---

yaml --- r: 275646 b: refs/heads/master c: 1eddb85 h: refs/heads/master v: v3
git-mirror · Nov 17, 2011 · 997adc0 · 997adc0
1 parent 72289e5
commit 997adc0
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Showing 2 changed files with 9 additions and 3 deletions.
diff --git a/[refs] b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: bd59d3a4444e5f941c863db1a7715edf7289e29a
+refs/heads/master: 1eddb85f889a5a9fe59ec184e06844716a00aded
diff --git a/trunk/arch/s390/kvm/priv.c b/trunk/arch/s390/kvm/priv.c
@@ -336,6 +336,7 @@ static int handle_tprot(struct kvm_vcpu *vcpu)
 	u64 address1 = disp1 + base1 ? vcpu->arch.guest_gprs[base1] : 0;
 	u64 address2 = disp2 + base2 ? vcpu->arch.guest_gprs[base2] : 0;
 	struct vm_area_struct *vma;
+	unsigned long user_address;
 
 	vcpu->stat.instruction_tprot++;
 
@@ -349,9 +350,14 @@ static int handle_tprot(struct kvm_vcpu *vcpu)
 		return -EOPNOTSUPP;
 
 
+	/* we must resolve the address without holding the mmap semaphore.
+	 * This is ok since the userspace hypervisor is not supposed to change
+	 * the mapping while the guest queries the memory. Otherwise the guest
+	 * might crash or get wrong info anyway. */
+	user_address = (unsigned long) __guestaddr_to_user(vcpu, address1);
+
 	down_read(&current->mm->mmap_sem);
-	vma = find_vma(current->mm,
-			(unsigned long) __guestaddr_to_user(vcpu, address1));
+	vma = find_vma(current->mm, user_address);
 	if (!vma) {
 		up_read(&current->mm->mmap_sem);
 		return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);