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Merge 4.14.154 into android-4.14-q
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Changes in 4.14.154
	bonding: fix state transition issue in link monitoring
	CDC-NCM: handle incomplete transfer of MTU
	ipv4: Fix table id reference in fib_sync_down_addr
	net: ethernet: octeon_mgmt: Account for second possible VLAN header
	net: fix data-race in neigh_event_send()
	net: qualcomm: rmnet: Fix potential UAF when unregistering
	net: usb: qmi_wwan: add support for DW5821e with eSIM support
	NFC: fdp: fix incorrect free object
	nfc: netlink: fix double device reference drop
	NFC: st21nfca: fix double free
	qede: fix NULL pointer deref in __qede_remove()
	ALSA: timer: Fix incorrectly assigned timer instance
	ALSA: bebob: fix to detect configured source of sampling clock for Focusrite Saffire Pro i/o series
	ALSA: hda/ca0132 - Fix possible workqueue stall
	mm: thp: handle page cache THP correctly in PageTransCompoundMap
	mm, vmstat: hide /proc/pagetypeinfo from normal users
	dump_stack: avoid the livelock of the dump_lock
	tools: gpio: Use !building_out_of_srctree to determine srctree
	perf tools: Fix time sorting
	drm/radeon: fix si_enable_smc_cac() failed issue
	HID: wacom: generic: Treat serial number and related fields as unsigned
	arm64: Do not mask out PTE_RDONLY in pte_same()
	ceph: fix use-after-free in __ceph_remove_cap()
	ceph: add missing check in d_revalidate snapdir handling
	iio: adc: stm32-adc: fix stopping dma
	iio: imu: adis16480: make sure provided frequency is positive
	iio: srf04: fix wrong limitation in distance measuring
	netfilter: nf_tables: Align nft_expr private data to 64-bit
	netfilter: ipset: Fix an error code in ip_set_sockfn_get()
	intel_th: pci: Add Comet Lake PCH support
	intel_th: pci: Add Jasper Lake PCH support
	can: usb_8dev: fix use-after-free on disconnect
	can: c_can: c_can_poll(): only read status register after status IRQ
	can: peak_usb: fix a potential out-of-sync while decoding packets
	can: rx-offload: can_rx_offload_queue_sorted(): fix error handling, avoid skb mem leak
	can: gs_usb: gs_can_open(): prevent memory leak
	can: mcba_usb: fix use-after-free on disconnect
	can: peak_usb: fix slab info leak
	configfs: Fix bool initialization/comparison
	configfs: stash the data we need into configfs_buffer at open time
	configfs_register_group() shouldn't be (and isn't) called in rmdirable parts
	configfs: new object reprsenting tree fragments
	configfs: provide exclusion between IO and removals
	configfs: fix a deadlock in configfs_symlink()
	usb: dwc3: Allow disabling of metastability workaround
	mfd: palmas: Assign the right powerhold mask for tps65917
	ASoC: tlv320aic31xx: Handle inverted BCLK in non-DSP modes
	mtd: spi-nor: enable 4B opcodes for mx66l51235l
	mtd: spi-nor: cadence-quadspi: add a delay in write sequence
	misc: pci_endpoint_test: Prevent some integer overflows
	PCI: dra7xx: Add shutdown handler to cleanly turn off clocks
	misc: pci_endpoint_test: Fix BUG_ON error during pci_disable_msi()
	mailbox: reset txdone_method TXDONE_BY_POLL if client knows_txdone
	ASoC: tlv320dac31xx: mark expected switch fall-through
	ASoC: davinci-mcasp: Handle return value of devm_kasprintf
	ASoC: davinci: Kill BUG_ON() usage
	ASoC: davinci-mcasp: Fix an error handling path in 'davinci_mcasp_probe()'
	i2c: omap: Trigger bus recovery in lockup case
	cpufreq: ti-cpufreq: add missing of_node_put()
	ARM: dts: dra7: Disable USB metastability workaround for USB2
	sched/fair: Fix low cpu usage with high throttling by removing expiration of cpu-local slices
	sched/fair: Fix -Wunused-but-set-variable warnings
	lib/scatterlist: Introduce sgl_alloc() and sgl_free()
	usbip: Fix vhci_urb_enqueue() URB null transfer buffer error path
	usbip: stub_rx: fix static checker warning on unnecessary checks
	usbip: Implement SG support to vhci-hcd and stub driver
	PCI: tegra: Enable Relaxed Ordering only for Tegra20 & Tegra30
	dmaengine: xilinx_dma: Fix control reg update in vdma_channel_set_config
	HID: intel-ish-hid: fix wrong error handling in ishtp_cl_alloc_tx_ring()
	RDMA/qedr: Fix reported firmware version
	net/mlx5: prevent memory leak in mlx5_fpga_conn_create_cq
	scsi: qla2xxx: fixup incorrect usage of host_byte
	RDMA/uverbs: Prevent potential underflow
	net: openvswitch: free vport unless register_netdevice() succeeds
	scsi: lpfc: Honor module parameter lpfc_use_adisc
	scsi: qla2xxx: Initialized mailbox to prevent driver load failure
	ipvs: don't ignore errors in case refcounting ip_vs module fails
	ipvs: move old_secure_tcp into struct netns_ipvs
	bonding: fix unexpected IFF_BONDING bit unset
	macsec: fix refcnt leak in module exit routine
	usb: fsl: Check memory resource before releasing it
	usb: gadget: udc: atmel: Fix interrupt storm in FIFO mode.
	usb: gadget: composite: Fix possible double free memory bug
	usb: gadget: configfs: fix concurrent issue between composite APIs
	usb: dwc3: remove the call trace of USBx_GFLADJ
	perf/x86/amd/ibs: Fix reading of the IBS OpData register and thus precise RIP validity
	perf/x86/amd/ibs: Handle erratum torvalds#420 only on the affected CPU family (10h)
	USB: Skip endpoints with 0 maxpacket length
	USB: ldusb: use unsigned size format specifiers
	RDMA/iw_cxgb4: Avoid freeing skb twice in arp failure case
	scsi: qla2xxx: stop timer in shutdown path
	fjes: Handle workqueue allocation failure
	net: hisilicon: Fix "Trying to free already-free IRQ"
	hv_netvsc: Fix error handling in netvsc_attach()
	NFSv4: Don't allow a cached open with a revoked delegation
	net: ethernet: arc: add the missed clk_disable_unprepare
	igb: Fix constant media auto sense switching when no cable is connected
	e1000: fix memory leaks
	x86/apic: Move pending interrupt check code into it's own function
	x86/apic: Drop logical_smp_processor_id() inline
	x86/apic/32: Avoid bogus LDR warnings
	can: flexcan: disable completely the ECC mechanism
	mm/filemap.c: don't initiate writeback if mapping has no dirty pages
	cgroup,writeback: don't switch wbs immediately on dead wbs if the memcg is dead
	usbip: Fix free of unallocated memory in vhci tx
	net: prevent load/store tearing on sk->sk_stamp
	drm/i915/gtt: Add read only pages to gen8_pte_encode
	drm/i915/gtt: Read-only pages for insert_entries on bdw+
	drm/i915/gtt: Disable read-only support under GVT
	drm/i915: Prevent writing into a read-only object via a GGTT mmap
	drm/i915/cmdparser: Check reg_table_count before derefencing.
	drm/i915/cmdparser: Do not check past the cmd length.
	drm/i915: Silence smatch for cmdparser
	drm/i915: Don't use GPU relocations prior to cmdparser stalls
	drm/i915: Move engine->needs_cmd_parser to engine->flags
	drm/i915: Rename gen7 cmdparser tables
	drm/i915: Disable Secure Batches for gen6+
	drm/i915: Remove Master tables from cmdparser
	drm/i915: Add support for mandatory cmdparsing
	drm/i915: Support ro ppgtt mapped cmdparser shadow buffers
	drm/i915: Allow parsing of unsized batches
	drm/i915: Add gen9 BCS cmdparsing
	drm/i915/cmdparser: Use explicit goto for error paths
	drm/i915/cmdparser: Add support for backward jumps
	drm/i915/cmdparser: Ignore Length operands during command matching
	drm/i915: Lower RM timeout to avoid DSI hard hangs
	drm/i915/gen8+: Add RC6 CTX corruption WA
	drm/i915/cmdparser: Fix jump whitelist clearing
	KVM: x86: use Intel speculation bugs and features as derived in generic x86 code
	x86/msr: Add the IA32_TSX_CTRL MSR
	x86/cpu: Add a helper function x86_read_arch_cap_msr()
	x86/cpu: Add a "tsx=" cmdline option with TSX disabled by default
	x86/speculation/taa: Add mitigation for TSX Async Abort
	x86/speculation/taa: Add sysfs reporting for TSX Async Abort
	kvm/x86: Export MDS_NO=0 to guests when TSX is enabled
	x86/tsx: Add "auto" option to the tsx= cmdline parameter
	x86/speculation/taa: Add documentation for TSX Async Abort
	x86/tsx: Add config options to set tsx=on|off|auto
	x86/speculation/taa: Fix printing of TAA_MSG_SMT on IBRS_ALL CPUs
	x86/bugs: Add ITLB_MULTIHIT bug infrastructure
	x86/cpu: Add Tremont to the cpu vulnerability whitelist
	cpu/speculation: Uninline and export CPU mitigations helpers
	Documentation: Add ITLB_MULTIHIT documentation
	kvm: x86, powerpc: do not allow clearing largepages debugfs entry
	kvm: Convert kvm_lock to a mutex
	kvm: mmu: Do not release the page inside mmu_set_spte()
	KVM: x86: make FNAME(fetch) and __direct_map more similar
	KVM: x86: remove now unneeded hugepage gfn adjustment
	KVM: x86: change kvm_mmu_page_get_gfn BUG_ON to WARN_ON
	KVM: x86: add tracepoints around __direct_map and FNAME(fetch)
	KVM: vmx, svm: always run with EFER.NXE=1 when shadow paging is active
	kvm: mmu: ITLB_MULTIHIT mitigation
	kvm: Add helper function for creating VM worker threads
	kvm: x86: mmu: Recovery of shattered NX large pages
	Linux 4.14.154

Signed-off-by: Greg Kroah-Hartman <[email protected]>
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2 parents 56ab794 + 775d01b commit b7f5267
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2 changes: 2 additions & 0 deletions Documentation/ABI/testing/sysfs-devices-system-cpu
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Expand Up @@ -381,6 +381,8 @@ What: /sys/devices/system/cpu/vulnerabilities
/sys/devices/system/cpu/vulnerabilities/spec_store_bypass
/sys/devices/system/cpu/vulnerabilities/l1tf
/sys/devices/system/cpu/vulnerabilities/mds
/sys/devices/system/cpu/vulnerabilities/tsx_async_abort
/sys/devices/system/cpu/vulnerabilities/itlb_multihit
Date: January 2018
Contact: Linux kernel mailing list <[email protected]>
Description: Information about CPU vulnerabilities
Expand Down
2 changes: 2 additions & 0 deletions Documentation/admin-guide/hw-vuln/index.rst
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Expand Up @@ -12,3 +12,5 @@ are configurable at compile, boot or run time.
spectre
l1tf
mds
tsx_async_abort
multihit.rst
163 changes: 163 additions & 0 deletions Documentation/admin-guide/hw-vuln/multihit.rst
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@@ -0,0 +1,163 @@
iTLB multihit
=============

iTLB multihit is an erratum where some processors may incur a machine check
error, possibly resulting in an unrecoverable CPU lockup, when an
instruction fetch hits multiple entries in the instruction TLB. This can
occur when the page size is changed along with either the physical address
or cache type. A malicious guest running on a virtualized system can
exploit this erratum to perform a denial of service attack.


Affected processors
-------------------

Variations of this erratum are present on most Intel Core and Xeon processor
models. The erratum is not present on:

- non-Intel processors

- Some Atoms (Airmont, Bonnell, Goldmont, GoldmontPlus, Saltwell, Silvermont)

- Intel processors that have the PSCHANGE_MC_NO bit set in the
IA32_ARCH_CAPABILITIES MSR.


Related CVEs
------------

The following CVE entry is related to this issue:

============== =================================================
CVE-2018-12207 Machine Check Error Avoidance on Page Size Change
============== =================================================


Problem
-------

Privileged software, including OS and virtual machine managers (VMM), are in
charge of memory management. A key component in memory management is the control
of the page tables. Modern processors use virtual memory, a technique that creates
the illusion of a very large memory for processors. This virtual space is split
into pages of a given size. Page tables translate virtual addresses to physical
addresses.

To reduce latency when performing a virtual to physical address translation,
processors include a structure, called TLB, that caches recent translations.
There are separate TLBs for instruction (iTLB) and data (dTLB).

Under this errata, instructions are fetched from a linear address translated
using a 4 KB translation cached in the iTLB. Privileged software modifies the
paging structure so that the same linear address using large page size (2 MB, 4
MB, 1 GB) with a different physical address or memory type. After the page
structure modification but before the software invalidates any iTLB entries for
the linear address, a code fetch that happens on the same linear address may
cause a machine-check error which can result in a system hang or shutdown.


Attack scenarios
----------------

Attacks against the iTLB multihit erratum can be mounted from malicious
guests in a virtualized system.


iTLB multihit system information
--------------------------------

The Linux kernel provides a sysfs interface to enumerate the current iTLB
multihit status of the system:whether the system is vulnerable and which
mitigations are active. The relevant sysfs file is:

/sys/devices/system/cpu/vulnerabilities/itlb_multihit

The possible values in this file are:

.. list-table::

* - Not affected
- The processor is not vulnerable.
* - KVM: Mitigation: Split huge pages
- Software changes mitigate this issue.
* - KVM: Vulnerable
- The processor is vulnerable, but no mitigation enabled


Enumeration of the erratum
--------------------------------

A new bit has been allocated in the IA32_ARCH_CAPABILITIES (PSCHANGE_MC_NO) msr
and will be set on CPU's which are mitigated against this issue.

======================================= =========== ===============================
IA32_ARCH_CAPABILITIES MSR Not present Possibly vulnerable,check model
IA32_ARCH_CAPABILITIES[PSCHANGE_MC_NO] '0' Likely vulnerable,check model
IA32_ARCH_CAPABILITIES[PSCHANGE_MC_NO] '1' Not vulnerable
======================================= =========== ===============================


Mitigation mechanism
-------------------------

This erratum can be mitigated by restricting the use of large page sizes to
non-executable pages. This forces all iTLB entries to be 4K, and removes
the possibility of multiple hits.

In order to mitigate the vulnerability, KVM initially marks all huge pages
as non-executable. If the guest attempts to execute in one of those pages,
the page is broken down into 4K pages, which are then marked executable.

If EPT is disabled or not available on the host, KVM is in control of TLB
flushes and the problematic situation cannot happen. However, the shadow
EPT paging mechanism used by nested virtualization is vulnerable, because
the nested guest can trigger multiple iTLB hits by modifying its own
(non-nested) page tables. For simplicity, KVM will make large pages
non-executable in all shadow paging modes.

Mitigation control on the kernel command line and KVM - module parameter
------------------------------------------------------------------------

The KVM hypervisor mitigation mechanism for marking huge pages as
non-executable can be controlled with a module parameter "nx_huge_pages=".
The kernel command line allows to control the iTLB multihit mitigations at
boot time with the option "kvm.nx_huge_pages=".

The valid arguments for these options are:

========== ================================================================
force Mitigation is enabled. In this case, the mitigation implements
non-executable huge pages in Linux kernel KVM module. All huge
pages in the EPT are marked as non-executable.
If a guest attempts to execute in one of those pages, the page is
broken down into 4K pages, which are then marked executable.

off Mitigation is disabled.

auto Enable mitigation only if the platform is affected and the kernel
was not booted with the "mitigations=off" command line parameter.
This is the default option.
========== ================================================================


Mitigation selection guide
--------------------------

1. No virtualization in use
^^^^^^^^^^^^^^^^^^^^^^^^^^^

The system is protected by the kernel unconditionally and no further
action is required.

2. Virtualization with trusted guests
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

If the guest comes from a trusted source, you may assume that the guest will
not attempt to maliciously exploit these errata and no further action is
required.

3. Virtualization with untrusted guests
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
If the guest comes from an untrusted source, the guest host kernel will need
to apply iTLB multihit mitigation via the kernel command line or kvm
module parameter.
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