1. 03 11月, 2014 39 次提交
  2. 02 11月, 2014 1 次提交
    • P
      KVM: vmx: defer load of APIC access page address during reset · a73896cb
      Paolo Bonzini 提交于
      Most call paths to vmx_vcpu_reset do not hold the SRCU lock.  Defer loading
      the APIC access page to the next vmentry.
      
      This avoids the following lockdep splat:
      
      [ INFO: suspicious RCU usage. ]
      3.18.0-rc2-test2+ #70 Not tainted
      -------------------------------
      include/linux/kvm_host.h:474 suspicious rcu_dereference_check() usage!
      
      other info that might help us debug this:
      
      rcu_scheduler_active = 1, debug_locks = 0
      1 lock held by qemu-system-x86/2371:
       #0:  (&vcpu->mutex){+.+...}, at: [<ffffffffa037d800>] vcpu_load+0x20/0xd0 [kvm]
      
      stack backtrace:
      CPU: 4 PID: 2371 Comm: qemu-system-x86 Not tainted 3.18.0-rc2-test2+ #70
      Hardware name: Dell Inc. OptiPlex 9010/0M9KCM, BIOS A12 01/10/2013
       0000000000000001 ffff880209983ca8 ffffffff816f514f 0000000000000000
       ffff8802099b8990 ffff880209983cd8 ffffffff810bd687 00000000000fee00
       ffff880208a2c000 ffff880208a10000 ffff88020ef50040 ffff880209983d08
      Call Trace:
       [<ffffffff816f514f>] dump_stack+0x4e/0x71
       [<ffffffff810bd687>] lockdep_rcu_suspicious+0xe7/0x120
       [<ffffffffa037d055>] gfn_to_memslot+0xd5/0xe0 [kvm]
       [<ffffffffa03807d3>] __gfn_to_pfn+0x33/0x60 [kvm]
       [<ffffffffa0380885>] gfn_to_page+0x25/0x90 [kvm]
       [<ffffffffa038aeec>] kvm_vcpu_reload_apic_access_page+0x3c/0x80 [kvm]
       [<ffffffffa08f0a9c>] vmx_vcpu_reset+0x20c/0x460 [kvm_intel]
       [<ffffffffa039ab8e>] kvm_vcpu_reset+0x15e/0x1b0 [kvm]
       [<ffffffffa039ac0c>] kvm_arch_vcpu_setup+0x2c/0x50 [kvm]
       [<ffffffffa037f7e0>] kvm_vm_ioctl+0x1d0/0x780 [kvm]
       [<ffffffff810bc664>] ? __lock_is_held+0x54/0x80
       [<ffffffff812231f0>] do_vfs_ioctl+0x300/0x520
       [<ffffffff8122ee45>] ? __fget+0x5/0x250
       [<ffffffff8122f0fa>] ? __fget_light+0x2a/0xe0
       [<ffffffff81223491>] SyS_ioctl+0x81/0xa0
       [<ffffffff816fed6d>] system_call_fastpath+0x16/0x1b
      Reported-by: NTakashi Iwai <tiwai@suse.de>
      Reported-by: NAlexei Starovoitov <alexei.starovoitov@gmail.com>
      Reviewed-by: NWanpeng Li <wanpeng.li@linux.intel.com>
      Tested-by: NWanpeng Li <wanpeng.li@linux.intel.com>
      Fixes: 38b99173Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      a73896cb