linux.git/virt/kvm/eventfd.c, branch v5.1

kvm: don't redefine flags as something else

2019-03-28T16:28:59+00:00

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 
Cc: "Radim Krčmář" 
Cc: kvm@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior 
Signed-off-by: Paolo Bonzini

kvm: Add memcg accounting to KVM allocations

2019-02-20T21:48:29+00:00

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 
Reviewed-by: Shakeel Butt 
Signed-off-by: Paolo Bonzini

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

2018-07-18T18:08:44+00:00

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

KVM: irqfd: fix race between EPOLLHUP and irq_bypass_register_consumer

2018-07-18T09:31:27+00:00

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 
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini 
Reviewed-by: David Hildenbrand

KVM/Eventfd: Avoid crash when assign and deassign specific eventfd in parallel.

2018-07-18T09:31:27+00:00

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 
Cc: Paolo Bonzini 
Cc: Radim Krčmář 
Cc: Dmitry Vyukov 
Signed-off-by: Tianyu Lan 
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini

fs: add new vfs_poll and file_can_poll helpers

2018-05-26T07:16:44+00:00

These abstract out calls to the poll method in preparation for changes
in how we poll.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Greg Kroah-Hartman 
Reviewed-by: Darrick J. Wong

vfs: do bulk POLL* -> EPOLL* replacement

2018-02-11T22:34:03+00:00

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/^\([^\"]*\)\(\\)/\\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 
Signed-off-by: Linus Torvalds

annotate poll-related wait keys

2017-11-27T21:19:54+00:00

__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

anntotate the places where ->poll() return values go

2017-11-27T21:19:53+00:00

Signed-off-by: Al Viro

Revert "KVM: Don't accept obviously wrong gsi values via KVM_IRQFD"

2017-09-19T06:37:17+00:00

This reverts commit 36ae3c0a36b7456432fedce38ae2f7bd3e01a563.

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 
Signed-off-by: Jan H. Schönherr 
Reviewed-by: David Hildenbrand 
Signed-off-by: Radim Krčmář