[PATCH 1/8] ioctl: add a stub for decoding kvm related ioctls

[Dmitry V. Levin]

On Fri, Dec 01, 2017 at 02:45:51PM +0900, Masatake YAMATO wrote:
> * kvm.c: New file.
> * Makefile.am (strace_SOURCES): Add kvm.c.
> * configure.ac: Check the existence of linux/kvm.h.

We usually write it this way:

* configure.ac (AC_CHECK_HEADERS): Add linux/kvm.h.

> * defs.h: Declare `kvm' as ioctl doecoder.
> * ioctl.c: Call `kvm_ioctl'.
> 
> Signed-off-by: Masatake YAMATO <yamato at redhat.com>
> ---
>  Makefile.am  |  1 +
>  configure.ac |  1 +
>  defs.h       |  1 +
>  ioctl.c      |  4 ++++
>  kvm.c        | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  5 files changed, 57 insertions(+)
>  create mode 100644 kvm.c
> 
> diff --git a/Makefile.am b/Makefile.am
> index 2586a3e0..60376056 100644
> --- a/Makefile.am
> +++ b/Makefile.am
> @@ -166,6 +166,7 @@ strace_SOURCES =	\
>  	kexec.c		\
>  	keyctl.c	\
>  	keyctl_kdf_params.h \
> +	kvm.c \
>  	ldt.c		\
>  	link.c		\
>  	linux/asm_stat.h \
> diff --git a/configure.ac b/configure.ac
> index 2fc45b76..fa451d84 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -395,6 +395,7 @@ AC_CHECK_HEADERS(m4_normalize([
>  	linux/ip_vs.h
>  	linux/ipc.h
>  	linux/kcmp.h
> +	linux/kvm.h
>  	linux/memfd.h
>  	linux/mmtimer.h
>  	linux/msg.h
> diff --git a/defs.h b/defs.h
> index b1a6b955..0187863e 100644
> --- a/defs.h
> +++ b/defs.h
> @@ -658,6 +658,7 @@ name ## _ioctl(struct tcb *, unsigned int request, kernel_ulong_t arg)	\
>  DECL_IOCTL(dm);
>  DECL_IOCTL(file);
>  DECL_IOCTL(fs_x);
> +DECL_IOCTL(kvm);
>  DECL_IOCTL(nsfs);
>  DECL_IOCTL(ptp);
>  DECL_IOCTL(scsi);
> diff --git a/ioctl.c b/ioctl.c
> index b61a5be5..35485172 100644
> --- a/ioctl.c
> +++ b/ioctl.c
> @@ -314,6 +314,10 @@ ioctl_decode(struct tcb *tcp)
>  	case 0xfd:
>  		return dm_ioctl(tcp, code, arg);
>  #endif
> +#ifdef HAVE_LINUX_KVM_H
> +	case 0xae:
> +		return kvm_ioctl(tcp, code, arg);
> +#endif

If you check HAVE_LINUX_KVM_H here, then ...

>  	default:
>  		break;
>  	}
> diff --git a/kvm.c b/kvm.c
> new file mode 100644
> index 00000000..8251ce7d
> --- /dev/null
> +++ b/kvm.c
> @@ -0,0 +1,50 @@
> +/*
> + * Support for decoding of KVM_* ioctl commands.
> + *
> + * Copyright (c) 2017 Masatake YAMATO <yamato at redhat.com>
> + * Copyright (c) 2017 Red Hat, Inc.
> + * All rights reserved.
> + *
> + * Redistribution and use in source and binary forms, with or without
> + * modification, are permitted provided that the following conditions
> + * are met:
> + * 1. Redistributions of source code must retain the above copyright
> + *    notice, this list of conditions and the following disclaimer.
> + * 2. Redistributions in binary form must reproduce the above copyright
> + *    notice, this list of conditions and the following disclaimer in the
> + *    documentation and/or other materials provided with the distribution.
> + * 3. The name of the author may not be used to endorse or promote products
> + *    derived from this software without specific prior written permission.
> + *
> + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
> + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
> + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
> + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
> + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
> + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
> + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
> + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
> + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
> + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
> + */
> +
> +#include "defs.h"
> +
> +#ifdef HAVE_LINUX_KVM_H
> +#include <linux/kvm.h>
> +
> +int
> +kvm_ioctl(struct tcb *const tcp, const unsigned int code, const kernel_ulong_t arg)
> +{
> +	switch (code) {
> +	default:
> +		return RVAL_DECODED;
> +	}
> +}
> +#else
> +int
> +kvm_ioctl(struct tcb *const tcp, const unsigned int code, const kernel_ulong_t arg)
> +{
> +	return RVAL_DECODED;
> +}
> +#endif /* HAVE_LINUX_KVM_H */

... there is no need for kvm_ioctl fallback here.


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