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[S390] Use gmap translation for accessing guest memory

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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 commit is contained in:
Carsten Otte 2011-07-24 10:48:22 +02:00 committed by Martin Schwidefsky
parent 598841ca99
commit 092670cd90
6 changed files with 197 additions and 113 deletions
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4
arch/s390/include/asm/kvm_host.h
View File

@ -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 */

247
arch/s390/kvm/gaccess.h
View File

@ -1,5 +1,5 @@
/*
* 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);
}
@ -206,12 +274,95 @@ static inline int __copy_from_guest_slow(struct kvm_vcpu *vcpu, void *to,
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);
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;
unsigned long origin = vcpu->arch.sie_block->gmsor;
unsigned long memsize = kvm_s390_vcpu_get_memsize(vcpu);
if ((guestsrc < 2 * PAGE_SIZE) && (guestsrc + n > 2 * PAGE_SIZE))
goto slowpath;
@ -228,52 +379,8 @@ static inline int copy_from_guest(struct kvm_vcpu *vcpu, void *to,
else if ((guestsrc >= prefix) && (guestsrc < prefix + 2 * PAGE_SIZE))
guestsrc -= prefix;
if (guestsrc + n > memsize)
return -EFAULT;
if (guestsrc + n < guestsrc)
return -EFAULT;
guestsrc += origin;
return copy_from_user(to, (void __user *) guestsrc, n);
return __copy_from_guest_fast(vcpu, to, guestsrc, n);
slowpath:
return __copy_from_guest_slow(vcpu, to, guestsrc, n);
}
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);
if (guestdest + n > memsize)
return -EFAULT;
if (guestdest + n < guestdest)
return -EFAULT;
guestdest += origin;
return copy_to_user((void __user *) guestdest, from, n);
}
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);
if (guestsrc + n > memsize)
return -EFAULT;
if (guestsrc + n < guestsrc)
return -EFAULT;
guestsrc += origin;
return copy_from_user(to, (void __user *) guestsrc, n);
}
#endif

26
arch/s390/kvm/intercept.c
View File

@ -165,29 +165,33 @@ 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 (rc) {
/* user will receive sigsegv, exit to user */
rc = -EOPNOTSUPP;
goto out;
}
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 + PAGE_SIZE,
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;
}
} else
rc = -EOPNOTSUPP;

4
arch/s390/kvm/kvm-s390.c
View File

@ -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) {

23
arch/s390/kvm/kvm-s390.h
View File

@ -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 */

6
arch/s390/kvm/sigp.c
View File

@ -189,10 +189,8 @@ static int __sigp_set_prefix(struct kvm_vcpu *vcpu, u16 cpu_addr, u32 address,
/* make sure that the new value is valid memory */
address = address & 0x7fffe000u;
if ((copy_from_user(&tmp, (void __user *)
(address + vcpu->arch.sie_block->gmsor) , 1)) ||
(copy_from_user(&tmp, (void __user *)(address +
vcpu->arch.sie_block->gmsor + PAGE_SIZE), 1))) {
if (copy_from_guest_absolute(vcpu, &tmp, address, 1) ||
copy_from_guest_absolute(vcpu, &tmp, address + PAGE_SIZE, 1)) {
*reg |= SIGP_STAT_INVALID_PARAMETER;
return 1; /* invalid parameter */
}