The code can be significantly shortened. There is no functional change,
except that for large (> PAGE_SIZE) copies the guest translation would
be done more frequently.
However, there is not a single user which does this currently. If one
gets added later on this functionality can be added easily again.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
The put_guest_u*/get_guest_u* are nothing but wrappers for the regular
put_user/get_user uaccess functions. The only difference is that before
accessing user space the guest address must be translated to a user space
address.
Change the order of arguments for the guest access functions so they
match their uaccess parts. Also remove the u* suffix, so we simply
have put_guest/get_guest which will automatically use the right size
dependent on pointer type of the destination/source that now must be
correct.
In result the same behaviour as put_user/get_user except that accesses
must be aligned.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Guest access functions like copy_to/from_guest() call __guestaddr_to_user()
which in turn call gmap_fault() in order to translate a guest address to a
user space address.
In error case __guest_addr_to_user() returns either -EFAULT or -ENOMEM.
The copy_to/from_guest functions just pass these return values down to the
callers.
The -ENOMEM case however is problematic since there are several places
which access guest memory like:
rc = copy_to_guest(...);
if (rc == -EFAULT)
error_handling();
So in case of -ENOMEM the code assumes that the guest memory access
succeeded even though it failed.
This can cause guest data or state corruption.
If __guestaddr_to_user() returns -ENOMEM the meaning is that a valid user
space mapping exists, but there was not enough memory available when trying
to build the guest mapping. In other words an out-of-memory situation
occured.
For normal user space accesses an out-of-memory situation causes the page
fault handler to map -ENOMEM to -EFAULT (see fixup code in do_no_context()).
We need to do exactly the same for the kvm gaccess functions.
So __guestaddr_to_user() should just map all error codes to -EFAULT.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Remove the file name from the comment at top of many files. In most
cases the file name was wrong anyway, so it's rather pointless.
Also unify the IBM copyright statement. We did have a lot of sightly
different statements and wanted to change them one after another
whenever a file gets touched. However that never happened. Instead
people start to take the old/"wrong" statements to use as a template
for new files.
So unify all of them in one go.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
This patch removes kvm-s390 internal assumption of a linear mapping
of guest address space to user space. Previously, guest memory was
translated to user addresses using a fixed offset (gmsor). The new
code uses gmap_fault to resolve guest addresses.
Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This patch relocates the variables kvm-s390 uses to track guest mem addr/size.
As discussed dropping the variables at struct kvm_arch level allows to use the
common vcpu->request based mechanism to reload guest memory if e.g. changes
via set_memory_region.
The kick mechanism introduced in this series is used to ensure running vcpus
leave guest state to catch the update.
Signed-off-by: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
All registers are unsigned long types. This patch changes all occurences
of guestaddr in gaccess from u64 to unsigned long.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
This patch contains the port of Qumranet's kvm kernel module to IBM zSeries
(aka s390x, mainframe) architecture. It uses the mainframe's virtualization
instruction SIE to run virtual machines with up to 64 virtual CPUs each.
This port is only usable on 64bit host kernels, and can only run 64bit guest
kernels. However, running 31bit applications in guest userspace is possible.
The following source files are introduced by this patch
arch/s390/kvm/kvm-s390.c similar to arch/x86/kvm/x86.c, this implements all
arch callbacks for kvm. __vcpu_run calls back into
sie64a to enter the guest machine context
arch/s390/kvm/sie64a.S assembler function sie64a, which enters guest
context via SIE, and switches world before and after that
include/asm-s390/kvm_host.h contains all vital data structures needed to run
virtual machines on the mainframe
include/asm-s390/kvm.h defines kvm_regs and friends for user access to
guest register content
arch/s390/kvm/gaccess.h functions similar to uaccess to access guest memory
arch/s390/kvm/kvm-s390.h header file for kvm-s390 internals, extended by
later patches
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
Heiko Carstens