3 files changed, 98 insertions, 0 deletions

diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c
index ea38d716e24d..a7559f7207df 100644
--- a/arch/s390/kvm/gaccess.c
+++ b/arch/s390/kvm/gaccess.c
@@ -864,6 +864,28 @@ int guest_translate_address(struct kvm_vcpu *vcpu, unsigned long gva, ar_t ar,
 }
 
 /**
+ * check_gva_range - test a range of guest virtual addresses for accessibility
+ */
+int check_gva_range(struct kvm_vcpu *vcpu, unsigned long gva, ar_t ar,
+                    unsigned long length, int is_write)
+{
+        unsigned long gpa;
+        unsigned long currlen;
+        int rc = 0;
+
+        ipte_lock(vcpu);
+        while (length > 0 && !rc) {
+                currlen = min(length, PAGE_SIZE - (gva % PAGE_SIZE));
+                rc = guest_translate_address(vcpu, gva, ar, &gpa, is_write);
+                gva += currlen;
+                length -= currlen;
+        }
+        ipte_unlock(vcpu);
+
+        return rc;
+}
+
+/**
  * kvm_s390_check_low_addr_prot_real - check for low-address protection
  * @gra: Guest real address
  *
diff --git a/arch/s390/kvm/gaccess.h b/arch/s390/kvm/gaccess.h
index 835e557dabf4..ef03726cc661 100644
--- a/arch/s390/kvm/gaccess.h
+++ b/arch/s390/kvm/gaccess.h
@@ -157,6 +157,8 @@ int read_guest_lc(struct kvm_vcpu *vcpu, unsigned long gra, void *data,
 
 int guest_translate_address(struct kvm_vcpu *vcpu, unsigned long gva,
                             ar_t ar, unsigned long *gpa, int write);
+int check_gva_range(struct kvm_vcpu *vcpu, unsigned long gva, ar_t ar,
+                    unsigned long length, int is_write);
 
 int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, ar_t ar, void *data,
                  unsigned long len, int write);
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 610e90afadf2..b7ecef98b668 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -25,6 +25,7 @@
 #include <linux/random.h>
 #include <linux/slab.h>
 #include <linux/timer.h>
+#include <linux/vmalloc.h>
 #include <asm/asm-offsets.h>
 #include <asm/lowcore.h>
 #include <asm/pgtable.h>
@@ -38,6 +39,8 @@
 #include "trace.h"
 #include "trace-s390.h"
 
+#define MEM_OP_MAX_SIZE 65536   /* Maximum transfer size for KVM_S390_MEM_OP */
+
 #define VCPU_STAT(x) offsetof(struct kvm_vcpu, stat.x), KVM_STAT_VCPU
 
 struct kvm_stats_debugfs_item debugfs_entries[] = {
@@ -177,6 +180,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
         case KVM_CAP_S390_USER_SIGP:
                 r = 1;
                 break;
+        case KVM_CAP_S390_MEM_OP:
+                r = MEM_OP_MAX_SIZE;
+                break;
         case KVM_CAP_NR_VCPUS:
         case KVM_CAP_MAX_VCPUS:
                 r = KVM_MAX_VCPUS;
@@ -2185,6 +2191,65 @@ static int kvm_vcpu_ioctl_enable_cap(struct kvm_vcpu *vcpu,
         return r;
 }
 
+static long kvm_s390_guest_mem_op(struct kvm_vcpu *vcpu,
+                                  struct kvm_s390_mem_op *mop)
+{
+        void __user *uaddr = (void __user *)mop->buf;
+        void *tmpbuf = NULL;
+        int r, srcu_idx;
+        const u64 supported_flags = KVM_S390_MEMOP_F_INJECT_EXCEPTION
+                                    | KVM_S390_MEMOP_F_CHECK_ONLY;
+
+        if (mop->flags & ~supported_flags)
+                return -EINVAL;
+
+        if (mop->size > MEM_OP_MAX_SIZE)
+                return -E2BIG;
+
+        if (!(mop->flags & KVM_S390_MEMOP_F_CHECK_ONLY)) {
+                tmpbuf = vmalloc(mop->size);
+                if (!tmpbuf)
+                        return -ENOMEM;
+        }
+
+        srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
+
+        switch (mop->op) {
+        case KVM_S390_MEMOP_LOGICAL_READ:
+                if (mop->flags & KVM_S390_MEMOP_F_CHECK_ONLY) {
+                        r = check_gva_range(vcpu, mop->gaddr, mop->ar, mop->size, false);
+                        break;
+                }
+                r = read_guest(vcpu, mop->gaddr, mop->ar, tmpbuf, mop->size);
+                if (r == 0) {
+                        if (copy_to_user(uaddr, tmpbuf, mop->size))
+                                r = -EFAULT;
+                }
+                break;
+        case KVM_S390_MEMOP_LOGICAL_WRITE:
+                if (mop->flags & KVM_S390_MEMOP_F_CHECK_ONLY) {
+                        r = check_gva_range(vcpu, mop->gaddr, mop->ar, mop->size, true);
+                        break;
+                }
+                if (copy_from_user(tmpbuf, uaddr, mop->size)) {
+                        r = -EFAULT;
+                        break;
+                }
+                r = write_guest(vcpu, mop->gaddr, mop->ar, tmpbuf, mop->size);
+                break;
+        default:
+                r = -EINVAL;
+        }
+
+        srcu_read_unlock(&vcpu->kvm->srcu, srcu_idx);
+
+        if (r > 0 && (mop->flags & KVM_S390_MEMOP_F_INJECT_EXCEPTION) != 0)
+                kvm_s390_inject_prog_irq(vcpu, &vcpu->arch.pgm);
+
+        vfree(tmpbuf);
+        return r;
+}
+
 long kvm_arch_vcpu_ioctl(struct file *filp,
                          unsigned int ioctl, unsigned long arg)
 {
@@ -2284,6 +2349,15 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
                 r = kvm_vcpu_ioctl_enable_cap(vcpu, &cap);
                 break;
         }
+        case KVM_S390_MEM_OP: {
+                struct kvm_s390_mem_op mem_op;
+
+                if (copy_from_user(&mem_op, argp, sizeof(mem_op)) == 0)
+                        r = kvm_s390_guest_mem_op(vcpu, &mem_op);
+                else
+                        r = -EFAULT;
+                break;
+        }
         default:
                 r = -ENOTTY;
         }