KVM: x86 emulator: Add Virtual-8086 mode of emulation
For some instructions CPU behaves differently for real-mode and virtual 8086. Let emulator know which mode cpu is in, so it will not poke into vcpu state directly. Signed-off-by: Gleb Natapov <gleb@redhat.com> Cc: stable@kernel.org Signed-off-by: Avi Kivity <avi@redhat.com>
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committed by
Marcelo Tosatti

parent
60a29d4ea4
commit
a004475567
@@ -899,6 +899,7 @@ x86_decode_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
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switch (mode) {
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case X86EMUL_MODE_REAL:
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case X86EMUL_MODE_VM86:
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case X86EMUL_MODE_PROT16:
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def_op_bytes = def_ad_bytes = 2;
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break;
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@@ -1525,7 +1526,7 @@ emulate_syscall(struct x86_emulate_ctxt *ctxt)
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/* syscall is not available in real mode */
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if (c->lock_prefix || ctxt->mode == X86EMUL_MODE_REAL
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|| !is_protmode(ctxt->vcpu))
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|| ctxt->mode == X86EMUL_MODE_VM86)
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return -1;
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setup_syscalls_segments(ctxt, &cs, &ss);
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@@ -1577,8 +1578,8 @@ emulate_sysenter(struct x86_emulate_ctxt *ctxt)
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if (c->lock_prefix)
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return -1;
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/* inject #GP if in real mode or paging is disabled */
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if (ctxt->mode == X86EMUL_MODE_REAL || !is_protmode(ctxt->vcpu)) {
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/* inject #GP if in real mode */
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if (ctxt->mode == X86EMUL_MODE_REAL) {
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kvm_inject_gp(ctxt->vcpu, 0);
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return -1;
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}
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@@ -1642,8 +1643,9 @@ emulate_sysexit(struct x86_emulate_ctxt *ctxt)
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if (c->lock_prefix)
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return -1;
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/* inject #GP if in real mode or paging is disabled */
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if (ctxt->mode == X86EMUL_MODE_REAL || !is_protmode(ctxt->vcpu)) {
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/* inject #GP if in real mode or Virtual 8086 mode */
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if (ctxt->mode == X86EMUL_MODE_REAL ||
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ctxt->mode == X86EMUL_MODE_VM86) {
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kvm_inject_gp(ctxt->vcpu, 0);
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return -1;
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}
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