1. 16 Jan, 2019 2 commits
    • WANG Chao's avatar
      x86, modpost: Replace last remnants of RETPOLINE with CONFIG_RETPOLINE · 64ac5483
      WANG Chao authored
      commit e4f35891 upstream.
      
      Commit
      
        4cd24de3 ("x86/retpoline: Make CONFIG_RETPOLINE depend on compiler support")
      
      replaced the RETPOLINE define with CONFIG_RETPOLINE checks. Remove the
      remaining pieces.
      
       [ bp: Massage commit message. ]
      
      Fixes: 4cd24de3 ("x86/retpoline: Make CONFIG_RETPOLINE depend on compiler support")
      Signed-off-by: default avatarWANG Chao <chao.wang@ucloud.cn>
      Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
      Reviewed-by: default avatarZhenzhong Duan <zhenzhong.duan@oracle.com>
      Reviewed-by: default avatarMasahiro Yamada <yamada.masahiro@socionext.com>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: Andi Kleen <ak@linux.intel.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: Arnd Bergmann <arnd@arndb.de>
      Cc: Daniel Borkmann <daniel@iogearbox.net>
      Cc: David Woodhouse <dwmw@amazon.co.uk>
      Cc: Geert Uytterhoeven <geert@linux-m68k.org>
      Cc: Jessica Yu <jeyu@kernel.org>
      Cc: Jiri Kosina <jkosina@suse.cz>
      Cc: Kees Cook <keescook@chromium.org>
      Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      Cc: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
      Cc: Michal Marek <michal.lkml@markovi.net>
      Cc: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Tim Chen <tim.c.chen@linux.intel.com>
      Cc: Vasily Gorbik <gor@linux.ibm.com>
      Cc: linux-kbuild@vger.kernel.org
      Cc: srinivas.eeda@oracle.com
      Cc: stable <stable@vger.kernel.org>
      Cc: x86-ml <x86@kernel.org>
      Link: https://lkml.kernel.org/r/20181210163725.95977-1-chao.wang@ucloud.cnSigned-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      64ac5483
    • Rik van Riel's avatar
      x86,kvm: move qemu/guest FPU switching out to vcpu_run · 4124a4cf
      Rik van Riel authored
      commit f775b13e upstream.
      
      Currently, every time a VCPU is scheduled out, the host kernel will
      first save the guest FPU/xstate context, then load the qemu userspace
      FPU context, only to then immediately save the qemu userspace FPU
      context back to memory. When scheduling in a VCPU, the same extraneous
      FPU loads and saves are done.
      
      This could be avoided by moving from a model where the guest FPU is
      loaded and stored with preemption disabled, to a model where the
      qemu userspace FPU is swapped out for the guest FPU context for
      the duration of the KVM_RUN ioctl.
      
      This is done under the VCPU mutex, which is also taken when other
      tasks inspect the VCPU FPU context, so the code should already be
      safe for this change. That should come as no surprise, given that
      s390 already has this optimization.
      
      This can fix a bug where KVM calls get_user_pages while owning the
      FPU, and the file system ends up requesting the FPU again:
      
          [258270.527947]  __warn+0xcb/0xf0
          [258270.527948]  warn_slowpath_null+0x1d/0x20
          [258270.527951]  kernel_fpu_disable+0x3f/0x50
          [258270.527953]  __kernel_fpu_begin+0x49/0x100
          [258270.527955]  kernel_fpu_begin+0xe/0x10
          [258270.527958]  crc32c_pcl_intel_update+0x84/0xb0
          [258270.527961]  crypto_shash_update+0x3f/0x110
          [258270.527968]  crc32c+0x63/0x8a [libcrc32c]
          [258270.527975]  dm_bm_checksum+0x1b/0x20 [dm_persistent_data]
          [258270.527978]  node_prepare_for_write+0x44/0x70 [dm_persistent_data]
          [258270.527985]  dm_block_manager_write_callback+0x41/0x50 [dm_persistent_data]
          [258270.527988]  submit_io+0x170/0x1b0 [dm_bufio]
          [258270.527992]  __write_dirty_buffer+0x89/0x90 [dm_bufio]
          [258270.527994]  __make_buffer_clean+0x4f/0x80 [dm_bufio]
          [258270.527996]  __try_evict_buffer+0x42/0x60 [dm_bufio]
          [258270.527998]  dm_bufio_shrink_scan+0xc0/0x130 [dm_bufio]
          [258270.528002]  shrink_slab.part.40+0x1f5/0x420
          [258270.528004]  shrink_node+0x22c/0x320
          [258270.528006]  do_try_to_free_pages+0xf5/0x330
          [258270.528008]  try_to_free_pages+0xe9/0x190
          [258270.528009]  __alloc_pages_slowpath+0x40f/0xba0
          [258270.528011]  __alloc_pages_nodemask+0x209/0x260
          [258270.528014]  alloc_pages_vma+0x1f1/0x250
          [258270.528017]  do_huge_pmd_anonymous_page+0x123/0x660
          [258270.528021]  handle_mm_fault+0xfd3/0x1330
          [258270.528025]  __get_user_pages+0x113/0x640
          [258270.528027]  get_user_pages+0x4f/0x60
          [258270.528063]  __gfn_to_pfn_memslot+0x120/0x3f0 [kvm]
          [258270.528108]  try_async_pf+0x66/0x230 [kvm]
          [258270.528135]  tdp_page_fault+0x130/0x280 [kvm]
          [258270.528149]  kvm_mmu_page_fault+0x60/0x120 [kvm]
          [258270.528158]  handle_ept_violation+0x91/0x170 [kvm_intel]
          [258270.528162]  vmx_handle_exit+0x1ca/0x1400 [kvm_intel]
      
      No performance changes were detected in quick ping-pong tests on
      my 4 socket system, which is expected since an FPU+xstate load is
      on the order of 0.1us, while ping-ponging between CPUs is on the
      order of 20us, and somewhat noisy.
      
      Cc: stable@vger.kernel.org
      Signed-off-by: default avatarRik van Riel <riel@redhat.com>
      Suggested-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      [Fixed a bug where reset_vcpu called put_fpu without preceding load_fpu,
       which happened inside from KVM_CREATE_VCPU ioctl. - Radim]
      Signed-off-by: default avatarRadim Krčmář <rkrcmar@redhat.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      4124a4cf
  2. 13 Jan, 2019 38 commits