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  1. 30 9月, 2017 1 次提交
  3. 29 9月, 2017 1 次提交
    • J
      x86/asm: Fix inline asm call constraints for GCC 4.4 · 520a13c5
      由 Josh Poimboeuf 提交于 
      The kernel test bot (run by Xiaolong Ye) reported that the following commit:

  f5caf621 ("x86/asm: Fix inline asm call constraints for Clang")

is causing double faults in a kernel compiled with GCC 4.4.

Linus subsequently diagnosed the crash pattern and the buggy commit and found that
the issue is with this code:

  register unsigned int __asm_call_sp asm("esp");
  #define ASM_CALL_CONSTRAINT "+r" (__asm_call_sp)

Even on a 64-bit kernel, it's using ESP instead of RSP.  That causes GCC
to produce the following bogus code:

  ffffffff8147461d:       89 e0                   mov    %esp,%eax
  ffffffff8147461f:       4c 89 f7                mov    %r14,%rdi
  ffffffff81474622:       4c 89 fe                mov    %r15,%rsi
  ffffffff81474625:       ba 20 00 00 00          mov    $0x20,%edx
  ffffffff8147462a:       89 c4                   mov    %eax,%esp
  ffffffff8147462c:       e8 bf 52 05 00          callq  ffffffff814c98f0 <copy_user_generic_unrolled>

Despite the absurdity of it backing up and restoring the stack pointer
for no reason, the bug is actually the fact that it's only backing up
and restoring the lower 32 bits of the stack pointer.  The upper 32 bits
are getting cleared out, corrupting the stack pointer.

So change the '__asm_call_sp' register variable to be associated with
the actual full-size stack pointer.

This also requires changing the __ASM_SEL() macro to be based on the
actual compiled arch size, rather than the CONFIG value, because
CONFIG_X86_64 compiles some files with '-m32' (e.g., realmode and vdso).
Otherwise Clang fails to build the kernel because it complains about the
use of a 64-bit register (RSP) in a 32-bit file.
Reported-and-Bisected-and-Tested-by: Nkernel test robot <xiaolong.ye@intel.com>
Diagnosed-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: LKP <lkp@01.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthias Kaehlcke <mka@chromium.org>
Cc: Miguel Bernal Marin <miguel.bernal.marin@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: f5caf621 ("x86/asm: Fix inline asm call constraints for Clang")
Link: http://lkml.kernel.org/r/20170928215826.6sdpmwtkiydiytim@trebleSigned-off-by: NIngo Molnar <mingo@kernel.org>
      520a13c5
  5. 25 9月, 2017 7 次提交
  7. 23 9月, 2017 1 次提交
    • J
      x86/asm: Fix inline asm call constraints for Clang · f5caf621
      由 Josh Poimboeuf 提交于 
      For inline asm statements which have a CALL instruction, we list the
stack pointer as a constraint to convince GCC to ensure the frame
pointer is set up first:

  static inline void foo()
  {
	register void *__sp asm(_ASM_SP);
	asm("call bar" : "+r" (__sp))
  }

Unfortunately, that pattern causes Clang to corrupt the stack pointer.

The fix is easy: convert the stack pointer register variable to a global
variable.

It should be noted that the end result is different based on the GCC
version.  With GCC 6.4, this patch has exactly the same result as
before:

	defconfig	defconfig-nofp	distro		distro-nofp
 before	9820389		9491555		8816046		8516940
 after	9820389		9491555		8816046		8516940

With GCC 7.2, however, GCC's behavior has changed.  It now changes its
behavior based on the conversion of the register variable to a global.
That somehow convinces it to *always* set up the frame pointer before
inserting *any* inline asm.  (Therefore, listing the variable as an
output constraint is a no-op and is no longer necessary.)  It's a bit
overkill, but the performance impact should be negligible.  And in fact,
there's a nice improvement with frame pointers disabled:

	defconfig	defconfig-nofp	distro		distro-nofp
 before	9796316		9468236		9076191		8790305
 after	9796957		9464267		9076381		8785949

So in summary, while listing the stack pointer as an output constraint
is no longer necessary for newer versions of GCC, it's still needed for
older versions.
Suggested-by: NAndrey Ryabinin <aryabinin@virtuozzo.com>
Reported-by: NMatthias Kaehlcke <mka@chromium.org>
Signed-off-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Miguel Bernal Marin <miguel.bernal.marin@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/3db862e970c432ae823cf515c52b54fec8270e0e.1505942196.git.jpoimboe@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      f5caf621
  9. 20 9月, 2017 12 次提交
  11. 19 9月, 2017 3 次提交
  13. 18 9月, 2017 4 次提交
  15. 16 9月, 2017 1 次提交
    • A
      xen: x86: mark xen_find_pt_base as __init · 51ae2538
      由 Arnd Bergmann 提交于 
      gcc-4.6 causes a harmless link-time warning:

WARNING: vmlinux.o(.text.unlikely+0x48e): Section mismatch in reference from the function xen_find_pt_base() to the function .init.text:m2p()
The function xen_find_pt_base() references
the function __init m2p().
This is often because xen_find_pt_base lacks a __init
annotation or the annotation of m2p is wrong.

Newer compilers inline this function, so it never shows up, but marking
it __init is the right way to avoid the warning.

Fixes: 70e61199 ("xen: move p2m list if conflicting with e820 map")
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NBoris Ostrovsky <boris.ostrovsky@oracle.com>
      51ae2538
  17. 15 9月, 2017 9 次提交
    • J
      kvm: nVMX: Handle deferred early VMLAUNCH/VMRESUME failure properly · 4f350c6d
      由 Jim Mattson 提交于 
      When emulating a nested VM-entry from L1 to L2, several control field
validation checks are deferred to the hardware. Should one of these
validation checks fail, vcpu_vmx_run will set the vmx->fail flag. When
this happens, the L2 guest state is not loaded (even in part), and
execution should continue in L1 with the next instruction after the
VMLAUNCH/VMRESUME.

The VMCS12 is not modified (except for the VM-instruction error
field), the VMCS12 MSR save/load lists are not processed, and the CPU
state is not loaded from the VMCS12 host area. Moreover, the vmcs02
exit reason is stale, so it should not be consulted for any reason.
Signed-off-by: NJim Mattson <jmattson@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      4f350c6d
    • J
      kvm: vmx: Handle VMLAUNCH/VMRESUME failure properly · b060ca3b
      由 Jim Mattson 提交于 
      On an early VMLAUNCH/VMRESUME failure (i.e. one which sets the
VM-instruction error field of the current VMCS), the launch state of
the current VMCS is not set to "launched," and the VM-exit information
fields of the current VMCS (including IDT-vectoring information and
exit reason) are stale.

On a late VMLAUNCH/VMRESUME failure (i.e. one which sets the high bit
of the exit reason field), the launch state of the current VMCS is not
set to "launched," and only two of the VM-exit information fields of
the current VMCS are modified (exit reason and exit
qualification). The remaining VM-exit information fields of the
current VMCS (including IDT-vectoring information, in particular) are
stale.
Signed-off-by: NJim Mattson <jmattson@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      b060ca3b
    • J
      kvm: nVMX: Remove nested_vmx_succeed after successful VM-entry · 7881f96c
      由 Jim Mattson 提交于 
      After a successful VM-entry, RFLAGS is cleared, with the exception of
bit 1, which is always set. This is handled by load_vmcs12_host_state.
Signed-off-by: NJim Mattson <jmattson@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      7881f96c
    • D
      kvm,x86: Fix apf_task_wake_one() wq serialization · a0cff57b
      由 Davidlohr Bueso 提交于 
      During code inspection, the following potential race was seen:

CPU0   	    		    	     	CPU1
kvm_async_pf_task_wait			apf_task_wake_one
					  [L] swait_active(&n->wq)
  [S] prepare_to_swait(&n.wq)
  [L] if (!hlist_unhahed(&n.link))
	schedule()			  [S] hlist_del_init(&n->link);

Properly serialize swait_active() checks such that a wakeup is
not missed.
Signed-off-by: NDavidlohr Bueso <dbueso@suse.de>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      a0cff57b
    • D
      kvm,lapic: Justify use of swait_active() · cc1b4680
      由 Davidlohr Bueso 提交于 
      A comment might serve future readers.
Signed-off-by: NDavidlohr Bueso <dbueso@suse.de>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      cc1b4680
    • J
      KVM: VMX: Do not BUG() on out-of-bounds guest IRQ · 3a8b0677
      由 Jan H. Schönherr 提交于 
      The value of the guest_irq argument to vmx_update_pi_irte() is
ultimately coming from a KVM_IRQFD API call. Do not BUG() in
vmx_update_pi_irte() if the value is out-of bounds. (Especially,
since KVM as a whole seems to hang after that.)

Instead, print a message only once if we find that we don't have a
route for a certain IRQ (which can be out-of-bounds or within the
array).

This fixes CVE-2017-1000252.

Fixes: efc64404 ("KVM: x86: Update IRTE for posted-interrupts")
Signed-off-by: NJan H. Schönherr <jschoenh@amazon.de>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      3a8b0677
    • J
      kvm: nVMX: Don't allow L2 to access the hardware CR8 · 51aa68e7
      由 Jim Mattson 提交于 
      If L1 does not specify the "use TPR shadow" VM-execution control in
vmcs12, then L0 must specify the "CR8-load exiting" and "CR8-store
exiting" VM-execution controls in vmcs02. Failure to do so will give
the L2 VM unrestricted read/write access to the hardware CR8.

This fixes CVE-2017-12154.
Signed-off-by: NJim Mattson <jmattson@google.com>
Reviewed-by: NDavid Hildenbrand <david@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      51aa68e7
    • B
      x86/cpu/AMD: Fix erratum 1076 (CPB bit) · f7f3dc00
      由 Borislav Petkov 提交于 
      CPUID Fn8000_0007_EDX[CPB] is wrongly 0 on models up to B1. But they do
support CPB (AMD's Core Performance Boosting cpufreq CPU feature), so fix that.
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sherry Hurwitz <sherry.hurwitz@amd.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170907170821.16021-1-bp@alien8.deSigned-off-by: NIngo Molnar <mingo@kernel.org>
      f7f3dc00
    • W
      KVM: async_pf: Fix #DF due to inject "Page not Present" and "Page Ready" exceptions simultaneously · 9a6e7c39
      由 Wanpeng Li 提交于 
      qemu-system-x86-8600  [004] d..1  7205.687530: kvm_entry: vcpu 2
qemu-system-x86-8600  [004] ....  7205.687532: kvm_exit: reason EXCEPTION_NMI rip 0xffffffffa921297d info ffffeb2c0e44e018 80000b0e
qemu-system-x86-8600  [004] ....  7205.687532: kvm_page_fault: address ffffeb2c0e44e018 error_code 0
qemu-system-x86-8600  [004] ....  7205.687620: kvm_try_async_get_page: gva = 0xffffeb2c0e44e018, gfn = 0x427e4e
qemu-system-x86-8600  [004] .N..  7205.687628: kvm_async_pf_not_present: token 0x8b002 gva 0xffffeb2c0e44e018
    kworker/4:2-7814  [004] ....  7205.687655: kvm_async_pf_completed: gva 0xffffeb2c0e44e018 address 0x7fcc30c4e000
qemu-system-x86-8600  [004] ....  7205.687703: kvm_async_pf_ready: token 0x8b002 gva 0xffffeb2c0e44e018
qemu-system-x86-8600  [004] d..1  7205.687711: kvm_entry: vcpu 2

After running some memory intensive workload in guest, I catch the kworker
which completes the GUP too quickly, and queues an "Page Ready" #PF exception
after the "Page not Present" exception before the next vmentry as the above
trace which will result in #DF injected to guest.

This patch fixes it by clearing the queue for "Page not Present" if "Page Ready"
occurs before the next vmentry since the GUP has already got the required page
and shadow page table has already been fixed by "Page Ready" handler.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: NWanpeng Li <wanpeng.li@hotmail.com>
Fixes: 7c90705b ("KVM: Inject asynchronous page fault into a PV guest if page is swapped out.")
[Changed indentation and added clearing of injected. - Radim]
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>
      9a6e7c39
  19. 14 9月, 2017 1 次提交