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Commit f9dc72e8 authored by Heiko Carstens's avatar Heiko Carstens Committed by Marcelo Tosatti
Browse files

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: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
parent 396083a9

arch/s390/kvm/gaccess.h

+41 −253
Original line number Diff line number Diff line
@@ -18,16 +18,19 @@ 
#include <asm/uaccess.h>

#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 (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)

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 = from;



	for (i = 0; i < n; i++) {

		rc = put_guest(vcpu, *(data++), (u8 *)guestdest++);

		if (rc < 0)

			return rc;

	}

	return 0;

}

	unsigned long _len, rc;

	void *uptr;



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)

	while (len) {

		uptr = to_guest ? (void *)to : (void *)from;

		uptr = __gptr_to_uptr(vcpu, uptr, prefixing);

		if (IS_ERR(uptr))

			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)

{

	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;

	}

	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)

		_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;



	/* 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);



		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;

		len -= _len;

		from += _len;

		to += _len;

	}



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);

	return 0;

}



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;

#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)



	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 */