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author | Paolo Bonzini <pbonzini@redhat.com> | 2014-05-06 16:33:01 +0200 |
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committer | Paolo Bonzini <pbonzini@redhat.com> | 2014-07-11 09:14:03 +0200 |
commit | 17052f16a51af6d8f4b7eee0631af675ac204f65 (patch) | |
tree | f2fa2f60c38e38ed175897b419ddb7b2df7901b2 | |
parent | KVM: emulate: avoid per-byte copying in instruction fetches (diff) | |
download | linux-17052f16a51af6d8f4b7eee0631af675ac204f65.tar.xz linux-17052f16a51af6d8f4b7eee0631af675ac204f65.zip |
KVM: emulate: put pointers in the fetch_cache
This simplifies the code a bit, especially the overflow checks.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-rw-r--r-- | arch/x86/include/asm/kvm_emulate.h | 4 | ||||
-rw-r--r-- | arch/x86/kvm/emulate.c | 34 | ||||
-rw-r--r-- | arch/x86/kvm/trace.h | 6 |
3 files changed, 20 insertions, 24 deletions
diff --git a/arch/x86/include/asm/kvm_emulate.h b/arch/x86/include/asm/kvm_emulate.h index fcf58cd25ebd..eb181178fe0b 100644 --- a/arch/x86/include/asm/kvm_emulate.h +++ b/arch/x86/include/asm/kvm_emulate.h @@ -242,8 +242,8 @@ struct operand { struct fetch_cache { u8 data[15]; - unsigned long start; - unsigned long end; + u8 *ptr; + u8 *end; }; struct read_cache { diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 02c668aca2b6..c16314807756 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -710,16 +710,15 @@ static int segmented_read_std(struct x86_emulate_ctxt *ctxt, */ static int __do_insn_fetch_bytes(struct x86_emulate_ctxt *ctxt, int op_size) { - struct fetch_cache *fc = &ctxt->fetch; int rc; - int size, cur_size; + int size; unsigned long linear; - + int cur_size = ctxt->fetch.end - ctxt->fetch.data; struct segmented_address addr = { .seg = VCPU_SREG_CS, - .ea = fc->end }; - cur_size = fc->end - fc->start; - size = min(15UL - cur_size, - PAGE_SIZE - offset_in_page(fc->end)); + .ea = ctxt->eip + cur_size }; + + size = min(15UL ^ cur_size, + PAGE_SIZE - offset_in_page(addr.ea)); /* * One instruction can only straddle two pages, @@ -732,19 +731,18 @@ static int __do_insn_fetch_bytes(struct x86_emulate_ctxt *ctxt, int op_size) rc = __linearize(ctxt, addr, size, false, true, &linear); if (unlikely(rc != X86EMUL_CONTINUE)) return rc; - rc = ctxt->ops->fetch(ctxt, linear, fc->data + cur_size, + rc = ctxt->ops->fetch(ctxt, linear, ctxt->fetch.end, size, &ctxt->exception); if (unlikely(rc != X86EMUL_CONTINUE)) return rc; - fc->end += size; + ctxt->fetch.end += size; return X86EMUL_CONTINUE; } static __always_inline int do_insn_fetch_bytes(struct x86_emulate_ctxt *ctxt, unsigned size) { - /* We have to be careful about overflow! */ - if (unlikely(ctxt->_eip > ctxt->fetch.end - size)) + if (unlikely(ctxt->fetch.end - ctxt->fetch.ptr < size)) return __do_insn_fetch_bytes(ctxt, size); else return X86EMUL_CONTINUE; @@ -753,26 +751,24 @@ static __always_inline int do_insn_fetch_bytes(struct x86_emulate_ctxt *ctxt, /* Fetch next part of the instruction being emulated. */ #define insn_fetch(_type, _ctxt) \ ({ _type _x; \ - struct fetch_cache *_fc; \ \ rc = do_insn_fetch_bytes(_ctxt, sizeof(_type)); \ if (rc != X86EMUL_CONTINUE) \ goto done; \ - _fc = &ctxt->fetch; \ - _x = *(_type __aligned(1) *) &_fc->data[ctxt->_eip - _fc->start]; \ ctxt->_eip += sizeof(_type); \ + _x = *(_type __aligned(1) *) ctxt->fetch.ptr; \ + ctxt->fetch.ptr += sizeof(_type); \ _x; \ }) #define insn_fetch_arr(_arr, _size, _ctxt) \ ({ \ - struct fetch_cache *_fc; \ rc = do_insn_fetch_bytes(_ctxt, _size); \ if (rc != X86EMUL_CONTINUE) \ goto done; \ - _fc = &ctxt->fetch; \ - memcpy(_arr, &_fc->data[ctxt->_eip - _fc->start], _size); \ ctxt->_eip += (_size); \ + memcpy(_arr, ctxt->fetch.ptr, _size); \ + ctxt->fetch.ptr += (_size); \ }) /* @@ -4228,8 +4224,8 @@ int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len) ctxt->memop.type = OP_NONE; ctxt->memopp = NULL; ctxt->_eip = ctxt->eip; - ctxt->fetch.start = ctxt->_eip; - ctxt->fetch.end = ctxt->fetch.start + insn_len; + ctxt->fetch.ptr = ctxt->fetch.data; + ctxt->fetch.end = ctxt->fetch.data + insn_len; ctxt->opcode_len = 1; if (insn_len > 0) memcpy(ctxt->fetch.data, insn, insn_len); diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h index 33574c95220d..e850a7d332be 100644 --- a/arch/x86/kvm/trace.h +++ b/arch/x86/kvm/trace.h @@ -721,10 +721,10 @@ TRACE_EVENT(kvm_emulate_insn, ), TP_fast_assign( - __entry->rip = vcpu->arch.emulate_ctxt.fetch.start; __entry->csbase = kvm_x86_ops->get_segment_base(vcpu, VCPU_SREG_CS); - __entry->len = vcpu->arch.emulate_ctxt._eip - - vcpu->arch.emulate_ctxt.fetch.start; + __entry->len = vcpu->arch.emulate_ctxt.fetch.ptr + - vcpu->arch.emulate_ctxt.fetch.data; + __entry->rip = vcpu->arch.emulate_ctxt._eip - __entry->len; memcpy(__entry->insn, vcpu->arch.emulate_ctxt.fetch.data, 15); |