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  1. 04 Dec, 2014 9 commits
  3. 03 Dec, 2014 1 commit
  5. 28 Nov, 2014 11 commits
  7. 24 Nov, 2014 2 commits
  9. 23 Nov, 2014 2 commits
  11. 21 Nov, 2014 3 commits
  13. 20 Nov, 2014 2 commits
  15. 19 Nov, 2014 9 commits
    • Nicholas Krause's avatar
      KVM: x86: Remove FIXMEs in emulate.c · 86619e7b
      Nicholas Krause authored 
      Remove FIXME comments about needing fault addresses to be returned.  These
are propaagated from walk_addr_generic to gva_to_gpa and from there to
ops->read_std and ops->write_std.
Signed-off-by: default avatarNicholas Krause <xerofoify@gmail.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      86619e7b
    • Paolo Bonzini's avatar
      KVM: emulator: remove duplicated limit check · 997b0412
      Paolo Bonzini authored 
      The check on the higher limit of the segment, and the check on the
maximum accessible size, is the same for both expand-up and
expand-down segments.  Only the computation of "lim" varies.
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      997b0412
    • Paolo Bonzini's avatar
      KVM: emulator: remove code duplication in register_address{,_increment} · 01485a22
      Paolo Bonzini authored 
      register_address has been a duplicate of address_mask ever since the
ancestor of __linearize was born in 90de84f5 (KVM: x86 emulator:
preserve an operand's segment identity, 2010-11-17).

However, we can put it to a better use by including the call to reg_read
in register_address.  Similarly, the call to reg_rmw can be moved to
register_address_increment.
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      01485a22
    • Nadav Amit's avatar
      KVM: x86: Move __linearize masking of la into switch · 31ff6488
      Nadav Amit authored 
      In __linearize there is check of the condition whether to check if masking of
the linear address is needed.  It occurs immediately after switch that
evaluates the same condition.  Merge them.
Signed-off-by: default avatarNadav Amit <namit@cs.technion.ac.il>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      31ff6488
    • Nadav Amit's avatar
      KVM: x86: Non-canonical access using SS should cause #SS · abc7d8a4
      Nadav Amit authored 
      When SS is used using a non-canonical address, an #SS exception is generated on
real hardware.  KVM emulator causes a #GP instead. Fix it to behave as real x86
CPU.
Signed-off-by: default avatarNadav Amit <namit@cs.technion.ac.il>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      abc7d8a4
    • Nadav Amit's avatar
      KVM: x86: Perform limit checks when assigning EIP · d50eaa18
      Nadav Amit authored 
      If branch (e.g., jmp, ret) causes limit violations, since the target IP >
limit, the #GP exception occurs before the branch.  In other words, the RIP
pushed on the stack should be that of the branch and not that of the target.

To do so, we can call __linearize, with new EIP, which also saves us the code
which performs the canonical address checks. On the case of assigning an EIP >=
2^32 (when switching cs.l), we also safe, as __linearize will check the new EIP
does not exceed the limit and would trigger #GP(0) otherwise.
Signed-off-by: default avatarNadav Amit <namit@cs.technion.ac.il>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      d50eaa18
    • Nadav Amit's avatar
      KVM: x86: Emulator performs privilege checks on __linearize · a7315d2f
      Nadav Amit authored 
      When segment is accessed, real hardware does not perform any privilege level
checks.  In contrast, KVM emulator does. This causes some discrepencies from
real hardware. For instance, reading from readable code segment may fail due to
incorrect segment checks. In addition, it introduces unnecassary overhead.

To reference Intel SDM 5.5 ("Privilege Levels"): "Privilege levels are checked
when the segment selector of a segment descriptor is loaded into a segment
register." The SDM never mentions privilege level checks during memory access,
except for loading far pointers in section 5.10 ("Pointer Validation"). Those
are actually segment selector loads and are emulated in the similarily (i.e.,
regardless to __linearize checks).

This behavior was also checked using sysexit. A data-segment whose DPL=0 was
loaded, and after sysexit (CPL=3) it is still accessible.

Therefore, all the privilege level checks in __linearize are removed.
Signed-off-by: default avatarNadav Amit <namit@cs.technion.ac.il>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      a7315d2f
    • Nadav Amit's avatar
      KVM: x86: Stack size is overridden by __linearize · 1c1c35ae
      Nadav Amit authored 
      When performing segmented-read/write in the emulator for stack operations, it
ignores the stack size, and uses the ad_bytes as indication for the pointer
size. As a result, a wrong address may be accessed.

To fix this behavior, we can remove the masking of address in __linearize and
perform it beforehand.  It is already done for the operands (so currently it is
inefficiently done twice). It is missing in two cases:
1. When using rip_relative
2. On fetch_bit_operand that changes the address.

This patch masks the address on these two occassions, and removes the masking
from __linearize.

Note that it does not mask EIP during fetch. In protected/legacy mode code
fetch when RIP >= 2^32 should result in #GP and not wrap-around. Since we make
limit checks within __linearize, this is the expected behavior.

Partial revert of commit 518547b3 (KVM: x86: Emulator does not
calculate address correctly, 2014-09-30).
Signed-off-by: default avatarNadav Amit <namit@cs.technion.ac.il>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      1c1c35ae
    • Nadav Amit's avatar
      KVM: x86: Revert NoBigReal patch in the emulator · 7d882ffa
      Nadav Amit authored 
      Commit 10e38fc7cab6 ("KVM: x86: Emulator flag for instruction that only support
16-bit addresses in real mode") introduced NoBigReal for instructions such as
MONITOR. Apparetnly, the Intel SDM description that led to this patch is
misleading.  Since no instruction is using NoBigReal, it is safe to remove it,
we fully understand what the SDM means.
Signed-off-by: default avatarNadav Amit <namit@cs.technion.ac.il>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      7d882ffa
  17. 18 Nov, 2014 1 commit
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