Cosmic update to v4.17.15 stable release

SRU Justification

    Impact:
       The upstream process for stable tree updates is quite similar
       in scope to the Ubuntu SRU process, e.g., each patch has to
       demonstrably fix a bug, and each patch is vetted by upstream
       by originating either directly from a mainline/stable Linux tree or
       a minimally backported form of that patch. The v4.17.15 upstream stable
       patch set is now available. It should be included in the Ubuntu
       kernel as well.

       git://git.kernel.org/

    TEST CASE: TBD

       The following patches from the v4.17.15 stable release shall be applied:

parisc: Enable CONFIG_MLONGCALLS by default
parisc: Define mb() and add memory barriers to assembler unlock sequences
Mark HI and TASKLET softirq synchronous
stop_machine: Disable preemption after queueing stopper threads
sched/deadline: Update rq_clock of later_rq when pushing a task
zram: remove BD_CAP_SYNCHRONOUS_IO with writeback feature
xen/netfront: don't cache skb_shinfo()
bpf, sockmap: fix leak in bpf_tcp_sendmsg wait for mem path
bpf, sockmap: fix bpf_tcp_sendmsg sock error handling
scsi: sr: Avoid that opening a CD-ROM hangs with runtime power management enabled
scsi: qla2xxx: Fix memory leak for allocating abort IOCB
init: rename and re-order boot_cpu_state_init()
root dentries need RCU-delayed freeing
make sure that __dentry_kill() always invalidates d_seq, unhashed or not
fix mntput/mntput race
fix __legitimize_mnt()/mntput() race
ARM: dts: imx6sx: fix irq for pcie bridge
x86/paravirt: Fix spectre-v2 mitigations for paravirt guests
x86/speculation: Protect against userspace-userspace spectreRSB
kprobes/x86: Fix %p uses in error messages
x86/irqflags: Provide a declaration for native_save_fl
x86/speculation/l1tf: Increase 32bit PAE __PHYSICAL_PAGE_SHIFT
x86/speculation/l1tf: Change order of offset/type in swap entry
x86/speculation/l1tf: Protect swap entries against L1TF
x86/speculation/l1tf: Protect PROT_NONE PTEs against speculation
x86/speculation/l1tf: Make sure the first page is always reserved
x86/speculation/l1tf: Add sysfs reporting for l1tf
x86/speculation/l1tf: Disallow non privileged high MMIO PROT_NONE mappings
x86/speculation/l1tf: Limit swap file size to MAX_PA/2
x86/bugs: Move the l1tf function and define pr_fmt properly
sched/smt: Update sched_smt_present at runtime
x86/smp: Provide topology_is_primary_thread()
x86/topology: Provide topology_smt_supported()
cpu/hotplug: Make bringup/teardown of smp threads symmetric
cpu/hotplug: Split do_cpu_down()
cpu/hotplug: Provide knobs to control SMT
x86/cpu: Remove the pointless CPU printout
x86/cpu/AMD: Remove the pointless detect_ht() call
x86/cpu/common: Provide detect_ht_early()
x86/cpu/topology: Provide detect_extended_topology_early()
x86/cpu/intel: Evaluate smp_num_siblings early
x86/CPU/AMD: Do not check CPUID max ext level before parsing SMP info
x86/cpu/AMD: Evaluate smp_num_siblings early
x86/apic: Ignore secondary threads if nosmt=force
x86/speculation/l1tf: Extend 64bit swap file size limit
x86/cpufeatures: Add detection of L1D cache flush support.
x86/CPU/AMD: Move TOPOEXT reenablement before reading smp_num_siblings
x86/speculation/l1tf: Protect PAE swap entries against L1TF
x86/speculation/l1tf: Fix up pte->pfn conversion for PAE
Revert "x86/apic: Ignore secondary threads if nosmt=force"
cpu/hotplug: Boot HT siblings at least once
x86/KVM: Warn user if KVM is loaded SMT and L1TF CPU bug being present
x86/KVM/VMX: Add module argument for L1TF mitigation
x86/KVM/VMX: Add L1D flush algorithm
x86/KVM/VMX: Add L1D MSR based flush
x86/KVM/VMX: Add L1D flush logic
x86/KVM/VMX: Split the VMX MSR LOAD structures to have an host/guest numbers
x86/KVM/VMX: Add find_msr() helper function
x86/KVM/VMX: Separate the VMX AUTOLOAD guest/host number accounting
x86/KVM/VMX: Extend add_atomic_switch_msr() to allow VMENTER only MSRs
x86/KVM/VMX: Use MSR save list for IA32_FLUSH_CMD if required
cpu/hotplug: Online siblings when SMT control is turned on
x86/litf: Introduce vmx status variable
x86/kvm: Drop L1TF MSR list approach
x86/l1tf: Handle EPT disabled state proper
x86/kvm: Move l1tf setup function
x86/kvm: Add static key for flush always
x86/kvm: Serialize L1D flush parameter setter
x86/kvm: Allow runtime control of L1D flush
cpu/hotplug: Expose SMT control init function
cpu/hotplug: Set CPU_SMT_NOT_SUPPORTED early
x86/bugs, kvm: Introduce boot-time control of L1TF mitigations
Documentation: Add section about CPU vulnerabilities
x86/speculation/l1tf: Unbreak !__HAVE_ARCH_PFN_MODIFY_ALLOWED architectures
x86/KVM/VMX: Initialize the vmx_l1d_flush_pages' content
Documentation/l1tf: Fix typos
cpu/hotplug: detect SMT disabled by BIOS
x86/KVM/VMX: Don't set l1tf_flush_l1d to true from vmx_l1d_flush()
x86/KVM/VMX: Replace 'vmx_l1d_flush_always' with 'vmx_l1d_flush_cond'
x86/KVM/VMX: Move the l1tf_flush_l1d test to vmx_l1d_flush()
x86/irq: Demote irq_cpustat_t::__softirq_pending to u16
x86/KVM/VMX: Introduce per-host-cpu analogue of l1tf_flush_l1d
x86: Don't include linux/irq.h from asm/hardirq.h
x86/irq: Let interrupt handlers set kvm_cpu_l1tf_flush_l1d
x86/KVM/VMX: Don't set l1tf_flush_l1d from vmx_handle_external_intr()
Documentation/l1tf: Remove Yonah processors from not vulnerable list
x86/speculation: Simplify sysfs report of VMX L1TF vulnerability
x86/speculation: Use ARCH_CAPABILITIES to skip L1D flush on vmentry
KVM: VMX: Tell the nested hypervisor to skip L1D flush on vmentry
cpu/hotplug: Fix SMT supported evaluation
x86/speculation/l1tf: Invert all not present mappings
x86/speculation/l1tf: Make pmd/pud_mknotpresent() invert
x86/mm/pat: Make set_memory_np() L1TF safe
x86/mm/kmmio: Make the tracer robust against L1TF
tools headers: Synchronize prctl.h ABI header
tools headers: Synchronise x86 cpufeatures.h for L1TF additions
x86/microcode: Allow late microcode loading with SMT disabled
x86/smp: fix non-SMP broken build due to redefinition of apic_id_is_primary_thread
cpu/hotplug: Non-SMP machines do not make use of booted_once
x86/init: fix build with CONFIG_SWAP=n
x86/CPU/AMD: Have smp_num_siblings and cpu_llc_id always be present
Linux 4.17.15