[PATCH v3 1/4] kvm: decode the argument for KVM_SET_USER_MEMORY_REGION ioctl command

[Masatake YAMATO]

On Mon, 4 Dec 2017 14:23:14 +0300, "Dmitry V. Levin" <ldv at altlinux.org> wrote:
> On Mon, Dec 04, 2017 at 08:04:49PM +0900, Masatake YAMATO wrote:
>> * configure.ac (AC_CHECK_TYPES): Add struct kvm_userspace_memory_region.
>> * xlat/kvm_mem_flags.in: New file.
>> * kvm.c: Include print_fields.h and xlat/kvm_mem_flags.h.
>> (kvm_ioctl_set_user_memory_region): New function.
>> (kvm_ioctl) <KVM_SET_USER_MEMORY_REGION>: Use it.
>> 
>> Change in v2:
>> * Use umove_or_printaddr instead of umove because umove_or_printaddr
>>   performs verbose(tcp) check and prints the zero address nicely.
>>   Suggested by ldv.
>> 
>> Change in v3:
>> * Verify the availability struct kvm_userspace_memory_region.
>>   Suggested by ldv.
>> 
>> Signed-off-by: Masatake YAMATO <yamato at redhat.com>
>> ---
>>  configure.ac          |  2 ++
>>  kvm.c                 | 27 +++++++++++++++++++++++++++
>>  xlat/kvm_mem_flags.in |  2 ++
>>  3 files changed, 31 insertions(+)
>>  create mode 100644 xlat/kvm_mem_flags.in
>> 
>> diff --git a/configure.ac b/configure.ac
>> index fa451d84..dad995c4 100644
>> --- a/configure.ac
>> +++ b/configure.ac
>> @@ -541,6 +541,8 @@ AC_CHECK_TYPES([struct statfs64], [
>>  
>>  AC_CHECK_TYPES([struct blk_user_trace_setup],,, [#include <linux/blktrace_api.h>])
>>  
>> +AC_CHECK_TYPES([struct kvm_userspace_memory_region],,, [#include <linux/kvm.h>])
>> +
>>  AC_CHECK_HEADERS([linux/btrfs.h], [
>>  	AC_CHECK_MEMBERS(m4_normalize([
>>  		struct btrfs_ioctl_feature_flags.compat_flags,
>> diff --git a/kvm.c b/kvm.c
>> index 9e4f9978..8f68aef5 100644
>> --- a/kvm.c
>> +++ b/kvm.c
>> @@ -32,6 +32,7 @@
>>  
>>  #ifdef HAVE_LINUX_KVM_H
>>  # include <linux/kvm.h>
>> +# include "print_fields.h"
>>  
>>  static int
>>  kvm_ioctl_create_vcpu(struct tcb *const tcp, const kernel_ulong_t arg)
>> @@ -42,12 +43,38 @@ kvm_ioctl_create_vcpu(struct tcb *const tcp, const kernel_ulong_t arg)
>>  	return RVAL_IOCTL_DECODED | RVAL_FD;
>>  }
>>  
>> +# include "xlat/kvm_mem_flags.h"
>> +static int
>> +kvm_ioctl_set_user_memory_region(struct tcb *const tcp, const kernel_ulong_t arg)
>> +{
>> +#ifdef HAVE_STRUCT_KVM_USERSPACE_MEMORY_REGION
>> +	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);
>> +
>> +	return RVAL_IOCTL_DECODED;
>> +#else
>> +	return RVAL_DECODED;
>> +#endif
>> +}
>> +
>>  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);
>> +	case KVM_SET_USER_MEMORY_REGION:
>> +		return kvm_ioctl_set_user_memory_region(tcp, arg);
> 
> If HAVE_STRUCT_KVM_USERSPACE_MEMORY_REGION is not set, then
> KVM_SET_USER_MEMORY_REGION is not available, too,
> and it's use also has to be guarded, e.g.
> 
> # ifdef HAVE_STRUCT_KVM_USERSPACE_MEMORY_REGION
> 	case KVM_SET_USER_MEMORY_REGION:
> 	return kvm_ioctl_set_user_memory_region(tcp, arg);
> # endif
> 
> This allows to move the whole definition
> of kvm_ioctl_set_user_memory_region inside
> HAVE_STRUCT_KVM_USERSPACE_MEMORY_REGION guard, too.

Oh, I see. This will be applicatable the rest ioctl
commands I decoded in the patch set.

O.k. I will make v4 patch set.

Masatake YAMATO

> 
> -- 
> ldv