From f9dc72e82d32cc9fe40d1dea7709d434bba2d4a9 Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Tue, 5 Mar 2013 13:14:45 +0100 Subject: [PATCH] s390/kvm,gaccess: shorten copy_to/from_guest code 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 Reviewed-by: Christian Borntraeger Signed-off-by: Martin Schwidefsky Signed-off-by: Christian Borntraeger Signed-off-by: Marcelo Tosatti --- arch/s390/kvm/gaccess.h | 294 ++++++---------------------------------- 1 file changed, 41 insertions(+), 253 deletions(-) diff --git a/arch/s390/kvm/gaccess.h b/arch/s390/kvm/gaccess.h index 82f450ecb585..8608d7e6a334 100644 --- a/arch/s390/kvm/gaccess.h +++ b/arch/s390/kvm/gaccess.h @@ -18,16 +18,19 @@ #include #include "kvm-s390.h" -static inline void *__gptr_to_uptr(struct kvm_vcpu *vcpu, void *gptr) +static inline void *__gptr_to_uptr(struct kvm_vcpu *vcpu, void *gptr, + int prefixing) { unsigned long prefix = vcpu->arch.sie_block->prefix; unsigned long gaddr = (unsigned long) gptr; unsigned long uaddr; - if (gaddr < 2 * PAGE_SIZE) - gaddr += prefix; - else if ((gaddr >= prefix) && (gaddr < prefix + 2 * PAGE_SIZE)) - gaddr -= prefix; + if (prefixing) { + if (gaddr < 2 * PAGE_SIZE) + gaddr += prefix; + else if ((gaddr >= prefix) && (gaddr < prefix + 2 * PAGE_SIZE)) + gaddr -= prefix; + } uaddr = gmap_fault(gaddr, vcpu->arch.gmap); if (IS_ERR_VALUE(uaddr)) uaddr = -EFAULT; @@ -36,7 +39,7 @@ static inline void *__gptr_to_uptr(struct kvm_vcpu *vcpu, void *gptr) #define get_guest(vcpu, x, gptr) \ ({ \ - __typeof__(gptr) __uptr = __gptr_to_uptr(vcpu, gptr); \ + __typeof__(gptr) __uptr = __gptr_to_uptr(vcpu, gptr, 1);\ int __mask = sizeof(__typeof__(*(gptr))) - 1; \ int __ret = PTR_RET(__uptr); \ \ @@ -49,7 +52,7 @@ static inline void *__gptr_to_uptr(struct kvm_vcpu *vcpu, void *gptr) #define put_guest(vcpu, x, gptr) \ ({ \ - __typeof__(gptr) __uptr = __gptr_to_uptr(vcpu, gptr); \ + __typeof__(gptr) __uptr = __gptr_to_uptr(vcpu, gptr, 1);\ int __mask = sizeof(__typeof__(*(gptr))) - 1; \ int __ret = PTR_RET(__uptr); \ \ @@ -60,255 +63,40 @@ static inline void *__gptr_to_uptr(struct kvm_vcpu *vcpu, void *gptr) __ret; \ }) -static inline int __copy_to_guest_slow(struct kvm_vcpu *vcpu, - unsigned long guestdest, - void *from, unsigned long n) -{ - int rc; - unsigned long i; - u8 *data = from; - - for (i = 0; i < n; i++) { - rc = put_guest(vcpu, *(data++), (u8 *)guestdest++); - if (rc < 0) - return rc; - } - return 0; -} - -static inline int __copy_to_guest_fast(struct kvm_vcpu *vcpu, - unsigned long guestdest, - void *from, unsigned long n) -{ - int r; - void __user *uptr; - unsigned long size; - - if (guestdest + n < guestdest) - return -EFAULT; - - /* simple case: all within one segment table entry? */ - if ((guestdest & PMD_MASK) == ((guestdest+n) & PMD_MASK)) { - uptr = (void __user *) gmap_fault(guestdest, vcpu->arch.gmap); - - if (IS_ERR((void __force *) uptr)) - return PTR_ERR((void __force *) uptr); - - r = copy_to_user(uptr, from, n); - - if (r) - r = -EFAULT; - - goto out; - } - - /* copy first segment */ - uptr = (void __user *)gmap_fault(guestdest, vcpu->arch.gmap); - - if (IS_ERR((void __force *) uptr)) - return PTR_ERR((void __force *) uptr); - - size = PMD_SIZE - (guestdest & ~PMD_MASK); - - r = copy_to_user(uptr, from, size); - - if (r) { - r = -EFAULT; - goto out; - } - from += size; - n -= size; - guestdest += size; - - /* copy full segments */ - while (n >= PMD_SIZE) { - uptr = (void __user *)gmap_fault(guestdest, vcpu->arch.gmap); - - if (IS_ERR((void __force *) uptr)) - return PTR_ERR((void __force *) uptr); - - r = copy_to_user(uptr, from, PMD_SIZE); - - if (r) { - r = -EFAULT; - goto out; - } - from += PMD_SIZE; - n -= PMD_SIZE; - guestdest += PMD_SIZE; - } - - /* copy the tail segment */ - if (n) { - uptr = (void __user *)gmap_fault(guestdest, vcpu->arch.gmap); - - if (IS_ERR((void __force *) uptr)) - return PTR_ERR((void __force *) uptr); - - r = copy_to_user(uptr, from, n); - - if (r) - r = -EFAULT; - } -out: - return r; -} - -static inline int copy_to_guest_absolute(struct kvm_vcpu *vcpu, - unsigned long guestdest, - void *from, unsigned long n) -{ - return __copy_to_guest_fast(vcpu, guestdest, from, n); -} - -static inline int copy_to_guest(struct kvm_vcpu *vcpu, unsigned long guestdest, - void *from, unsigned long n) -{ - unsigned long prefix = vcpu->arch.sie_block->prefix; - - if ((guestdest < 2 * PAGE_SIZE) && (guestdest + n > 2 * PAGE_SIZE)) - goto slowpath; - - if ((guestdest < prefix) && (guestdest + n > prefix)) - goto slowpath; - - if ((guestdest < prefix + 2 * PAGE_SIZE) - && (guestdest + n > prefix + 2 * PAGE_SIZE)) - goto slowpath; - - if (guestdest < 2 * PAGE_SIZE) - guestdest += prefix; - else if ((guestdest >= prefix) && (guestdest < prefix + 2 * PAGE_SIZE)) - guestdest -= prefix; - - return __copy_to_guest_fast(vcpu, guestdest, from, n); -slowpath: - return __copy_to_guest_slow(vcpu, guestdest, from, n); -} - -static inline int __copy_from_guest_slow(struct kvm_vcpu *vcpu, void *to, - unsigned long guestsrc, - unsigned long n) +static inline int __copy_guest(struct kvm_vcpu *vcpu, unsigned long to, + unsigned long from, unsigned long len, + int to_guest, int prefixing) { - int rc; - unsigned long i; - u8 *data = to; - - for (i = 0; i < n; i++) { - rc = get_guest(vcpu, *(data++), (u8 *)guestsrc++); - if (rc < 0) - return rc; + unsigned long _len, rc; + void *uptr; + + while (len) { + uptr = to_guest ? (void *)to : (void *)from; + uptr = __gptr_to_uptr(vcpu, uptr, prefixing); + if (IS_ERR(uptr)) + return -EFAULT; + _len = PAGE_SIZE - ((unsigned long)uptr & (PAGE_SIZE - 1)); + _len = min(_len, len); + if (to_guest) + rc = copy_to_user(uptr, (void *)from, _len); + else + rc = copy_from_user((void *)to, uptr, _len); + if (rc) + return -EFAULT; + len -= _len; + from += _len; + to += _len; } return 0; } -static inline int __copy_from_guest_fast(struct kvm_vcpu *vcpu, void *to, - unsigned long guestsrc, - unsigned long n) -{ - int r; - void __user *uptr; - unsigned long size; - - if (guestsrc + n < guestsrc) - return -EFAULT; - - /* simple case: all within one segment table entry? */ - if ((guestsrc & PMD_MASK) == ((guestsrc+n) & PMD_MASK)) { - uptr = (void __user *) gmap_fault(guestsrc, vcpu->arch.gmap); - - if (IS_ERR((void __force *) uptr)) - return PTR_ERR((void __force *) uptr); - - r = copy_from_user(to, uptr, n); - - if (r) - r = -EFAULT; - - goto out; - } - - /* copy first segment */ - uptr = (void __user *)gmap_fault(guestsrc, vcpu->arch.gmap); - - if (IS_ERR((void __force *) uptr)) - return PTR_ERR((void __force *) uptr); - - size = PMD_SIZE - (guestsrc & ~PMD_MASK); - - r = copy_from_user(to, uptr, size); - - if (r) { - r = -EFAULT; - goto out; - } - to += size; - n -= size; - guestsrc += size; - - /* copy full segments */ - while (n >= PMD_SIZE) { - uptr = (void __user *)gmap_fault(guestsrc, vcpu->arch.gmap); - - if (IS_ERR((void __force *) uptr)) - return PTR_ERR((void __force *) uptr); +#define copy_to_guest(vcpu, to, from, size) \ + __copy_guest(vcpu, to, (unsigned long)from, size, 1, 1) +#define copy_from_guest(vcpu, to, from, size) \ + __copy_guest(vcpu, (unsigned long)to, from, size, 0, 1) +#define copy_to_guest_absolute(vcpu, to, from, size) \ + __copy_guest(vcpu, to, (unsigned long)from, size, 1, 0) +#define copy_from_guest_absolute(vcpu, to, from, size) \ + __copy_guest(vcpu, (unsigned long)to, from, size, 0, 0) - r = copy_from_user(to, uptr, PMD_SIZE); - - if (r) { - r = -EFAULT; - goto out; - } - to += PMD_SIZE; - n -= PMD_SIZE; - guestsrc += PMD_SIZE; - } - - /* copy the tail segment */ - if (n) { - uptr = (void __user *)gmap_fault(guestsrc, vcpu->arch.gmap); - - if (IS_ERR((void __force *) uptr)) - return PTR_ERR((void __force *) uptr); - - r = copy_from_user(to, uptr, n); - - if (r) - r = -EFAULT; - } -out: - return r; -} - -static inline int copy_from_guest_absolute(struct kvm_vcpu *vcpu, void *to, - unsigned long guestsrc, - unsigned long n) -{ - return __copy_from_guest_fast(vcpu, to, guestsrc, n); -} - -static inline int copy_from_guest(struct kvm_vcpu *vcpu, void *to, - unsigned long guestsrc, unsigned long n) -{ - unsigned long prefix = vcpu->arch.sie_block->prefix; - - if ((guestsrc < 2 * PAGE_SIZE) && (guestsrc + n > 2 * PAGE_SIZE)) - goto slowpath; - - if ((guestsrc < prefix) && (guestsrc + n > prefix)) - goto slowpath; - - if ((guestsrc < prefix + 2 * PAGE_SIZE) - && (guestsrc + n > prefix + 2 * PAGE_SIZE)) - goto slowpath; - - if (guestsrc < 2 * PAGE_SIZE) - guestsrc += prefix; - else if ((guestsrc >= prefix) && (guestsrc < prefix + 2 * PAGE_SIZE)) - guestsrc -= prefix; - - return __copy_from_guest_fast(vcpu, to, guestsrc, n); -slowpath: - return __copy_from_guest_slow(vcpu, to, guestsrc, n); -} -#endif +#endif /* __KVM_S390_GACCESS_H */ -- GitLab