[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: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index 8264b0b..e5d082c 100644 (file)
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -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 */

diff --git a/arch/s390/kvm/gaccess.h b/arch/s390/kvm/gaccess.h
index 03c716a..c86f6ae 100644 (file)
--- a/arch/s390/kvm/gaccess.h
+++ b/arch/s390/kvm/gaccess.h
@@ -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);
 }
@@ -206,74 +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);
 
-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);
+       size = PMD_SIZE - (guestsrc & ~PMD_MASK);
 
-       if (guestdest + n > memsize)
-               return -EFAULT;
+       r = copy_from_user(to, uptr, size);
 
-       if (guestdest + n < guestdest)
-               return -EFAULT;
+       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);
 
-       guestdest += origin;
+               if (IS_ERR((void __force *) uptr))
+                       return PTR_ERR((void __force *) uptr);
 
-       return copy_to_user((void __user *) guestdest, from, n);
+               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)
 {
-       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;
 
-       guestsrc += origin;
+       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_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);
 }
 #endif

diff --git a/arch/s390/kvm/intercept.c b/arch/s390/kvm/intercept.c
index 654fc1f..c7c5189 100644 (file)
--- a/arch/s390/kvm/intercept.c
+++ b/arch/s390/kvm/intercept.c
@@ -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;
                }

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 3ebb4ba..5a99f34 100644 (file)
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -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) {

diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h
index 65e2201..63e5190 100644 (file)
--- a/arch/s390/kvm/kvm-s390.h
+++ b/arch/s390/kvm/kvm-s390.h
@@ -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 */

diff --git a/arch/s390/kvm/sigp.c b/arch/s390/kvm/sigp.c
index 702276f..d6a50c1 100644 (file)
--- a/arch/s390/kvm/sigp.c
+++ b/arch/s390/kvm/sigp.c
@@ -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 */
        }