From: Janosch Frank <frankja@linux.ibm.com>
Subject: KVM: s390: Fix pfmf and conditional skey emulation
Patch-mainline: v4.19-rc3
Git-commit: a11bdb1a6b782ee97587f92fae798efc78c31093
References: FATE#326372, LTC#169184, bsc#1113484

Summary:     kernel: Introduce huge page KVM backing support
Description: This adds the KVM support for libhugetlbfs backings of
             s390 KVM guests.

Upstream-Description:

             KVM: s390: Fix pfmf and conditional skey emulation

             We should not return with a lock.
             We also have to increase the address when we do page clearing.

             Fixes: bd096f644319 ("KVM: s390: Add skey emulation fault handling")
             Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
             Message-Id: <20180830081355.59234-1-frankja@linux.ibm.com>
             Reviewed-by: David Hildenbrand <david@redhat.com>
             Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 arch/s390/kvm/priv.c |   30 ++++++++++++++++++------------
 1 file changed, 18 insertions(+), 12 deletions(-)

--- a/arch/s390/kvm/priv.c
+++ b/arch/s390/kvm/priv.c
@@ -283,9 +283,11 @@ retry:
 			goto retry;
 		}
 	}
-	if (rc)
-		return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
 	up_read(&current->mm->mmap_sem);
+	if (rc == -EFAULT)
+		return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
+	if (rc < 0)
+		return rc;
 	vcpu->run->s.regs.gprs[reg1] &= ~0xff;
 	vcpu->run->s.regs.gprs[reg1] |= key;
 	return 0;
@@ -327,9 +329,11 @@ retry:
 			goto retry;
 		}
 	}
-	if (rc < 0)
-		return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
 	up_read(&current->mm->mmap_sem);
+	if (rc == -EFAULT)
+		return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
+	if (rc < -1)
+		return rc;
 	kvm_s390_set_psw_cc(vcpu, rc);
 	return 0;
 }
@@ -393,12 +397,12 @@ static int handle_sske(struct kvm_vcpu *
 					      FAULT_FLAG_WRITE, &unlocked);
 			rc = !rc ? -EAGAIN : rc;
 		}
+		up_read(&current->mm->mmap_sem);
 		if (rc == -EFAULT)
 			return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
-
-		up_read(&current->mm->mmap_sem);
-		if (rc >= 0)
-			start += PAGE_SIZE;
+		if (rc < 0)
+			return rc;
+		start += PAGE_SIZE;
 	}
 
 	if (m3 & (SSKE_MC | SSKE_MR)) {
@@ -1000,13 +1004,15 @@ static int handle_pfmf(struct kvm_vcpu *
 						      FAULT_FLAG_WRITE, &unlocked);
 				rc = !rc ? -EAGAIN : rc;
 			}
+			up_read(&current->mm->mmap_sem);
 			if (rc == -EFAULT)
 				return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
-
-			up_read(&current->mm->mmap_sem);
-			if (rc >= 0)
-				start += PAGE_SIZE;
+			if (rc == -EAGAIN)
+				continue;
+			if (rc < 0)
+				return rc;
 		}
+		start += PAGE_SIZE;
 	}
 	if (vcpu->run->s.regs.gprs[reg1] & PFMF_FSC) {
 		if (psw_bits(vcpu->arch.sie_block->gpsw).eaba == PSW_BITS_AMODE_64BIT) {