KVM: s390: convert handle_tpi()

Convert handle_tpi() to new guest access functions.

The code now sets up a structure which is copied with a single call to
guest space instead of issuing several separate guest access calls.
This is necessary since the to be copied data may cross a page boundary.
If a protection exception happens while accessing any of the pages, the
instruction is suppressed and may not have modified any memory contents.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c
index 5abfd531a8f1316d7e5f7df2edc826359c4db0a4..4f6bc165d79b572f616ff5271aa5a7dc521bf8eb 100644 (file)
--- a/arch/s390/kvm/priv.c
+++ b/arch/s390/kvm/priv.c
@@ -224,9 +224,12 @@ static int handle_test_block(struct kvm_vcpu *vcpu)
 static int handle_tpi(struct kvm_vcpu *vcpu)
 {
        struct kvm_s390_interrupt_info *inti;
+       unsigned long len;
+       u32 tpi_data[3];
+       int cc, rc;
        u64 addr;
-       int cc;
 
+       rc = 0;
        addr = kvm_s390_get_base_disp_s(vcpu);
        if (addr & 3)
                return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
@@ -235,30 +238,33 @@ static int handle_tpi(struct kvm_vcpu *vcpu)
        if (!inti)
                goto no_interrupt;
        cc = 1;
+       tpi_data[0] = inti->io.subchannel_id << 16 | inti->io.subchannel_nr;
+       tpi_data[1] = inti->io.io_int_parm;
+       tpi_data[2] = inti->io.io_int_word;
        if (addr) {
                /*
                 * Store the two-word I/O interruption code into the
                 * provided area.
                 */
-               if (put_guest(vcpu, inti->io.subchannel_id, (u16 __user *)addr)
-                   || put_guest(vcpu, inti->io.subchannel_nr, (u16 __user *)(addr + 2))
-                   || put_guest(vcpu, inti->io.io_int_parm, (u32 __user *)(addr + 4)))
-                       return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
+               len = sizeof(tpi_data) - 4;
+               rc = write_guest(vcpu, addr, &tpi_data, len);
+               if (rc)
+                       return kvm_s390_inject_prog_cond(vcpu, rc);
        } else {
                /*
                 * Store the three-word I/O interruption code into
                 * the appropriate lowcore area.
                 */
-               put_guest(vcpu, inti->io.subchannel_id, (u16 __user *) __LC_SUBCHANNEL_ID);
-               put_guest(vcpu, inti->io.subchannel_nr, (u16 __user *) __LC_SUBCHANNEL_NR);
-               put_guest(vcpu, inti->io.io_int_parm, (u32 __user *) __LC_IO_INT_PARM);
-               put_guest(vcpu, inti->io.io_int_word, (u32 __user *) __LC_IO_INT_WORD);
+               len = sizeof(tpi_data);
+               if (write_guest_lc(vcpu, __LC_SUBCHANNEL_ID, &tpi_data, len))
+                       rc = -EFAULT;
        }
        kfree(inti);
 no_interrupt:
        /* Set condition code and we're done. */
-       kvm_s390_set_psw_cc(vcpu, cc);
-       return 0;
+       if (!rc)
+               kvm_s390_set_psw_cc(vcpu, cc);
+       return rc ? -EFAULT : 0;
 }
 
 static int handle_tsch(struct kvm_vcpu *vcpu)