commit a0465f9ae4758207264a1318bb8aed617c0ea959
author Thomas Huth <thuth@linux.vnet.ibm.com> Tue Feb 04 14:48:07 2014 +0100
committer Christian Borntraeger <borntraeger@de.ibm.com> Fri May 30 09:39:36 2014 +0200
tree 5ffee52ce78ef810c6ac70fd277eb32046060a78
parent 9fbc02760d61fddc7716f9e6aa6ed1ff33e65405

KVM: s390: Enable DAT support for TPROT handler

The TPROT instruction can be used to check the accessability of storage
for any kind of logical addresses. So far, our handler only supported
real addresses. This patch now also enables support for addresses that
have to be translated via DAT first. And while we're at it, change the
code to use the common KVM function gfn_to_hva_prot() to check for the
validity and writability of the memory page.

Signed-off-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>

arch/s390/kvm/priv.c

diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c
index 6296159..f89c1cd 100644
--- a/arch/s390/kvm/priv.c
+++ b/arch/s390/kvm/priv.c
@@ -930,8 +930,9 @@
 static int handle_tprot(struct kvm_vcpu *vcpu)
 {
 	u64 address1, address2;
-	struct vm_area_struct *vma;
-	unsigned long user_address;
+	unsigned long hva, gpa;
+	int ret = 0, cc = 0;
+	bool writable;
 
 	vcpu->stat.instruction_tprot++;
 
@@ -942,32 +943,41 @@
 
 	/* we only handle the Linux memory detection case:
 	 * access key == 0
-	 * guest DAT == off
 	 * everything else goes to userspace. */
 	if (address2 & 0xf0)
 		return -EOPNOTSUPP;
 	if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_DAT)
-		return -EOPNOTSUPP;
+		ipte_lock(vcpu);
+	ret = guest_translate_address(vcpu, address1, &gpa, 1);
+	if (ret == PGM_PROTECTION) {
+		/* Write protected? Try again with read-only... */
+		cc = 1;
+		ret = guest_translate_address(vcpu, address1, &gpa, 0);
+	}
+	if (ret) {
+		if (ret == PGM_ADDRESSING || ret == PGM_TRANSLATION_SPEC) {
+			ret = kvm_s390_inject_program_int(vcpu, ret);
+		} else if (ret > 0) {
+			/* Translation not available */
+			kvm_s390_set_psw_cc(vcpu, 3);
+			ret = 0;
+		}
+		goto out_unlock;
+	}
 
-	down_read(&current->mm->mmap_sem);
-	user_address = __gmap_translate(address1, vcpu->arch.gmap);
-	if (IS_ERR_VALUE(user_address))
-		goto out_inject;
-	vma = find_vma(current->mm, user_address);
-	if (!vma)
-		goto out_inject;
-	vcpu->arch.sie_block->gpsw.mask &= ~(3ul << 44);
-	if (!(vma->vm_flags & VM_WRITE) && (vma->vm_flags & VM_READ))
-		vcpu->arch.sie_block->gpsw.mask |= (1ul << 44);
-	if (!(vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_READ))
-		vcpu->arch.sie_block->gpsw.mask |= (2ul << 44);
-
-	up_read(&current->mm->mmap_sem);
-	return 0;
-
-out_inject:
-	up_read(&current->mm->mmap_sem);
-	return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
+	hva = gfn_to_hva_prot(vcpu->kvm, gpa_to_gfn(gpa), &writable);
+	if (kvm_is_error_hva(hva)) {
+		ret = kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
+	} else {
+		if (!writable)
+			cc = 1;		/* Write not permitted ==> read-only */
+		kvm_s390_set_psw_cc(vcpu, cc);
+		/* Note: CC2 only occurs for storage keys (not supported yet) */
+	}
+out_unlock:
+	if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_DAT)
+		ipte_unlock(vcpu);
+	return ret;
 }
 
 int kvm_s390_handle_e5(struct kvm_vcpu *vcpu)