Make the guest's kvmclock count up from zero, not from the host boot
time.  The guest cannot rely on that anyway because it changes on
migration, the numbers are easier on the eye and finally it matches the
desired semantics of the Hyper-V time reference counter.
Reviewed-by: NRoman Kagan <rkagan@virtuozzo.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

We will use it in the next patches for KVM_GET_CLOCK and as a basis for the
contents of the Hyper-V TSC page.  Get the values from the Linux
timekeeper even if kvmclock is not enabled.
Reviewed-by: NRoman Kagan <rkagan@virtuozzo.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

This commit exports the following information to
user-space via the newly created per-vcpu debugfs
directory:

 - TSC offset (as a signed number)
 - TSC scaling ratio
 - TSC scaling ratio fractinal bits

The original intention of this commit was to
export only the TSC offset, but the TSC scaling
information is exported for completeness.

We need to retrieve the TSC offset from user-space
in order to support the merging of host and guest
traces in trace-cmd. Today, we use the kvm_write_tsc_offset
tracepoint, but it has a number of problems (mainly,
it requires a running VM to be rebooted, ftrace setup,
and also tracepoints are not supposed to be ABIs).

The merging of host and guest traces is explained
in more detail in this thread:

 [Qemu-devel] [RFC] host and guest kernel trace merging
 https://lists.nongnu.org/archive/html/qemu-devel/2016-03/msg00887.html

This commit creates the following files in debugfs:

/sys/kernel/debug/kvm/66828-10/vcpu0/tsc-offset
/sys/kernel/debug/kvm/66828-10/vcpu0/tsc-scaling-ratio
/sys/kernel/debug/kvm/66828-10/vcpu0/tsc-scaling-ratio-frac-bits

The last two are only created if TSC scaling is supported.
Signed-off-by: NLuiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Two stubs are added:

 o kvm_arch_has_vcpu_debugfs(): must return true if the arch
   supports creating debugfs entries in the vcpu debugfs dir
   (which will be implemented by the next commit)

 o kvm_arch_create_vcpu_debugfs(): code that creates debugfs
   entries in the vcpu debugfs dir

For x86, this commit introduces a new file to avoid growing
arch/x86/kvm/x86.c even more.
Signed-off-by: NLuiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The TSC offset can now be read directly from struct kvm_arch_vcpu.
Signed-off-by: NLuiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

A future commit will want to easily read a vCPU's TSC offset,
so we store it in struct kvm_arch_vcpu_arch for easy access.
Signed-off-by: NLuiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

This patch implements update_pi_irte function hook to allow SVM
communicate to IOMMU driver regarding how to set up IRTE for handling
posted interrupt.

In case AVIC is enabled, during vcpu_load/unload, SVM needs to update
IOMMU IRTE with appropriate host physical APIC ID. Also, when
vcpu_blocking/unblocking, SVM needs to update the is-running bit in
the IOMMU IRTE. Both are achieved via calling amd_iommu_update_ga().

However, if GA mode is not enabled for the pass-through device,
IOMMU driver will simply just return when calling amd_iommu_update_ga.
Signed-off-by: NSuravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Reviewed-by: NRadim Krčmář <rkrcmar@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

This patch introduces avic_ga_log_notifier, which will be called
by IOMMU driver whenever it handles the Guest vAPIC (GA) log entry.
Reviewed-by: NRadim Krčmář <rkrcmar@redhat.com>
Signed-off-by: NSuravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Introduces per-VM AVIC ID and helper functions to manage the IDs.
Currently, the ID will be used to implement 32-bit AVIC IOMMU GA tag.

The ID is 24-bit one-based indexing value, and is managed via helper
functions to get the next ID, or to free an ID once a VM is destroyed.
There should be no ID conflict for any active VMs.
Reviewed-by: NRadim Krčmář <rkrcmar@redhat.com>
Signed-off-by: NSuravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

vms and vcpus have statistics associated with them which can be viewed
within the debugfs. Currently it is assumed within the vcpu_stat_get() and
vm_stat_get() functions that all of these statistics are represented as
u32s, however the next patch adds some u64 vcpu statistics.

Change all vcpu statistics to u64 and modify vcpu_stat_get() accordingly.
Since vcpu statistics are per vcpu, they will only be updated by a single
vcpu at a time so this shouldn't present a problem on 32-bit machines
which can't atomically increment 64-bit numbers. However vm statistics
could potentially be updated by multiple vcpus from that vm at a time.
To avoid the overhead of atomics make all vm statistics ulong such that
they are 64-bit on 64-bit systems where they can be atomically incremented
and are 32-bit on 32-bit systems which may not be able to atomically
increment 64-bit numbers. Modify vm_stat_get() to expect ulongs.
Signed-off-by: NSuraj Jitindar Singh <sjitindarsingh@gmail.com>
Reviewed-by: NDavid Matlack <dmatlack@google.com>
Acked-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>

Expose the feature to L1 hypervisor if host CPU supports it, since
certain hypervisors requires it for own purposes.

According to Intel SDM A.1, if CPU supports the feature,
VMX_INSTRUCTION_INFO field of VMCS will contain detailed information
about INS/OUTS instructions handling. This field is already copied to
VMCS12 for L1 hypervisor (see prepare_vmcs12 routine) independently
feature presence.
Signed-off-by: NJan Dakinevich <jan.dakinevich@gmail.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

setup_vmcs_config takes a pointer to the vmcs_config global.  The
indirection is somewhat pointless, but just keep things consistent
for now.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

handle_external_intr does not enable interrupts anymore, vcpu_enter_guest
does it after calling guest_exit_irqoff.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

These are mostly related to nested VMX.  They needn't have
a loglevel as high as KERN_WARN, and mustn't be allowed to
pollute the host logs.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

If EPT support is exposed to L1 hypervisor, guest linear-address field
of VMCS should contain GVA of L2, the access to which caused EPT violation.
Signed-off-by: NJan Dakinevich <jan.dakinevich@gmail.com>
Reviewed-by: NWanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Commit 61abdbe0 ("kvm: x86: make lapic hrtimer pinned") pins the emulated
lapic timer. This patch does the same for the emulated nested preemption
timer to avoid vmexit an unrelated vCPU and the latency of kicking IPI to
another vCPU.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Yunhong Jiang <yunhong.jiang@intel.com>
Signed-off-by: NWanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The validity check for the guest line address is inefficient,
check the invalid value instead of enumerating the valid ones.
Signed-off-by: NLiang Li <liang.z.li@intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Expose AVX512DQ, AVX512BW, AVX512VL feature to guest.
Its spec can be found at:
https://software.intel.com/sites/default/files/managed/b4/3a/319433-024.pdfSigned-off-by: NLuwei Kang <luwei.kang@intel.com>
[Resolved a trivial conflict with removed F(PCOMMIT).]
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

That parameter isn't used in these functions,
it's probably a historical artifact.
Signed-off-by: NBandan Das <bsd@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

APIC map table is recalculated during reset APIC ID to the initial value
when enabling LAPIC. This patch move the recalculate_apic_map() to the
next branch since we don't need to recalculate apic map twice in current
codes.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: NWanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

When the host supported TSC scaling, L2 would use a TSC multiplier of
0, which causes a VM entry failure. Now L2's TSC uses the same
multiplier as L1.
Signed-off-by: NPeter Feiner <pfeiner@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

If vmcs12 does not intercept APIC_BASE writes, then KVM will handle the
write with vmcs02 as the current VMCS.
This will incorrectly apply modifications intended for vmcs01 to vmcs02
and L2 can use it to gain access to L0's x2APIC registers by disabling
virtualized x2APIC while using msr bitmap that assumes enabled.

Postpone execution of vmx_set_virtual_x2apic_mode until vmcs01 is the
current VMCS.  An alternative solution would temporarily make vmcs01 the
current VMCS, but it requires more care.

Fixes: 8d14695f ("x86, apicv: add virtual x2apic support")
Reported-by: NJim Mattson <jmattson@google.com>
Reviewed-by: NWanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

msr bitmap can be used to avoid a VM exit (interception) on guest MSR
accesses.  In some configurations of VMX controls, the guest can even
directly access host's x2APIC MSRs.  See SDM 29.5 VIRTUALIZING MSR-BASED
APIC ACCESSES.

L2 could read all L0's x2APIC MSRs and write TPR, EOI, and SELF_IPI.
To do so, L1 would first trick KVM to disable all possible interceptions
by enabling APICv features and then would turn those features off;
nested_vmx_merge_msr_bitmap() only disabled interceptions, so VMX would
not intercept previously enabled MSRs even though they were not safe
with the new configuration.

Correctly re-enabling interceptions is not enough as a second bug would
still allow L1+L2 to access host's MSRs: msr bitmap was shared for all
VMCSs, so L1 could trigger a race to get the desired combination of msr
bitmap and VMX controls.

This fix allocates a msr bitmap for every L1 VCPU, allows only safe
x2APIC MSRs from L1's msr bitmap, and disables msr bitmaps if they would
have to intercept everything anyway.

Fixes: 3af18d9c ("KVM: nVMX: Prepare for using hardware MSR bitmap")
Reported-by: NJim Mattson <jmattson@google.com>
Suggested-by: NWincy Van <fanwenyi0529@gmail.com>
Reviewed-by: NWanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

Frank reported kernel panic when he disabled several cores in BIOS
via following option:

  Core Disable Bitmap(Hex)   [0]

with number 0xFFE, which leaves 16 CPUs in system (out of 48).

The kernel panic below goes along with following messages:

 smpboot: Max logical packages: 2^M
 smpboot: APIC(0) Converting physical 0 to logical package 0^M
 smpboot: APIC(20) Converting physical 1 to logical package 1^M
 smpboot: APIC(40) Package 2 exceeds logical package map^M
 smpboot: CPU 8 APICId 40 disabled^M
 smpboot: APIC(60) Package 3 exceeds logical package map^M
 smpboot: CPU 12 APICId 60 disabled^M
 ...
 general protection fault: 0000 [#1] SMP^M
 Modules linked in:^M
 CPU: 15 PID: 1 Comm: swapper/0 Not tainted 4.7.0-rc5+ #1^M
 Hardware name: SGI UV300/UV300, BIOS SGI UV 300 series BIOS 05/25/2016^M
 task: ffff8801673e0000 ti: ffff8801673ac000 task.ti: ffff8801673ac000^M
 RIP: 0010:[<ffffffff81014d54>]  [<ffffffff81014d54>] uncore_change_context+0xd4/0x180^M
 ...
  [<ffffffff810158ac>] uncore_event_init_cpu+0x6c/0x70^M
  [<ffffffff81d8c91c>] intel_uncore_init+0x1c2/0x2dd^M
  [<ffffffff81d8c75a>] ? uncore_cpu_setup+0x17/0x17^M
  [<ffffffff81002190>] do_one_initcall+0x50/0x190^M
  [<ffffffff810ab193>] ? parse_args+0x293/0x480^M
  [<ffffffff81d87365>] kernel_init_freeable+0x1a5/0x249^M
  [<ffffffff81d86a35>] ? set_debug_rodata+0x12/0x12^M
  [<ffffffff816dc19e>] kernel_init+0xe/0x110^M
  [<ffffffff816e93bf>] ret_from_fork+0x1f/0x40^M
  [<ffffffff816dc190>] ? rest_init+0x80/0x80^M

The reason for the panic is wrong value of __max_logical_packages,
which lets logical_package_map uninitialized and the uncore code
relying on this map being properly initialized (maybe we should
add some safety checks there as well).

The __max_logical_packages is computed as:

  DIV_ROUND_UP(total_cpus, ncpus);
  - ncpus being number of cores

With above BIOS setup we get total_cpus == 16 which set
__max_logical_packages to 2 (ncpus is 12).

Once topology_update_package_map processes CPU with logical
pkg over 2 we display above messages and fail to initialize
the physical_to_logical_pkg map, which makes the uncore code
crash.

The fix is to remove logical_package_map bitmap completely
and keep and update the logical_packages number instead.

After we enumerate all the present CPUs, we check if the
enumerated logical packages count is within its computed
maximum from BIOS data.

If it's not the case, we set this maximum to the new enumerated
value and freeze any new addition of logical packages.

The freeze is because lot of init code like uncore/rapl/cqm
depends on having maximum logical package value set to allocate
their data, so we can't change it later on.

Prarit Bhargava tested the patch and confirms that it solves
the problem:

  From dmidecode:
          Core Count: 24
          Core Enabled: 24
          Thread Count: 48

Orig kernel boot log:

 [    0.464981] smpboot: Max logical packages: 19
 [    0.469861] smpboot: APIC(0) Converting physical 0 to logical package 0
 [    0.477261] smpboot: APIC(40) Converting physical 1 to logical package 1
 [    0.484760] smpboot: APIC(80) Converting physical 2 to logical package 2
 [    0.492258] smpboot: APIC(c0) Converting physical 3 to logical package 3

1.  nr_cpus=8, should stop enumerating in package 0:

 [    0.533664] smpboot: APIC(0) Converting physical 0 to logical package 0
 [    0.539596] smpboot: Max logical packages: 19

2.  max_cpus=8, should still enumerate all packages:

 [    0.526494] smpboot: APIC(0) Converting physical 0 to logical package 0
 [    0.532428] smpboot: APIC(40) Converting physical 1 to logical package 1
 [    0.538456] smpboot: APIC(80) Converting physical 2 to logical package 2
 [    0.544486] smpboot: APIC(c0) Converting physical 3 to logical package 3
 [    0.550524] smpboot: Max logical packages: 19

3.  nr_cpus=49 ( 2 socket + 1 core on 3rd socket), should stop enumerating in
    package 2:

 [    0.521378] smpboot: APIC(0) Converting physical 0 to logical package 0
 [    0.527314] smpboot: APIC(40) Converting physical 1 to logical package 1
 [    0.533345] smpboot: APIC(80) Converting physical 2 to logical package 2
 [    0.539368] smpboot: Max logical packages: 19

4.  maxcpus=49, should still enumerate all packages:

 [    0.525591] smpboot: APIC(0) Converting physical 0 to logical package 0
 [    0.531525] smpboot: APIC(40) Converting physical 1 to logical package 1
 [    0.537547] smpboot: APIC(80) Converting physical 2 to logical package 2
 [    0.543579] smpboot: APIC(c0) Converting physical 3 to logical package 3
 [    0.549624] smpboot: Max logical packages: 19

5.  kdump (nr_cpus=1) works as well.
Reported-by: NFrank Ramsay <framsay@redhat.com>
Tested-by: NPrarit Bhargava <prarit@redhat.com>
Signed-off-by: NJiri Olsa <jolsa@kernel.org>
Reviewed-by: NPrarit Bhargava <prarit@redhat.com>
Acked-by: NPeter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20160815101700.GA30090@kravaSigned-off-by: NIngo Molnar <mingo@kernel.org>

Similar to:

  efaad554 ("x86/microcode/intel: Fix initrd loading with CONFIG_RANDOMIZE_MEMORY=y")

... fix microcode loading from the initrd on AMD by adding the
randomization offset to the microcode patch container within the initrd.
Reported-and-tested-by: NBrian Gerst <brgerst@gmail.com>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-tip-commits@vger.kernel.org
Link: http://lkml.kernel.org/r/20160817113314.GA19221@nazgul.tnicSigned-off-by: NIngo Molnar <mingo@kernel.org>

The value of temp_level4_pgt is the physical address of the
top-level page directory, so use __pa() to compute it.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NIngo Molnar <mingo@kernel.org>

There are bug reports about miscounting uncore counters on some
client machines like Sandybridge, Broadwell and Skylake. It is
very likely to be observed on idle systems.

This issue is caused by a hardware issue. PERF_GLOBAL_CTL could be
cleared after Package C7, and nothing will be count.
The related errata (HSD 158) could be found in:

  www.intel.com/content/dam/www/public/us/en/documents/specification-updates/4th-gen-core-family-desktop-specification-update.pdf

This patch tries to work around this issue by re-enabling PERF_GLOBAL_CTL
in ->enable_box(). The workaround does not cover all cases. It helps for new
events after returning from C7. But it cannot prevent C7, it will still
miscount if a counter is already active.

There is no drawback in leaving it enabled, so it does not need
disable_box() here.
Signed-off-by: NKan Liang <kan.liang@intel.com>
Cc: <stable@vger.kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
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 <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1470925874-59943-1-git-send-email-kan.liang@intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Some uncore boxes' num_counters value for Haswell server and
Broadwell server are not correct (too large, off by one).

This issue was found by comparing the code with the document. Although
there is no bug report from users yet, accessing non-existent counters
is dangerous and the behavior is undefined: it may cause miscounting or
even crashes.

This patch makes them consistent with the uncore document.
Reported-by: NLukasz Odzioba <lukasz.odzioba@intel.com>
Signed-off-by: NKan Liang <kan.liang@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
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 <vincent.weaver@maine.edu>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/1470925820-59847-1-git-send-email-kan.liang@intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Since instruction decoder now supports EVEX-encoded instructions, two fixes
are needed to correctly handle them in uprobes.

Extended bits for MODRM.rm field need to be sanitized just like we do it
for VEX3, to avoid encoding wrong register for register-relative access.

EVEX has _two_ extended bits: b and x. Theoretically, EVEX.x should be
ignored by the CPU (since GPRs go only up to 15, not 31), but let's be
paranoid here: proper encoding for register-relative access
should have EVEX.x = 1.

Secondly, we should fetch vex.vvvv for EVEX too.
This is now super easy because instruction decoder populates
vex_prefix.bytes[2] for all flavors of (e)vex encodings, even for VEX2.
Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com>
Acked-by: NMasami Hiramatsu <mhiramat@kernel.org>
Acked-by: NSrikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: linux-kernel@vger.kernel.org
Cc: <stable@vger.kernel.org> # v4.1+
Fixes: 8a764a87 ("x86/asm/decoder: Create artificial 3rd byte for 2-byte VEX")
Link: http://lkml.kernel.org/r/20160811154521.20469-1-dvlasenk@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

I made a mistake while converting the driver to the hotplug state
machine and as a result x2apic_cluster_probe() was accessing
cpus_in_cluster before allocating it.

This patch fixes it by setting the cpumask after the allocation the
memory succeeded.

While at it, I marked two functions static which are only used within
this file.
Reported-by: NLaura Abbott <labbott@redhat.com>
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 6b2c2847 ("x86/x2apic: Convert to CPU hotplug state machine")
Link: http://lkml.kernel.org/r/1470924515-9444-1-git-send-email-bigeasy@linutronix.deSigned-off-by: NIngo Molnar <mingo@kernel.org>

This problem has actually been in the UV code for a while, but we didn't
catch it until recently, because we had been relying on EFI_OLD_MEMMAP
to allow our systems to boot for a period of time.  We noticed the issue
when trying to kexec a recent community kernel, where we hit this NULL
pointer dereference in efi_sync_low_kernel_mappings():

 [    0.337515] BUG: unable to handle kernel NULL pointer dereference at 0000000000000880
 [    0.346276] IP: [<ffffffff8105df8d>] efi_sync_low_kernel_mappings+0x5d/0x1b0

The problem doesn't show up with EFI_OLD_MEMMAP because we skip the
chunk of setup_efi_state() that sets the efi_loader_signature for the
kexec'd kernel.  When the kexec'd kernel boots, it won't set EFI_BOOT in
setup_arch, so we completely avoid the bug.

We always kexec with noefi on the command line, so this shouldn't be an
issue, but since we're not actually checking for efi_runtime_disabled in
uv_bios_init(), we end up trying to do EFI runtime callbacks when we
shouldn't be. This patch just adds a check for efi_runtime_disabled in
uv_bios_init() so that we don't map in uv_systab when runtime_disabled ==
true.
Signed-off-by: NAlex Thorlton <athorlton@sgi.com>
Signed-off-by: NMatt Fleming <matt@codeblueprint.co.uk>
Cc: <stable@vger.kernel.org> # v4.7
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Travis <travis@sgi.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russ Anderson <rja@sgi.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1470912120-22831-2-git-send-email-matt@codeblueprint.co.ukSigned-off-by: NIngo Molnar <mingo@kernel.org>

On my Dell XPS 13 9350 with firmware 1.4.4 and SGX on, if I boot
Fedora 24's grub2-efi off a hard disk, my first 1MB of RAM looks
like:

 efi: mem00: [Runtime Data       |RUN|  |  |  |  |  |  |   |WB|WT|WC|UC] range=[0x0000000000000000-0x0000000000000fff] (0MB)
 efi: mem01: [Boot Data          |   |  |  |  |  |  |  |   |WB|WT|WC|UC] range=[0x0000000000001000-0x0000000000027fff] (0MB)
 efi: mem02: [Loader Data        |   |  |  |  |  |  |  |   |WB|WT|WC|UC] range=[0x0000000000028000-0x0000000000029fff] (0MB)
 efi: mem03: [Reserved           |   |  |  |  |  |  |  |   |WB|WT|WC|UC] range=[0x000000000002a000-0x000000000002bfff] (0MB)
 efi: mem04: [Runtime Data       |RUN|  |  |  |  |  |  |   |WB|WT|WC|UC] range=[0x000000000002c000-0x000000000002cfff] (0MB)
 efi: mem05: [Loader Data        |   |  |  |  |  |  |  |   |WB|WT|WC|UC] range=[0x000000000002d000-0x000000000002dfff] (0MB)
 efi: mem06: [Conventional Memory|   |  |  |  |  |  |  |   |WB|WT|WC|UC] range=[0x000000000002e000-0x0000000000057fff] (0MB)
 efi: mem07: [Reserved           |   |  |  |  |  |  |  |   |WB|WT|WC|UC] range=[0x0000000000058000-0x0000000000058fff] (0MB)
 efi: mem08: [Conventional Memory|   |  |  |  |  |  |  |   |WB|WT|WC|UC] range=[0x0000000000059000-0x000000000009ffff] (0MB)

My EBDA is at 0x2c000, which blocks off everything from 0x2c000 and
up, and my trampoline is 0x6000 bytes (6 pages), so it doesn't fit
in the loader data range at 0x28000.

Without this patch, it panics due to a failure to allocate the
trampoline.  With this patch, it works:

 [  +0.001744] Base memory trampoline at [ffff880000001000] 1000 size 24576
Signed-off-by: NAndy Lutomirski <luto@kernel.org>
Reviewed-by: NMatt Fleming <matt@codeblueprint.co.uk>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mario Limonciello <mario_limonciello@dell.com>
Cc: Matt Fleming <mfleming@suse.de>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/998c77b3bf709f3dfed85cb30701ed1a5d8a438b.1470821230.git.luto@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

If reserve_real_mode() fails, panicing immediately means we're
doomed.  Make it safe to try more than once to allocate the
trampoline:

 - Degrade a failure from panic() to pr_info().  (If we make it to
   setup_real_mode() without reserving the trampoline, we'll panic
   them.)

 - Factor out helpers so that platform code can supply a specific
   address to try.

 - Warn if reserve_real_mode() is called after we're done with the
   memblock allocator.  If that were to happen, we would behave
   unpredictably.
Signed-off-by: NAndy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mario Limonciello <mario_limonciello@dell.com>
Cc: Matt Fleming <mfleming@suse.de>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/876e383038f3e9971aa72fd20a4f5da05f9d193d.1470821230.git.luto@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

There's no need to run setup_real_mode() as early as we run it.
Defer it to the same early_initcall that sets up the page
permissions for the real mode code.

This should be a code size reduction.  More importantly, it give us
a longer window in which we can allocate the real mode trampoline.
Signed-off-by: NAndy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mario Limonciello <mario_limonciello@dell.com>
Cc: Matt Fleming <mfleming@suse.de>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/fd62f0da4f79357695e9bf3e365623736b05f119.1470821230.git.luto@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

The initialization process for trampoline_cr4_features and
mmu_cr4_features was confusing.  The intent is for mmu_cr4_features
and *trampoline_cr4_features to stay in sync, but
trampoline_cr4_features is NULL until setup_real_mode() runs.  The
old code synchronized *trampoline_cr4_features *twice*, once in
setup_real_mode() and once in setup_arch().  It also initialized
mmu_cr4_features in setup_real_mode(), which causes the actual value
of mmu_cr4_features to potentially depend on when setup_real_mode()
is called.

With this patch, mmu_cr4_features is initialized directly in
setup_arch(), and *trampoline_cr4_features is synchronized to
mmu_cr4_features when the trampoline is set up.

After this patch, it should be safe to defer setup_real_mode().
Signed-off-by: NAndy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mario Limonciello <mario_limonciello@dell.com>
Cc: Matt Fleming <mfleming@suse.de>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/d48a263f9912389b957dd495a7127b009259ffe0.1470821230.git.luto@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

reserve_bios_regions() is a quirk that reserves memory that we might
otherwise think is available.  There's no need to run it so early,
and running it before we have the memory map initialized with its
non-quirky inputs makes it hard to make reserve_bios_regions() more
intelligent.

Move it right after we populate the memblock state.
Signed-off-by: NAndy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mario Limonciello <mario_limonciello@dell.com>
Cc: Matt Fleming <mfleming@suse.de>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/59f58618911005c799c6c9979ce6ae4881d907c2.1470821230.git.luto@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Since commit:

  52aec330 ("x86/tlb: replace INVALIDATE_TLB_VECTOR by CALL_FUNCTION_VECTOR")

the TLB remote shootdown is done through call function vector. That
commit didn't take care of irq_tlb_count, which a later commit:

  fd0f5869 ("x86: Distinguish TLB shootdown interrupts from other functions call interrupts")

... tried to fix.

The fix assumes every increase of irq_tlb_count has a corresponding
increase of irq_call_count. So the irq_call_count is always bigger than
irq_tlb_count and we could substract irq_tlb_count from irq_call_count.

Unfortunately this is not true for the smp_call_function_single() case.
The IPI is only sent if the target CPU's call_single_queue is empty when
adding a csd into it in generic_exec_single. That means if two threads
are both adding flush tlb csds to the same CPU's call_single_queue, only
one IPI is sent. In other words, the irq_call_count is incremented by 1
but irq_tlb_count is incremented by 2. Over time, irq_tlb_count will be
bigger than irq_call_count and the substract will produce a very large
irq_call_count value due to overflow.

Considering that:

  1) it's not worth to send more IPIs for the sake of accurate counting of
     irq_call_count in generic_exec_single();

  2) it's not easy to tell if the call function interrupt is for TLB
     shootdown in __smp_call_function_single_interrupt().

Not to exclude TLB shootdown from call function count seems to be the
simplest fix and this patch just does that.

This bug was found by LKP's cyclic performance regression tracking recently
with the vm-scalability test suite. I have bisected to commit:

  3dec0ba0 ("mm/rmap: share the i_mmap_rwsem")

This commit didn't do anything wrong but revealed the irq_call_count
problem. IIUC, the commit makes rwc->remap_one in rmap_walk_file
concurrent with multiple threads.  When remap_one is try_to_unmap_one(),
then multiple threads could queue flush TLB to the same CPU but only
one IPI will be sent.

Since the commit was added in Linux v3.19, the counting problem only
shows up from v3.19 onwards.
Signed-off-by: NAaron Lu <aaron.lu@intel.com>
Cc: Alex Shi <alex.shi@linaro.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tomoki Sekiyama <tomoki.sekiyama.qu@hitachi.com>
Link: http://lkml.kernel.org/r/20160811074430.GA18163@aaronlu.sh.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

A recent patch changed the format of a swap PTE.

The comment explaining the format of the swap PTE is wrong about
the bits used for the swap type field.  Amusingly, the ASCII art
and the patch description are correct, but the comment itself
is wrong.

As I was looking at this, I also noticed that the
SWP_OFFSET_FIRST_BIT has an off-by-one error.  This does not
really hurt anything.  It just wasted a bit of space in the PTE,
giving us 2^59 bytes of addressable space in our swapfiles
instead of 2^60.  But, it doesn't match with the comments, and it
wastes a bit of space, so fix it.
Signed-off-by: NDave Hansen <dave.hansen@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave@sr71.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Toshi Kani <toshi.kani@hp.com>
Fixes: 00839ee3 ("x86/mm: Move swap offset/type up in PTE to work around erratum")
Link: http://lkml.kernel.org/r/20160810172325.E56AD7DA@viggo.jf.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

debug_putstr() is used to output strings without using printf-like
formatting but debug_putstr(v) is defined as early_printk(v) in
arch/x86/lib/kaslr.c.

This makes clang reports the following warning when building
with -Wformat-security:

    arch/x86/lib/kaslr.c:57:15: warning: format string is not a string
    literal (potentially insecure) [-Wformat-security]
            debug_putstr(purpose);
                         ^~~~~~~

Fix this by using "%s" in early_printk().
Signed-off-by: NNicolas Iooss <nicolas.iooss_linux@m4x.org>
Acked-by: NKees Cook <keescook@chromium.org>
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: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.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/20160806102039.27221-1-nicolas.iooss_linux@m4x.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

The Memory Protection Keys "rights register" (PKRU) is
XSAVE-managed, and is saved/restored along with the FPU state.

When kernel code accesses FPU regsisters, it does a delicate
dance with preempt.  Otherwise, the context switching code can
get confused as to whether the most up-to-date state is in the
registers themselves or in the XSAVE buffer.

But, PKRU is not a normal FPU register.  Using it does not
generate the normal device-not-available (#NM) exceptions which
means we can not manage it lazily, and the kernel completley
disallows using lazy mode when it is enabled.

The dance with preempt *only* occurs when managing the FPU
lazily.  Since we never manage PKRU lazily, we do not have to do
the dance with preempt; we can access it directly.  Doing it
this way saves a ton of complicated code (and is faster too).

Further, the XSAVES reenabling failed to patch a bit of code
in fpu__xfeature_set_state() the checked for compacted buffers.
That check caused fpu__xfeature_set_state() to silently refuse to
work when the kernel is using compacted XSAVE buffers.  This
broke execute-only and future pkey_mprotect() support when using
compact XSAVE buffers.

But, removing fpu__xfeature_set_state() gets rid of this issue,
in addition to the nice cleanup and speedup.

This fixes the same thing as a fix that Sai posted:

  https://lkml.org/lkml/2016/7/25/637

The fix that he posted is a much more obviously correct, but I
think we should just do this instead.
Reported-by: NSai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Signed-off-by: NDave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Dave Hansen <dave@sr71.net>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Ravi Shankar <ravi.v.shankar@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-Cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/20160727232040.7D060DAD@viggo.jf.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>