kvm.c - platform/external/strace - Gitiles

 /*
  * Support for decoding of KVM_* ioctl commands.
  *
  * Copyright (c) 2017 Masatake YAMATO <yamato@redhat.com>
  * Copyright (c) 2017 Red Hat, Inc.
  * Copyright (c) 2017-2018 The strace developers.
  * 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>
 # include "print_fields.h"
 # include "arch_kvm.c"
 # include "xmalloc.h"
 # include "mmap_cache.h"

 struct vcpu_info {
 	struct vcpu_info *next;
 	int fd;
 	int cpuid;
 	long mmap_addr;
 	unsigned long mmap_len;
 	bool resolved;
 };

 static bool dump_kvm_run_structure;

 static struct vcpu_info *
 vcpu_find(struct tcb *const tcp, int fd)
 {
 	for (struct vcpu_info *vcpu_info = tcp->vcpu_info_list;
 	     vcpu_info;
 	     vcpu_info = vcpu_info->next)
 		if (vcpu_info->fd == fd)
 			return vcpu_info;

 	return NULL;
 }

 static struct vcpu_info *
 vcpu_alloc(struct tcb *const tcp, int fd, int cpuid)
 {
 	struct vcpu_info *vcpu_info = xcalloc(1, sizeof(*vcpu_info));

 	vcpu_info->fd = fd;
 	vcpu_info->cpuid = cpuid;

 	vcpu_info->next = tcp->vcpu_info_list;
 	tcp->vcpu_info_list = vcpu_info;

 	return vcpu_info;
 }

 void
 kvm_vcpu_info_free(struct tcb *tcp)
 {
 	struct vcpu_info *head, *next;

 	for (head = tcp->vcpu_info_list; head; head = next) {
 		next = head->next;
 		free(head);
 	}

 	tcp->vcpu_info_list = NULL;
 }

 static void
 vcpu_register(struct tcb *const tcp, int fd, int cpuid)
 {
 	if (fd < 0)
 		return;

 	struct vcpu_info *vcpu_info = vcpu_find(tcp, fd);

 	if (!vcpu_info)
 		vcpu_info = vcpu_alloc(tcp, fd, cpuid);
 	else if (vcpu_info->cpuid != cpuid)
 	{
 		vcpu_info->cpuid = cpuid;
 		vcpu_info->resolved = false;
 	}
 }

 static bool
 is_map_for_file(struct mmap_cache_entry_t *map_info, void *data)
 {
 	/* major version for anon inode may be given in get_anon_bdev()
 	 * in linux kernel.
 	 *
 	 * 	*p = MKDEV(0, dev & MINORMASK);
 	 *-----------------^
 	 */
 	return map_info->binary_filename &&
 		map_info->major == 0 &&
 		strcmp(map_info->binary_filename, data) == 0;
 }

 static unsigned long
 map_len(struct mmap_cache_entry_t *map_info)
 {
 	return map_info->start_addr < map_info->end_addr
 		? map_info->end_addr - map_info->start_addr
 		: 0;
 }

 #define VCPU_DENTRY_PREFIX "anon_inode:kvm-vcpu:"

 static struct vcpu_info*
 vcpu_get_info(struct tcb *const tcp, int fd)
 {
 	struct vcpu_info *vcpu_info = vcpu_find(tcp, fd);
 	struct mmap_cache_entry_t *map_info;
 	const char *cpuid_str;

 	enum mmap_cache_rebuild_result mc_stat =
 		mmap_cache_rebuild_if_invalid(tcp, __func__);
 	if (mc_stat == MMAP_CACHE_REBUILD_NOCACHE)
 		return NULL;

 	if (vcpu_info && vcpu_info->resolved) {
 		if (mc_stat == MMAP_CACHE_REBUILD_READY)
 			return vcpu_info;
 		else {
 			map_info = mmap_cache_search(tcp, vcpu_info->mmap_addr);
 			if (map_info) {
 				cpuid_str =
 					STR_STRIP_PREFIX(map_info->binary_filename,
 							 VCPU_DENTRY_PREFIX);
 				if (cpuid_str != map_info->binary_filename) {
 					int cpuid = string_to_uint(cpuid_str);
 					if (cpuid < 0)
 						return NULL;
 					if (vcpu_info->cpuid == cpuid)
 						return vcpu_info;
 				}
 			}

 			/* The vcpu vma may be mremap'ed. */
 			vcpu_info->resolved = false;
 		}
 	}

 	/* Slow path: !vcpu_info || !vcpu_info->resolved */
 	char path[PATH_MAX + 1];
 	cpuid_str = path;
 	if (getfdpath(tcp, fd, path, sizeof(path)) >= 0)
 		cpuid_str = STR_STRIP_PREFIX(path, VCPU_DENTRY_PREFIX);
 	if (cpuid_str == path)
 		map_info = NULL;
 	else
 		map_info = mmap_cache_search_custom(tcp, is_map_for_file, path);

 	if (map_info) {
 		int cpuid = string_to_uint(cpuid_str);
 		if (cpuid < 0)
 			return NULL;
 		if (!vcpu_info)
 			vcpu_info = vcpu_alloc(tcp, fd, cpuid);
 		else if (vcpu_info->cpuid != cpuid)
 			vcpu_info->cpuid = cpuid;
 		vcpu_info->mmap_addr = map_info->start_addr;
 		vcpu_info->mmap_len  = map_len(map_info);
 		vcpu_info->resolved  = true;
 		return vcpu_info;
 	}

 	return NULL;
 }

 static int
 kvm_ioctl_create_vcpu(struct tcb *const tcp, const kernel_ulong_t arg)
 {
 	uint32_t cpuid = arg;

 	if (entering(tcp)) {
 		tprintf(", %u", cpuid);
 		if (dump_kvm_run_structure)
 			return 0;
 	} else if (!syserror(tcp)) {
 		vcpu_register(tcp, tcp->u_rval, cpuid);
 	}

 	return RVAL_IOCTL_DECODED | RVAL_FD;
 }

 # ifdef HAVE_STRUCT_KVM_USERSPACE_MEMORY_REGION
 #  include "xlat/kvm_mem_flags.h"
 static int
 kvm_ioctl_set_user_memory_region(struct tcb *const tcp, const kernel_ulong_t arg)
 {
 	struct kvm_userspace_memory_region u_memory_region;

 	tprints(", ");
 	if (umove_or_printaddr(tcp, arg, &u_memory_region))
 		return RVAL_IOCTL_DECODED;

 	PRINT_FIELD_U("{", u_memory_region, slot);
 	PRINT_FIELD_FLAGS(", ", u_memory_region, flags, kvm_mem_flags,
 			  "KVM_MEM_???");
 	PRINT_FIELD_X(", ", u_memory_region, guest_phys_addr);
 	PRINT_FIELD_U(", ", u_memory_region, memory_size);
 	PRINT_FIELD_X(", ", u_memory_region, userspace_addr);
 	tprints("}");

 	return RVAL_IOCTL_DECODED;
 }
 # endif /* HAVE_STRUCT_KVM_USERSPACE_MEMORY_REGION */

 # ifdef HAVE_STRUCT_KVM_REGS
 static int
 kvm_ioctl_decode_regs(struct tcb *const tcp, const unsigned int code,
 		      const kernel_ulong_t arg)
 {
 	struct kvm_regs regs;

 	if (code == KVM_GET_REGS && entering(tcp))
 		return 0;

 	tprints(", ");
 	if (!umove_or_printaddr(tcp, arg, &regs))
 		arch_print_kvm_regs(tcp, arg, &regs);

 	return RVAL_IOCTL_DECODED;
 }
 # endif /* HAVE_STRUCT_KVM_REGS */

 # ifdef HAVE_STRUCT_KVM_CPUID2
 #  include "xlat/kvm_cpuid_flags.h"
 static bool
 print_kvm_cpuid_entry(struct tcb *const tcp,
 		      void* elem_buf, size_t elem_size, void* data)
 {
 	const struct kvm_cpuid_entry2 *entry = elem_buf;
 	PRINT_FIELD_X("{", *entry, function);
 	PRINT_FIELD_X(", ", *entry, index);
 	PRINT_FIELD_FLAGS(", ", *entry, flags, kvm_cpuid_flags,
 			  "KVM_CPUID_FLAG_???");
 	PRINT_FIELD_X(", ", *entry, eax);
 	PRINT_FIELD_X(", ", *entry, ebx);
 	PRINT_FIELD_X(", ", *entry, ecx);
 	PRINT_FIELD_X(", ", *entry, edx);
 	tprints("}");

 	return true;
 }

 static int
 kvm_ioctl_decode_cpuid2(struct tcb *const tcp, const unsigned int code,
 			const kernel_ulong_t arg)
 {
 	struct kvm_cpuid2 cpuid;

 	if (entering(tcp) && (code == KVM_GET_SUPPORTED_CPUID
 #  ifdef KVM_GET_EMULATED_CPUID
 			      || code == KVM_GET_EMULATED_CPUID
 #  endif
 			     ))
 		return 0;

 	tprints(", ");
 	if (!umove_or_printaddr(tcp, arg, &cpuid)) {
 		PRINT_FIELD_U("{", cpuid, nent);

 		tprints(", entries=");
 		if (abbrev(tcp)) {
 			tprints("[");
 			if (cpuid.nent)
 				tprints("...");
 			tprints("]");

 		} else {
 			struct kvm_cpuid_entry2 entry;
 			print_array(tcp, arg + sizeof(cpuid), cpuid.nent,
 				    &entry, sizeof(entry), tfetch_mem,
 				    print_kvm_cpuid_entry, NULL);
 		}
 		tprints("}");
 	}

 	return RVAL_IOCTL_DECODED;
 }
 # endif /* HAVE_STRUCT_KVM_CPUID2 */

 # ifdef HAVE_STRUCT_KVM_SREGS
 static int
 kvm_ioctl_decode_sregs(struct tcb *const tcp, const unsigned int code,
 		       const kernel_ulong_t arg)
 {
 	struct kvm_sregs sregs;

 	if (code == KVM_GET_SREGS && entering(tcp))
 		return 0;

 	tprints(", ");
 	if (!umove_or_printaddr(tcp, arg, &sregs))
 		arch_print_kvm_sregs(tcp, arg, &sregs);

 	return RVAL_IOCTL_DECODED;
 }
 # endif /* HAVE_STRUCT_KVM_SREGS */

 # include "xlat/kvm_cap.h"
 static int
 kvm_ioctl_decode_check_extension(struct tcb *const tcp, const unsigned int code,
 				 const kernel_ulong_t arg)
 {
 	tprints(", ");
 	printxval_index(kvm_cap, arg, "KVM_CAP_???");
 	return RVAL_IOCTL_DECODED;
 }

 # include "xlat/kvm_exit_reason.h"
 static void
 kvm_ioctl_run_attach_auxstr(struct tcb *const tcp,
 			    struct vcpu_info *info)

 {
 	static struct kvm_run vcpu_run_struct;

 	if (info->mmap_len < sizeof(vcpu_run_struct))
 		return;

 	if (umove(tcp, info->mmap_addr, &vcpu_run_struct) < 0)
 		return;

 	tcp->auxstr = xlat_idx(kvm_exit_reason, ARRAY_SIZE(kvm_exit_reason) - 1,
 			       vcpu_run_struct.exit_reason);
 	if (!tcp->auxstr)
 		tcp->auxstr = "KVM_EXIT_???";
 }

 static int
 kvm_ioctl_decode_run(struct tcb *const tcp)
 {

 	if (entering(tcp))
 		return 0;

 	int r = RVAL_DECODED;

 	if (syserror(tcp))
 		return r;

 	if (dump_kvm_run_structure) {
 		tcp->auxstr = NULL;
 		int fd = tcp->u_arg[0];
 		struct vcpu_info *info = vcpu_get_info(tcp, fd);

 		if (info) {
 			kvm_ioctl_run_attach_auxstr(tcp, info);
 			if (tcp->auxstr)
 				r |= RVAL_STR;
 		}
 	}

 	return r;
 }

 int
 kvm_ioctl(struct tcb *const tcp, const unsigned int code, const kernel_ulong_t arg)
 {
 	switch (code) {
 	case KVM_CREATE_VCPU:
 		return kvm_ioctl_create_vcpu(tcp, arg);

 # ifdef HAVE_STRUCT_KVM_USERSPACE_MEMORY_REGION
 	case KVM_SET_USER_MEMORY_REGION:
 		return kvm_ioctl_set_user_memory_region(tcp, arg);
 # endif

 # ifdef HAVE_STRUCT_KVM_REGS
 	case KVM_SET_REGS:
 	case KVM_GET_REGS:
 		return kvm_ioctl_decode_regs(tcp, code, arg);
 # endif

 # ifdef HAVE_STRUCT_KVM_SREGS
 	case KVM_SET_SREGS:
 	case KVM_GET_SREGS:
 		return kvm_ioctl_decode_sregs(tcp, code, arg);
 # endif

 # ifdef HAVE_STRUCT_KVM_CPUID2
        case KVM_SET_CPUID2:
        case KVM_GET_SUPPORTED_CPUID:
 #  ifdef KVM_GET_EMULATED_CPUID
        case KVM_GET_EMULATED_CPUID:
 #  endif
                return kvm_ioctl_decode_cpuid2(tcp, code, arg);
 # endif

 	case KVM_CHECK_EXTENSION:
 		return kvm_ioctl_decode_check_extension(tcp, code, arg);

 	case KVM_CREATE_VM:
 		return RVAL_DECODED | RVAL_FD;

 	case KVM_RUN:
 		return kvm_ioctl_decode_run(tcp);

 	case KVM_GET_VCPU_MMAP_SIZE:
 	case KVM_GET_API_VERSION:
 	default:
 		return RVAL_DECODED;
 	}
 }

 void
 kvm_run_structure_decoder_init(void)
 {
 	dump_kvm_run_structure = true;
 	mmap_cache_enable();
 }

 #endif /* HAVE_LINUX_KVM_H */
	/*
	* Support for decoding of KVM_* ioctl commands.
	*
	* Copyright (c) 2017 Masatake YAMATO <yamato@redhat.com>
	* Copyright (c) 2017 Red Hat, Inc.
	* Copyright (c) 2017-2018 The strace developers.
	* 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>
	# include "print_fields.h"
	# include "arch_kvm.c"
	# include "xmalloc.h"
	# include "mmap_cache.h"

	struct vcpu_info {
	struct vcpu_info *next;
	int fd;
	int cpuid;
	long mmap_addr;
	unsigned long mmap_len;
	bool resolved;
	};

	static bool dump_kvm_run_structure;

	static struct vcpu_info *
	vcpu_find(struct tcb *const tcp, int fd)
	{
	for (struct vcpu_info *vcpu_info = tcp->vcpu_info_list;
	vcpu_info;
	vcpu_info = vcpu_info->next)
	if (vcpu_info->fd == fd)
	return vcpu_info;

	return NULL;
	}

	static struct vcpu_info *
	vcpu_alloc(struct tcb *const tcp, int fd, int cpuid)
	{
	struct vcpu_info vcpu_info = xcalloc(1, sizeof(vcpu_info));

	vcpu_info->fd = fd;
	vcpu_info->cpuid = cpuid;

	vcpu_info->next = tcp->vcpu_info_list;
	tcp->vcpu_info_list = vcpu_info;

	return vcpu_info;
	}

	void
	kvm_vcpu_info_free(struct tcb *tcp)
	{
	struct vcpu_info head, next;

	for (head = tcp->vcpu_info_list; head; head = next) {
	next = head->next;
	free(head);
	}

	tcp->vcpu_info_list = NULL;
	}

	static void
	vcpu_register(struct tcb *const tcp, int fd, int cpuid)
	{
	if (fd < 0)
	return;

	struct vcpu_info *vcpu_info = vcpu_find(tcp, fd);

	if (!vcpu_info)
	vcpu_info = vcpu_alloc(tcp, fd, cpuid);
	else if (vcpu_info->cpuid != cpuid)
	{
	vcpu_info->cpuid = cpuid;
	vcpu_info->resolved = false;
	}
	}

	static bool
	is_map_for_file(struct mmap_cache_entry_t map_info, void data)
	{
	/* major version for anon inode may be given in get_anon_bdev()
	* in linux kernel.
	*
	* *p = MKDEV(0, dev & MINORMASK);
	*-----------------^
	*/
	return map_info->binary_filename &&
	map_info->major == 0 &&
	strcmp(map_info->binary_filename, data) == 0;
	}

	static unsigned long
	map_len(struct mmap_cache_entry_t *map_info)
	{
	return map_info->start_addr < map_info->end_addr
	? map_info->end_addr - map_info->start_addr
	: 0;
	}

	#define VCPU_DENTRY_PREFIX "anon_inode:kvm-vcpu:"

	static struct vcpu_info*
	vcpu_get_info(struct tcb *const tcp, int fd)
	{
	struct vcpu_info *vcpu_info = vcpu_find(tcp, fd);
	struct mmap_cache_entry_t *map_info;
	const char *cpuid_str;

	enum mmap_cache_rebuild_result mc_stat =
	mmap_cache_rebuild_if_invalid(tcp, __func__);
	if (mc_stat == MMAP_CACHE_REBUILD_NOCACHE)
	return NULL;

	if (vcpu_info && vcpu_info->resolved) {
	if (mc_stat == MMAP_CACHE_REBUILD_READY)
	return vcpu_info;
	else {
	map_info = mmap_cache_search(tcp, vcpu_info->mmap_addr);
	if (map_info) {
	cpuid_str =
	STR_STRIP_PREFIX(map_info->binary_filename,
	VCPU_DENTRY_PREFIX);
	if (cpuid_str != map_info->binary_filename) {
	int cpuid = string_to_uint(cpuid_str);
	if (cpuid < 0)
	return NULL;
	if (vcpu_info->cpuid == cpuid)
	return vcpu_info;
	}
	}

	/* The vcpu vma may be mremap'ed. */
	vcpu_info->resolved = false;
	}
	}

	/* Slow path: !vcpu_info \|\| !vcpu_info->resolved */
	char path[PATH_MAX + 1];
	cpuid_str = path;
	if (getfdpath(tcp, fd, path, sizeof(path)) >= 0)
	cpuid_str = STR_STRIP_PREFIX(path, VCPU_DENTRY_PREFIX);
	if (cpuid_str == path)
	map_info = NULL;
	else
	map_info = mmap_cache_search_custom(tcp, is_map_for_file, path);

	if (map_info) {
	int cpuid = string_to_uint(cpuid_str);
	if (cpuid < 0)
	return NULL;
	if (!vcpu_info)
	vcpu_info = vcpu_alloc(tcp, fd, cpuid);
	else if (vcpu_info->cpuid != cpuid)
	vcpu_info->cpuid = cpuid;
	vcpu_info->mmap_addr = map_info->start_addr;
	vcpu_info->mmap_len = map_len(map_info);
	vcpu_info->resolved = true;
	return vcpu_info;
	}

	return NULL;
	}

	static int
	kvm_ioctl_create_vcpu(struct tcb *const tcp, const kernel_ulong_t arg)
	{
	uint32_t cpuid = arg;

	if (entering(tcp)) {
	tprintf(", %u", cpuid);
	if (dump_kvm_run_structure)
	return 0;
	} else if (!syserror(tcp)) {
	vcpu_register(tcp, tcp->u_rval, cpuid);
	}

	return RVAL_IOCTL_DECODED \| RVAL_FD;
	}

	# ifdef HAVE_STRUCT_KVM_USERSPACE_MEMORY_REGION
	# include "xlat/kvm_mem_flags.h"
	static int
	kvm_ioctl_set_user_memory_region(struct tcb *const tcp, const kernel_ulong_t arg)
	{
	struct kvm_userspace_memory_region u_memory_region;

	tprints(", ");
	if (umove_or_printaddr(tcp, arg, &u_memory_region))
	return RVAL_IOCTL_DECODED;

	PRINT_FIELD_U("{", u_memory_region, slot);
	PRINT_FIELD_FLAGS(", ", u_memory_region, flags, kvm_mem_flags,
	"KVM_MEM_???");
	PRINT_FIELD_X(", ", u_memory_region, guest_phys_addr);
	PRINT_FIELD_U(", ", u_memory_region, memory_size);
	PRINT_FIELD_X(", ", u_memory_region, userspace_addr);
	tprints("}");

	return RVAL_IOCTL_DECODED;
	}
	# endif /* HAVE_STRUCT_KVM_USERSPACE_MEMORY_REGION */

	# ifdef HAVE_STRUCT_KVM_REGS
	static int
	kvm_ioctl_decode_regs(struct tcb *const tcp, const unsigned int code,
	const kernel_ulong_t arg)
	{
	struct kvm_regs regs;

	if (code == KVM_GET_REGS && entering(tcp))
	return 0;

	tprints(", ");
	if (!umove_or_printaddr(tcp, arg, &regs))
	arch_print_kvm_regs(tcp, arg, &regs);

	return RVAL_IOCTL_DECODED;
	}
	# endif /* HAVE_STRUCT_KVM_REGS */

	# ifdef HAVE_STRUCT_KVM_CPUID2
	# include "xlat/kvm_cpuid_flags.h"
	static bool
	print_kvm_cpuid_entry(struct tcb *const tcp,
	void* elem_buf, size_t elem_size, void* data)
	{
	const struct kvm_cpuid_entry2 *entry = elem_buf;
	PRINT_FIELD_X("{", *entry, function);
	PRINT_FIELD_X(", ", *entry, index);
	PRINT_FIELD_FLAGS(", ", *entry, flags, kvm_cpuid_flags,
	"KVM_CPUID_FLAG_???");
	PRINT_FIELD_X(", ", *entry, eax);
	PRINT_FIELD_X(", ", *entry, ebx);
	PRINT_FIELD_X(", ", *entry, ecx);
	PRINT_FIELD_X(", ", *entry, edx);
	tprints("}");

	return true;
	}

	static int
	kvm_ioctl_decode_cpuid2(struct tcb *const tcp, const unsigned int code,
	const kernel_ulong_t arg)
	{
	struct kvm_cpuid2 cpuid;

	if (entering(tcp) && (code == KVM_GET_SUPPORTED_CPUID
	# ifdef KVM_GET_EMULATED_CPUID
	\|\| code == KVM_GET_EMULATED_CPUID
	# endif
	))
	return 0;

	tprints(", ");
	if (!umove_or_printaddr(tcp, arg, &cpuid)) {
	PRINT_FIELD_U("{", cpuid, nent);

	tprints(", entries=");
	if (abbrev(tcp)) {
	tprints("[");
	if (cpuid.nent)
	tprints("...");
	tprints("]");

	} else {
	struct kvm_cpuid_entry2 entry;
	print_array(tcp, arg + sizeof(cpuid), cpuid.nent,
	&entry, sizeof(entry), tfetch_mem,
	print_kvm_cpuid_entry, NULL);
	}
	tprints("}");
	}

	return RVAL_IOCTL_DECODED;
	}
	# endif /* HAVE_STRUCT_KVM_CPUID2 */

	# ifdef HAVE_STRUCT_KVM_SREGS
	static int
	kvm_ioctl_decode_sregs(struct tcb *const tcp, const unsigned int code,
	const kernel_ulong_t arg)
	{
	struct kvm_sregs sregs;

	if (code == KVM_GET_SREGS && entering(tcp))
	return 0;

	tprints(", ");
	if (!umove_or_printaddr(tcp, arg, &sregs))
	arch_print_kvm_sregs(tcp, arg, &sregs);

	return RVAL_IOCTL_DECODED;
	}
	# endif /* HAVE_STRUCT_KVM_SREGS */

	# include "xlat/kvm_cap.h"
	static int
	kvm_ioctl_decode_check_extension(struct tcb *const tcp, const unsigned int code,
	const kernel_ulong_t arg)
	{
	tprints(", ");
	printxval_index(kvm_cap, arg, "KVM_CAP_???");
	return RVAL_IOCTL_DECODED;
	}

	# include "xlat/kvm_exit_reason.h"
	static void
	kvm_ioctl_run_attach_auxstr(struct tcb *const tcp,
	struct vcpu_info *info)

	{
	static struct kvm_run vcpu_run_struct;

	if (info->mmap_len < sizeof(vcpu_run_struct))
	return;

	if (umove(tcp, info->mmap_addr, &vcpu_run_struct) < 0)
	return;

	tcp->auxstr = xlat_idx(kvm_exit_reason, ARRAY_SIZE(kvm_exit_reason) - 1,
	vcpu_run_struct.exit_reason);
	if (!tcp->auxstr)
	tcp->auxstr = "KVM_EXIT_???";
	}

	static int
	kvm_ioctl_decode_run(struct tcb *const tcp)
	{

	if (entering(tcp))
	return 0;

	int r = RVAL_DECODED;

	if (syserror(tcp))
	return r;

	if (dump_kvm_run_structure) {
	tcp->auxstr = NULL;
	int fd = tcp->u_arg[0];
	struct vcpu_info *info = vcpu_get_info(tcp, fd);

	if (info) {
	kvm_ioctl_run_attach_auxstr(tcp, info);
	if (tcp->auxstr)
	r \|= RVAL_STR;
	}
	}

	return r;
	}

	int
	kvm_ioctl(struct tcb *const tcp, const unsigned int code, const kernel_ulong_t arg)
	{
	switch (code) {
	case KVM_CREATE_VCPU:
	return kvm_ioctl_create_vcpu(tcp, arg);

	# ifdef HAVE_STRUCT_KVM_USERSPACE_MEMORY_REGION
	case KVM_SET_USER_MEMORY_REGION:
	return kvm_ioctl_set_user_memory_region(tcp, arg);
	# endif

	# ifdef HAVE_STRUCT_KVM_REGS
	case KVM_SET_REGS:
	case KVM_GET_REGS:
	return kvm_ioctl_decode_regs(tcp, code, arg);
	# endif

	# ifdef HAVE_STRUCT_KVM_SREGS
	case KVM_SET_SREGS:
	case KVM_GET_SREGS:
	return kvm_ioctl_decode_sregs(tcp, code, arg);
	# endif

	# ifdef HAVE_STRUCT_KVM_CPUID2
	case KVM_SET_CPUID2:
	case KVM_GET_SUPPORTED_CPUID:
	# ifdef KVM_GET_EMULATED_CPUID
	case KVM_GET_EMULATED_CPUID:
	# endif
	return kvm_ioctl_decode_cpuid2(tcp, code, arg);
	# endif

	case KVM_CHECK_EXTENSION:
	return kvm_ioctl_decode_check_extension(tcp, code, arg);

	case KVM_CREATE_VM:
	return RVAL_DECODED \| RVAL_FD;

	case KVM_RUN:
	return kvm_ioctl_decode_run(tcp);

	case KVM_GET_VCPU_MMAP_SIZE:
	case KVM_GET_API_VERSION:
	default:
	return RVAL_DECODED;
	}
	}

	void
	kvm_run_structure_decoder_init(void)
	{
	dump_kvm_run_structure = true;
	mmap_cache_enable();
	}

	#endif /* HAVE_LINUX_KVM_H */