Commit Graph

99 Commits

Author SHA1 Message Date
Bandan Das
1498507a47 KVM: emulate: move init_decode_cache to emulate.c
Core emulator functions all belong in emulator.c,
x86 should have no knowledge of emulator internals

Signed-off-by: Bandan Das <bsd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-07-11 09:13:59 +02:00
Paolo Bonzini
54cfdb3e95 KVM: emulate: speed up emulated moves
We can just blindly move all 16 bytes of ctxt->src's value to ctxt->dst.
write_register_operand will take care of writing only the lower bytes.

Avoiding a call to memcpy (the compiler optimizes it out) gains about
200 cycles on kvm-unit-tests for register-to-register moves, and makes
them about as fast as arithmetic instructions.

We could perhaps get a larger speedup by moving all instructions _except_
moves out of x86_emulate_insn, removing opcode_len, and replacing the
switch statement with an inlined em_mov.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-07-11 09:13:58 +02:00
Jan Kiszka
6cbc5f5a80 KVM: nSVM: Set correct port for IOIO interception evaluation
Obtaining the port number from DX is bogus as a) there are immediate
port accesses and b) user space may have changed the register content
while processing the PIO access. Forward the correct value from the
instruction emulator instead.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-07-09 18:09:56 +02:00
Nadav Amit
67f4d4288c KVM: x86: rdpmc emulation checks the counter incorrectly
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: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-06-18 17:46:18 +02:00
Paolo Bonzini
fb5e336b97 KVM: x86: drop set_rflags callback
Not needed anymore now that the CPL is computed directly
during task switch.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-05-22 17:47:16 +02:00
Borislav Petkov
b51e974fcd kvm, emulator: Rename VendorSpecific flag
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: Borislav Petkov <bp@suse.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2013-10-30 18:54:40 +01:00
Borislav Petkov
1ce19dc16c kvm, emulator: Use opcode length
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: Borislav Petkov <bp@suse.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2013-10-30 18:54:39 +01:00
Gleb Natapov
b3356bf0db KVM: emulator: optimize "rep ins" handling
Optimize "rep ins" by allowing emulator to write back more than one
datum at a time. Introduce new operand type OP_MEM_STR which tells
writeback() that dst contains pointer to an array that should be written
back as opposite to just one data element.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-09-06 18:07:38 +03:00
Gleb Natapov
9d1b39a967 KVM: emulator: make x86 emulation modes enum instead of defines
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-09-06 18:07:01 +03:00
Mathias Krause
0225fb509d KVM: x86 emulator: constify emulate_ops
We never change emulate_ops[] at runtime so it should be r/o.

Signed-off-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-09-05 12:41:48 +03:00
Avi Kivity
dd856efafe KVM: x86 emulator: access GPRs on demand
Instead of populating the entire register file, read in registers
as they are accessed, and write back only the modified ones.  This
saves a VMREAD and VMWRITE on Intel (for rsp, since it is not usually
used during emulation), and a two 128-byte copies for the registers.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-08-27 18:38:55 -03:00
Avi Kivity
cbd27ee783 KVM: x86 emulator: initialize memop
memop is not initialized; this can lead to a two-byte operation
following a 4-byte operation to see garbage values.  Usually
truncation fixes things fot us later on, but at least in one case
(call abs) it doesn't.

Fix by moving memop to the auto-initialized field area.

Signed-off-by: Avi Kivity <avi@redhat.com>
2012-07-09 14:19:02 +03:00
Avi Kivity
0017f93a27 KVM: x86 emulator: change ->get_cpuid() accessor to use the x86 semantics
Instead of getting an exact leaf, follow the spec and fall back to the last
main leaf instead.  This lets us easily emulate the cpuid instruction in the
emulator.

Signed-off-by: Avi Kivity <avi@redhat.com>
2012-07-09 14:19:00 +03:00
Avi Kivity
cbe2c9d30a KVM: x86 emulator: MMX support
General support for the MMX instruction set.  Special care is taken
to trap pending x87 exceptions so that they are properly reflected
to the guest.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-04-16 20:36:16 -03:00
Kevin Wolf
4cee4798a3 KVM: x86 emulator: Allow PM/VM86 switch during task switch
Task switches can switch between Protected Mode and VM86. The current
mode must be updated during the task switch emulation so that the new
segment selectors are interpreted correctly.

In order to let privilege checks succeed, rflags needs to be updated in
the vcpu struct as this causes a CPL update.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-08 14:10:29 +02:00
Kevin Wolf
7f3d35fddd KVM: x86 emulator: Fix task switch privilege checks
Currently, all task switches check privileges against the DPL of the
TSS. This is only correct for jmp/call to a TSS. If a task gate is used,
the DPL of this take gate is used for the check instead. Exceptions,
external interrupts and iret shouldn't perform any check.

[avi: kill kvm-kmod remnants]

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-08 14:10:26 +02:00
Stephan Bärwolf
c2226fc9e8 KVM: x86: fix missing checks in syscall emulation
On hosts without this patch, 32bit guests will crash (and 64bit guests
may behave in a wrong way) for example by simply executing following
nasm-demo-application:

    [bits 32]
    global _start
    SECTION .text
    _start: syscall

(I tested it with winxp and linux - both always crashed)

    Disassembly of section .text:

    00000000 <_start>:
       0:   0f 05                   syscall

The reason seems a missing "invalid opcode"-trap (int6) for the
syscall opcode "0f05", which is not available on Intel CPUs
within non-longmodes, as also on some AMD CPUs within legacy-mode.
(depending on CPU vendor, MSR_EFER and cpuid)

Because previous mentioned OSs may not engage corresponding
syscall target-registers (STAR, LSTAR, CSTAR), they remain
NULL and (non trapping) syscalls are leading to multiple
faults and finally crashs.

Depending on the architecture (AMD or Intel) pretended by
guests, various checks according to vendor's documentation
are implemented to overcome the current issue and behave
like the CPUs physical counterparts.

[mtosatti: cleanup/beautify code]

Signed-off-by: Stephan Baerwolf <stephan.baerwolf@tu-ilmenau.de>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-02-01 11:43:40 +02:00
Stephan Bärwolf
bdb42f5afe KVM: x86: extend "struct x86_emulate_ops" with "get_cpuid"
In order to be able to proceed checks on CPU-specific properties
within the emulator, function "get_cpuid" is introduced.
With "get_cpuid" it is possible to virtually call the guests
"cpuid"-opcode without changing the VM's context.

[mtosatti: cleanup/beautify code]

Signed-off-by: Stephan Baerwolf <stephan.baerwolf@tu-ilmenau.de>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-02-01 11:43:33 +02:00
Avi Kivity
222d21aa07 KVM: x86 emulator: implement RDPMC (0F 33)
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-12-27 11:24:43 +02:00
Xiao Guangrong
1cb3f3ae5a KVM: x86: retry non-page-table writing instructions
If the emulation is caused by #PF and it is non-page_table writing instruction,
it means the VM-EXIT is caused by shadow page protected, we can zap the shadow
page and retry this instruction directly

The idea is from Avi

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-12-27 11:16:50 +02:00
Avi Kivity
b1ea50b2b6 KVM: x86 emulator: expand decode flags to 64 bits
Unifiying the operands means not taking advantage of the fact that some
operand types can only go into certain operands (for example, DI can only
be used by the destination), so we need more bits to hold the operand type.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-09-25 19:52:49 +03:00
Avi Kivity
f09ed83e21 KVM: x86 emulator: move memop, memopp into emulation context
Simplifies further generalization of decode.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-09-25 19:52:47 +03:00
Avi Kivity
9dac77fa40 KVM: x86 emulator: fold decode_cache into x86_emulate_ctxt
This saves a lot of pointless casts x86_emulate_ctxt and decode_cache.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-07-12 13:16:09 +03:00
Avi Kivity
36dd9bb5ce KVM: x86 emulator: rename decode_cache::eip to _eip
The name eip conflicts with a field of the same name in x86_emulate_ctxt,
which we plan to fold decode_cache into.

The name _eip is unfortunate, but what's really needed is a refactoring
here, not a better name.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-07-12 13:16:09 +03:00
Takuya Yoshikawa
b5c9ff731f KVM: x86 emulator: Avoid clearing the whole decode_cache
During tracing the emulator, we noticed that init_emulate_ctxt()
sometimes took a bit longer time than we expected.

This patch is for mitigating the problem by some degree.

By looking into the function, we soon notice that it clears the whole
decode_cache whose size is about 2.5K bytes now.  Furthermore, most of
the bytes are taken for the two read_cache arrays, which are used only
by a few instructions.

Considering the fact that we are not assuming the cache arrays have
been cleared when we store actual data, we do not need to clear the
arrays: 2K bytes elimination.  In addition, we can avoid clearing the
fetch_cache and regs arrays.

This patch changes the initialization not to clear the arrays.

On our 64-bit host, init_emulate_ctxt() becomes 0.3 to 0.5us faster with
this patch applied.

Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Cc: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-07-12 11:45:09 +03:00
Takuya Yoshikawa
7b105ca290 KVM: x86 emulator: Stop passing ctxt->ops as arg of emul functions
Dereference it in the actual users.

This not only cleans up the emulator but also makes it easy to convert
the old emulation functions to the new em_xxx() form later.

Note: Remove some inline keywords to let the compiler decide inlining.

Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-07-12 11:44:59 +03:00
Avi Kivity
1aa366163b KVM: x86 emulator: consolidate segment accessors
Instead of separate accessors for the segment selector and cached descriptor,
use one accessor for both.  This simplifies the code somewhat.

Signed-off-by: Avi Kivity <avi@redhat.com>
2011-05-22 08:47:39 -04:00
Avi Kivity
40e19b519c KVM: SVM: Get rid of x86_intercept_map::valid
By reserving 0 as an invalid x86_intercept_stage, we no longer
need to store a valid flag in x86_intercept_map.

Signed-off-by: Avi Kivity <avi@redhat.com>
2011-05-22 08:39:37 -04:00
Avi Kivity
13db70eca6 KVM: x86 emulator: drop x86_emulate_ctxt::vcpu
No longer used.

Signed-off-by: Avi Kivity <avi@redhat.com>
2011-05-22 08:39:24 -04:00
Avi Kivity
bcaf5cc543 KVM: x86 emulator: add new ->wbinvd() callback
Instead of calling kvm_emulate_wbinvd() directly.

Signed-off-by: Avi Kivity <avi@redhat.com>
2011-05-22 08:39:20 -04:00
Avi Kivity
d6aa10003b KVM: x86 emulator: add ->fix_hypercall() callback
Artificial, but needed to remove direct calls to KVM.

Signed-off-by: Avi Kivity <avi@redhat.com>
2011-05-22 08:39:18 -04:00
Avi Kivity
6c3287f7c5 KVM: x86 emulator: add new ->halt() callback
Instead of reaching into vcpu internals.

Signed-off-by: Avi Kivity <avi@redhat.com>
2011-05-22 08:39:17 -04:00
Avi Kivity
3cb16fe78c KVM: x86 emulator: make emulate_invlpg() an emulator callback
Removing direct calls to KVM.

Signed-off-by: Avi Kivity <avi@redhat.com>
2011-05-22 08:39:15 -04:00
Avi Kivity
1ac9d0cfb0 KVM: x86 emulator: add and use new callbacks set_idt(), set_gdt()
Replacing direct calls to realmode_lgdt(), realmode_lidt().

Signed-off-by: Avi Kivity <avi@redhat.com>
2011-05-22 08:39:08 -04:00
Avi Kivity
2953538ebb KVM: x86 emulator: drop vcpu argument from intercept callback
Making the emulator caller agnostic.

Signed-off-by: Avi Kivity <avi@redhat.com>
2011-05-22 08:39:05 -04:00
Avi Kivity
717746e382 KVM: x86 emulator: drop vcpu argument from cr/dr/cpl/msr callbacks
Making the emulator caller agnostic.

Signed-off-by: Avi Kivity <avi@redhat.com>
2011-05-22 08:39:03 -04:00
Avi Kivity
4bff1e86ad KVM: x86 emulator: drop vcpu argument from segment/gdt/idt callbacks
Making the emulator caller agnostic.

[Takuya Yoshikawa: fix typo leading to LDT failures]

Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-05-22 08:35:20 -04:00
Avi Kivity
ca1d4a9e77 KVM: x86 emulator: drop vcpu argument from pio callbacks
Making the emulator caller agnostic.

Signed-off-by: Avi Kivity <avi@redhat.com>
2011-05-11 07:57:11 -04:00
Avi Kivity
0f65dd70a4 KVM: x86 emulator: drop vcpu argument from memory read/write callbacks
Making the emulator caller agnostic.

Signed-off-by: Avi Kivity <avi@redhat.com>
2011-05-11 07:57:10 -04:00
Nelson Elhage
3d9b938eef KVM: emulator: Use linearize() when fetching instructions
Since segments need to be handled slightly differently when fetching
instructions, we add a __linearize helper that accepts a new 'fetch' boolean.

[avi: fix oops caused by wrong segmented_address initialization order]

Signed-off-by: Nelson Elhage <nelhage@ksplice.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-05-11 07:57:10 -04:00
Joerg Roedel
f6511935f4 KVM: SVM: Add checks for IO instructions
This patch adds code to check for IOIO intercepts on
instructions decoded by the KVM instruction emulator.

[avi: fix build error due to missing #define D2bvIP]

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-05-11 07:57:03 -04:00
Joerg Roedel
8061252ee0 KVM: SVM: Add intercept checks for remaining twobyte instructions
This patch adds intercepts checks for the remaining twobyte
instructions to the KVM instruction emulator.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-05-11 07:57:02 -04:00
Joerg Roedel
3b88e41a41 KVM: SVM: Add intercept check for accessing dr registers
This patch adds the intercept checks for instruction
accessing the debug registers.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-05-11 07:57:01 -04:00
Joerg Roedel
cfec82cb7d KVM: SVM: Add intercept check for emulated cr accesses
This patch adds all necessary intercept checks for
instructions that access the crX registers.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-05-11 07:57:01 -04:00
Joerg Roedel
8a76d7f25f KVM: x86: Add x86 callback for intercept check
This patch adds a callback into kvm_x86_ops so that svm and
vmx code can do intercept checks on emulated instructions.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-05-11 07:57:01 -04:00
Joerg Roedel
8ea7d6aef8 KVM: x86 emulator: Add flag to check for protected mode instructions
This patch adds a flag for the opcoded to tag instruction
which are only recognized in protected mode. The necessary
check is added too.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-05-11 07:57:01 -04:00
Joerg Roedel
d09beabd7c KVM: x86 emulator: Add check_perm callback
This patch adds a check_perm callback for each opcode into
the instruction emulator. This will be used to do all
necessary permission checks on instructions before checking
whether they are intercepted or not.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-05-11 07:57:01 -04:00
Joerg Roedel
775fde8648 KVM: x86 emulator: Don't write-back cpu-state on X86EMUL_INTERCEPTED
This patch prevents the changed CPU state to be written back
when the emulator detected that the instruction was
intercepted by the guest.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-05-11 07:57:00 -04:00
Avi Kivity
3c6e276f22 KVM: x86 emulator: add SVM intercepts
Add intercept codes for instructions defined by SVM as
interceptable.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-05-11 07:57:00 -04:00
Avi Kivity
c4f035c60d KVM: x86 emulator: add framework for instruction intercepts
When running in guest mode, certain instructions can be intercepted by
hardware.  This also holds for nested guests running on emulated
virtualization hardware, in particular instructions emulated by kvm
itself.

This patch adds a framework for intercepting instructions.  If an
instruction is marked for interception, and if we're running in guest
mode, a callback is called to check whether an intercept is needed or
not.  The callback is called at three points in time: immediately after
beginning execution, after checking privilge exceptions, and after
checking memory exception.  This suits the different interception points
defined for different instructions and for the various virtualization
instruction sets.

In addition, a new X86EMUL_INTERCEPT is defined, which any callback or
memory access may define, allowing the more complicated intercepts to be
implemented in existing callbacks.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-05-11 07:57:00 -04:00