Intel's VMX is daft and resets the hidden TSS limit register to 0x67
on VMX reload, and the 0x67 is not configurable.  KVM currently
reloads TR using the LTR instruction on every exit, but this is quite
slow because LTR is serializing.

The 0x67 limit is entirely harmless unless ioperm() is in use, so
defer the reload until a task using ioperm() is actually running.

Here's some poorly done benchmarking using kvm-unit-tests:

Before:

cpuid 1313
vmcall 1195
mov_from_cr8 11
mov_to_cr8 17
inl_from_pmtimer 6770
inl_from_qemu 6856
inl_from_kernel 2435
outl_to_kernel 1402

After:

cpuid 1291
vmcall 1181
mov_from_cr8 11
mov_to_cr8 16
inl_from_pmtimer 6457
inl_from_qemu 6209
inl_from_kernel 2339
outl_to_kernel 1391
Signed-off-by: NAndy Lutomirski <luto@kernel.org>
[Force-reload TR in invalidate_tss_limit. - Paolo]
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Historically, the entire TSS + io bitmap structure was cacheline
aligned, but commit ca241c75 ("x86: unify tss_struct") changed it
(presumably inadvertently) so that the fixed-layout hardware part is
cacheline-aligned and the io bitmap is after the padding.  This wastes
24 bytes (the hardware part should be 104 bytes, but this pads it to
128 bytes) and, serves no purpose, and causes sizeof(struct
x86_hw_tss) to have a confusing value.

Drop the pointless alignment.
Signed-off-by: NAndy Lutomirski <luto@kernel.org>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Use actual pointer types for pointers (instead of unsigned long) and
replace hardcoded constants with the appropriate self-documenting
macros.

The function is still a bit messy, but this seems a lot better than
before to me.

This is mostly borrowed from a patch by Thomas Garnier.

Cc: Thomas Garnier <thgarnie@google.com>
Cc: Jim Mattson <jmattson@google.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NAndy Lutomirski <luto@kernel.org>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

It was a bit buggy (it didn't list all segment types that needed
64-bit fixups), but the bug was irrelevant because it wasn't called
in any interesting context on 64-bit kernels and was only used for
data segents on 32-bit kernels.

To avoid confusion, make it explicitly 32-bit only.

Cc: Thomas Garnier <thgarnie@google.com>
Cc: Jim Mattson <jmattson@google.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NAndy Lutomirski <luto@kernel.org>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The current CPU's TSS base is a foregone conclusion, so there's no need
to parse it out of the segment tables.  This should save a couple cycles
(as STR is surely microcoded and poorly optimized) but, more importantly,
it's a cleanup and it means that segment_base() will never be called on
64-bit kernels.

Cc: Thomas Garnier <thgarnie@google.com>
Cc: Jim Mattson <jmattson@google.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NAndy Lutomirski <luto@kernel.org>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Rather than open-coding the kernel TSS limit in set_tss_desc(), make
it a real macro near the TSS layout definition.

This is purely a cleanup.

Cc: Thomas Garnier <thgarnie@google.com>
Cc: Jim Mattson <jmattson@google.com>
Signed-off-by: NAndy Lutomirski <luto@kernel.org>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

handle_vmon gets a reference on VMXON region page,
but does not release it. Release the reference.

Found by syzkaller; based on a patch by Dmitry.
Reported-by: NDmitry Vyukov <dvyukov@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Merge branch 'kvm-ppc-next' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc into HEAD

Paul Mackerras writes:
"Please do a pull from my kvm-ppc-next branch to get some fixes which I
would like to have in 4.11.  There are four small commits there; two
are fixes for potential host crashes in the new HPT resizing code, and
the other two are changes to printks to make KVM on PPC a little less
noisy."

The new HPT resizing code added in commit b5baa687 ("KVM: PPC:
Book3S HV: KVM-HV HPT resizing implementation", 2016-12-20) doesn't
have code to handle the new HPTE format which POWER9 uses.  Thus it
would be best not to advertise it to userspace on POWER9 systems
until it works properly.

Also, since resize_hpt_rehash_hpte() contains BUG_ON() calls that
could be hit on POWER9, let's prevent it from being called on POWER9
for now.
Acked-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>

* Return an error code without storing it in an intermediate variable.

* Delete the local variable "r" and the jump label "out" which became
  unnecessary with this refactoring.
Signed-off-by: NMarkus Elfring <elfring@users.sourceforge.net>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

* Return an error code without storing it in an intermediate variable.

* Delete the local variable "r" and the jump label "out" which became
  unnecessary with this refactoring.
Signed-off-by: NMarkus Elfring <elfring@users.sourceforge.net>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

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

  This issue was detected by using the Coccinelle software.

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

The FPU is always active now when running KVM.
Reviewed-by: NDavid Matlack <dmatlack@google.com>
Reviewed-by: NBandan Das <bsd@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The purpose of the KVM_SET_SIGNAL_MASK API is to let userspace "kick"
a VCPU out of KVM_RUN through a POSIX signal.  A signal is attached
to a dummy signal handler; by blocking the signal outside KVM_RUN and
unblocking it inside, this possible race is closed:

          VCPU thread                     service thread
   --------------------------------------------------------------
        check flag
                                          set flag
                                          raise signal
        (signal handler does nothing)
        KVM_RUN

However, one issue with KVM_SET_SIGNAL_MASK is that it has to take
tsk->sighand->siglock on every KVM_RUN.  This lock is often on a
remote NUMA node, because it is on the node of a thread's creator.
Taking this lock can be very expensive if there are many userspace
exits (as is the case for SMP Windows VMs without Hyper-V reference
time counter).

As an alternative, we can put the flag directly in kvm_run so that
KVM can see it:

          VCPU thread                     service thread
   --------------------------------------------------------------
                                          raise signal
        signal handler
          set run->immediate_exit
        KVM_RUN
          check run->immediate_exit
Reviewed-by: NRadim Krčmář <rkrcmar@redhat.com>
Reviewed-by: NDavid Hildenbrand <david@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The average user likely does not know what a "htab" or "LPID" is,
and it's annoying that these messages are quickly filling the dmesg
log when you're doing boot cycle tests, so let's turn it into a debug
message instead.
Signed-off-by: NThomas Huth <thuth@redhat.com>
Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>

kvm_ppc_mmu_book3s_32/64 xlat() logs "KVM can't copy data" error
upon failing to copy user data to kernel space. This floods kernel
log once such fails occur in short time period. Ratelimit this
error to avoid flooding kernel logs upon copy data failures.
Signed-off-by: NVipin K Parashar <vipin@linux.vnet.ibm.com>
Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>

Provide versions of struct gfn_to_hva_cache functions that
take vcpu as a parameter instead of struct kvm.  The existing functions
are not needed anymore, so delete them.  This allows dirty pages to
be logged in the vcpu dirty ring, instead of the global dirty ring,
for ring-based dirty memory tracking.
Signed-off-by: NLei Cao <lei.cao@stratus.com>
Message-Id: <CY1PR08MB19929BD2AC47A291FD680E83F04F0@CY1PR08MB1992.namprd08.prod.outlook.com>
Reviewed-by: NRadim Krčmář <rkrcmar@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

This will make it easier to support multiple address spaces in
kvm_gfn_to_hva_cache_init.  Instead of having to check the address
space id, we can keep on checking just the generation number.
Reviewed-by: NRadim Krčmář <rkrcmar@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

This will make it a bit simpler to handle multiple address spaces
in gfn_to_hva_cache.
Reviewed-by: NRadim Krčmář <rkrcmar@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Reviewed-by: NRadim Krčmář <rkrcmar@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

No point in registering the device if it cannot work.
The hypercall does not advertise itself, so we have to call it.
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

resize_hpt_release(), called once the HPT resize of a KVM guest is
completed (successfully or unsuccessfully) frees the state structure for
the resize.  It is currently not safe to call with a NULL pointer.

However, one of the error paths in kvm_vm_ioctl_resize_hpt_commit() can
invoke it with a NULL pointer.  This will occur if userspace improperly
invokes KVM_PPC_RESIZE_HPT_COMMIT without previously calling
KVM_PPC_RESIZE_HPT_PREPARE, or if it calls COMMIT twice without an
intervening PREPARE.

To fix this potential crash bug - and maybe others like it, make it safe
(and a no-op) to call resize_hpt_release() with a NULL resize pointer.

Found by Dan Carpenter with a static checker.
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>

The hashtable and guarding spinlock are global data structures,
we can inititalize them statically.
Signed-off-by: NDavid Hildenbrand <david@redhat.com>
Message-Id: <20170124212116.4568-1-david@redhat.com>
Reviewed-by: NRadim Krčmář <rkrcmar@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Nested_vmx_run is split into two parts: the part that handles the
VMLAUNCH/VMRESUME instruction, and the part that modifies the vcpu state
to transition from VMX root mode to VMX non-root mode. The latter will
be used when restoring the checkpointed state of a vCPU that was in VMX
operation when a snapshot was taken.
Signed-off-by: NJim Mattson <jmattson@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The checks performed on the contents of the vmcs12 are extracted from
nested_vmx_run so that they can be used to validate a vmcs12 that has
been restored from a checkpoint.
Signed-off-by: NJim Mattson <jmattson@google.com>
[Change prepare_vmcs02 and nested_vmx_load_cr3's last argument to u32,
 to match check_vmentry_postreqs.  Update comments for singlestep
 handling. - Paolo]
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Perform the checks on vmcs12 state early, but defer the gpa->hpa lookups
until after prepare_vmcs02. Later, when we restore the checkpointed
state of a vCPU in guest mode, we will not be able to do the gpa->hpa
lookups when the restore is done.
Signed-off-by: NJim Mattson <jmattson@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Handle_vmptrld is split into two parts: the part that handles the
VMPTRLD instruction, and the part that establishes the current VMCS
pointer.  The latter will be used when restoring the checkpointed state
of a vCPU that had a valid VMCS pointer when a snapshot was taken.
Signed-off-by: NJim Mattson <jmattson@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Handle_vmon is split into two parts: the part that handles the VMXON
instruction, and the part that modifies the vcpu state to transition
from legacy mode to VMX operation. The latter will be used when
restoring the checkpointed state of a vCPU that was in VMX operation
when a snapshot was taken.
Signed-off-by: NJim Mattson <jmattson@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Split prepare_vmcs12 into two parts: the part that stores the current L2
guest state and the part that sets up the exit information fields. The
former will be used when checkpointing the vCPU's VMX state.

Modify prepare_vmcs02 so that it can construct a vmcs02 midway through
L2 execution, using the checkpointed L2 guest state saved into the
cached vmcs12 above.
Signed-off-by: NJim Mattson <jmattson@google.com>
[Rebasing: add from_vmentry argument to prepare_vmcs02 instead of using
 vmx->nested.nested_run_pending, because it is no longer 1 at the
 point prepare_vmcs02 is called. - Paolo]
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Since bf9f6ac8 ("KVM: Update Posted-Interrupts Descriptor when vCPU
is blocked", 2015-09-18) the posted interrupt descriptor is checked
unconditionally for PIR.ON.  Therefore we don't need KVM_REQ_EVENT to
trigger the scan and, if NMIs or SMIs are not involved, we can avoid
the complicated event injection path.

Calling kvm_vcpu_kick if PIR.ON=1 is also useless, though it has been
there since APICv was introduced.

However, without the KVM_REQ_EVENT safety net KVM needs to be much
more careful about races between vmx_deliver_posted_interrupt and
vcpu_enter_guest.  First, the IPI for posted interrupts may be issued
between setting vcpu->mode = IN_GUEST_MODE and disabling interrupts.
If that happens, kvm_trigger_posted_interrupt returns true, but
smp_kvm_posted_intr_ipi doesn't do anything about it.  The guest is
entered with PIR.ON, but the posted interrupt IPI has not been sent
and the interrupt is only delivered to the guest on the next vmentry
(if any).  To fix this, disable interrupts before setting vcpu->mode.
This ensures that the IPI is delayed until the guest enters non-root mode;
it is then trapped by the processor causing the interrupt to be injected.

Second, the IPI may be issued between kvm_x86_ops->sync_pir_to_irr(vcpu)
and vcpu->mode = IN_GUEST_MODE.  In this case, kvm_vcpu_kick is called
but it (correctly) doesn't do anything because it sees vcpu->mode ==
OUTSIDE_GUEST_MODE.  Again, the guest is entered with PIR.ON but no
posted interrupt IPI is pending; this time, the fix for this is to move
the RVI update after IN_GUEST_MODE.

Both issues were mostly masked by the liberal usage of KVM_REQ_EVENT,
though the second could actually happen with VT-d posted interrupts.
In both race scenarios KVM_REQ_EVENT would cancel guest entry, resulting
in another vmentry which would inject the interrupt.

This saves about 300 cycles on the self_ipi_* tests of vmexit.flat.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Calls to apic_find_highest_irr are scanning IRR twice, once
in vmx_sync_pir_from_irr and once in apic_search_irr.  Change
sync_pir_from_irr to get the new maximum IRR from kvm_apic_update_irr;
now that it does the computation, it can also do the RVI write.

In order to avoid complications in svm.c, make the callback optional.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Add return value to __kvm_apic_update_irr/kvm_apic_update_irr.
Move vmx_sync_pir_to_irr around.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

vcpu_run calls kvm_vcpu_running, not kvm_arch_vcpu_runnable,
and the former does not call check_nested_events.

Once KVM_REQ_EVENT is removed from the APICv interrupt injection
path, however, this would leave no place to trigger a vmexit
from L2 to L1, causing a missed interrupt delivery while in guest
mode.  This is caught by the "ack interrupt on exit" test in
vmx.flat.

[This does not change the calls to check_nested_events in
 inject_pending_event.  That is material for a separate cleanup.]
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Pending interrupts might be in the PI descriptor when the
LAPIC is restored from an external state; we do not want
them to be injected.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

As in the SVM patch, the guest physical address is passed by
VMX to x86_emulate_instruction already, so mark the GPA as available
in vcpu->arch.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Merge branch 'kvm-ppc-next' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc into HEAD

This brings in two fixes for potential host crashes, from Ben
Herrenschmidt and Nick Piggin.

The newly added hypercall doesn't work on x86-32:

arch/x86/kvm/x86.c: In function 'kvm_pv_clock_pairing':
arch/x86/kvm/x86.c:6163:6: error: implicit declaration of function 'kvm_get_walltime_and_clockread';did you mean 'kvm_get_time_scale'? [-Werror=implicit-function-declaration]

This adds an #ifdef around it, matching the one around the related
functions that are also only implemented on 64-bit systems.

Fixes: 55dd00a7 ("KVM: x86: add KVM_HC_CLOCK_PAIRING hypercall")
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Merge tag 'kvmarm-for-4.11' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

kvmarm updates for 4.11

- GICv3 save restore
- Cache flushing fixes
- MSI injection fix for GICv3 ITS
- Physical timer emulation support

Fix to return error code -ENOMEM from the memory alloc error handling
case instead of 0, as done elsewhere in this function.
Signed-off-by: NWei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>