KVM: x86 emulator: retire ->write_std()

Theoretically used to acccess memory known to be ordinary RAM, it was
never implemented.  It is questionable whether it is possible to implement
it correctly.
Signed-off-by: Avi Kivity <avi@qumranet.com>

drivers/kvm/x86.c

@@ -1162,15 +1162,6 @@ int emulator_read_std(unsigned long addr,
 }
 EXPORT_SYMBOL_GPL(emulator_read_std);
 
-static int emulator_write_std(unsigned long addr,
-			      const void *val,
-			      unsigned int bytes,
-			      struct kvm_vcpu *vcpu)
-{
-	pr_unimpl(vcpu, "emulator_write_std: addr %lx n %d\n", addr, bytes);
-	return X86EMUL_UNHANDLEABLE;
-}
-
 static int emulator_read_emulated(unsigned long addr,
 				  void *val,
 				  unsigned int bytes,
@@ -1367,7 +1358,6 @@ EXPORT_SYMBOL_GPL(kvm_report_emulation_failure);
 
 struct x86_emulate_ops emulate_ops = {
 	.read_std            = emulator_read_std,
-	.write_std           = emulator_write_std,
 	.read_emulated       = emulator_read_emulated,
 	.write_emulated      = emulator_write_emulated,
 	.cmpxchg_emulated    = emulator_cmpxchg_emulated,

drivers/kvm/x86_emulate.h

@@ -62,17 +62,6 @@ struct x86_emulate_ops {
 	int (*read_std)(unsigned long addr, void *val,
 			unsigned int bytes, struct kvm_vcpu *vcpu);
 
-	/*
-	 * write_std: Write bytes of standard (non-emulated/special) memory.
-	 *            Used for stack operations, and others.
-	 *  @addr:  [IN ] Linear address to which to write.
-	 *  @val:   [IN ] Value to write to memory (low-order bytes used as
-	 *                required).
-	 *  @bytes: [IN ] Number of bytes to write to memory.
-	 */
-	int (*write_std)(unsigned long addr, const void *val,
-			 unsigned int bytes, struct kvm_vcpu *vcpu);
-
 	/*
 	 * read_emulated: Read bytes from emulated/special memory area.
 	 *  @addr:  [IN ] Linear address from which to read.