linux-toradex.git/virt/kvm/kvm_main.c, branch v4.16-rc3

Merge tag 'kvm-4.16-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm

2018-02-10T21:16:35+00:00

Pull KVM updates from Radim Krčmář:
 "ARM:

   - icache invalidation optimizations, improving VM startup time

   - support for forwarded level-triggered interrupts, improving
     performance for timers and passthrough platform devices

   - a small fix for power-management notifiers, and some cosmetic
     changes

  PPC:

   - add MMIO emulation for vector loads and stores

   - allow HPT guests to run on a radix host on POWER9 v2.2 CPUs without
     requiring the complex thread synchronization of older CPU versions

   - improve the handling of escalation interrupts with the XIVE
     interrupt controller

   - support decrement register migration

   - various cleanups and bugfixes.

  s390:

   - Cornelia Huck passed maintainership to Janosch Frank

   - exitless interrupts for emulated devices

   - cleanup of cpuflag handling

   - kvm_stat counter improvements

   - VSIE improvements

   - mm cleanup

  x86:

   - hypervisor part of SEV

   - UMIP, RDPID, and MSR_SMI_COUNT emulation

   - paravirtualized TLB shootdown using the new KVM_VCPU_PREEMPTED bit

   - allow guests to see TOPOEXT, GFNI, VAES, VPCLMULQDQ, and more
     AVX512 features

   - show vcpu id in its anonymous inode name

   - many fixes and cleanups

   - per-VCPU MSR bitmaps (already merged through x86/pti branch)

   - stable KVM clock when nesting on Hyper-V (merged through
     x86/hyperv)"

* tag 'kvm-4.16-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (197 commits)
  KVM: PPC: Book3S: Add MMIO emulation for VMX instructions
  KVM: PPC: Book3S HV: Branch inside feature section
  KVM: PPC: Book3S HV: Make HPT resizing work on POWER9
  KVM: PPC: Book3S HV: Fix handling of secondary HPTEG in HPT resizing code
  KVM: PPC: Book3S PR: Fix broken select due to misspelling
  KVM: x86: don't forget vcpu_put() in kvm_arch_vcpu_ioctl_set_sregs()
  KVM: PPC: Book3S PR: Fix svcpu copying with preemption enabled
  KVM: PPC: Book3S HV: Drop locks before reading guest memory
  kvm: x86: remove efer_reload entry in kvm_vcpu_stat
  KVM: x86: AMD Processor Topology Information
  x86/kvm/vmx: do not use vm-exit instruction length for fast MMIO when running nested
  kvm: embed vcpu id to dentry of vcpu anon inode
  kvm: Map PFN-type memory regions as writable (if possible)
  x86/kvm: Make it compile on 32bit and with HYPYERVISOR_GUEST=n
  KVM: arm/arm64: Fixup userspace irqchip static key optimization
  KVM: arm/arm64: Fix userspace_irqchip_in_use counting
  KVM: arm/arm64: Fix incorrect timer_is_pending logic
  MAINTAINERS: update KVM/s390 maintainers
  MAINTAINERS: add Halil as additional vfio-ccw maintainer
  MAINTAINERS: add David as a reviewer for KVM/s390
  ...

Merge tag 'usercopy-v4.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

2018-02-04T00:25:42+00:00

Pull hardened usercopy whitelisting from Kees Cook:
 "Currently, hardened usercopy performs dynamic bounds checking on slab
  cache objects. This is good, but still leaves a lot of kernel memory
  available to be copied to/from userspace in the face of bugs.

  To further restrict what memory is available for copying, this creates
  a way to whitelist specific areas of a given slab cache object for
  copying to/from userspace, allowing much finer granularity of access
  control.

  Slab caches that are never exposed to userspace can declare no
  whitelist for their objects, thereby keeping them unavailable to
  userspace via dynamic copy operations. (Note, an implicit form of
  whitelisting is the use of constant sizes in usercopy operations and
  get_user()/put_user(); these bypass all hardened usercopy checks since
  these sizes cannot change at runtime.)

  This new check is WARN-by-default, so any mistakes can be found over
  the next several releases without breaking anyone's system.

  The series has roughly the following sections:
   - remove %p and improve reporting with offset
   - prepare infrastructure and whitelist kmalloc
   - update VFS subsystem with whitelists
   - update SCSI subsystem with whitelists
   - update network subsystem with whitelists
   - update process memory with whitelists
   - update per-architecture thread_struct with whitelists
   - update KVM with whitelists and fix ioctl bug
   - mark all other allocations as not whitelisted
   - update lkdtm for more sensible test overage"

* tag 'usercopy-v4.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (38 commits)
  lkdtm: Update usercopy tests for whitelisting
  usercopy: Restrict non-usercopy caches to size 0
  kvm: x86: fix KVM_XEN_HVM_CONFIG ioctl
  kvm: whitelist struct kvm_vcpu_arch
  arm: Implement thread_struct whitelist for hardened usercopy
  arm64: Implement thread_struct whitelist for hardened usercopy
  x86: Implement thread_struct whitelist for hardened usercopy
  fork: Provide usercopy whitelisting for task_struct
  fork: Define usercopy region in thread_stack slab caches
  fork: Define usercopy region in mm_struct slab caches
  net: Restrict unwhitelisted proto caches to size 0
  sctp: Copy struct sctp_sock.autoclose to userspace using put_user()
  sctp: Define usercopy region in SCTP proto slab cache
  caif: Define usercopy region in caif proto slab cache
  ip: Define usercopy region in IP proto slab cache
  net: Define usercopy region in struct proto slab cache
  scsi: Define usercopy region in scsi_sense_cache slab cache
  cifs: Define usercopy region in cifs_request slab cache
  vxfs: Define usercopy region in vxfs_inode slab cache
  ufs: Define usercopy region in ufs_inode_cache slab cache
  ...

mm, mmu_notifier: annotate mmu notifiers with blockable invalidate callbacks

2018-02-01T01:18:38+00:00

Commit 4d4bbd8526a8 ("mm, oom_reaper: skip mm structs with mmu
notifiers") prevented the oom reaper from unmapping private anonymous
memory with the oom reaper when the oom victim mm had mmu notifiers
registered.

The rationale is that doing mmu_notifier_invalidate_range_{start,end}()
around the unmap_page_range(), which is needed, can block and the oom
killer will stall forever waiting for the victim to exit, which may not
be possible without reaping.

That concern is real, but only true for mmu notifiers that have
blockable invalidate_range_{start,end}() callbacks.  This patch adds a
"flags" field to mmu notifier ops that can set a bit to indicate that
these callbacks do not block.

The implementation is steered toward an expensive slowpath, such as
after the oom reaper has grabbed mm->mmap_sem of a still alive oom
victim.

[rientjes@google.com: mmu_notifier_invalidate_range_end() can also call the invalidate_range() must not block, fix comment]
  Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1801091339570.240101@chino.kir.corp.google.com
[akpm@linux-foundation.org: make mm_has_blockable_invalidate_notifiers() return bool, use rwsem_is_locked()]
Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1712141329500.74052@chino.kir.corp.google.com
Signed-off-by: David Rientjes 
Acked-by: Michal Hocko 
Acked-by: Paolo Bonzini 
Acked-by: Christian König 
Acked-by: Dimitri Sivanich 
Cc: Andrea Arcangeli 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Cc: Oded Gabbay 
Cc: Alex Deucher 
Cc: David Airlie 
Cc: Joerg Roedel 
Cc: Doug Ledford 
Cc: Jani Nikula 
Cc: Mike Marciniszyn 
Cc: Sean Hefty 
Cc: Boris Ostrovsky 
Cc: Jérôme Glisse 
Cc: Radim Krčmář 
Signed-off-by: David Rientjes 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branch 'work.get_user_pages_fast' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2018-01-31T18:01:08+00:00

Pull get_user_pages_fast updates from Al Viro:
 "A bit more get_user_pages work"

* 'work.get_user_pages_fast' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  kvm: switch get_user_page_nowait() to get_user_pages_unlocked()
  __get_user_pages_locked(): get rid of notify_drop argument
  get_user_pages_unlocked(): pass true to __get_user_pages_locked() notify_drop
  cris: switch to get_user_pages_fast()
  fold __get_user_pages_unlocked() into its sole remaining caller

kvm: embed vcpu id to dentry of vcpu anon inode

2018-01-31T17:25:34+00:00

All d-entries for vcpu have the same, "anon_inode:kvm-vcpu". That means
it is impossible to know the mapping between fds for vcpu and vcpu
from userland.

    # LC_ALL=C ls -l /proc/617/fd | grep vcpu
    lrwx------. 1 qemu qemu 64 Jan  7 16:50 18 -> anon_inode:kvm-vcpu
    lrwx------. 1 qemu qemu 64 Jan  7 16:50 19 -> anon_inode:kvm-vcpu

It is also impossible to know the mapping between vma for kvm_run
structure and vcpu from userland.

    # LC_ALL=C grep vcpu /proc/617/maps
    7f9d842d0000-7f9d842d3000 rw-s 00000000 00:0d 20393                      anon_inode:kvm-vcpu
    7f9d842d3000-7f9d842d6000 rw-s 00000000 00:0d 20393                      anon_inode:kvm-vcpu

This change adds vcpu id to d-entries for vcpu. With this change
you can get the following output:

    # LC_ALL=C ls -l /proc/617/fd | grep vcpu
    lrwx------. 1 qemu qemu 64 Jan  7 16:50 18 -> anon_inode:kvm-vcpu:0
    lrwx------. 1 qemu qemu 64 Jan  7 16:50 19 -> anon_inode:kvm-vcpu:1

    # LC_ALL=C grep vcpu /proc/617/maps
    7f9d842d0000-7f9d842d3000 rw-s 00000000 00:0d 20393                      anon_inode:kvm-vcpu:0
    7f9d842d3000-7f9d842d6000 rw-s 00000000 00:0d 20393                      anon_inode:kvm-vcpu:1

With the mappings known from the output, a tool like strace can report more details
of qemu-kvm process activities. Here is the strace output of my local prototype:

    # ./strace -KK -f -p 617 2>&1 | grep 'KVM_RUN\| K'
    ...
    [pid   664] ioctl(18, KVM_RUN, 0)       = 0 (KVM_EXIT_MMIO)
     K ready_for_interrupt_injection=1, if_flag=0, flags=0, cr8=0000000000000000, apic_base=0x000000fee00d00
     K phys_addr=0, len=1634035803, [33, 0, 0, 0, 0, 0, 0, 0], is_write=112
    [pid   664] ioctl(18, KVM_RUN, 0)       = 0 (KVM_EXIT_MMIO)
     K ready_for_interrupt_injection=1, if_flag=1, flags=0, cr8=0000000000000000, apic_base=0x000000fee00d00
     K phys_addr=0, len=1634035803, [33, 0, 0, 0, 0, 0, 0, 0], is_write=112
    ...

Signed-off-by: Masatake YAMATO 
Acked-by: Christian Borntraeger 
Signed-off-by: Radim Krčmář

kvm: Map PFN-type memory regions as writable (if possible)

2018-01-31T17:25:33+00:00

For EPT-violations that are triggered by a read, the pages are also mapped with
write permissions (if their memory region is also writable). That would avoid
getting yet another fault on the same page when a write occurs.

This optimization only happens when you have a "struct page" backing the memory
region. So also enable it for memory regions that do not have a "struct page".

Cc: Paolo Bonzini 
Cc: Radim Krčmář 
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: KarimAllah Ahmed 
Reviewed-by: Paolo Bonzini 
Signed-off-by: Radim Krčmář

kvm: whitelist struct kvm_vcpu_arch

2018-01-15T20:08:07+00:00

On x86, ARM and s390, struct kvm_vcpu_arch has a usercopy region
that is read and written by the KVM_GET/SET_CPUID2 ioctls (x86)
or KVM_GET/SET_ONE_REG (ARM/s390).  Without whitelisting the area,
KVM is completely broken on those architectures with usercopy hardening
enabled.

For now, allow writing to the entire struct on all architectures.
The KVM tree will not refine this to an architecture-specific
subset of struct kvm_vcpu_arch.

Cc: kernel-hardening@lists.openwall.com
Cc: Kees Cook 
Cc: Christian Borntraeger 
Cc: Christoffer Dall 
Cc: Radim Krčmář 
Signed-off-by: Paolo Bonzini 
Acked-by: Christoffer Dall 
Acked-by: Marc Zyngier 
Acked-by: Christian Borntraeger 
Signed-off-by: Kees Cook

KVM: introduce kvm_arch_vcpu_async_ioctl

2017-12-14T08:26:59+00:00

After the vcpu_load/vcpu_put pushdown, the handling of asynchronous VCPU
ioctl is already much clearer in that it is obvious that they bypass
vcpu_load and vcpu_put.

However, it is still not perfect in that the different state of the VCPU
mutex is still hidden in the caller.  Separate those ioctls into a new
function kvm_arch_vcpu_async_ioctl that returns -ENOIOCTLCMD for more
"traditional" synchronous ioctls.

Cc: James Hogan 
Cc: Paul Mackerras 
Cc: Christian Borntraeger 
Reviewed-by: Christoffer Dall 
Reviewed-by: Cornelia Huck 
Suggested-by: Cornelia Huck 
Signed-off-by: Paolo Bonzini

KVM: Move vcpu_load to arch-specific kvm_arch_vcpu_ioctl

2017-12-14T08:26:58+00:00

Move the calls to vcpu_load() and vcpu_put() in to the architecture
specific implementations of kvm_arch_vcpu_ioctl() which dispatches
further architecture-specific ioctls on to other functions.

Some architectures support asynchronous vcpu ioctls which cannot call
vcpu_load() or take the vcpu->mutex, because that would prevent
concurrent execution with a running VCPU, which is the intended purpose
of these ioctls, for example because they inject interrupts.

We repeat the separate checks for these specifics in the architecture
code for MIPS, S390 and PPC, and avoid taking the vcpu->mutex and
calling vcpu_load for these ioctls.

Signed-off-by: Christoffer Dall 
Signed-off-by: Paolo Bonzini

KVM: Move vcpu_load to arch-specific kvm_arch_vcpu_ioctl_set_fpu

2017-12-14T08:26:57+00:00

Move vcpu_load() and vcpu_put() into the architecture specific
implementations of kvm_arch_vcpu_ioctl_set_fpu().

Reviewed-by: David Hildenbrand 
Signed-off-by: Christoffer Dall 
Reviewed-by: Cornelia Huck 
Signed-off-by: Paolo Bonzini