pc-bios/optionrom/kvmvapic.S

   1 #
   2 # Local APIC acceleration for Windows XP and related guests
   3 #
   4 # Copyright 2011 Red Hat, Inc. and/or its affiliates
   5 #
   6 # Author: Avi Kivity <avi@redhat.com>
   7 #
   8 # This work is licensed under the terms of the GNU GPL, version 2, or (at your
   9 # option) any later version.  See the COPYING file in the top-level directory.
  10 #
  11
  12         .text 0
  13         .code16
  14 .global _start
  15 _start:
  16         .short 0xaa55
  17         .byte (_end - _start) / 512
  18         # clear vapic area: firmware load using rep insb may cause
  19         # stale tpr/isr/irr data to corrupt the vapic area.
  20         push %es
  21         push %cs
  22         pop %es
  23         xor %ax, %ax
  24         mov $vapic_size/2, %cx
  25         lea vapic, %di
  26         cld
  27         rep stosw
  28         pop %es
  29         mov $vapic_base, %ax
  30         out %ax, $0x7e
  31         lret
  32
  33         .code32
  34 vapic_size = 2*4096
  35
  36 .macro fixup delta=-4
  37 777:
  38         .text 1
  39         .long 777b + \delta  - vapic_base
  40         .text 0
  41 .endm
  42
  43 .macro reenable_vtpr
  44         out %al, $0x7e
  45 .endm
  46
  47 .text 1
  48         fixup_start = .
  49 .text 0
  50
  51 .align 16
  52
  53 vapic_base:
  54         .ascii "kvm aPiC"
  55
  56         /* relocation data */
  57         .long vapic_base        ; fixup
  58         .long fixup_start       ; fixup
  59         .long fixup_end         ; fixup
  60
  61         .long vapic             ; fixup
  62         .long vapic_size
  63 vcpu_shift:
  64         .long 0
  65 real_tpr:
  66         .long 0
  67         .long up_set_tpr        ; fixup
  68         .long up_set_tpr_eax    ; fixup
  69         .long up_get_tpr_eax    ; fixup
  70         .long up_get_tpr_ecx    ; fixup
  71         .long up_get_tpr_edx    ; fixup
  72         .long up_get_tpr_ebx    ; fixup
  73         .long 0 /* esp. won't work. */
  74         .long up_get_tpr_ebp    ; fixup
  75         .long up_get_tpr_esi    ; fixup
  76         .long up_get_tpr_edi    ; fixup
  77         .long up_get_tpr_stack  ; fixup
  78         .long mp_set_tpr        ; fixup
  79         .long mp_set_tpr_eax    ; fixup
  80         .long mp_get_tpr_eax    ; fixup
  81         .long mp_get_tpr_ecx    ; fixup
  82         .long mp_get_tpr_edx    ; fixup
  83         .long mp_get_tpr_ebx    ; fixup
  84         .long 0 /* esp. won't work. */
  85         .long mp_get_tpr_ebp    ; fixup
  86         .long mp_get_tpr_esi    ; fixup
  87         .long mp_get_tpr_edi    ; fixup
  88         .long mp_get_tpr_stack  ; fixup
  89
  90 .macro kvm_hypercall
  91         .byte 0x0f, 0x01, 0xc1
  92 .endm
  93
  94 kvm_hypercall_vapic_poll_irq = 1
  95
  96 pcr_cpu = 0x51
  97
  98 .align 64
  99
 100 mp_get_tpr_eax:
 101         pushf
 102         cli
 103         reenable_vtpr
 104         push %ecx
 105
 106         fs/movzbl pcr_cpu, %eax
 107
 108         mov vcpu_shift, %ecx    ; fixup
 109         shl %cl, %eax
 110         testb $1, vapic+4(%eax) ; fixup delta=-5
 111         jz mp_get_tpr_bad
 112         movzbl vapic(%eax), %eax ; fixup
 113
 114 mp_get_tpr_out:
 115         pop %ecx
 116         popf
 117         ret
 118
 119 mp_get_tpr_bad:
 120         mov real_tpr, %eax      ; fixup
 121         mov (%eax), %eax
 122         jmp mp_get_tpr_out
 123
 124 mp_get_tpr_ebx:
 125         mov %eax, %ebx
 126         call mp_get_tpr_eax
 127         xchg %eax, %ebx
 128         ret
 129
 130 mp_get_tpr_ecx:
 131         mov %eax, %ecx
 132         call mp_get_tpr_eax
 133         xchg %eax, %ecx
 134         ret
 135
 136 mp_get_tpr_edx:
 137         mov %eax, %edx
 138         call mp_get_tpr_eax
 139         xchg %eax, %edx
 140         ret
 141
 142 mp_get_tpr_esi:
 143         mov %eax, %esi
 144         call mp_get_tpr_eax
 145         xchg %eax, %esi
 146         ret
 147
 148 mp_get_tpr_edi:
 149         mov %eax, %edi
 150         call mp_get_tpr_edi
 151         xchg %eax, %edi
 152         ret
 153
 154 mp_get_tpr_ebp:
 155         mov %eax, %ebp
 156         call mp_get_tpr_eax
 157         xchg %eax, %ebp
 158         ret
 159
 160 mp_get_tpr_stack:
 161         call mp_get_tpr_eax
 162         xchg %eax, 4(%esp)
 163         ret
 164
 165 mp_set_tpr_eax:
 166         push %eax
 167         call mp_set_tpr
 168         ret
 169
 170 mp_set_tpr:
 171         pushf
 172         push %eax
 173         push %ecx
 174         push %edx
 175         push %ebx
 176         cli
 177         reenable_vtpr
 178
 179 mp_set_tpr_failed:
 180         fs/movzbl pcr_cpu, %edx
 181
 182         mov vcpu_shift, %ecx    ; fixup
 183         shl %cl, %edx
 184
 185         testb $1, vapic+4(%edx) ; fixup delta=-5
 186         jz mp_set_tpr_bad
 187
 188         mov vapic(%edx), %eax   ; fixup
 189
 190         mov %eax, %ebx
 191         mov 24(%esp), %bl
 192
 193         /* %ebx = new vapic (%bl = tpr, %bh = isr, %b3 = irr) */
 194
 195         lock cmpxchg %ebx, vapic(%edx) ; fixup
 196         jnz mp_set_tpr_failed
 197
 198         /* compute ppr */
 199         cmp %bh, %bl
 200         jae mp_tpr_is_bigger
 201 mp_isr_is_bigger:
 202         mov %bh, %bl
 203 mp_tpr_is_bigger:
 204         /* %bl = ppr */
 205         mov %bl, %ch   /* ch = ppr */
 206         rol $8, %ebx
 207         /* now: %bl = irr, %bh = ppr */
 208         cmp %bh, %bl
 209         ja mp_set_tpr_poll_irq
 210
 211 mp_set_tpr_out:
 212         pop %ebx
 213         pop %edx
 214         pop %ecx
 215         pop %eax
 216         popf
 217         ret $4
 218
 219 mp_set_tpr_poll_irq:
 220         mov $kvm_hypercall_vapic_poll_irq, %eax
 221         kvm_hypercall
 222         jmp mp_set_tpr_out
 223
 224 mp_set_tpr_bad:
 225         mov 24(%esp), %ecx
 226         mov real_tpr, %eax      ; fixup
 227         mov %ecx, (%eax)
 228         jmp mp_set_tpr_out
 229
 230 up_get_tpr_eax:
 231         reenable_vtpr
 232         movzbl vapic, %eax ; fixup
 233         ret
 234
 235 up_get_tpr_ebx:
 236         reenable_vtpr
 237         movzbl vapic, %ebx ; fixup
 238         ret
 239
 240 up_get_tpr_ecx:
 241         reenable_vtpr
 242         movzbl vapic, %ecx ; fixup
 243         ret
 244
 245 up_get_tpr_edx:
 246         reenable_vtpr
 247         movzbl vapic, %edx ; fixup
 248         ret
 249
 250 up_get_tpr_esi:
 251         reenable_vtpr
 252         movzbl vapic, %esi ; fixup
 253         ret
 254
 255 up_get_tpr_edi:
 256         reenable_vtpr
 257         movzbl vapic, %edi ; fixup
 258         ret
 259
 260 up_get_tpr_ebp:
 261         reenable_vtpr
 262         movzbl vapic, %ebp ; fixup
 263         ret
 264
 265 up_get_tpr_stack:
 266         reenable_vtpr
 267         movzbl vapic, %eax ; fixup
 268         xchg %eax, 4(%esp)
 269         ret
 270
 271 up_set_tpr_eax:
 272         push %eax
 273         call up_set_tpr
 274         ret
 275
 276 up_set_tpr:
 277         pushf
 278         push %eax
 279         push %ecx
 280         push %ebx
 281         reenable_vtpr
 282
 283 up_set_tpr_failed:
 284         mov vapic, %eax ; fixup
 285
 286         mov %eax, %ebx
 287         mov 20(%esp), %bl
 288
 289         /* %ebx = new vapic (%bl = tpr, %bh = isr, %b3 = irr) */
 290
 291         lock cmpxchg %ebx, vapic ; fixup
 292         jnz up_set_tpr_failed
 293
 294         /* compute ppr */
 295         cmp %bh, %bl
 296         jae up_tpr_is_bigger
 297 up_isr_is_bigger:
 298         mov %bh, %bl
 299 up_tpr_is_bigger:
 300         /* %bl = ppr */
 301         mov %bl, %ch   /* ch = ppr */
 302         rol $8, %ebx
 303         /* now: %bl = irr, %bh = ppr */
 304         cmp %bh, %bl
 305         ja up_set_tpr_poll_irq
 306
 307 up_set_tpr_out:
 308         pop %ebx
 309         pop %ecx
 310         pop %eax
 311         popf
 312         ret $4
 313
 314 up_set_tpr_poll_irq:
 315         mov $kvm_hypercall_vapic_poll_irq, %eax
 316         kvm_hypercall
 317         jmp up_set_tpr_out
 318
 319 .text 1
 320         fixup_end = .
 321 .text 0
 322
 323 /*
 324  * vapic format:
 325  *  per-vcpu records of size 2^vcpu shift.
 326  *     byte 0: tpr (r/w)
 327  *     byte 1: highest in-service interrupt (isr) (r/o); bits 3:0 are zero
 328  *     byte 2: zero (r/o)
 329  *     byte 3: highest pending interrupt (irr) (r/o)
 330  */
 331 .text 2
 332
 333 .align 128
 334
 335 vapic:
 336 . = . + vapic_size
 337
 338 .byte 0  # reserve space for signature
 339 .align 512, 0
 340
 341 _end: