Commit 092670cd authored by Carsten Otte's avatar Carsten Otte Committed by Martin Schwidefsky
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[S390] Use gmap translation for accessing guest memory 



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: default avatarCarsten Otte <cotte@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 598841ca

arch/s390/include/asm/kvm_host.h

+1 −3
Original line number Diff line number Diff line
@@ -93,9 +93,7 @@ struct kvm_s390_sie_block { 
	__u32	scaol;			/* 0x0064 */

	__u8	reserved68[4];		/* 0x0068 */

	__u32	todpr;			/* 0x006c */

	__u8	reserved70[16];		/* 0x0070 */

	__u64	gmsor;			/* 0x0080 */

	__u64	gmslm;			/* 0x0088 */

	__u8	reserved70[32];		/* 0x0070 */

	psw_t	gpsw;			/* 0x0090 */

	__u64	gg14;			/* 0x00a0 */

	__u64	gg15;			/* 0x00a8 */

arch/s390/kvm/gaccess.h

+175 −68
Original line number Diff line number Diff line 
/*

 * gaccess.h -  access guest memory

 * access.h -  access guest memory

 *

 * Copyright IBM Corp. 2008,2009

 *
@@ -22,20 +22,13 @@ static inline void __user *__guestaddr_to_user(struct kvm_vcpu *vcpu, 
					       unsigned long guestaddr)

{

	unsigned long prefix  = vcpu->arch.sie_block->prefix;

	unsigned long origin  = vcpu->arch.sie_block->gmsor;

	unsigned long memsize = kvm_s390_vcpu_get_memsize(vcpu);



	if (guestaddr < 2 * PAGE_SIZE)

		guestaddr += prefix;

	else if ((guestaddr >= prefix) && (guestaddr < prefix + 2 * PAGE_SIZE))

		guestaddr -= prefix;



	if (guestaddr > memsize)

		return (void __user __force *) ERR_PTR(-EFAULT);



	guestaddr += origin;



	return (void __user *) guestaddr;

	return (void __user *) gmap_fault(guestaddr, vcpu->arch.gmap);

}



static inline int get_guest_u64(struct kvm_vcpu *vcpu, unsigned long guestaddr,
@@ -141,11 +134,11 @@ static inline int put_guest_u8(struct kvm_vcpu *vcpu, unsigned long guestaddr, 


static inline int __copy_to_guest_slow(struct kvm_vcpu *vcpu,

				       unsigned long guestdest,

				       const void *from, unsigned long n)

				       void *from, unsigned long n)

{

	int rc;

	unsigned long i;

	const u8 *data = from;

	u8 *data = from;



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

		rc = put_guest_u8(vcpu, guestdest++, *(data++));
@@ -155,12 +148,95 @@ static inline int __copy_to_guest_slow(struct kvm_vcpu *vcpu, 
	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,

				const void *from, unsigned long n)

				void *from, unsigned long n)

{

	unsigned long prefix  = vcpu->arch.sie_block->prefix;

	unsigned long origin  = vcpu->arch.sie_block->gmsor;

	unsigned long memsize = kvm_s390_vcpu_get_memsize(vcpu);



	if ((guestdest < 2 * PAGE_SIZE) && (guestdest + n > 2 * PAGE_SIZE))

		goto slowpath;
@@ -177,15 +253,7 @@ static inline int copy_to_guest(struct kvm_vcpu *vcpu, unsigned long guestdest, 
	else if ((guestdest >= prefix) && (guestdest < prefix + 2 * PAGE_SIZE))

		guestdest -= prefix;



	if (guestdest + n > memsize)

		return -EFAULT;



	if (guestdest + n < guestdest)

		return -EFAULT;



	guestdest += origin;



	return copy_to_user((void __user *) guestdest, from, n);

	return __copy_to_guest_fast(vcpu, guestdest, from, n);

slowpath:

	return __copy_to_guest_slow(vcpu, guestdest, from, n);

}
@@ -206,74 +274,113 @@ static inline int __copy_from_guest_slow(struct kvm_vcpu *vcpu, void *to, 
	return 0;

}



static inline int copy_from_guest(struct kvm_vcpu *vcpu, void *to,

				  unsigned long guestsrc, unsigned long n)

static inline int __copy_from_guest_fast(struct kvm_vcpu *vcpu, void *to,

					 unsigned long guestsrc,

					 unsigned long n)

{

	unsigned long prefix  = vcpu->arch.sie_block->prefix;

	unsigned long origin  = vcpu->arch.sie_block->gmsor;

	unsigned long memsize = kvm_s390_vcpu_get_memsize(vcpu);

	int r;

	void __user *uptr;

	unsigned long size;



	if ((guestsrc < 2 * PAGE_SIZE) && (guestsrc + n > 2 * PAGE_SIZE))

		goto slowpath;

	if (guestsrc + n < guestsrc)

		return -EFAULT;



	if ((guestsrc < prefix) && (guestsrc + n > prefix))

		goto slowpath;

	/* 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 ((guestsrc < prefix + 2 * PAGE_SIZE)

	    && (guestsrc + n > prefix + 2 * PAGE_SIZE))

		goto slowpath;

		if (IS_ERR((void __force *) uptr))

			return PTR_ERR((void __force *) uptr);



	if (guestsrc < 2 * PAGE_SIZE)

		guestsrc += prefix;

	else if ((guestsrc >= prefix) && (guestsrc < prefix + 2 * PAGE_SIZE))

		guestsrc -= prefix;

		r = copy_from_user(to, uptr, n);



	if (guestsrc + n > memsize)

		return -EFAULT;

		if (r)

			r = -EFAULT;



	if (guestsrc + n < guestsrc)

		return -EFAULT;

		goto out;

	}



	guestsrc += origin;

	/* copy first segment */

	uptr = (void __user *)gmap_fault(guestsrc, vcpu->arch.gmap);



	return copy_from_user(to, (void __user *) guestsrc, n);

slowpath:

	return __copy_from_guest_slow(vcpu, to, guestsrc, n);

	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;



static inline int copy_to_guest_absolute(struct kvm_vcpu *vcpu,

					 unsigned long guestdest,

					 const void *from, unsigned long n)

{

	unsigned long origin  = vcpu->arch.sie_block->gmsor;

	unsigned long memsize = kvm_s390_vcpu_get_memsize(vcpu);

	/* copy full segments */

	while (n >= PMD_SIZE) {

		uptr = (void __user *)gmap_fault(guestsrc, vcpu->arch.gmap);



	if (guestdest + n > memsize)

		return -EFAULT;

		if (IS_ERR((void __force *) uptr))

			return PTR_ERR((void __force *) uptr);



	if (guestdest + n < guestdest)

		return -EFAULT;

		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);



	guestdest += origin;

		r = copy_from_user(to, uptr, n);



	return copy_to_user((void __user *) guestdest, from, 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)

{

	unsigned long origin  = vcpu->arch.sie_block->gmsor;

	unsigned long memsize = kvm_s390_vcpu_get_memsize(vcpu);

	return __copy_from_guest_fast(vcpu, to, guestsrc, n);

}



	if (guestsrc + n > memsize)

		return -EFAULT;

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 + n < guestsrc)

		return -EFAULT;

	if ((guestsrc < 2 * PAGE_SIZE) && (guestsrc + n > 2 * PAGE_SIZE))

		goto slowpath;



	if ((guestsrc < prefix) && (guestsrc + n > prefix))

		goto slowpath;



	guestsrc += origin;

	if ((guestsrc < prefix + 2 * PAGE_SIZE)

	    && (guestsrc + n > prefix + 2 * PAGE_SIZE))

		goto slowpath;



	return copy_from_user(to, (void __user *) guestsrc, n);

	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

arch/s390/kvm/intercept.c

+14 −10
Original line number Diff line number Diff line
@@ -165,26 +165,30 @@ static int handle_validity(struct kvm_vcpu *vcpu) 
	int rc;



	vcpu->stat.exit_validity++;

	if ((viwhy == 0x37) && (vcpu->arch.sie_block->prefix

		<= kvm_s390_vcpu_get_memsize(vcpu) - 2*PAGE_SIZE)) {

		rc = fault_in_pages_writeable((char __user *)

			 vcpu->arch.sie_block->gmsor +

			 vcpu->arch.sie_block->prefix,

			 2*PAGE_SIZE);

	if (viwhy == 0x37) {

		vmaddr = gmap_fault(vcpu->arch.sie_block->prefix,

				    vcpu->arch.gmap);

		if (IS_ERR_VALUE(vmaddr)) {

			rc = -EOPNOTSUPP;

			goto out;

		}

		rc = fault_in_pages_writeable((char __user *) vmaddr,

			 PAGE_SIZE);

		if (rc) {

			/* user will receive sigsegv, exit to user */

			rc = -EOPNOTSUPP;

			goto out;

		}

		vmaddr = gmap_fault(vcpu->arch.sie_block->prefix,

		vmaddr = gmap_fault(vcpu->arch.sie_block->prefix + PAGE_SIZE,

				    vcpu->arch.gmap);

		if (IS_ERR_VALUE(vmaddr)) {

			rc = -EOPNOTSUPP;

			goto out;

		}

		vmaddr = gmap_fault(vcpu->arch.sie_block->prefix + PAGE_SIZE,

				    vcpu->arch.gmap);

		if (IS_ERR_VALUE(vmaddr)) {

		rc = fault_in_pages_writeable((char __user *) vmaddr,

			 PAGE_SIZE);

		if (rc) {

			/* user will receive sigsegv, exit to user */

			rc = -EOPNOTSUPP;

			goto out;

		}

arch/s390/kvm/kvm-s390.c

+2 −2
Original line number Diff line number Diff line
@@ -549,7 +549,7 @@ rerun_vcpu: 
	return rc;

}



static int __guestcopy(struct kvm_vcpu *vcpu, u64 guestdest, const void *from,

static int __guestcopy(struct kvm_vcpu *vcpu, u64 guestdest, void *from,

		       unsigned long n, int prefix)

{

	if (prefix)
@@ -566,7 +566,7 @@ static int __guestcopy(struct kvm_vcpu *vcpu, u64 guestdest, const void *from, 
 */

int kvm_s390_vcpu_store_status(struct kvm_vcpu *vcpu, unsigned long addr)

{

	const unsigned char archmode = 1;

	unsigned char archmode = 1;

	int prefix;



	if (addr == KVM_S390_STORE_STATUS_NOADDR) {

arch/s390/kvm/kvm-s390.h

+0 −23
Original line number Diff line number Diff line
@@ -58,31 +58,8 @@ int kvm_s390_inject_vcpu(struct kvm_vcpu *vcpu, 
int kvm_s390_inject_program_int(struct kvm_vcpu *vcpu, u16 code);

int kvm_s390_inject_sigp_stop(struct kvm_vcpu *vcpu, int action);



static inline long kvm_s390_vcpu_get_memsize(struct kvm_vcpu *vcpu)

{

	return vcpu->arch.sie_block->gmslm

		- vcpu->arch.sie_block->gmsor

		- VIRTIODESCSPACE + 1ul;

}



static inline void kvm_s390_vcpu_set_mem(struct kvm_vcpu *vcpu)

{

	int idx;

	struct kvm_memory_slot *mem;

	struct kvm_memslots *memslots;



	idx = srcu_read_lock(&vcpu->kvm->srcu);

	memslots = kvm_memslots(vcpu->kvm);



	mem = &memslots->memslots[0];



	vcpu->arch.sie_block->gmsor = mem->userspace_addr;

	vcpu->arch.sie_block->gmslm =

		mem->userspace_addr +

		(mem->npages << PAGE_SHIFT) +

		VIRTIODESCSPACE - 1ul;



	srcu_read_unlock(&vcpu->kvm->srcu, idx);

}



/* implemented in priv.c */

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