KVM: s390: Implement TEST BLOCK

This patch provides a simple version for the mandatory TEST BLOCK
instruction interception, so that guests that use this instruction
do not crash anymore.

Signed-off-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 28 insertions, 0 deletions

diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c
index 59200ee275e5..6f9599416bae 100644
--- a/arch/s390/kvm/priv.c
+++ b/arch/s390/kvm/priv.c
@@ -128,6 +128,33 @@ static int handle_skey(struct kvm_vcpu *vcpu)
         return 0;
 }
 
+static int handle_test_block(struct kvm_vcpu *vcpu)
+{
+        unsigned long hva;
+        gpa_t addr;
+        int reg2;
+
+        if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)
+                return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP);
+
+        kvm_s390_get_regs_rre(vcpu, NULL, &reg2);
+        addr = vcpu->run->s.regs.gprs[reg2] & PAGE_MASK;
+        addr = kvm_s390_real_to_abs(vcpu, addr);
+
+        hva = gfn_to_hva(vcpu->kvm, gpa_to_gfn(addr));
+        if (kvm_is_error_hva(hva))
+                return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
+        /*
+         * We don't expect errors on modern systems, and do not care
+         * about storage keys (yet), so let's just clear the page.
+         */
+        if (clear_user((void __user *)hva, PAGE_SIZE) != 0)
+                return -EFAULT;
+        kvm_s390_set_psw_cc(vcpu, 0);
+        vcpu->run->s.regs.gprs[0] = 0;
+        return 0;
+}
+
 static int handle_tpi(struct kvm_vcpu *vcpu)
 {
         struct kvm_s390_interrupt_info *inti;
@@ -444,6 +471,7 @@ static const intercept_handler_t b2_handlers[256] = {
         [0x29] = handle_skey,
         [0x2a] = handle_skey,
         [0x2b] = handle_skey,
+        [0x2c] = handle_test_block,
         [0x30] = handle_io_inst,
         [0x31] = handle_io_inst,
         [0x32] = handle_io_inst,