Implement invalidation of specific pairs of GVA page table entries in
one or both of the GVA page tables. This is used when existing mappings
are replaced in the guest TLB by emulated TLBWI/TLBWR instructions. Due
to the sharing of page tables in the host kernel range, we should be
careful not to allow host pages to be invalidated.

Add a helper kvm_mips_walk_pgd() which can be used when walking of
either GPA (future patches) or GVA page tables is needed, optionally
with allocation of page tables along the way when they don't exist.

GPA page table walking will need to be protected by the kvm->mmu_lock,
so we also add a small MMU page cache in each KVM VCPU, like that found
for other architectures but smaller. This allows enough pages to be
pre-allocated to handle a single fault without holding the lock,
allowing the helper to run with the lock held without having to handle
allocation failures.

Using the same mechanism for GVA allows the same code to be used, and
allows it to use the same cache of allocated pages if the GPA walk
didn't need to allocate any new tables.
Signed-off-by: NJames Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

Implement invalidation of large ranges of virtual addresses from GVA
page tables in response to a guest ASID change (immediately for guest
kernel page table, lazily for guest user page table).

We iterate through a range of page tables invalidating entries and
freeing fully invalidated tables. To minimise overhead the exact ranges
invalidated depends on the flags argument to kvm_mips_flush_gva_pt(),
which also allows it to be used in future KVM_CAP_SYNC_MMU patches in
response to GPA changes, which unlike guest TLB mapping changes affects
guest KSeg0 mappings.
Signed-off-by: NJames Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

Refactor kvm_mips_host_tlb_inv() to also be able to invalidate any
matching TLB entry in the kernel ASID rather than assuming only the TLB
entries in the user ASID can change. Two new bool user/kernel arguments
allow the caller to indicate whether the mapping should affect each of
the ASIDs for guest user/kernel mode.

- kvm_mips_invalidate_guest_tlb() (used by TLBWI/TLBWR emulation) can
  now invalidate any corresponding TLB entry in both the kernel ASID
  (guest kernel may have accessed any guest mapping), and the user ASID
  if the entry being replaced is in guest USeg (where guest user may
  also have accessed it).

- The tlbmod fault handler (and the KSeg0 / TLB mapped / commpage fault
  handlers in later patches) can now invalidate the corresponding TLB
  entry in whichever ASID is currently active, since only a single page
  table will have been updated anyway.
Signed-off-by: NJames Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

kvm_mips_host_tlb_inv() uses the TLBP instruction to probe the host TLB
for an entry matching the given guest virtual address, and determines
whether a match was found based on whether CP0_Index > 0. This is
technically incorrect as an index of 0 (with the high bit clear) is a
perfectly valid TLB index.

This is harmless at the moment due to the use of at least 1 wired TLB
entry for the KVM commpage, however we will soon be ridding ourselves of
that particular wired entry so lets fix the condition in case the entry
needing invalidation does land at TLB index 0.
Signed-off-by: NJames Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

Use functions from the general MIPS TLB exception vector generation code
(tlbex.c) to construct a fast path TLB refill handler similar to the
general one, but cut down and capable of preserving K0 and K1.
Signed-off-by: NJames Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

tlbex.c uses the implementation dependent $22 CP0 register group on
NetLogic cores, with the help of the c0_kscratch() helper. Allow these
registers to be allocated by the KVM entry code too instead of assuming
KScratch registers are all $31, which will also allow pgd_reg to be
handled since it is allocated that way.

We also drop the masking of kscratch_mask with 0xfc, as it is redundant
for the standard KScratch registers (Config4.KScrExist won't have the
low 2 bits set anyway), and apparently not necessary for NetLogic.
Signed-off-by: NJames Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

Activate the GVA page tables when in guest context. This will allow the
normal Linux TLB refill handler to fill from it when guest memory is
read, as well as preventing accidental reading from user memory.
Signed-off-by: NJames Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

Allocate GVA -> HPA page tables for guest kernel and guest user mode on
each VCPU, to allow for fast path TLB refill handling to be added later.

In the process kvm_arch_vcpu_init() needs updating to pass on any error
from the vcpu_init() callback.
Signed-off-by: NJames Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

Wire up a vcpu uninit implementation callback. This will be used for the
clean up of GVA->HPA page tables.
Signed-off-by: NJames Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

Set init_mm as the active_mm and update mm_cpumask(current->mm) to
reflect that it isn't active when in guest context. This prevents cache
management code from attempting cache flushes on host virtual addresses
while in guest context, for example due to a cache management IPIs or
later when writing of dynamically translated code hits copy on write.

We do this using helpers in static kernel code to avoid having to export
init_mm to modules.
Signed-off-by: NJames Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

We only need the guest ASID loaded while in guest context, i.e. while
running guest code and while handling guest exits. We load the guest
ASID when entering the guest, however we restore the host ASID later
than necessary, when the VCPU state is saved i.e. vcpu_put() or slightly
earlier if preempted after returning to the host.

This mismatch is both unpleasant and causes redundant host ASID restores
in kvm_trap_emul_vcpu_put(). Lets explicitly restore the host ASID when
returning to the host, and don't bother restoring the host ASID on
context switch in unless we're already in guest context.
Signed-off-by: NJames Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

Add implementation callbacks for entering the guest (vcpu_run()) and
reentering the guest (vcpu_reenter()), allowing implementation specific
operations to be performed before entering the guest or after returning
to the host without cluttering kvm_arch_vcpu_ioctl_run().

This allows the T&E specific lazy user GVA flush to be moved into
trap_emul.c, along with disabling of the HTW. We also move
kvm_mips_deliver_interrupts() as VZ will need to restore the guest timer
state prior to delivering interrupts.
Signed-off-by: NJames Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

The kvm_vcpu_arch structure contains both mm_structs for allocating MMU
contexts (primarily the ASID) but it also copies the resulting ASIDs
into guest_{user,kernel}_asid[] arrays which are referenced from uasm
generated code.

This duplication doesn't seem to serve any purpose, and it gets in the
way of generalising the ASID handling across guest kernel/user modes, so
lets just extract the ASID straight out of the mm_struct on demand, and
in fact there are convenient cpu_context() and cpu_asid() macros for
doing so.

To reduce the verbosity of this code we do also add kern_mm and user_mm
local variables where the kernel and user mm_structs are used.
Signed-off-by: NJames Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

The MIPS KVM host and guest GVA ASIDs may need regenerating when
scheduling a process in guest context, which is done from the
kvm_arch_vcpu_load() / kvm_arch_vcpu_put() functions in mmu.c.

However this is a fairly implementation specific detail. VZ for example
may use GuestIDs instead of normal ASIDs to distinguish mappings
belonging to different guests, and even on VZ without GuestID the root
TLB will be used differently to trap & emulate.

Trap & emulate GVA ASIDs only relate to the user part of the full
address space, so can be left active during guest exit handling (guest
context) to allow guest instructions to be easily read and translated.

VZ root ASIDs however are for GPA mappings so can't be left active
during normal kernel code. They also aren't useful for accessing guest
virtual memory, and we should have CP0_BadInstr[P] registers available
to provide encodings of trapping guest instructions anyway.

Therefore move the ASID preemption handling into the implementation
callback.
Signed-off-by: NJames Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

Convert the get_regs() and set_regs() callbacks to vcpu_load() and
vcpu_put(), which provide a cpu argument and more closely match the
kvm_arch_vcpu_load() / kvm_arch_vcpu_put() that they are called by.

This is in preparation for moving ASID management into the
implementations.
Signed-off-by: NJames Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

KVM T&E uses an ASID for guest kernel mode and an ASID for guest user
mode. The current ASID is saved when the guest is scheduled out, and
restored when scheduling back in, with checks for whether the ASID needs
to be regenerated.

This isn't really necessary as the ASID can be easily determined by the
current guest mode, so lets simplify it to just read the required ASID
from guest_kernel_asid or guest_user_asid even if the ASID hasn't been
regenerated.
Signed-off-by: NJames Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

MIPS incompletely implements the KVM_NMI ioctl to supposedly perform a
CPU reset, but all it actually does is invalidate the ASIDs. It doesn't
expose the KVM_CAP_USER_NMI capability which is supposed to indicate the
presence of the KVM_NMI ioctl, and no user software actually uses it on
MIPS.

Since this is dead code that would technically need updating for GVA
page table handling in upcoming patches, remove it now. If we wanted to
implement NMI injection later it can always be done properly along with
the KVM_CAP_USER_NMI capability, and if we wanted to implement a proper
CPU reset it would be better done with a separate ioctl.
Signed-off-by: NJames Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

The protected cache ops contain no out of line fixup code to return an
error code in the event of a fault, with the cache op being skipped in
that case. For KVM however we'd like to detect this case as page
faulting will be disabled so it could happen during normal operation if
the GVA page tables were flushed, and need to be handled by the caller.

Add the out-of-line fixup code to load the error value -EFAULT into the
return variable, and adapt the protected cache line functions to pass
the error back to the caller.
Signed-off-by: NJames Hogan <james.hogan@imgtec.com>
Acked-by: NRalf Baechle <ralf@linux-mips.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

Export to TLB exception code generating functions so that KVM can
construct a fast TLB refill handler for guest context without
reinventing the wheel quite so much.
Signed-off-by: NJames Hogan <james.hogan@imgtec.com>
Acked-by: NRalf Baechle <ralf@linux-mips.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

Add include guards in asm/uasm.h to allow it to be safely used by a new
header asm/tlbex.h in the next patch to expose TLB exception building
functions for KVM to use.
Signed-off-by: NJames Hogan <james.hogan@imgtec.com>
Acked-by: NRalf Baechle <ralf@linux-mips.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

Export pmd_init(), invalid_pmd_table and tlbmiss_handler_setup_pgd to
GPL kernel modules so that MIPS KVM can use the inline page table
management functions and switch between page tables:

- pmd_init() will be used directly by KVM to initialise newly allocated
  pmd tables with invalid lower level table pointers.

- invalid_pmd_table is used by pud_present(), pud_none(), and
  pud_clear(), which KVM will use to test and clear pud entries.

- tlbmiss_handler_setup_pgd() will be called by KVM entry code to switch
  to the appropriate GVA page tables.
Signed-off-by: NJames Hogan <james.hogan@imgtec.com>
Acked-by: NRalf Baechle <ralf@linux-mips.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

pgd_alloc() references init_mm which is not exported to modules. In
order for KVM to be able to use pgd_alloc() to allocate GVA page tables,
move pgd_alloc() into a new pgtable.c file and export it to modules.
Signed-off-by: NJames Hogan <james.hogan@imgtec.com>
Acked-by: NRalf Baechle <ralf@linux-mips.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

* Return directly after a call of the function "copy_from_user" failed
  in a case block.

* Delete the jump label "out" which became unnecessary with
  this refactoring.
Signed-off-by: NMarkus Elfring <elfring@users.sourceforge.net>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJames Hogan <james.hogan@imgtec.com>

This reverts commit bc613494.

A CPUID instruction executed in VMX non-root mode always causes a
VM-exit, regardless of the leaf being queried.

Fixes: bc613494 ("KVM: nested VMX: disable perf cpuid reporting")
Signed-off-by: NJim Mattson <jmattson@google.com>
[The issue solved by bc613494 has been resolved with ff651cb6
 ("KVM: nVMX: Add nested msr load/restore algorithm").]
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

Vector population count instructions for dwords and qwords are to be
used in future Intel Xeon & Xeon Phi processors. The bit 14 of
CPUID[level:0x07, ECX] indicates that the new instructions are
supported by a processor.

The spec can be found in the Intel Software Developer Manual (SDM)
or in the Instruction Set Extensions Programming Reference (ISE).
Signed-off-by: NPiotr Luc <piotr.luc@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: x86@kernel.org
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

Vector population count instructions for dwords and qwords are going to be
available in future Intel Xeon & Xeon Phi processors. Bit 14 of
CPUID[level:0x07, ECX] indicates that the instructions are supported by a
processor.

The specification can be found in the Intel Software Developer Manual (SDM)
and in the Instruction Set Extensions Programming Reference (ISE).

Populate the feature bit and clear it when xsave is disabled.
Signed-off-by: NPiotr Luc <piotr.luc@intel.com>
Reviewed-by: NBorislav Petkov <bp@suse.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: kvm@vger.kernel.org
Cc: Radim Krčmář <rkrcmar@redhat.com>
Link: http://lkml.kernel.org/r/20170110173403.6010-2-piotr.luc@intel.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Some machines, such as the Lenovo ThinkPad W541 with firmware GNET80WW
(2.28), include memory map entries with phys_addr=0x0 and num_pages=0.

These machines fail to boot after the following commit,

  commit 8e80632f ("efi/esrt: Use efi_mem_reserve() and avoid a kmalloc()")

Fix this by removing such bogus entries from the memory map.

Furthermore, currently the log output for this case (with efi=debug)
looks like:

 [    0.000000] efi: mem45: [Reserved           |   |  |  |  |  |  |  |  |  |  |  |  ] range=[0x0000000000000000-0xffffffffffffffff] (0MB)

This is clearly wrong, and also not as informative as it could be.  This
patch changes it so that if we find obviously invalid memory map
entries, we print an error and skip those entries.  It also detects the
display of the address range calculation overflow, so the new output is:

 [    0.000000] efi: [Firmware Bug]: Invalid EFI memory map entries:
 [    0.000000] efi: mem45: [Reserved           |   |  |  |  |  |  |  |   |  |  |  |  ] range=[0x0000000000000000-0x0000000000000000] (invalid)

It also detects memory map sizes that would overflow the physical
address, for example phys_addr=0xfffffffffffff000 and
num_pages=0x0200000000000001, and prints:

 [    0.000000] efi: [Firmware Bug]: Invalid EFI memory map entries:
 [    0.000000] efi: mem45: [Reserved           |   |  |  |  |  |  |  |   |  |  |  |  ] range=[phys_addr=0xfffffffffffff000-0x20ffffffffffffffff] (invalid)

It then removes these entries from the memory map.
Signed-off-by: NPeter Jones <pjones@redhat.com>
Signed-off-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
[ardb: refactor for clarity with no functional changes, avoid PAGE_SHIFT]
Signed-off-by: NMatt Fleming <matt@codeblueprint.co.uk>
[Matt: Include bugzilla info in commit log]
Cc: <stable@vger.kernel.org> # v4.9+
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=191121Signed-off-by: NIngo Molnar <mingo@kernel.org>

As Peter suggested [1] rejecting non sampling PEBS events,
because they dont make any sense and could cause bugs
in the NMI handler [2].

  [1] http://lkml.kernel.org/r/20170103094059.GC3093@worktop
  [2] http://lkml.kernel.org/r/1482931866-6018-3-git-send-email-jolsa@kernel.orgSigned-off-by: NJiri Olsa <jolsa@redhat.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vince@deater.net>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/20170103142454.GA26251@kravaSigned-off-by: NIngo Molnar <mingo@kernel.org>

It's possible to set up PEBS events to get only errors and not
any data, like on SNB-X (model 45) and IVB-EP (model 62)
via 2 perf commands running simultaneously:

    taskset -c 1 ./perf record -c 4 -e branches:pp -j any -C 10

This leads to a soft lock up, because the error path of the
intel_pmu_drain_pebs_nhm() does not account event->hw.interrupt
for error PEBS interrupts, so in case you're getting ONLY
errors you don't have a way to stop the event when it's over
the max_samples_per_tick limit:

  NMI watchdog: BUG: soft lockup - CPU#22 stuck for 22s! [perf_fuzzer:5816]
  ...
  RIP: 0010:[<ffffffff81159232>]  [<ffffffff81159232>] smp_call_function_single+0xe2/0x140
  ...
  Call Trace:
   ? trace_hardirqs_on_caller+0xf5/0x1b0
   ? perf_cgroup_attach+0x70/0x70
   perf_install_in_context+0x199/0x1b0
   ? ctx_resched+0x90/0x90
   SYSC_perf_event_open+0x641/0xf90
   SyS_perf_event_open+0x9/0x10
   do_syscall_64+0x6c/0x1f0
   entry_SYSCALL64_slow_path+0x25/0x25

Add perf_event_account_interrupt() which does the interrupt
and frequency checks and call it from intel_pmu_drain_pebs_nhm()'s
error path.

We keep the pending_kill and pending_wakeup logic only in the
__perf_event_overflow() path, because they make sense only if
there's any data to deliver.
Signed-off-by: NJiri Olsa <jolsa@kernel.org>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vince@deater.net>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1482931866-6018-2-git-send-email-jolsa@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

info->si_addr is of type void __user *, so it should be compared against
something from the same address space.

This fixes the following sparse error:

  arch/x86/mm/mpx.c:296:27: error: incompatible types in comparison expression (different address spaces)
Signed-off-by: NTobias Klauser <tklauser@distanz.ch>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

The Intel Denverton microserver uses a 25 MHz TSC crystal,
so we can derive its exact [*] TSC frequency
using CPUID and some arithmetic, eg.:

  TSC: 1800 MHz (25000000 Hz * 216 / 3 / 1000000)

[*] 'exact' is only as good as the crystal, which should be +/- 20ppm
Signed-off-by: NLen Brown <len.brown@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/306899f94804aece6d8fa8b4223ede3b48dbb59c.1484287748.git.len.brown@intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

When CONFIG_RANDOMIZE_MODULE_REGION_FULL=y, the offset between loaded
modules and the core kernel may exceed 4 GB, putting symbols exported
by the core kernel out of the reach of the ordinary adrp/add instruction
pairs used to generate relative symbol references. So make the adr_l
macro emit a movz/movk sequence instead when executing in module context.

While at it, remove the pointless special case for the stack pointer.
Acked-by: NMark Rutland <mark.rutland@arm.com>
Acked-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

This is CVE-2017-2583.  On Intel this causes a failed vmentry because
SS's type is neither 3 nor 7 (even though the manual says this check is
only done for usable SS, and the dmesg splat says that SS is unusable!).
On AMD it's worse: svm.c is confused and sets CPL to 0 in the vmcb.

The fix fabricates a data segment descriptor when SS is set to a null
selector, so that CPL and SS.DPL are set correctly in the VMCS/vmcb.
Furthermore, only allow setting SS to a NULL selector if SS.RPL < 3;
this in turn ensures CPL < 3 because RPL must be equal to CPL.

Thanks to Andy Lutomirski and Willy Tarreau for help in analyzing
the bug and deciphering the manuals.
Reported-by: NXiaohan Zhang <zhangxiaohan1@huawei.com>
Fixes: 79d5b4c3
Cc: stable@nongnu.org
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Reported by syzkaller:

    BUG: unable to handle kernel NULL pointer dereference at 00000000000001b0
    IP: _raw_spin_lock+0xc/0x30
    PGD 3e28eb067
    PUD 3f0ac6067
    PMD 0
    Oops: 0002 [#1] SMP
    CPU: 0 PID: 2431 Comm: test Tainted: G           OE   4.10.0-rc1+ #3
    Call Trace:
     ? kvm_ioapic_scan_entry+0x3e/0x110 [kvm]
     kvm_arch_vcpu_ioctl_run+0x10a8/0x15f0 [kvm]
     ? pick_next_task_fair+0xe1/0x4e0
     ? kvm_arch_vcpu_load+0xea/0x260 [kvm]
     kvm_vcpu_ioctl+0x33a/0x600 [kvm]
     ? hrtimer_try_to_cancel+0x29/0x130
     ? do_nanosleep+0x97/0xf0
     do_vfs_ioctl+0xa1/0x5d0
     ? __hrtimer_init+0x90/0x90
     ? do_nanosleep+0x5b/0xf0
     SyS_ioctl+0x79/0x90
     do_syscall_64+0x6e/0x180
     entry_SYSCALL64_slow_path+0x25/0x25
    RIP: _raw_spin_lock+0xc/0x30 RSP: ffffa43688973cc0

The syzkaller folks reported a NULL pointer dereference due to
ENABLE_CAP succeeding even without an irqchip.  The Hyper-V
synthetic interrupt controller is activated, resulting in a
wrong request to rescan the ioapic and a NULL pointer dereference.

    #include <sys/ioctl.h>
    #include <sys/mman.h>
    #include <sys/types.h>
    #include <linux/kvm.h>
    #include <pthread.h>
    #include <stddef.h>
    #include <stdint.h>
    #include <stdlib.h>
    #include <string.h>
    #include <unistd.h>

    #ifndef KVM_CAP_HYPERV_SYNIC
    #define KVM_CAP_HYPERV_SYNIC 123
    #endif

    void* thr(void* arg)
    {
	struct kvm_enable_cap cap;
	cap.flags = 0;
	cap.cap = KVM_CAP_HYPERV_SYNIC;
	ioctl((long)arg, KVM_ENABLE_CAP, &cap);
	return 0;
    }

    int main()
    {
	void *host_mem = mmap(0, 0x1000, PROT_READ|PROT_WRITE,
			MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
	int kvmfd = open("/dev/kvm", 0);
	int vmfd = ioctl(kvmfd, KVM_CREATE_VM, 0);
	struct kvm_userspace_memory_region memreg;
	memreg.slot = 0;
	memreg.flags = 0;
	memreg.guest_phys_addr = 0;
	memreg.memory_size = 0x1000;
	memreg.userspace_addr = (unsigned long)host_mem;
	host_mem[0] = 0xf4;
	ioctl(vmfd, KVM_SET_USER_MEMORY_REGION, &memreg);
	int cpufd = ioctl(vmfd, KVM_CREATE_VCPU, 0);
	struct kvm_sregs sregs;
	ioctl(cpufd, KVM_GET_SREGS, &sregs);
	sregs.cr0 = 0;
	sregs.cr4 = 0;
	sregs.efer = 0;
	sregs.cs.selector = 0;
	sregs.cs.base = 0;
	ioctl(cpufd, KVM_SET_SREGS, &sregs);
	struct kvm_regs regs = { .rflags = 2 };
	ioctl(cpufd, KVM_SET_REGS, &regs);
	ioctl(vmfd, KVM_CREATE_IRQCHIP, 0);
	pthread_t th;
	pthread_create(&th, 0, thr, (void*)(long)cpufd);
	usleep(rand() % 10000);
	ioctl(cpufd, KVM_RUN, 0);
	pthread_join(th, 0);
	return 0;
    }

This patch fixes it by failing ENABLE_CAP if without an irqchip.
Reported-by: NDmitry Vyukov <dvyukov@google.com>
Fixes: 5c919412 (kvm/x86: Hyper-V synthetic interrupt controller)
Cc: stable@vger.kernel.org # 4.5+
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: NWanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Introduces segemented_write_std.

Switches from emulated reads/writes to standard read/writes in fxsave,
fxrstor, sgdt, and sidt.  This fixes CVE-2017-2584, a longstanding
kernel memory leak.

Since commit 283c95d0 ("KVM: x86: emulate FXSAVE and FXRSTOR",
2016-11-09), which is luckily not yet in any final release, this would
also be an exploitable kernel memory *write*!
Reported-by: NDmitry Vyukov <dvyukov@google.com>
Cc: stable@vger.kernel.org
Fixes: 96051572
Fixes: 283c95d0Suggested-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NSteve Rutherford <srutherford@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

KVM's lapic emulation uses static_key_deferred (apic_{hw,sw}_disabled).
These are implemented with delayed_work structs which can still be
pending when the KVM module is unloaded. We've seen this cause kernel
panics when the kvm_intel module is quickly reloaded.

Use the new static_key_deferred_flush() API to flush pending updates on
module unload.
Signed-off-by: NDavid Matlack <dmatlack@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

When unwinding a task, the end of the stack is always at the same offset
right below the saved pt_regs, regardless of which syscall was used to
enter the kernel.  That convention allows the unwinder to verify that a
stack is sane.

However, newly forked tasks don't always follow that convention, as
reported by the following unwinder warning seen by Dave Jones:

  WARNING: kernel stack frame pointer at ffffc90001443f30 in kworker/u8:8:30468 has bad value           (null)

The warning was due to the following call chain:

  (ftrace handler)
  call_usermodehelper_exec_async+0x5/0x140
  ret_from_fork+0x22/0x30

The problem is that ret_from_fork() doesn't create a stack frame before
calling other functions.  Fix that by carefully using the frame pointer
macros.

In addition to conforming to the end of stack convention, this also
makes related stack traces more sensible by making it clear to the user
that ret_from_fork() was involved.
Reported-by: NDave Jones <davej@codemonkey.org.uk>
Signed-off-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/8854cdaab980e9700a81e9ebf0d4238e4bbb68ef.1483978430.git.jpoimboe@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

In the following commit:

  0100301b ("sched/x86: Rewrite the switch_to() code")

... the layout of the 'inactive_task_frame' struct was designed to have
a frame pointer header embedded in it, so that the unwinder could use
the 'bp' and 'ret_addr' fields to report __schedule() on the stack (or
ret_from_fork() for newly forked tasks which haven't actually run yet).

Finish the job by changing get_frame_pointer() to return a pointer to
inactive_task_frame's 'bp' field rather than 'bp' itself.  This allows
the unwinder to start one frame higher on the stack, so that it properly
reports __schedule().
Reported-by: NMiroslav Benes <mbenes@suse.cz>
Signed-off-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/598e9f7505ed0aba86e8b9590aa528c6c7ae8dcd.1483978430.git.jpoimboe@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

There are a handful of callers to save_stack_trace_tsk() and
show_stack() which try to unwind the stack of a task other than current.
In such cases, it's remotely possible that the task is running on one
CPU while the unwinder is reading its stack from another CPU, causing
the unwinder to see stack corruption.

These cases seem to be mostly harmless.  The unwinder has checks which
prevent it from following bad pointers beyond the bounds of the stack.
So it's not really a bug as long as the caller understands that
unwinding another task will not always succeed.

In such cases, it's possible that the unwinder may read a KASAN-poisoned
region of the stack.  Account for that by using READ_ONCE_NOCHECK() when
reading the stack of another task.

Use READ_ONCE() when reading the stack of the current task, since KASAN
warnings can still be useful for finding bugs in that case.
Reported-by: NDmitry Vyukov <dvyukov@google.com>
Signed-off-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/4c575eb288ba9f73d498dfe0acde2f58674598f1.1483978430.git.jpoimboe@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

There are a handful of callers to save_stack_trace_tsk() and
show_stack() which try to unwind the stack of a task other than current.
In such cases, it's remotely possible that the task is running on one
CPU while the unwinder is reading its stack from another CPU, causing
the unwinder to see stack corruption.

These cases seem to be mostly harmless.  The unwinder has checks which
prevent it from following bad pointers beyond the bounds of the stack.
So it's not really a bug as long as the caller understands that
unwinding another task will not always succeed.

Since stack "corruption" on another task's stack isn't necessarily a
bug, silence the warnings when unwinding tasks other than current.
Reported-by: NDave Jones <davej@codemonkey.org.uk>
Signed-off-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/00d8c50eea3446c1524a2a755397a3966629354c.1483978430.git.jpoimboe@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>