@@ -263,6 +263,8 @@ struct operand {
u64 mm_val;
void *data;
};
+ unsigned long hva;
+ void *opaque;
};
struct fetch_cache {
@@ -1546,9 +1546,37 @@ exception:
}
static int prepare_memory_operand(struct x86_emulate_ctxt *ctxt,
- struct operand *op)
+ struct operand *op,
+ bool write)
{
- return segmented_read(ctxt, op->addr.mem, &op->val, op->bytes);
+ int rc;
+ unsigned long gva;
+ unsigned int size = op->bytes;
+
+ rc = linearize(ctxt, op->addr.mem, size, write, &gva);
+ if (rc != X86EMUL_CONTINUE)
+ return rc;
+
+ rc = ctxt->ops->memory_prepare(ctxt, gva, size,
+ &ctxt->exception, true,
+ &op->opaque, &op->hva);
+ if (rc != X86EMUL_CONTINUE)
+ return rc;
+
+ if (likely(!kvm_is_error_hva(op->hva))) {
+ rc = __copy_from_user(&op->val, (void __user *)op->hva,
+ size);
+ if (!write)
+ ctxt->ops->memory_finish(ctxt, op->opaque, op->hva);
+
+ if (likely(!rc))
+ return X86EMUL_CONTINUE;
+
+ /* Should not happen. */
+ op->hva = KVM_HVA_ERR_BAD;
+ }
+
+ return read_emulated(ctxt, gva, &op->val, size);
}
static int cmpxchg_memory_operand(struct x86_emulate_ctxt *ctxt,
@@ -1563,6 +1591,17 @@ static int cmpxchg_memory_operand(struct x86_emulate_ctxt *ctxt,
static int write_memory_operand(struct x86_emulate_ctxt *ctxt,
struct operand *op)
{
+ int rc;
+
+ if (likely(!kvm_is_error_hva(op->hva))) {
+ rc = __copy_to_user((void __user *)op->hva, &op->val,
+ op->bytes);
+ ctxt->ops->memory_finish(ctxt, op->opaque, op->hva);
+
+ if (likely(!rc))
+ return X86EMUL_CONTINUE;
+ }
+
return segmented_write(ctxt, op->addr.mem,
&op->val,
op->bytes);
@@ -4604,14 +4643,14 @@ int x86_emulate_insn(struct x86_emulate_ctxt *ctxt)
}
if ((ctxt->src.type == OP_MEM) && !(ctxt->d & NoAccess)) {
- rc = prepare_memory_operand(ctxt, &ctxt->src);
+ rc = prepare_memory_operand(ctxt, &ctxt->src, false);
if (rc != X86EMUL_CONTINUE)
goto done;
ctxt->src.orig_val64 = ctxt->src.val64;
}
if (ctxt->src2.type == OP_MEM) {
- rc = prepare_memory_operand(ctxt, &ctxt->src2);
+ rc = prepare_memory_operand(ctxt, &ctxt->src2, false);
if (rc != X86EMUL_CONTINUE)
goto done;
}
@@ -4622,7 +4661,8 @@ int x86_emulate_insn(struct x86_emulate_ctxt *ctxt)
if ((ctxt->dst.type == OP_MEM) && !(ctxt->d & Mov)) {
/* optimisation - avoid slow emulated read if Mov */
- rc = prepare_memory_operand(ctxt, &ctxt->dst);
+ rc = prepare_memory_operand(ctxt, &ctxt->dst,
+ !(ctxt->d & NoWrite));
if (rc != X86EMUL_CONTINUE)
goto done;
}
memory_prepare lets us replace segmented_read/segmented_write with direct calls to __copy_from_user/__copy_to_user. This saves about 70 cycles (15%) on arithmetic with a memory source operand, and about 150 cycles (25%) on arithmetic with a memory destination operand. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> --- arch/x86/include/asm/kvm_emulate.h | 2 ++ arch/x86/kvm/emulate.c | 50 ++++++++++++++++++++++++++++++++++---- 2 files changed, 47 insertions(+), 5 deletions(-)