KVM: Cleanup string I/O instruction emulation

Both vmx and svm decode the I/O instructions, and both botch the job,
requiring the instruction prefixes to be fetched in order to completely
decode the instruction.

So, if we see a string I/O instruction, use the x86 emulator to decode it,
as it already has all the prefix decoding machinery.

This patch defines ins/outs opcodes in x86_emulate.c and calls
emulate_instruction() from io_interception() (svm.c) and from handle_io()
(vmx.c).  It removes all vmx/svm prefix instruction decoders
(get_addr_size(), io_get_override(), io_address(), get_io_count())

Signed-off-by: Laurent Vivier <Laurent.Vivier@bull.net>
Signed-off-by: Avi Kivity <avi@qumranet.com>

1 files changed, 44 insertions, 5 deletions

diff --git a/drivers/kvm/x86_emulate.c b/drivers/kvm/x86_emulate.c
index 44eb28d31499..d553719fc4cb 100644
--- a/drivers/kvm/x86_emulate.c
+++ b/drivers/kvm/x86_emulate.c
@@ -103,9 +103,12 @@ static u8 opcode_table[256] = {
         /* 0x58 - 0x5F */
         ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
         ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
-        /* 0x60 - 0x6F */
+        /* 0x60 - 0x6B */
         0, 0, 0, DstReg | SrcMem32 | ModRM | Mov /* movsxd (x86/64) */ ,
-        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        0, 0, 0, 0, 0, 0, 0, 0,
+        /* 0x6C - 0x6F */
+        SrcNone  | ByteOp  | ImplicitOps, SrcNone  | ImplicitOps, /* insb, insw/insd */
+        SrcNone  | ByteOp  | ImplicitOps, SrcNone  | ImplicitOps, /* outsb, outsw/outsd */
         /* 0x70 - 0x7F */
         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
         /* 0x80 - 0x87 */
@@ -428,10 +431,11 @@ struct operand {
 })
 
 /* Access/update address held in a register, based on addressing mode. */
+#define address_mask(reg)                                               \
+        ((ad_bytes == sizeof(unsigned long)) ?                          \
+                (reg) : ((reg) & ((1UL << (ad_bytes << 3)) - 1)))
 #define register_address(base, reg)                                     \
-        ((base) + ((ad_bytes == sizeof(unsigned long)) ? (reg) :        \
-                   ((reg) & ((1UL << (ad_bytes << 3)) - 1))))
-
+        ((base) + address_mask(reg))
 #define register_address_increment(reg, inc)                            \
         do {                                                            \
                 /* signed type ensures sign extension to long */        \
@@ -1116,6 +1120,41 @@ done:
 special_insn:
         if (twobyte)
                 goto twobyte_special_insn;
+        switch(b) {
+        case 0x6c:              /* insb */
+        case 0x6d:              /* insw/insd */
+                 if (kvm_setup_pio(ctxt->vcpu, NULL,
+                                1,                                      /* in */
+                                (d & ByteOp) ? 1 : op_bytes,            /* size */
+                                rep_prefix ?
+                                address_mask(_regs[VCPU_REGS_RCX]) : 1, /* count */
+                                1,                                      /* strings */
+                                (_eflags & EFLG_DF),                    /* down */
+                                register_address(ctxt->es_base,
+                                                 _regs[VCPU_REGS_RDI]), /* address */
+                                rep_prefix,
+                                _regs[VCPU_REGS_RDX]                    /* port */
+                                ) == 0)
+                        return -1;
+                return 0;
+        case 0x6e:              /* outsb */
+        case 0x6f:              /* outsw/outsd */
+                if (kvm_setup_pio(ctxt->vcpu, NULL,
+                                0,                                      /* in */
+                                (d & ByteOp) ? 1 : op_bytes,            /* size */
+                                rep_prefix ?
+                                address_mask(_regs[VCPU_REGS_RCX]) : 1, /* count */
+                                1,                                      /* strings */
+                                (_eflags & EFLG_DF),                    /* down */
+                                register_address(override_base ?
+                                                 *override_base : ctxt->ds_base,
+                                                 _regs[VCPU_REGS_RSI]), /* address */
+                                rep_prefix,
+                                _regs[VCPU_REGS_RDX]                    /* port */
+                                ) == 0)
+                        return -1;
+                return 0;
+        }
         if (rep_prefix) {
                 if (_regs[VCPU_REGS_RCX] == 0) {
                         ctxt->vcpu->rip = _eip;