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target-i386: fix segment limit check in ljmp

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The current implementation has three bugs,
 * segment limits are not enforced in protected mode if the L bit is set
   in the target segment descriptor
 * segment limits are not enforced in compatibility mode (ljmp to 32-bit
   code segment in long mode)
 * #GP(new_cs) is generated rather than #GP(0)

Now the segment limits are enforced if we're not in long mode OR the
target code segment doesn't have the L bit set.

Signed-off-by: Andrew Oates <aoates@google.com>
Message-Id: <20180816011903.39816-1-andrew@andrewoates.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Andrew Oates 2018-08-15 21:19:03 -04:00 committed by Paolo Bonzini
parent 0aca060526
commit db7196db5d
1 changed files with 2 additions and 2 deletions
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4
target/i386/seg_helper.c
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@ -1633,8 +1633,8 @@ void helper_ljmp_protected(CPUX86State *env, int new_cs, target_ulong new_eip,
} }
limit = get_seg_limit(e1, e2); limit = get_seg_limit(e1, e2);
if (new_eip > limit && if (new_eip > limit &&
!(env->hflags & HF_LMA_MASK) && !(e2 & DESC_L_MASK)) { (!(env->hflags & HF_LMA_MASK) || !(e2 & DESC_L_MASK))) {
raise_exception_err_ra(env, EXCP0D_GPF, new_cs & 0xfffc, GETPC()); raise_exception_err_ra(env, EXCP0D_GPF, 0, GETPC());
} }
cpu_x86_load_seg_cache(env, R_CS, (new_cs & 0xfffc) | cpl, cpu_x86_load_seg_cache(env, R_CS, (new_cs & 0xfffc) | cpl,
get_seg_base(e1, e2), limit, e2); get_seg_base(e1, e2), limit, e2);