4a12f95177 KVM: mark kvm->busses as rcu protected
mark kvm->busses as rcu protected and use the correct access
function everywhere.

found by sparse
virt/kvm/kvm_main.c:3490:15: error: incompatible types in comparison expression (different address spaces)
virt/kvm/kvm_main.c:3509:15: error: incompatible types in comparison expression (different address spaces)
virt/kvm/kvm_main.c:3561:15: error: incompatible types in comparison expression (different address spaces)
virt/kvm/kvm_main.c:3644:15: error: incompatible types in comparison expression (different address spaces)

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2017-07-07 15:24:16 +02:00
Ingo Molnar ac6424b981 sched/wait: Rename wait_queue_t => wait_queue_entry_t
Rename:

	wait_queue_t		=>	wait_queue_entry_t

'wait_queue_t' was always a slight misnomer: its name implies that it's a "queue",
but in reality it's a queue *entry*. The 'real' queue is the wait queue head,
which had to carry the name.

Start sorting this out by renaming it to 'wait_queue_entry_t'.

This also allows the real structure name 'struct __wait_queue' to
lose its double underscore and become 'struct wait_queue_entry',
which is the more canonical nomenclature for such data types.

Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-06-20 12:18:27 +02:00
David Hildenbrand 993225adf4 KVM: x86: rename kvm_vcpu_request_scan_ioapic()
Let's rename it into a proper arch specific callback.

Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2017-04-12 20:17:14 +02:00
David Hildenbrand 90db10434b KVM: kvm_io_bus_unregister_dev() should never fail
No caller currently checks the return value of
kvm_io_bus_unregister_dev(). This is evil, as all callers silently go on
freeing their device. A stale reference will remain in the io_bus,
getting at least used again, when the iobus gets teared down on
kvm_destroy_vm() - leading to use after free errors.

There is nothing the callers could do, except retrying over and over
again.

So let's simply remove the bus altogether, print an error and make
sure no one can access this broken bus again (returning -ENOMEM on any
attempt to access it).

Fixes: e93f8a0f82 ("KVM: convert io_bus to SRCU")
Cc: stable@vger.kernel.org # 3.4+
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-03-23 19:02:25 +01:00
Paolo Bonzini 36343f6ea7 KVM: fix OOPS on flush_work
The conversion done by commit 3706feacd0 ("KVM: Remove deprecated
create_singlethread_workqueue") is broken.  It flushes a single work
item &irqfd->shutdown instead of all of them, and even worse if there
is no irqfd on the list then you get a NULL pointer dereference.
Revert the virt/kvm/eventfd.c part of that patch; to avoid the
deprecated function, just allocate our own workqueue---it does
not even have to be unbound---with alloc_workqueue.

Fixes: 3706feacd0
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-10-26 14:06:51 +02:00
Bhaktipriya Shridhar 3706feacd0 KVM: Remove deprecated create_singlethread_workqueue
The workqueue "irqfd_cleanup_wq" queues a single work item
&irqfd->shutdown and hence doesn't require ordering. It is a host-wide
workqueue for issuing deferred shutdown requests aggregated from all
vm* instances. It is not being used on a memory reclaim path.
Hence, it has been converted to use system_wq.
The work item has been flushed in kvm_irqfd_release().

The workqueue "wqueue" queues a single work item &timer->expired
and hence doesn't require ordering. Also, it is not being used on
a memory reclaim path. Hence, it has been converted to use system_wq.

System workqueues have been able to handle high level of concurrency
for a long time now and hence it's not required to have a singlethreaded
workqueue just to gain concurrency. Unlike a dedicated per-cpu workqueue
created with create_singlethread_workqueue(), system_wq allows multiple
work items to overlap executions even on the same CPU; however, a
per-cpu workqueue doesn't have any CPU locality or global ordering
guarantee unless the target CPU is explicitly specified and thus the
increase of local concurrency shouldn't make any difference.

Signed-off-by: Bhaktipriya Shridhar <bhaktipriya96@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-09-07 19:34:28 +02:00
Alex Williamson 14717e2031 kvm: Conditionally register IRQ bypass consumer
If we don't support a mechanism for bypassing IRQs, don't register as
a consumer.  This eliminates meaningless dev_info()s when the connect
fails between producer and consumer, such as on AMD systems where
kvm_x86_ops->update_pi_irte is not implemented

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-05-11 22:37:55 +02:00
Paolo Bonzini b97e6de9c9 KVM: x86: merge kvm_arch_set_irq with kvm_set_msi_inatomic
We do not want to do too much work in atomic context, in particular
not walking all the VCPUs of the virtual machine.  So we want
to distinguish the architecture-specific injection function for irqfd
from kvm_set_msi.  Since it's still empty, reuse the newly added
kvm_arch_set_irq and rename it to kvm_arch_set_irq_inatomic.

Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-11-04 16:24:35 +01:00
Andrey Smetanin c9a5eccac1 kvm/eventfd: add arch-specific set_irq
Allow for arch-specific interrupt types to be set.  For that, add
kvm_arch_set_irq() which takes interrupt type-specific action if it
recognizes the interrupt type given, and -EWOULDBLOCK otherwise.

The default implementation always returns -EWOULDBLOCK.

Signed-off-by: Andrey Smetanin <asmetanin@virtuozzo.com>
Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Vitaly Kuznetsov <vkuznets@redhat.com>
CC: "K. Y. Srinivasan" <kys@microsoft.com>
CC: Gleb Natapov <gleb@kernel.org>
CC: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-10-16 10:34:29 +02:00
Andrey Smetanin ba1aefcd6d kvm/eventfd: factor out kvm_notify_acked_gsi()
Factor out kvm_notify_acked_gsi() helper to iterate over EOI listeners
and notify those matching the given gsi.

It will be reused in the upcoming Hyper-V SynIC implementation.

Signed-off-by: Andrey Smetanin <asmetanin@virtuozzo.com>
Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Vitaly Kuznetsov <vkuznets@redhat.com>
CC: "K. Y. Srinivasan" <kys@microsoft.com>
CC: Gleb Natapov <gleb@kernel.org>
CC: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-10-16 10:34:29 +02:00
Andrey Smetanin 351dc6477c kvm/eventfd: avoid loop inside irqfd_update()
The loop(for) inside irqfd_update() is unnecessary
because any other value for irq_entry.type will just trigger
schedule_work(&irqfd->inject) in irqfd_wakeup.

Signed-off-by: Andrey Smetanin <asmetanin@virtuozzo.com>
Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Vitaly Kuznetsov <vkuznets@redhat.com>
CC: "K. Y. Srinivasan" <kys@microsoft.com>
CC: Gleb Natapov <gleb@kernel.org>
CC: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-10-16 10:34:28 +02:00
Feng Wu f70c20aaf1 KVM: Add an arch specific hooks in 'struct kvm_kernel_irqfd'
This patch adds an arch specific hooks 'arch_update' in
'struct kvm_kernel_irqfd'. On Intel side, it is used to
update the IRTE when VT-d posted-interrupts is used.

Signed-off-by: Feng Wu <feng.wu@intel.com>
Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-10-01 15:06:47 +02:00
Eric Auger 9016cfb577 KVM: eventfd: add irq bypass consumer management
This patch adds the registration/unregistration of an
irq_bypass_consumer on irqfd assignment/deassignment.

Signed-off-by: Eric Auger <eric.auger@linaro.org>
Signed-off-by: Feng Wu <feng.wu@intel.com>
Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-10-01 15:06:46 +02:00
Eric Auger 1a02b27035 KVM: introduce kvm_arch functions for IRQ bypass
This patch introduces
- kvm_arch_irq_bypass_add_producer
- kvm_arch_irq_bypass_del_producer
- kvm_arch_irq_bypass_stop
- kvm_arch_irq_bypass_start

They make possible to specialize the KVM IRQ bypass consumer in
case CONFIG_KVM_HAVE_IRQ_BYPASS is set.

Signed-off-by: Eric Auger <eric.auger@linaro.org>
[Add weak implementations of the callbacks. - Feng]
Signed-off-by: Feng Wu <feng.wu@intel.com>
Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-10-01 15:06:45 +02:00
Eric Auger 166c9775f1 KVM: create kvm_irqfd.h
Move _irqfd_resampler and _irqfd struct declarations in a new
public header: kvm_irqfd.h. They are respectively renamed into
kvm_kernel_irqfd_resampler and kvm_kernel_irqfd. Those datatypes
will be used by architecture specific code, in the context of
IRQ bypass manager integration.

Signed-off-by: Eric Auger <eric.auger@linaro.org>
Signed-off-by: Feng Wu <feng.wu@intel.com>
Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-10-01 15:06:44 +02:00
Jason Wang e9ea5069d9 kvm: add capability for any-length ioeventfds
Cc: Gleb Natapov <gleb@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-10-01 15:06:31 +02:00
Jason Wang eefd6b06b1 kvm: fix double free for fast mmio eventfd
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:[<ffffffffc07e25d8>]  [<ffffffffc07e25d8>] 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:
[<ffffffffc07e2622>] ioeventfd_destructor+0x12/0x20 [kvm]
[<ffffffffc07df69a>] kvm_put_kvm+0xca/0x210 [kvm]
[<ffffffffc07df818>] kvm_vcpu_release+0x18/0x20 [kvm]
[<ffffffff811f69f7>] __fput+0xe7/0x250
[<ffffffff811f6bae>] ____fput+0xe/0x10
[<ffffffff81093f04>] task_work_run+0xd4/0xf0
[<ffffffff81079358>] do_exit+0x368/0xa50
[<ffffffff81082c8f>] ? recalc_sigpending+0x1f/0x60
[<ffffffff81079ad5>] do_group_exit+0x45/0xb0
[<ffffffff81085c71>] get_signal+0x291/0x750
[<ffffffff810144d8>] do_signal+0x28/0xab0
[<ffffffff810f3a3b>] ? do_futex+0xdb/0x5d0
[<ffffffff810b7028>] ? __wake_up_locked_key+0x18/0x20
[<ffffffff810f3fa6>] ? SyS_futex+0x76/0x170
[<ffffffff81014fc9>] do_notify_resume+0x69/0xb0
[<ffffffff817cb9af>] 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  [<ffffffffc07e25d8>] ioeventfd_release+0x28/0x60 [kvm]
 RSP <ffff88020e7f3bc8>

Cc: stable@vger.kernel.org
Cc: Gleb Natapov <gleb@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-09-15 16:59:31 +02:00
Jason Wang 85da11ca58 kvm: factor out core eventfd assign/deassign logic
This patch factors out core eventfd assign/deassign logic and leaves
the argument checking and bus index selection to callers.

Cc: stable@vger.kernel.org
Cc: Gleb Natapov <gleb@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-09-15 16:58:47 +02:00
Jason Wang 8453fecbec kvm: don't try to register to KVM_FAST_MMIO_BUS for non mmio eventfd
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: stable@vger.kernel.org
Cc: Gleb Natapov <gleb@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-09-15 16:58:27 +02:00
Andre Przywara af669ac6dc KVM: move iodev.h from virt/kvm/ to include/kvm
iodev.h contains definitions for the kvm_io_bus framework. This is
needed both by the generic KVM code in virt/kvm as well as by
architecture specific code under arch/. Putting the header file in
virt/kvm and using local includes in the architecture part seems at
least dodgy to me, so let's move the file into include/kvm, so that a
more natural "#include <kvm/iodev.h>" can be used by all of the code.
This also solves a problem later when using struct kvm_io_device
in arm_vgic.h.
Fixing up the FSF address in the GPL header and a wrong include path
on the way.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-03-26 21:43:12 +00:00
Nikolay Nikolaev e32edf4fd0 KVM: Redesign kvm_io_bus_ API to pass VCPU structure to the callbacks.
This is needed in e.g. ARM vGIC emulation, where the MMIO handling
depends on the VCPU that does the access.

Signed-off-by: Nikolay Nikolaev <n.nikolaev@virtualopensystems.com>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-03-26 21:43:11 +00:00
Eric Auger 01c94e64f5 KVM: introduce kvm_arch_intc_initialized and use it in irqfd
Introduce __KVM_HAVE_ARCH_INTC_INITIALIZED define and
associated kvm_arch_intc_initialized function. This latter
allows to test whether the virtual interrupt controller is initialized
and ready to accept virtual IRQ injection. On some architectures,
the virtual interrupt controller is dynamically instantiated, justifying
that kind of check.

The new function can now be used by irqfd to check whether the
virtual interrupt controller is ready on KVM_IRQFD request. If not,
KVM_IRQFD returns -EAGAIN.

Signed-off-by: Eric Auger <eric.auger@linaro.org>
Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-03-12 15:15:32 +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
Christoffer Dall 29f1b65b59 KVM: EVENTFD: Remove inclusion of irq.h
Commit c77dcac (KVM: Move more code under CONFIG_HAVE_KVM_IRQFD) added
functionality that depends on definitions in ioapic.h when
__KVM_HAVE_IOAPIC is defined.

At the same time, kvm-arm commit 0ba0951 (KVM: EVENTFD: remove inclusion
of irq.h) removed the inclusion of irq.h, an architecture-specific header
that is not present on ARM but which happened to include ioapic.h on x86.

Include ioapic.h directly in eventfd.c if __KVM_HAVE_IOAPIC is defined.
This fixes x86 and lets ARM use eventfd.c.

Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-24 12:06:25 +02:00
Paolo Bonzini c77dcacb39 KVM: Move more code under CONFIG_HAVE_KVM_IRQFD
Commits e4d57e1ee1 (KVM: Move irq notifier implementation into
eventfd.c, 2014-06-30) included the irq notifier code unconditionally
in eventfd.c, while it was under CONFIG_HAVE_KVM_IRQCHIP before.

Similarly, commit 297e21053a (KVM: Give IRQFD its own separate enabling
Kconfig option, 2014-06-30) moved code from CONFIG_HAVE_IRQ_ROUTING
to CONFIG_HAVE_KVM_IRQFD but forgot to move the pieces that used to be
under CONFIG_HAVE_KVM_IRQCHIP.

Together, this broke compilation without CONFIG_KVM_XICS.  Fix by adding
or changing the #ifdefs so that they point at CONFIG_HAVE_KVM_IRQFD.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-08-06 14:24:47 +02:00
Paul Mackerras 297e21053a KVM: Give IRQFD its own separate enabling Kconfig option
Currently, the IRQFD code is conditional on CONFIG_HAVE_KVM_IRQ_ROUTING.
So that we can have the IRQFD code compiled in without having the
IRQ routing code, this creates a new CONFIG_HAVE_KVM_IRQFD, makes
the IRQFD code conditional on it instead of CONFIG_HAVE_KVM_IRQ_ROUTING,
and makes all the platforms that currently select HAVE_KVM_IRQ_ROUTING
also select HAVE_KVM_IRQFD.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Tested-by: Eric Auger <eric.auger@linaro.org>
Tested-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-08-05 14:26:28 +02:00