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>

diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c
index 59200ee..6f95994 100644 (file)
--- 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,