1 files changed, 300 insertions, 79 deletions

diff --git a/arch/s390/kvm/gaccess.h b/arch/s390/kvm/gaccess.h
index 374a439ccc60..0149cf15058a 100644
--- a/arch/s390/kvm/gaccess.h
+++ b/arch/s390/kvm/gaccess.h
@@ -1,7 +1,7 @@
 /*
  * access guest memory
  *
- * Copyright IBM Corp. 2008, 2009
+ * Copyright IBM Corp. 2008, 2014
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License (version 2 only)
@@ -15,100 +15,321 @@
 
 #include <linux/compiler.h>
 #include <linux/kvm_host.h>
-#include <asm/uaccess.h>
+#include <linux/uaccess.h>
+#include <linux/ptrace.h>
 #include "kvm-s390.h"
 
-/* Convert real to absolute address by applying the prefix of the CPU */
+/**
+ * kvm_s390_real_to_abs - convert guest real address to guest absolute address
+ * @vcpu - guest virtual cpu
+ * @gra - guest real address
+ *
+ * Returns the guest absolute address that corresponds to the passed guest real
+ * address @gra of a virtual guest cpu by applying its prefix.
+ */
 static inline unsigned long kvm_s390_real_to_abs(struct kvm_vcpu *vcpu,
-                                                 unsigned long gaddr)
+                                                 unsigned long gra)
 {
-        unsigned long prefix  = vcpu->arch.sie_block->prefix;
-        if (gaddr < 2 * PAGE_SIZE)
-                gaddr += prefix;
-        else if (gaddr >= prefix && gaddr < prefix + 2 * PAGE_SIZE)
-                gaddr -= prefix;
-        return gaddr;
+        unsigned long prefix  = kvm_s390_get_prefix(vcpu);
+
+        if (gra < 2 * PAGE_SIZE)
+                gra += prefix;
+        else if (gra >= prefix && gra < prefix + 2 * PAGE_SIZE)
+                gra -= prefix;
+        return gra;
 }
 
-static inline void __user *__gptr_to_uptr(struct kvm_vcpu *vcpu,
-                                          void __user *gptr,
-                                          int prefixing)
+/**
+ * kvm_s390_logical_to_effective - convert guest logical to effective address
+ * @vcpu: guest virtual cpu
+ * @ga: guest logical address
+ *
+ * Convert a guest vcpu logical address to a guest vcpu effective address by
+ * applying the rules of the vcpu's addressing mode defined by PSW bits 31
+ * and 32 (extendended/basic addressing mode).
+ *
+ * Depending on the vcpu's addressing mode the upper 40 bits (24 bit addressing
+ * mode), 33 bits (31 bit addressing mode) or no bits (64 bit addressing mode)
+ * of @ga will be zeroed and the remaining bits will be returned.
+ */
+static inline unsigned long kvm_s390_logical_to_effective(struct kvm_vcpu *vcpu,
+                                                          unsigned long ga)
 {
-        unsigned long gaddr = (unsigned long) gptr;
-        unsigned long uaddr;
-
-        if (prefixing)
-                gaddr = kvm_s390_real_to_abs(vcpu, gaddr);
-        uaddr = gmap_fault(gaddr, vcpu->arch.gmap);
-        if (IS_ERR_VALUE(uaddr))
-                uaddr = -EFAULT;
-        return (void __user *)uaddr;
+        psw_t *psw = &vcpu->arch.sie_block->gpsw;
+
+        if (psw_bits(*psw).eaba == PSW_AMODE_64BIT)
+                return ga;
+        if (psw_bits(*psw).eaba == PSW_AMODE_31BIT)
+                return ga & ((1UL << 31) - 1);
+        return ga & ((1UL << 24) - 1);
 }
 
-#define get_guest(vcpu, x, gptr)                                \
-({                                                              \
-        __typeof__(gptr) __uptr = __gptr_to_uptr(vcpu, gptr, 1);\
-        int __mask = sizeof(__typeof__(*(gptr))) - 1;           \
-        int __ret;                                              \
-                                                                \
-        if (IS_ERR((void __force *)__uptr)) {                   \
-                __ret = PTR_ERR((void __force *)__uptr);        \
-        } else {                                                \
-                BUG_ON((unsigned long)__uptr & __mask);         \
-                __ret = get_user(x, __uptr);                    \
-        }                                                       \
-        __ret;                                                  \
-})
+/*
+ * put_guest_lc, read_guest_lc and write_guest_lc are guest access functions
+ * which shall only be used to access the lowcore of a vcpu.
+ * These functions should be used for e.g. interrupt handlers where no
+ * guest memory access protection facilities, like key or low address
+ * protection, are applicable.
+ * At a later point guest vcpu lowcore access should happen via pinned
+ * prefix pages, so that these pages can be accessed directly via the
+ * kernel mapping. All of these *_lc functions can be removed then.
+ */
 
-#define put_guest(vcpu, x, gptr)                                \
+/**
+ * put_guest_lc - write a simple variable to a guest vcpu's lowcore
+ * @vcpu: virtual cpu
+ * @x: value to copy to guest
+ * @gra: vcpu's destination guest real address
+ *
+ * Copies a simple value from kernel space to a guest vcpu's lowcore.
+ * The size of the variable may be 1, 2, 4 or 8 bytes. The destination
+ * must be located in the vcpu's lowcore. Otherwise the result is undefined.
+ *
+ * Returns zero on success or -EFAULT on error.
+ *
+ * Note: an error indicates that either the kernel is out of memory or
+ *       the guest memory mapping is broken. In any case the best solution
+ *       would be to terminate the guest.
+ *       It is wrong to inject a guest exception.
+ */
+#define put_guest_lc(vcpu, x, gra)                              \
 ({                                                              \
-        __typeof__(gptr) __uptr = __gptr_to_uptr(vcpu, gptr, 1);\
-        int __mask = sizeof(__typeof__(*(gptr))) - 1;           \
-        int __ret;                                              \
+        struct kvm_vcpu *__vcpu = (vcpu);                       \
+        __typeof__(*(gra)) __x = (x);                           \
+        unsigned long __gpa;                                    \
                                                                 \
-        if (IS_ERR((void __force *)__uptr)) {                   \
-                __ret = PTR_ERR((void __force *)__uptr);        \
-        } else {                                                \
-                BUG_ON((unsigned long)__uptr & __mask);         \
-                __ret = put_user(x, __uptr);                    \
-        }                                                       \
-        __ret;                                                  \
+        __gpa = (unsigned long)(gra);                           \
+        __gpa += kvm_s390_get_prefix(__vcpu);                   \
+        kvm_write_guest(__vcpu->kvm, __gpa, &__x, sizeof(__x)); \
 })
 
-static inline int __copy_guest(struct kvm_vcpu *vcpu, unsigned long to,
-                               unsigned long from, unsigned long len,
-                               int to_guest, int prefixing)
+/**
+ * write_guest_lc - copy data from kernel space to guest vcpu's lowcore
+ * @vcpu: virtual cpu
+ * @gra: vcpu's source guest real address
+ * @data: source address in kernel space
+ * @len: number of bytes to copy
+ *
+ * Copy data from kernel space to guest vcpu's lowcore. The entire range must
+ * be located within the vcpu's lowcore, otherwise the result is undefined.
+ *
+ * Returns zero on success or -EFAULT on error.
+ *
+ * Note: an error indicates that either the kernel is out of memory or
+ *       the guest memory mapping is broken. In any case the best solution
+ *       would be to terminate the guest.
+ *       It is wrong to inject a guest exception.
+ */
+static inline __must_check
+int write_guest_lc(struct kvm_vcpu *vcpu, unsigned long gra, void *data,
+                   unsigned long len)
+{
+        unsigned long gpa = gra + kvm_s390_get_prefix(vcpu);
+
+        return kvm_write_guest(vcpu->kvm, gpa, data, len);
+}
+
+/**
+ * read_guest_lc - copy data from guest vcpu's lowcore to kernel space
+ * @vcpu: virtual cpu
+ * @gra: vcpu's source guest real address
+ * @data: destination address in kernel space
+ * @len: number of bytes to copy
+ *
+ * Copy data from guest vcpu's lowcore to kernel space. The entire range must
+ * be located within the vcpu's lowcore, otherwise the result is undefined.
+ *
+ * Returns zero on success or -EFAULT on error.
+ *
+ * Note: an error indicates that either the kernel is out of memory or
+ *       the guest memory mapping is broken. In any case the best solution
+ *       would be to terminate the guest.
+ *       It is wrong to inject a guest exception.
+ */
+static inline __must_check
+int read_guest_lc(struct kvm_vcpu *vcpu, unsigned long gra, void *data,
+                  unsigned long len)
+{
+        unsigned long gpa = gra + kvm_s390_get_prefix(vcpu);
+
+        return kvm_read_guest(vcpu->kvm, gpa, data, len);
+}
+
+int guest_translate_address(struct kvm_vcpu *vcpu, unsigned long gva,
+                            unsigned long *gpa, int write);
+
+int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, void *data,
+                 unsigned long len, int write);
+
+int access_guest_real(struct kvm_vcpu *vcpu, unsigned long gra,
+                      void *data, unsigned long len, int write);
+
+/**
+ * write_guest - copy data from kernel space to guest space
+ * @vcpu: virtual cpu
+ * @ga: guest address
+ * @data: source address in kernel space
+ * @len: number of bytes to copy
+ *
+ * Copy @len bytes from @data (kernel space) to @ga (guest address).
+ * In order to copy data to guest space the PSW of the vcpu is inspected:
+ * If DAT is off data will be copied to guest real or absolute memory.
+ * If DAT is on data will be copied to the address space as specified by
+ * the address space bits of the PSW:
+ * Primary, secondory or home space (access register mode is currently not
+ * implemented).
+ * The addressing mode of the PSW is also inspected, so that address wrap
+ * around is taken into account for 24-, 31- and 64-bit addressing mode,
+ * if the to be copied data crosses page boundaries in guest address space.
+ * In addition also low address and DAT protection are inspected before
+ * copying any data (key protection is currently not implemented).
+ *
+ * This function modifies the 'struct kvm_s390_pgm_info pgm' member of @vcpu.
+ * In case of an access exception (e.g. protection exception) pgm will contain
+ * all data necessary so that a subsequent call to 'kvm_s390_inject_prog_vcpu()'
+ * will inject a correct exception into the guest.
+ * If no access exception happened, the contents of pgm are undefined when
+ * this function returns.
+ *
+ * Returns:  - zero on success
+ *           - a negative value if e.g. the guest mapping is broken or in
+ *             case of out-of-memory. In this case the contents of pgm are
+ *             undefined. Also parts of @data may have been copied to guest
+ *             space.
+ *           - a positive value if an access exception happened. In this case
+ *             the returned value is the program interruption code and the
+ *             contents of pgm may be used to inject an exception into the
+ *             guest. No data has been copied to guest space.
+ *
+ * Note: in case an access exception is recognized no data has been copied to
+ *       guest space (this is also true, if the to be copied data would cross
+ *       one or more page boundaries in guest space).
+ *       Therefore this function may be used for nullifying and suppressing
+ *       instruction emulation.
+ *       It may also be used for terminating instructions, if it is undefined
+ *       if data has been changed in guest space in case of an exception.
+ */
+static inline __must_check
+int write_guest(struct kvm_vcpu *vcpu, unsigned long ga, void *data,
+                unsigned long len)
+{
+        return access_guest(vcpu, ga, data, len, 1);
+}
+
+/**
+ * read_guest - copy data from guest space to kernel space
+ * @vcpu: virtual cpu
+ * @ga: guest address
+ * @data: destination address in kernel space
+ * @len: number of bytes to copy
+ *
+ * Copy @len bytes from @ga (guest address) to @data (kernel space).
+ *
+ * The behaviour of read_guest is identical to write_guest, except that
+ * data will be copied from guest space to kernel space.
+ */
+static inline __must_check
+int read_guest(struct kvm_vcpu *vcpu, unsigned long ga, void *data,
+               unsigned long len)
+{
+        return access_guest(vcpu, ga, data, len, 0);
+}
+
+/**
+ * write_guest_abs - copy data from kernel space to guest space absolute
+ * @vcpu: virtual cpu
+ * @gpa: guest physical (absolute) address
+ * @data: source address in kernel space
+ * @len: number of bytes to copy
+ *
+ * Copy @len bytes from @data (kernel space) to @gpa (guest absolute address).
+ * It is up to the caller to ensure that the entire guest memory range is
+ * valid memory before calling this function.
+ * Guest low address and key protection are not checked.
+ *
+ * Returns zero on success or -EFAULT on error.
+ *
+ * If an error occurs data may have been copied partially to guest memory.
+ */
+static inline __must_check
+int write_guest_abs(struct kvm_vcpu *vcpu, unsigned long gpa, void *data,
+                    unsigned long len)
+{
+        return kvm_write_guest(vcpu->kvm, gpa, data, len);
+}
+
+/**
+ * read_guest_abs - copy data from guest space absolute to kernel space
+ * @vcpu: virtual cpu
+ * @gpa: guest physical (absolute) address
+ * @data: destination address in kernel space
+ * @len: number of bytes to copy
+ *
+ * Copy @len bytes from @gpa (guest absolute address) to @data (kernel space).
+ * It is up to the caller to ensure that the entire guest memory range is
+ * valid memory before calling this function.
+ * Guest key protection is not checked.
+ *
+ * Returns zero on success or -EFAULT on error.
+ *
+ * If an error occurs data may have been copied partially to kernel space.
+ */
+static inline __must_check
+int read_guest_abs(struct kvm_vcpu *vcpu, unsigned long gpa, void *data,
+                   unsigned long len)
+{
+        return kvm_read_guest(vcpu->kvm, gpa, data, len);
+}
+
+/**
+ * write_guest_real - copy data from kernel space to guest space real
+ * @vcpu: virtual cpu
+ * @gra: guest real address
+ * @data: source address in kernel space
+ * @len: number of bytes to copy
+ *
+ * Copy @len bytes from @data (kernel space) to @gra (guest real address).
+ * It is up to the caller to ensure that the entire guest memory range is
+ * valid memory before calling this function.
+ * Guest low address and key protection are not checked.
+ *
+ * Returns zero on success or -EFAULT on error.
+ *
+ * If an error occurs data may have been copied partially to guest memory.
+ */
+static inline __must_check
+int write_guest_real(struct kvm_vcpu *vcpu, unsigned long gra, void *data,
+                     unsigned long len)
+{
+        return access_guest_real(vcpu, gra, data, len, 1);
+}
+
+/**
+ * read_guest_real - copy data from guest space real to kernel space
+ * @vcpu: virtual cpu
+ * @gra: guest real address
+ * @data: destination address in kernel space
+ * @len: number of bytes to copy
+ *
+ * Copy @len bytes from @gra (guest real address) to @data (kernel space).
+ * It is up to the caller to ensure that the entire guest memory range is
+ * valid memory before calling this function.
+ * Guest key protection is not checked.
+ *
+ * Returns zero on success or -EFAULT on error.
+ *
+ * If an error occurs data may have been copied partially to kernel space.
+ */
+static inline __must_check
+int read_guest_real(struct kvm_vcpu *vcpu, unsigned long gra, void *data,
+                    unsigned long len)
 {
-        unsigned long _len, rc;
-        void __user *uptr;
-
-        while (len) {
-                uptr = to_guest ? (void __user *)to : (void __user *)from;
-                uptr = __gptr_to_uptr(vcpu, uptr, prefixing);
-                if (IS_ERR((void __force *)uptr))
-                        return -EFAULT;
-                _len = PAGE_SIZE - ((unsigned long)uptr & (PAGE_SIZE - 1));
-                _len = min(_len, len);
-                if (to_guest)
-                        rc = copy_to_user((void __user *) uptr, (void *)from, _len);
-                else
-                        rc = copy_from_user((void *)to, (void __user *)uptr, _len);
-                if (rc)
-                        return -EFAULT;
-                len -= _len;
-                from += _len;
-                to += _len;
-        }
-        return 0;
+        return access_guest_real(vcpu, gra, data, len, 0);
 }
 
-#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)
+void ipte_lock(struct kvm_vcpu *vcpu);
+void ipte_unlock(struct kvm_vcpu *vcpu);
+int ipte_lock_held(struct kvm_vcpu *vcpu);
+int kvm_s390_check_low_addr_protection(struct kvm_vcpu *vcpu, unsigned long ga);
 
 #endif /* __KVM_S390_GACCESS_H */