diff options
Diffstat (limited to 'drivers/kvm/x86_emulate.c')
| -rw-r--r-- | drivers/kvm/x86_emulate.c | 38 |
1 files changed, 36 insertions, 2 deletions
diff --git a/drivers/kvm/x86_emulate.c b/drivers/kvm/x86_emulate.c index 8e2162fc6f7..6e7f774d175 100644 --- a/drivers/kvm/x86_emulate.c +++ b/drivers/kvm/x86_emulate.c @@ -414,8 +414,7 @@ static u16 twobyte_table[256] = { /* Fetch next part of the instruction being emulated. */ #define insn_fetch(_type, _size, _eip) \ ({ unsigned long _x; \ - rc = ops->read_std((unsigned long)(_eip) + ctxt->cs_base, &_x, \ - (_size), ctxt->vcpu); \ + rc = do_insn_fetch(ctxt, ops, (_eip), &_x, (_size)); \ if (rc != 0) \ goto done; \ (_eip) += (_size); \ @@ -446,6 +445,41 @@ static u16 twobyte_table[256] = { register_address_increment(c->eip, rel); \ } while (0) +static int do_fetch_insn_byte(struct x86_emulate_ctxt *ctxt, + struct x86_emulate_ops *ops, + unsigned long linear, u8 *dest) +{ + struct fetch_cache *fc = &ctxt->decode.fetch; + int rc; + int size; + + if (linear < fc->start || linear >= fc->end) { + size = min(15UL, PAGE_SIZE - offset_in_page(linear)); + rc = ops->read_std(linear, fc->data, size, ctxt->vcpu); + if (rc) + return rc; + fc->start = linear; + fc->end = linear + size; + } + *dest = fc->data[linear - fc->start]; + return 0; +} + +static int do_insn_fetch(struct x86_emulate_ctxt *ctxt, + struct x86_emulate_ops *ops, + unsigned long eip, void *dest, unsigned size) +{ + int rc = 0; + + eip += ctxt->cs_base; + while (size--) { + rc = do_fetch_insn_byte(ctxt, ops, eip++, dest++); + if (rc) + return rc; + } + return 0; +} + /* * Given the 'reg' portion of a ModRM byte, and a register block, return a * pointer into the block that addresses the relevant register. |