Commit Graph

20158 Commits

Author SHA1 Message Date
Nadav Amit
5b7f6a1e6f KVM: x86: Combine the lgdt and lidt emulation logic
LGDT and LIDT emulation logic is almost identical. Merge the logic into a
single point to avoid redundancy. This will be used by the next patch that
will ensure the bases of the loaded GDTR and IDTR are canonical.

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-07 15:44:08 +01:00
Nadav Amit
38827dbd3f KVM: x86: Do not update EFLAGS on faulting emulation
If the emulation ends in fault, eflags should not be updated.  However, several
instruction emulations (actually all the fastops) currently update eflags, if
the fault was detected afterwards (e.g., #PF during writeback).

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-07 15:44:08 +01:00
Nadav Amit
9d88fca71a KVM: x86: MOV to CR3 can set bit 63
Although Intel SDM mentions bit 63 is reserved, MOV to CR3 can have bit 63 set.
As Intel SDM states in section 4.10.4 "Invalidation of TLBs and
Paging-Structure Caches": " MOV to CR3. ... If CR4.PCIDE = 1 and bit 63 of the
instruction’s source operand is 0 ..."

In other words, bit 63 is not reserved. KVM emulator currently consider bit 63
as reserved. Fix it.

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-07 15:44:07 +01:00
Nadav Amit
0fcc207c66 KVM: x86: Emulate push sreg as done in Core
According to Intel SDM push of segment selectors is done in the following
manner: "if the operand size is 32-bits, either a zero-extended value is pushed
on the stack or the segment selector is written on the stack using a 16-bit
move. For the last case, all recent Core and Atom processors perform a 16-bit
move, leaving the upper portion of the stack location unmodified."

This patch modifies the behavior to match the core behavior.

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-07 15:44:06 +01:00
Nadav Amit
5aca372236 KVM: x86: Wrong flags on CMPS and SCAS emulation
CMPS and SCAS instructions are evaluated in the wrong order.  For reference (of
CMPS), see http://www.fermimn.gov.it/linux/quarta/x86/cmps.htm : "Note that the
direction of subtraction for CMPS is [SI] - [DI] or [ESI] - [EDI]. The left
operand (SI or ESI) is the source and the right operand (DI or EDI) is the
destination. This is the reverse of the usual Intel convention in which the
left operand is the destination and the right operand is the source."

Introducing em_cmp_r for this matter that performs comparison in reverse order
using fastop infrastructure to avoid a wrapper function.

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-07 15:44:06 +01:00
Nadav Amit
807c142595 KVM: x86: SYSCALL cannot clear eflags[1]
SYSCALL emulation currently clears in 64-bit mode eflags according to
MSR_SYSCALL_MASK.  However, on bare-metal eflags[1] which is fixed to one
cannot be cleared, even if MSR_SYSCALL_MASK masks the bit.  This wrong behavior
may result in failed VM-entry, as VT disallows entry with eflags[1] cleared.

This patch sets the bit after masking eflags on syscall.

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-07 15:44:05 +01:00
Nadav Amit
b5bbf10ee6 KVM: x86: Emulation of MOV-sreg to memory uses incorrect size
In x86, you can only MOV-sreg to memory with either 16-bits or 64-bits size.
In contrast, KVM may write to 32-bits memory on MOV-sreg. This patch fixes KVM
behavior, and sets the destination operand size to two, if the destination is
memory.

When destination is registers, and the operand size is 32-bits, the high
16-bits in modern CPUs is filled with zero.  This is handled correctly.

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-07 15:44:04 +01:00
Nadav Amit
82b32774c2 KVM: x86: Breakpoints do not consider CS.base
x86 debug registers hold a linear address. Therefore, breakpoints detection
should consider CS.base, and check whether instruction linear address equals
(CS.base + RIP). This patch introduces a function to evaluate RIP linear
address and uses it for breakpoints detection.

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-07 15:44:04 +01:00
Nadav Amit
7305eb5d8c KVM: x86: Clear DR6[0:3] on #DB during handle_dr
DR6[0:3] (previous breakpoint indications) are cleared when #DB is injected
during handle_exception, just as real hardware does.  Similarily, handle_dr
should clear DR6[0:3].

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-07 15:44:03 +01:00
Nadav Amit
6d2a0526b0 KVM: x86: Emulator should set DR6 upon GD like real CPU
It should clear B0-B3 and set BD.

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-07 15:44:02 +01:00
Nadav Amit
3ffb24681c KVM: x86: No error-code on real-mode exceptions
Real-mode exceptions do not deliver error code. As can be seen in Intel SDM
volume 2, real-mode exceptions do not have parentheses, which indicate
error-code.  To avoid significant changes of the code, the error code is
"removed" during exception queueing.

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-07 15:44:02 +01:00
Nadav Amit
5b38ab877e KVM: x86: decode_modrm does not regard modrm correctly
In one occassion, decode_modrm uses the rm field after it is extended with
REX.B to determine the addressing mode. Doing so causes it not to read the
offset for rip-relative addressing with REX.B=1.

This patch moves the fetch where we already mask REX.B away instead.

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-07 15:44:01 +01:00
Wei Wang
4114c27d45 KVM: x86: reset RVI upon system reset
A bug was reported as follows: when running Windows 7 32-bit guests on qemu-kvm,
sometimes the guests run into blue screen during reboot. The problem was that a
guest's RVI was not cleared when it rebooted. This patch has fixed the problem.

Signed-off-by: Wei Wang <wei.w.wang@intel.com>
Signed-off-by: Yang Zhang <yang.z.zhang@intel.com>
Tested-by: Rongrong Liu <rongrongx.liu@intel.com>, Da Chun <ngugc@qq.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-07 15:44:00 +01:00
Paolo Bonzini
a2ae9df7c9 kvm: x86: vmx: avoid returning bool to distinguish success from error
Return a negative error code instead, and WARN() when we should be covering
the entire 2-bit space of vmcs_field_type's return value.  For increased
robustness, add a BUILD_BUG_ON checking the range of vmcs_field_to_offset.

Suggested-by: Tiejun Chen <tiejun.chen@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-07 15:44:00 +01:00
Tiejun Chen
34a1cd60d1 kvm: x86: vmx: move some vmx setting from vmx_init() to hardware_setup()
Instead of vmx_init(), actually it would make reasonable sense to do
anything specific to vmx hardware setting in vmx_x86_ops->hardware_setup().

Signed-off-by: Tiejun Chen <tiejun.chen@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-07 15:43:59 +01:00
Tiejun Chen
f2c7648d91 kvm: x86: vmx: move down hardware_setup() and hardware_unsetup()
Just move this pair of functions down to make sure later we can
add something dependent on others.

Signed-off-by: Tiejun Chen <tiejun.chen@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-07 15:43:59 +01:00
Tiejun Chen
c6338ce494 kvm: kvmclock: use get_cpu() and put_cpu()
We can use get_cpu() and put_cpu() to replace
preempt_disable()/cpu = smp_processor_id() and
preempt_enable() for slightly better code.

Signed-off-by: Tiejun Chen <tiejun.chen@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-03 12:07:33 +01:00
Radim Krčmář
f30ebc312c KVM: x86: optimize some accesses to LVTT and SPIV
We mirror a subset of these registers in separate variables.
Using them directly should be faster.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-03 12:07:32 +01:00
Radim Krčmář
a323b40982 KVM: x86: detect LVTT changes under APICv
APIC-write VM exits are "trap-like": they save CS:RIP values for the
instruction after the write, and more importantly, the handler will
already see the new value in the virtual-APIC page.  This means that
apic_reg_write cannot use kvm_apic_get_reg to omit timer cancelation
when mode changes.

timer_mode_mask shouldn't be changing as it depends on cpuid.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-03 12:07:32 +01:00
Radim Krčmář
e462755cae KVM: x86: detect SPIV changes under APICv
APIC-write VM exits are "trap-like": they save CS:RIP values for the
instruction after the write, and more importantly, the handler will
already see the new value in the virtual-APIC page.

This caused a bug if you used KVM_SET_IRQCHIP to set the SW-enabled bit
in the SPIV register.  The chain of events is as follows:

* When the irqchip is added to the destination VM, the apic_sw_disabled
static key is incremented (1)

* When the KVM_SET_IRQCHIP ioctl is invoked, it is decremented (0)

* When the guest disables the bit in the SPIV register, e.g. as part of
shutdown, apic_set_spiv does not notice the change and the static key is
_not_ incremented.

* When the guest is destroyed, the static key is decremented (-1),
resulting in this trace:

  WARNING: at kernel/jump_label.c:81 __static_key_slow_dec+0xa6/0xb0()
  jump label: negative count!

  [<ffffffff816bf898>] dump_stack+0x19/0x1b
  [<ffffffff8107c6f1>] warn_slowpath_common+0x61/0x80
  [<ffffffff8107c76c>] warn_slowpath_fmt+0x5c/0x80
  [<ffffffff811931e6>] __static_key_slow_dec+0xa6/0xb0
  [<ffffffff81193226>] static_key_slow_dec_deferred+0x16/0x20
  [<ffffffffa0637698>] kvm_free_lapic+0x88/0xa0 [kvm]
  [<ffffffffa061c63e>] kvm_arch_vcpu_uninit+0x2e/0xe0 [kvm]
  [<ffffffffa05ff301>] kvm_vcpu_uninit+0x21/0x40 [kvm]
  [<ffffffffa067cec7>] vmx_free_vcpu+0x47/0x70 [kvm_intel]
  [<ffffffffa061bc50>] kvm_arch_vcpu_free+0x50/0x60 [kvm]
  [<ffffffffa061ca22>] kvm_arch_destroy_vm+0x102/0x260 [kvm]
  [<ffffffff810b68fd>] ? synchronize_srcu+0x1d/0x20
  [<ffffffffa06030d1>] kvm_put_kvm+0xe1/0x1c0 [kvm]
  [<ffffffffa06036f8>] kvm_vcpu_release+0x18/0x20 [kvm]
  [<ffffffff81215c62>] __fput+0x102/0x310
  [<ffffffff81215f4e>] ____fput+0xe/0x10
  [<ffffffff810ab664>] task_work_run+0xb4/0xe0
  [<ffffffff81083944>] do_exit+0x304/0xc60
  [<ffffffff816c8dfc>] ? _raw_spin_unlock_irq+0x2c/0x50
  [<ffffffff810fd22d>] ?  trace_hardirqs_on_caller+0xfd/0x1c0
  [<ffffffff8108432c>] do_group_exit+0x4c/0xc0
  [<ffffffff810843b4>] SyS_exit_group+0x14/0x20
  [<ffffffff816d33a9>] system_call_fastpath+0x16/0x1b

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-03 12:07:31 +01:00
Chao Peng
612263b30c KVM: x86: Enable Intel AVX-512 for guest
Expose Intel AVX-512 feature bits to guest. Also add checks for
xcr0 AVX512 related bits according to spec:
http://download-software.intel.com/sites/default/files/managed/71/2e/319433-017.pdf

Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-03 12:07:30 +01:00
Radim Krčmář
1e0ad70cc1 KVM: x86: fix deadline tsc interrupt injection
The check in kvm_set_lapic_tscdeadline_msr() was trying to prevent a
situation where we lose a pending deadline timer in a MSR write.
Losing it is fine, because it effectively occurs before the timer fired,
so we should be able to cancel or postpone it.

Another problem comes from interaction with QEMU, or other userspace
that can set deadline MSR without a good reason, when timer is already
pending:  one guest's deadline request results in more than one
interrupt because one is injected immediately on MSR write from
userspace and one through hrtimer later.

The solution is to remove the injection when replacing a pending timer
and to improve the usual QEMU path, we inject without a hrtimer when the
deadline has already passed.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Reported-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-03 12:07:28 +01:00
Radim Krčmář
5d87db7119 KVM: x86: add apic_timer_expired()
Make the code reusable.

If the timer was already pending, we shouldn't be waiting in a queue,
so wake_up can be skipped, simplifying the path.

There is no 'reinject' case => the comment is removed.
Current race behaves correctly.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-03 12:07:27 +01:00
Nadav Amit
16f8a6f979 KVM: vmx: Unavailable DR4/5 is checked before CPL
If DR4/5 is accessed when it is unavailable (since CR4.DE is set), then #UD
should be generated even if CPL>0. This is according to Intel SDM Table 6-2:
"Priority Among Simultaneous Exceptions and Interrupts".

Note, that this may happen on the first DR access, even if the host does not
sets debug breakpoints. Obviously, it occurs when the host debugs the guest.

This patch moves the DR4/5 checks from __kvm_set_dr/_kvm_get_dr to handle_dr.
The emulator already checks DR4/5 availability in check_dr_read. Nested
virutalization related calls to kvm_set_dr/kvm_get_dr would not like to inject
exceptions to the guest.

As for SVM, the patch follows the previous logic as much as possible. Anyhow,
it appears the DR interception code might be buggy - even if the DR access
may cause an exception, the instruction is skipped.

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-03 12:07:26 +01:00
Nadav Amit
c49c759f7a KVM: x86: Emulator performs code segment checks on read access
When read access is performed using a readable code segment, the "conforming"
and "non-conforming" checks should not be done.  As a result, read using
non-conforming readable code segment fails.

This is according to Intel SDM 5.6.1 ("Accessing Data in Code Segments").

The fix is not to perform the "non-conforming" checks if the access is not a
fetch; the relevant checks are already done when loading the segment.

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-03 12:07:25 +01:00
Nadav Amit
0e8a09969a KVM: x86: Clear DR7.LE during task-switch
DR7.LE should be cleared during task-switch. This feature is poorly documented.
For reference, see:
http://pdos.csail.mit.edu/6.828/2005/readings/i386/s12_02.htm

SDM [17.2.4]:
  This feature is not supported in the P6 family processors, later IA-32
  processors, and Intel 64 processors.

AMD [2:13.1.1.4]:
  This bit is ignored by implementations of the AMD64 architecture.

Intel's formulation could mean that it isn't even zeroed, but current
hardware indeed does not behave like that.

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-03 12:07:25 +01:00
Nadav Amit
518547b32a KVM: x86: Emulator does not calculate address correctly
In long-mode, when the address size is 4 bytes, the linear address is not
truncated as the emulator mistakenly does.  Instead, the offset within the
segment (the ea field) should be truncated according to the address size.

As Intel SDM says: "In 64-bit mode, the effective address components are added
and the effective address is truncated ... before adding the full 64-bit
segment base."

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-03 12:07:24 +01:00
Nadav Amit
6bdf06625d KVM: x86: DR7.GD should be cleared upon any #DB exception
Intel SDM 17.2.4 (Debug Control Register (DR7)) says: "The processor clears the
GD flag upon entering to the debug exception handler." This sentence may be
misunderstood as if it happens only on #DB due to debug-register protection,
but it happens regardless to the cause of the #DB.

Fix the behavior to match both real hardware and Bochs.

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-03 12:07:23 +01:00
Nadav Amit
394457a928 KVM: x86: some apic broadcast modes does not work
KVM does not deliver x2APIC broadcast messages with physical mode.  Intel SDM
(10.12.9 ICR Operation in x2APIC Mode) states: "A destination ID value of
FFFF_FFFFH is used for broadcast of interrupts in both logical destination and
physical destination modes."

In addition, the local-apic enables cluster mode broadcast. As Intel SDM
10.6.2.2 says: "Broadcast to all local APICs is achieved by setting all
destination bits to one." This patch enables cluster mode broadcast.

The fix tries to combine broadcast in different modes through a unified code.

One rare case occurs when the source of IPI has its APIC disabled.  In such
case, the source can still issue IPIs, but since the source is not obliged to
have the same LAPIC mode as the enabled ones, we cannot rely on it.
Since it is a rare case, it is unoptimized and done on the slow-path.

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Reviewed-by: Wanpeng Li <wanpeng.li@linux.intel.com>
[As per Radim's review, use unsigned int for X2APIC_BROADCAST, return bool from
 kvm_apic_broadcast. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-03 12:07:22 +01:00
Andy Lutomirski
52ce3c21ae x86,kvm,vmx: Don't trap writes to CR4.TSD
CR4.TSD is guest-owned; don't trap writes to it in VMX guests.  This
avoids a VM exit on context switches into or out of a PR_TSC_SIGSEGV
task.

I think that this fixes an unintentional side-effect of:
    4c38609ac5 KVM: VMX: Make guest cr4 mask more conservative

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-03 12:07:22 +01:00
Nadav Amit
bf0b682c9b KVM: x86: Sysexit emulation does not mask RIP/RSP
If the operand size is not 64-bit, then the sysexit instruction should assign
ECX to RSP and EDX to RIP.  The current code assigns the full 64-bits.

Fix it by masking.

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-03 12:07:21 +01:00
Nadav Amit
58b7075d05 KVM: x86: Distinguish between stack operation and near branches
In 64-bit, stack operations default to 64-bits, but can be overriden (to
16-bit) using opsize override prefix. In contrast, near-branches are always
64-bit.  This patch distinguish between the different behaviors.

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-03 12:07:20 +01:00
Nadav Amit
f7784046ab KVM: x86: Getting rid of grp45 in emulator
Breaking grp45 to the relevant functions to speed up the emulation and simplify
the code. In addition, it is necassary the next patch will distinguish between
far and near branches according to the flags.

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-03 12:07:20 +01:00
Nadav Amit
4be4de7ef9 KVM: x86: Use new is_noncanonical_address in _linearize
Replace the current canonical address check with the new function which is
identical.

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-03 12:07:19 +01:00
Paolo Bonzini
d09155d2f3 KVM: emulator: always inline __linearize
The two callers have a lot of constant arguments that can be
optimized out.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-03 12:07:18 +01:00
Linus Torvalds
7501a53329 A small set of x86 fixes. The most serious is an SRCU lockdep fix.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull kvm fixes from Paolo Bonzini:
 "A small set of x86 fixes.  The most serious is an SRCU lockdep fix.

  A bit late - needed some time to test the SRCU fix, which only came in
  on Friday"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: vmx: defer load of APIC access page address during reset
  KVM: nVMX: Disable preemption while reading from shadow VMCS
  KVM: x86: Fix far-jump to non-canonical check
  KVM: emulator: fix execution close to the segment limit
  KVM: emulator: fix error code for __linearize
2014-11-02 12:31:02 -08:00
Paolo Bonzini
a73896cb5b KVM: vmx: defer load of APIC access page address during reset
Most call paths to vmx_vcpu_reset do not hold the SRCU lock.  Defer loading
the APIC access page to the next vmentry.

This avoids the following lockdep splat:

[ INFO: suspicious RCU usage. ]
3.18.0-rc2-test2+ #70 Not tainted
-------------------------------
include/linux/kvm_host.h:474 suspicious rcu_dereference_check() usage!

other info that might help us debug this:

rcu_scheduler_active = 1, debug_locks = 0
1 lock held by qemu-system-x86/2371:
 #0:  (&vcpu->mutex){+.+...}, at: [<ffffffffa037d800>] vcpu_load+0x20/0xd0 [kvm]

stack backtrace:
CPU: 4 PID: 2371 Comm: qemu-system-x86 Not tainted 3.18.0-rc2-test2+ #70
Hardware name: Dell Inc. OptiPlex 9010/0M9KCM, BIOS A12 01/10/2013
 0000000000000001 ffff880209983ca8 ffffffff816f514f 0000000000000000
 ffff8802099b8990 ffff880209983cd8 ffffffff810bd687 00000000000fee00
 ffff880208a2c000 ffff880208a10000 ffff88020ef50040 ffff880209983d08
Call Trace:
 [<ffffffff816f514f>] dump_stack+0x4e/0x71
 [<ffffffff810bd687>] lockdep_rcu_suspicious+0xe7/0x120
 [<ffffffffa037d055>] gfn_to_memslot+0xd5/0xe0 [kvm]
 [<ffffffffa03807d3>] __gfn_to_pfn+0x33/0x60 [kvm]
 [<ffffffffa0380885>] gfn_to_page+0x25/0x90 [kvm]
 [<ffffffffa038aeec>] kvm_vcpu_reload_apic_access_page+0x3c/0x80 [kvm]
 [<ffffffffa08f0a9c>] vmx_vcpu_reset+0x20c/0x460 [kvm_intel]
 [<ffffffffa039ab8e>] kvm_vcpu_reset+0x15e/0x1b0 [kvm]
 [<ffffffffa039ac0c>] kvm_arch_vcpu_setup+0x2c/0x50 [kvm]
 [<ffffffffa037f7e0>] kvm_vm_ioctl+0x1d0/0x780 [kvm]
 [<ffffffff810bc664>] ? __lock_is_held+0x54/0x80
 [<ffffffff812231f0>] do_vfs_ioctl+0x300/0x520
 [<ffffffff8122ee45>] ? __fget+0x5/0x250
 [<ffffffff8122f0fa>] ? __fget_light+0x2a/0xe0
 [<ffffffff81223491>] SyS_ioctl+0x81/0xa0
 [<ffffffff816fed6d>] system_call_fastpath+0x16/0x1b

Reported-by: Takashi Iwai <tiwai@suse.de>
Reported-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Reviewed-by: Wanpeng Li <wanpeng.li@linux.intel.com>
Tested-by: Wanpeng Li <wanpeng.li@linux.intel.com>
Fixes: 38b9917350
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-02 08:37:18 +01:00
Jan Kiszka
282da870f4 KVM: nVMX: Disable preemption while reading from shadow VMCS
In order to access the shadow VMCS, we need to load it. At this point,
vmx->loaded_vmcs->vmcs and the actually loaded one start to differ. If
we now get preempted by Linux, vmx_vcpu_put and, on return, the
vmx_vcpu_load will work against the wrong vmcs. That can cause
copy_shadow_to_vmcs12 to corrupt the vmcs12 state.

Fix the issue by disabling preemption during the copy operation.
copy_vmcs12_to_shadow is safe from this issue as it is executed by
vmx_vcpu_run when preemption is already disabled before vmentry.

This bug is exposed by running Jailhouse within KVM on CPUs with
shadow VMCS support.  Jailhouse never expects an interrupt pending
vmexit, but the bug can cause it if, after copy_shadow_to_vmcs12
is preempted, the active VMCS happens to have the virtual interrupt
pending flag set in the CPU-based execution controls.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-02 07:55:46 +01:00
Nadav Amit
7e46dddd6f KVM: x86: Fix far-jump to non-canonical check
Commit d1442d85cc ("KVM: x86: Handle errors when RIP is set during far
jumps") introduced a bug that caused the fix to be incomplete.  Due to
incorrect evaluation, far jump to segment with L bit cleared (i.e., 32-bit
segment) and RIP with any of the high bits set (i.e, RIP[63:32] != 0) set may
not trigger #GP.  As we know, this imposes a security problem.

In addition, the condition for two warnings was incorrect.

Fixes: d1442d85cc
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
[Add #ifdef CONFIG_X86_64 to avoid complaints of undefined behavior. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-02 07:54:55 +01:00
Andy Lutomirski
653bc77af6 x86_64, entry: Fix out of bounds read on sysenter
Rusty noticed a Really Bad Bug (tm) in my NT fix.  The entry code
reads out of bounds, causing the NT fix to be unreliable.  But, and
this is much, much worse, if your stack is somehow just below the
top of the direct map (or a hole), you read out of bounds and crash.

Excerpt from the crash:

[    1.129513] RSP: 0018:ffff88001da4bf88  EFLAGS: 00010296

  2b:*    f7 84 24 90 00 00 00     testl  $0x4000,0x90(%rsp)

That read is deterministically above the top of the stack.  I
thought I even single-stepped through this code when I wrote it to
check the offset, but I clearly screwed it up.

Fixes: 8c7aa698ba ("x86_64, entry: Filter RFLAGS.NT on entry from userspace")
Reported-by: Rusty Russell <rusty@ozlabs.org>
Cc: stable@vger.kernel.org
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-31 18:47:09 -07:00
Linus Torvalds
19e0d5f16a Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Ingo Molnar:
 "Fixes from all around the place:

   - hyper-V 32-bit PAE guest kernel fix
   - two IRQ allocation fixes on certain x86 boards
   - intel-mid boot crash fix
   - intel-quark quirk
   - /proc/interrupts duplicate irq chip name fix
   - cma boot crash fix
   - syscall audit fix
   - boot crash fix with certain TSC configurations (seen on Qemu)
   - smpboot.c build warning fix"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86, pageattr: Prevent overflow in slow_virt_to_phys() for X86_PAE
  ACPI, irq, x86: Return IRQ instead of GSI in mp_register_gsi()
  x86, intel-mid: Create IRQs for APB timers and RTC timers
  x86: Don't enable F00F workaround on Intel Quark processors
  x86/irq: Fix XT-PIC-XT-PIC in /proc/interrupts
  x86, cma: Reserve DMA contiguous area after initmem_init()
  i386/audit: stop scribbling on the stack frame
  x86, apic: Handle a bad TSC more gracefully
  x86: ACPI: Do not translate GSI number if IOAPIC is disabled
  x86/smpboot: Move data structure to its primary usage scope
2014-10-31 14:30:16 -07:00
Linus Torvalds
f5fa363026 Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Ingo Molnar:
 "Various scheduler fixes all over the place: three SCHED_DL fixes,
  three sched/numa fixes, two generic race fixes and a comment fix"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/dl: Fix preemption checks
  sched: Update comments for CLONE_NEWNS
  sched: stop the unbound recursion in preempt_schedule_context()
  sched/fair: Fix division by zero sysctl_numa_balancing_scan_size
  sched/fair: Care divide error in update_task_scan_period()
  sched/numa: Fix unsafe get_task_struct() in task_numa_assign()
  sched/deadline: Fix races between rt_mutex_setprio() and dl_task_timer()
  sched/deadline: Don't replenish from a !SCHED_DEADLINE entity
  sched: Fix race between task_group and sched_task_group
2014-10-31 14:05:35 -07:00
Linus Torvalds
5656b408ff Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Ingo Molnar:
 "Mostly tooling fixes, plus on the kernel side:

   - a revert for a newly introduced PMU driver which isn't complete yet
     and where we ran out of time with fixes (to be tried again in
     v3.19) - this makes up for a large chunk of the diffstat.

   - compilation warning fixes

   - a printk message fix

   - event_idx usage fixes/cleanups"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf probe: Trivial typo fix for --demangle
  perf tools: Fix report -F dso_from for data without branch info
  perf tools: Fix report -F dso_to for data without branch info
  perf tools: Fix report -F symbol_from for data without branch info
  perf tools: Fix report -F symbol_to for data without branch info
  perf tools: Fix report -F mispredict for data without branch info
  perf tools: Fix report -F in_tx for data without branch info
  perf tools: Fix report -F abort for data without branch info
  perf tools: Make CPUINFO_PROC an array to support different kernel versions
  perf callchain: Use global caching provided by libunwind
  perf/x86/intel: Revert incomplete and undocumented Broadwell client support
  perf/x86: Fix compile warnings for intel_uncore
  perf: Fix typos in sample code in the perf_event.h header
  perf: Fix and clean up initialization of pmu::event_idx
  perf: Fix bogus kernel printk
  perf diff: Add missing hists__init() call at tool start
2014-10-31 14:01:47 -07:00
Paolo Bonzini
fd56e1546a KVM: emulator: fix execution close to the segment limit
Emulation of code that is 14 bytes to the segment limit or closer
(e.g. RIP = 0xFFFFFFF2 after reset) is broken because we try to read as
many as 15 bytes from the beginning of the instruction, and __linearize
fails when the passed (address, size) pair reaches out of the segment.

To fix this, let __linearize return the maximum accessible size (clamped
to 2^32-1) for usage in __do_insn_fetch_bytes, and avoid the limit check
by passing zero for the desired size.

For expand-down segments, __linearize is performing a redundant check.
(u32)(addr.ea + size - 1) <= lim can only happen if addr.ea is close
to 4GB; in this case, addr.ea + size - 1 will also fail the check against
the upper bound of the segment (which is provided by the D/B bit).
After eliminating the redundant check, it is simple to compute
the *max_size for expand-down segments too.

Now that the limit check is done in __do_insn_fetch_bytes, we want
to inject a general protection fault there if size < op_size (like
__linearize would have done), instead of just aborting.

This fixes booting Tiano Core from emulated flash with EPT disabled.

Cc: stable@vger.kernel.org
Fixes: 719d5a9b24
Reported-by: Borislav Petkov <bp@suse.de>
Tested-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-10-29 13:13:48 +01:00
Paolo Bonzini
3606189fa3 KVM: emulator: fix error code for __linearize
The error code for #GP and #SS is zero when the segment is used to
access an operand or an instruction.  It is only non-zero when
a segment register is being loaded; for limit checks this means
cases such as:

* for #GP, when RIP is beyond the limit on a far call (before the first
instruction is executed).  We do not implement this check, but it
would be in em_jmp_far/em_call_far.

* for #SS, if the new stack overflows during an inter-privilege-level
call to a non-conforming code segment.  We do not implement stack
switching at all.

So use an error code of zero.

Reviewed-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-10-29 12:40:28 +01:00
Ingo Molnar
1776b10627 perf/x86/intel: Revert incomplete and undocumented Broadwell client support
These patches:

  86a349a28b ("perf/x86/intel: Add Broadwell core support")
  c46e665f03 ("perf/x86: Add INST_RETIRED.ALL workarounds")
  fdda3c4aac ("perf/x86/intel: Use Broadwell cache event list for Haswell")

introduced magic constants and unexplained changes:

  https://lkml.org/lkml/2014/10/28/1128
  https://lkml.org/lkml/2014/10/27/325
  https://lkml.org/lkml/2014/8/27/546
  https://lkml.org/lkml/2014/10/28/546

Peter Zijlstra has attempted to help out, to clean up the mess:

  https://lkml.org/lkml/2014/10/28/543

But has not received helpful and constructive replies which makes
me doubt wether it can all be finished in time until v3.18 is
released.

Despite various review feedback the author (Andi Kleen) has answered
only few of the review questions and has generally been uncooperative,
only giving replies when prompted repeatedly, and only giving minimal
answers instead of constructively explaining and helping along the effort.

That kind of behavior is not acceptable.

There's also a boot crash on Intel E5-1630 v3 CPUs reported for another
commit from Andi Kleen:

  e735b9db12 ("perf/x86/intel/uncore: Add Haswell-EP uncore support")

  https://lkml.org/lkml/2014/10/22/730

Which is not yet resolved. The uncore driver is independent in theory,
but the crash makes me worry about how well all these patches were
tested and makes me uneasy about the level of interminging that the
Broadwell and Haswell code has received by the commits above.

As a first step to resolve the mess revert the Broadwell client commits
back to the v3.17 version, before we run out of time and problematic
code hits a stable upstream kernel.

( If the Haswell-EP crash is not resolved via a simple fix then we'll have
  to revert the Haswell-EP uncore driver as well. )

The Broadwell client series has to be submitted in a clean fashion, with
single, well documented changes per patch. If they are submitted in time
and are accepted during review then they can possibly go into v3.19 but
will need additional scrutiny due to the rocky history of this patch set.

Cc: Andi Kleen <ak@linux.intel.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: eranian@google.com
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1409683455-29168-3-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-10-29 11:07:58 +01:00
Dexuan Cui
d1cd121083 x86, pageattr: Prevent overflow in slow_virt_to_phys() for X86_PAE
pte_pfn() returns a PFN of long (32 bits in 32-PAE), so "long <<
PAGE_SHIFT" will overflow for PFNs above 4GB.

Due to this issue, some Linux 32-PAE distros, running as guests on Hyper-V,
with 5GB memory assigned, can't load the netvsc driver successfully and
hence the synthetic network device can't work (we can use the kernel parameter
mem=3000M to work around the issue).

Cast pte_pfn() to phys_addr_t before shifting.

Fixes: "commit d765653445: x86, mm: Create slow_virt_to_phys()"
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: gregkh@linuxfoundation.org
Cc: linux-mm@kvack.org
Cc: olaf@aepfle.de
Cc: apw@canonical.com
Cc: jasowang@redhat.com
Cc: dave.hansen@intel.com
Cc: riel@redhat.com
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1414580017-27444-1-git-send-email-decui@microsoft.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-10-29 10:57:21 +01:00
Jiang Liu
b77e8f4353 ACPI, irq, x86: Return IRQ instead of GSI in mp_register_gsi()
Function mp_register_gsi() returns blindly the GSI number for the ACPI
SCI interrupt. That causes a regression when the GSI for ACPI SCI is
shared with other devices.

The regression was caused by commit 84245af729 "x86, irq, ACPI:
Change __acpi_register_gsi to return IRQ number instead of GSI" and
exposed on a SuperMicro system, which shares one GSI between ACPI SCI
and PCI device, with following failure:

http://sourceforge.net/p/linux1394/mailman/linux1394-user/?viewmonth=201410
[    0.000000] ACPI: INT_SRC_OVR (bus 0 bus_irq 9 global_irq 20 low
level)
[    2.699224] firewire_ohci 0000:06:00.0: failed to allocate interrupt
20

Return mp_map_gsi_to_irq(gsi, 0) instead of the GSI number.

Reported-and-Tested-by: Daniel Robbins <drobbins@funtoo.org>
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Len Brown <len.brown@intel.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: <stable@vger.kernel.org> # 3.17
Link: http://lkml.kernel.org/r/1414387308-27148-4-git-send-email-jiang.liu@linux.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-10-29 08:52:30 +01:00
Jiang Liu
f18298595a x86, intel-mid: Create IRQs for APB timers and RTC timers
Intel MID platforms has no legacy interrupts, so no IRQ descriptors
preallocated. We need to call mp_map_gsi_to_irq() to create IRQ
descriptors for APB timers and RTC timers, otherwise it may cause
invalid memory access as:
[    0.116839] BUG: unable to handle kernel NULL pointer dereference at
0000003a
[    0.123803] IP: [<c1071c0e>] setup_irq+0xf/0x4d

Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: David Cohen <david.a.cohen@linux.intel.com>
Cc: <stable@vger.kernel.org> # 3.17
Link: http://lkml.kernel.org/r/1414387308-27148-3-git-send-email-jiang.liu@linux.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-10-29 08:52:23 +01:00
Dave Jones
d4e1a0af1d x86: Don't enable F00F workaround on Intel Quark processors
The Intel Quark processor is a part of family 5, but does not have the
F00F bug present in Pentiums of the same family.

Pentiums were models 0 through 8, Quark is model 9.

Signed-off-by: Dave Jones <davej@redhat.com>
Cc: Bryan O'Donoghue <pure.logic@nexus-software.ie>
Link: http://lkml.kernel.org/r/20141028175753.GA12743@redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-10-29 08:52:09 +01:00