Memory is always the destination for BitOp instructions.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

We did not do that when interruptibility was added to the emulator,
because at the time pop to segment was not implemented.  Now it is,
add it.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

In 64-bit mode, when the destination is a register, the assignment is done
according to the operand size. Otherwise (memory operand or no 64-bit mode), a
16-bit assignment is performed.

Currently, 16-bit assignment is always done to the destination.
Signed-off-by: NNadav Amit <namit@cs.technion.ac.il>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

cmpxchg16b is currently unimplemented in the emulator. The least we can do is
return error upon the emulation of this instruction.
Signed-off-by: NNadav Amit <namit@cs.technion.ac.il>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The rdpmc emulation checks that the counter (ECX) is not higher than 2, without
taking into considerations bits 30:31 role (e.g., bit 30 marks whether the
counter is fixed). The fix uses the pmu information for checking the validity
of the pmu counter.
Signed-off-by: NNadav Amit <namit@cs.technion.ac.il>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

If the operand-size prefix (0x66) is used in 64-bit mode, the emulator would
assume the destination operand is 64-bit, when it should be 32-bit.

Reminder: movnti does not support 16-bit operands and its default operand size
is 32-bit.
Signed-off-by: NNadav Amit <namit@cs.technion.ac.il>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The current implementation of cmpxchg does not update the flags correctly,
since the accumulator should be compared with the destination and not the other
way around. The current implementation does not update the flags correctly.
Signed-off-by: NNadav Amit <namit@cs.technion.ac.il>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The SGDT and SIDT instructions are not privilaged, i.e. they can be executed
with CPL>0.
Signed-off-by: NNadav Amit <namit@cs.technion.ac.il>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The current emulator implementation ignores the high 32 bits of the base in
long-mode.  During segment load from the LDT, the base of the LDT is calculated
incorrectly and may cause the wrong segment to be loaded.
Signed-off-by: NNadav Amit <namit@cs.technion.ac.il>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The current implementation ignores the LDTR/TR base high 32-bits on long-mode.
As a result the loaded segment descriptor may be incorrect.
Signed-off-by: NNadav Amit <namit@cs.technion.ac.il>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Currently the emulator does not recognize vex-prefix instructions.  However, it
may incorrectly decode lgdt/lidt instructions and try to execute them. This
patch returns unhandlable error on their emulation.
Signed-off-by: NNadav Amit <namit@cs.technion.ac.il>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

MOV CR/DR instructions ignore the mod field (in the ModR/M byte). As the SDM
states: "The 2 bits in the mod field are ignored".  Accordingly, the second
operand of these instructions is always a general purpose register.

The current emulator implementation does not do so. If the mod bits do not
equal 3, it expects the second operand to be in memory.
Signed-off-by: NNadav Amit <namit@cs.technion.ac.il>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Table 7-1 of the SDM mentions a check that the code segment's
DPL must match the selector's RPL.  This was not done by KVM,
fix it.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

During task switch, all of CS.DPL, CS.RPL, SS.DPL must match (in addition
to all the other requirements) and will be the new CPL.  So far this
worked by carefully setting the CS selector and flag before doing the
task switch; setting CS.selector will already change the CPL.

However, this will not work once we get the CPL from SS.DPL, because
then you will have to set the full segment descriptor cache to change
the CPL.  ctxt->ops->cpl(ctxt) will then return the old CPL during the
task switch, and the check that SS.DPL == CPL will fail.

Temporarily assume that the CPL comes from CS.RPL during task switch
to a protected-mode task.  This is the same approach used in QEMU's
emulation code, which (until version 2.0) manually tracks the CPL.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The IN instruction is not be affected by REP-prefix as INS is.  Therefore, the
emulation should ignore the REP prefix as well.  The current emulator
implementation tries to perform writeback when IN instruction with REP-prefix
is emulated. This causes it to perform wrong memory write or spurious #GP
exception to be injected to the guest.
Signed-off-by: NNadav Amit <namit@cs.technion.ac.il>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

According to Intel specifications, PAE and non-PAE does not have any reserved
bits.  In long-mode, regardless to PCIDE, only the high bits (above the
physical address) are reserved.
Signed-off-by: NNadav Amit <namit@cs.technion.ac.il>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

According to Intel specifications, only general purpose registers and segment
selectors should be saved in the old TSS during 32-bit task-switch.
Signed-off-by: NNadav Amit <namit@cs.technion.ac.il>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

Add emulation for 0x66 prefixed instruction of 0f 28 opcode
that has been added earlier.
Signed-off-by: NIgor Mammedov <imammedo@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

HCK memory driver test fails when testing 32-bit Windows 8.1
with baloon driver.

tracing KVM shows error:
reason EXIT_ERR rip 0x81c18326 info 0 0

x/10i 0x81c18326-20
0x0000000081c18312:  add    %al,(%eax)
0x0000000081c18314:  add    %cl,-0x7127711d(%esi)
0x0000000081c1831a:  rolb   $0x0,0x80ec(%ecx)
0x0000000081c18321:  and    $0xfffffff0,%esp
0x0000000081c18324:  mov    %esp,%esi
0x0000000081c18326:  movaps %xmm0,(%esi)
0x0000000081c18329:  movaps %xmm1,0x10(%esi)
0x0000000081c1832d:  movaps %xmm2,0x20(%esi)
0x0000000081c18331:  movaps %xmm3,0x30(%esi)
0x0000000081c18335:  movaps %xmm4,0x40(%esi)

which points to MOVAPS instruction currently no emulated by KVM.
Fix it by adding appropriate entries to opcode table in KVM's emulator.
Signed-off-by: NIgor Mammedov <imammedo@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Make code shorter.
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

All decode_register() callers check if instruction has rex prefix
to properly decode one byte operand. It make sense to move the check
inside.
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

When I was looking at RHEL5.9's failure to start with
unrestricted_guest=0/emulate_invalid_guest_state=1, I got it working with a
slightly older tree than kvm.git.  I now debugged the remaining failure,
which was introduced by commit 660696d1 (KVM: X86 emulator: fix
source operand decoding for 8bit mov[zs]x instructions, 2013-04-24)
introduced a similar mis-emulation to the one in commit 8acb4207 (KVM:
fix sil/dil/bpl/spl in the mod/rm fields, 2013-05-30).  The incorrect
decoding occurs in 8-bit movzx/movsx instructions whose 8-bit operand
is sil/dil/bpl/spl.

Needless to say, "movzbl %bpl, %eax" does occur in RHEL5.9's decompression
prolog, just a handful of instructions before finally giving control to
the decompressed vmlinux and getting out of the invalid guest state.

Because OpMem8 bypasses decode_modrm, the same handling of the REX prefix
must be applied to OpMem8.
Reported-by: NMichele Baldessari <michele@redhat.com>
Cc: stable@vger.kernel.org
Cc: Gleb Natapov <gleb@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

Yet another instruction that we fail to emulate, this time found
in Windows 2008R2 32-bit.
Reviewed-by: NGleb Natapov <gleb@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

This basically came from the need to be able to boot 32-bit Atom SMP
guests on an AMD host, i.e. a host which doesn't support MOVBE. As a
matter of fact, qemu has since recently received MOVBE support but we
cannot share that with kvm emulation and thus we have to do this in the
host. We're waay faster in kvm anyway. :-)

So, we piggyback on the #UD path and emulate the MOVBE functionality.
With it, an 8-core SMP guest boots in under 6 seconds.

Also, requesting MOVBE emulation needs to happen explicitly to work,
i.e. qemu -cpu n270,+movbe...

Just FYI, a fairly straight-forward boot of a MOVBE-enabled 3.9-rc6+
kernel in kvm executes MOVBE ~60K times.
Signed-off-by: NAndre Przywara <andre@andrep.de>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Add initial support for handling three-byte instructions in the
emulator.
Signed-off-by: NBorislav Petkov <bp@suse.de>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Call it EmulateOnUD which is exactly what we're trying to do with
vendor-specific instructions.

Rename ->only_vendor_specific_insn to something shorter, while at it.
Signed-off-by: NBorislav Petkov <bp@suse.de>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Add a field to the current emulation context which contains the
instruction opcode length. This will streamline handling of opcodes of
different length.
Signed-off-by: NBorislav Petkov <bp@suse.de>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Opcode CA

This gets used by a DOS based NetWare guest.
Signed-off-by: NBruce Rogers <brogers@suse.com>
Reviewed-by: NGleb Natapov <gleb@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The x86-64 extended low-byte registers were fetched correctly from reg,
but not from mod/rm.

This fixes another bug in the boot of RHEL5.9 64-bit, but it is still
not enough.

Cc: <stable@vger.kernel.org> # 3.9
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

This is encountered when booting RHEL5.9 64-bit.  There is another bug
after this one that is not a simple emulation failure, but this one lets
the boot proceed a bit.

Cc: <stable@vger.kernel.org> # 3.9
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

Signed-off-by: NAvi Kivity <avi.kivity@gmail.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

Signed-off-by: NAvi Kivity <avi.kivity@gmail.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

Since DIV and IDIV can generate exceptions, we need an additional output
parameter indicating whether an execption has occured.  To avoid increasing
register pressure on i386, we use %rsi, which is already allocated for
the fastop code pointer.

Gleb: added comment about fop usage as exception indication.
Signed-off-by: NAvi Kivity <avi.kivity@gmail.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

Signed-off-by: NAvi Kivity <avi.kivity@gmail.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

This makes OpAccHi useful.
Signed-off-by: NAvi Kivity <avi.kivity@gmail.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

Signed-off-by: NAvi Kivity <avi.kivity@gmail.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

Single-operand MUL and DIV access an extended accumulator: AX for byte
instructions, and DX:AX, EDX:EAX, or RDX:RAX for larger-sized instructions.
Add support for fetching the extended accumulator.

In order not to change things too much, RDX is loaded into Src2, which is
already loaded by fastop().  This avoids increasing register pressure on
i386.

Gleb: disable src writeback for ByteOp div/mul.
Signed-off-by: NAvi Kivity <avi.kivity@gmail.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

Some instructions write back the source operand, not just the destination.
Add support for doing this via the decode flags.

Gleb: add BUG_ON() to prevent source to be memory operand.
Signed-off-by: NAvi Kivity <avi.kivity@gmail.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

This is an almost-undocumented instruction available in 32-bit mode.
I say "almost" undocumented because AMD documents it in their opcode
maps just to say that it is unavailable in 64-bit mode (sections
"A.2.1 One-Byte Opcodes" and "B.3 Invalid and Reassigned Instructions
in 64-Bit Mode").

It is roughly equivalent to "sbb %al, %al" except it does not
set the flags.  Use fastop to emulate it, but do not use the opcode
directly because it would fail if the host is 64-bit!
Reported-by: NJun'ichi Nomura <j-nomura@ce.jp.nec.com>
Cc: stable@vger.kernel.org # 3.9
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

This is used by SGABIOS, KVM breaks with emulate_invalid_guest_state=1.
It is just a MOV in disguise, with a funny source address.
Reported-by: NJun'ichi Nomura <j-nomura@ce.jp.nec.com>
Cc: stable@vger.kernel.org # 3.9
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>