On 1/18/22 16:37, Sven Schnelle wrote: > Hi Janis, > > Janis Schoetterl-Glausch <scgl@xxxxxxxxxxxxx> writes: > >> KVM needs a mechanism to do accesses to guest memory that honor >> storage key protection. >> Since the copy_to/from_user implementation makes use of move >> instructions that support having an additional access key supplied, >> we can implement __copy_from/to_user_with_key by enhancing the >> existing implementation. >> >> Signed-off-by: Janis Schoetterl-Glausch <scgl@xxxxxxxxxxxxx> > > This doesn't apply to my master branch. Maybe it's due to the prerequisite patch missing? https://lore.kernel.org/linux-s390/YeGBmPBJ8NMi0Rkp@osiris/T/#t > >> diff --git a/arch/s390/lib/uaccess.c b/arch/s390/lib/uaccess.c >> index d3a700385875..ce7a150dd93a 100644 >> --- a/arch/s390/lib/uaccess.c >> +++ b/arch/s390/lib/uaccess.c >> @@ -59,11 +59,13 @@ static inline int copy_with_mvcos(void) >> #endif >> >> static inline unsigned long copy_from_user_mvcos(void *x, const void __user *ptr, >> - unsigned long size) >> + unsigned long size, char key) >> { >> unsigned long tmp1, tmp2; >> union oac spec = { >> + .oac2.key = key, >> .oac2.as = PSW_BITS_AS_SECONDARY, >> + .oac2.k = 1, >> .oac2.a = 1, >> }; >> >> @@ -94,19 +96,19 @@ static inline unsigned long copy_from_user_mvcos(void *x, const void __user *ptr >> } >> >> static inline unsigned long copy_from_user_mvcp(void *x, const void __user *ptr, >> - unsigned long size) >> + unsigned long size, char key) > > Any special reason for using 'char' as type for key here? Given the left shift > below i would prefer 'unsigned char' to avoid having to think about > whether this can overflow. The end result wouldn't look different, > so more or less a cosmetic issue. Will do. [...] > > With that minor nitpick: > > Reviewed-by: Sven Schnelle <svens@xxxxxxxxxxxxx> Thanks!
