[PATCH v1 05/13] KVM: s390: get rid of gmap_fault()

[Claudio Imbrenda <imbrenda@linux.ibm.com>]

All gmap page faults are already handled in kvm by the function
kvm_s390_handle_dat_fault(); only few users of gmap_fault remained, all
within kvm.

Convert those calls to use kvm_s390_handle_dat_fault() instead.

Remove gmap_fault() entirely since it has no more users.

Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
---
 arch/s390/include/asm/gmap.h |   1 -
 arch/s390/kvm/intercept.c    |   4 +-
 arch/s390/kvm/kvm-s390.c     |  17 +++--
 arch/s390/kvm/kvm-s390.h     |   7 ++
 arch/s390/mm/gmap.c          | 124 -----------------------------------
 5 files changed, 22 insertions(+), 131 deletions(-)

diff --git a/arch/s390/include/asm/gmap.h b/arch/s390/include/asm/gmap.h
index 13f51a6a5bb1..3f4184be297f 100644
--- a/arch/s390/include/asm/gmap.h
+++ b/arch/s390/include/asm/gmap.h
@@ -113,7 +113,6 @@ int gmap_unmap_segment(struct gmap *gmap, unsigned long to, unsigned long len);
 unsigned long __gmap_translate(struct gmap *, unsigned long gaddr);
 unsigned long gmap_translate(struct gmap *, unsigned long gaddr);
 int __gmap_link(struct gmap *gmap, unsigned long gaddr, unsigned long vmaddr);
-int gmap_fault(struct gmap *, unsigned long gaddr, unsigned int fault_flags);
 void gmap_discard(struct gmap *, unsigned long from, unsigned long to);
 void __gmap_zap(struct gmap *, unsigned long gaddr);
 void gmap_unlink(struct mm_struct *, unsigned long *table, unsigned long vmaddr);
diff --git a/arch/s390/kvm/intercept.c b/arch/s390/kvm/intercept.c
index 92ae003cd215..83a4b0edf239 100644
--- a/arch/s390/kvm/intercept.c
+++ b/arch/s390/kvm/intercept.c
@@ -368,7 +368,7 @@ static int handle_mvpg_pei(struct kvm_vcpu *vcpu)
 					      reg2, &srcaddr, GACC_FETCH, 0);
 	if (rc)
 		return kvm_s390_inject_prog_cond(vcpu, rc);
-	rc = gmap_fault(vcpu->arch.gmap, srcaddr, 0);
+	rc = kvm_s390_handle_dat_fault(vcpu, srcaddr, 0);
 	if (rc != 0)
 		return rc;
 
@@ -377,7 +377,7 @@ static int handle_mvpg_pei(struct kvm_vcpu *vcpu)
 					      reg1, &dstaddr, GACC_STORE, 0);
 	if (rc)
 		return kvm_s390_inject_prog_cond(vcpu, rc);
-	rc = gmap_fault(vcpu->arch.gmap, dstaddr, FAULT_FLAG_WRITE);
+	rc = kvm_s390_handle_dat_fault(vcpu, dstaddr, FOLL_WRITE);
 	if (rc != 0)
 		return rc;
 
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index bdbb143a75c9..d8c8e91356ca 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -4795,8 +4795,17 @@ static void kvm_s390_assert_primary_as(struct kvm_vcpu *vcpu)
 		current->thread.gmap_int_code, current->thread.gmap_teid.val);
 }
 
-static int kvm_s390_handle_dat_fault(struct kvm_vcpu *vcpu, gfn_t gfn, gpa_t gaddr,
-				     unsigned int flags)
+/*
+ * __kvm_s390_handle_dat_fault() - handle a dat fault for the gmap of a vcpu
+ * @vcpu: the vCPU whose gmap is to be fixed up
+ * @gfn: the guest frame number used for memslots (including fake memslots)
+ * @gaddr: the gmap address, does not have to match @gfn for ucontrol gmaps
+ * @flags: FOLL_* flags
+ *
+ * Return: 0 on success, < 0 in case or error.
+ * Context: The mm lock must not be held before calling.
+ */
+int __kvm_s390_handle_dat_fault(struct kvm_vcpu *vcpu, gfn_t gfn, gpa_t gaddr, unsigned int flags)
 {
 	struct kvm_memory_slot *slot;
 	unsigned int fault_flags;
@@ -4925,7 +4934,7 @@ static int vcpu_post_run_handle_fault(struct kvm_vcpu *vcpu)
 			}
 			gfn = gpa_to_gfn(gaddr_tmp);
 		}
-		return kvm_s390_handle_dat_fault(vcpu, gfn, gaddr, flags);
+		return __kvm_s390_handle_dat_fault(vcpu, gfn, gaddr, flags);
 		break;
 	default:
 		KVM_BUG(1, vcpu->kvm, "Unexpected program interrupt 0x%x, TEID 0x%016lx",
@@ -5818,7 +5827,7 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
 	}
 #endif
 	case KVM_S390_VCPU_FAULT: {
-		r = gmap_fault(vcpu->arch.gmap, arg, 0);
+		r = kvm_s390_handle_dat_fault(vcpu, arg, 0);
 		break;
 	}
 	case KVM_ENABLE_CAP:
diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h
index 597d7a71deeb..7f4b5ef80a6f 100644
--- a/arch/s390/kvm/kvm-s390.h
+++ b/arch/s390/kvm/kvm-s390.h
@@ -408,6 +408,13 @@ void kvm_s390_vcpu_unsetup_cmma(struct kvm_vcpu *vcpu);
 void kvm_s390_set_cpu_timer(struct kvm_vcpu *vcpu, __u64 cputm);
 __u64 kvm_s390_get_cpu_timer(struct kvm_vcpu *vcpu);
 int kvm_s390_cpus_from_pv(struct kvm *kvm, u16 *rc, u16 *rrc);
+int __kvm_s390_handle_dat_fault(struct kvm_vcpu *vcpu, gfn_t gfn, gpa_t gaddr, unsigned int flags);
+
+static inline int kvm_s390_handle_dat_fault(struct kvm_vcpu *vcpu, gpa_t gaddr, unsigned int flags)
+{
+	return __kvm_s390_handle_dat_fault(vcpu, gpa_to_gfn(gaddr), gaddr, flags);
+}
+
 
 /* implemented in diag.c */
 int kvm_s390_handle_diag(struct kvm_vcpu *vcpu);
diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
index 3aacef77c174..8da4f7438511 100644
--- a/arch/s390/mm/gmap.c
+++ b/arch/s390/mm/gmap.c
@@ -607,130 +607,6 @@ int __gmap_link(struct gmap *gmap, unsigned long gaddr, unsigned long vmaddr)
 }
 EXPORT_SYMBOL(__gmap_link);
 
-/**
- * fixup_user_fault_nowait - manually resolve a user page fault without waiting
- * @mm:		mm_struct of target mm
- * @address:	user address
- * @fault_flags:flags to pass down to handle_mm_fault()
- * @unlocked:	did we unlock the mmap_lock while retrying
- *
- * This function behaves similarly to fixup_user_fault(), but it guarantees
- * that the fault will be resolved without waiting. The function might drop
- * and re-acquire the mm lock, in which case @unlocked will be set to true.
- *
- * The guarantee is that the fault is handled without waiting, but the
- * function itself might sleep, due to the lock.
- *
- * Context: Needs to be called with mm->mmap_lock held in read mode, and will
- * return with the lock held in read mode; @unlocked will indicate whether
- * the lock has been dropped and re-acquired. This is the same behaviour as
- * fixup_user_fault().
- *
- * Return: 0 on success, -EAGAIN if the fault cannot be resolved without
- * waiting, -EFAULT if the fault cannot be resolved, -ENOMEM if out of
- * memory.
- */
-static int fixup_user_fault_nowait(struct mm_struct *mm, unsigned long address,
-				   unsigned int fault_flags, bool *unlocked)
-{
-	struct vm_area_struct *vma;
-	unsigned int test_flags;
-	vm_fault_t fault;
-	int rc;
-
-	fault_flags |= FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_RETRY_NOWAIT;
-	test_flags = fault_flags & FAULT_FLAG_WRITE ? VM_WRITE : VM_READ;
-
-	vma = find_vma(mm, address);
-	if (unlikely(!vma || address < vma->vm_start))
-		return -EFAULT;
-	if (unlikely(!(vma->vm_flags & test_flags)))
-		return -EFAULT;
-
-	fault = handle_mm_fault(vma, address, fault_flags, NULL);
-	/* the mm lock has been dropped, take it again */
-	if (fault & VM_FAULT_COMPLETED) {
-		*unlocked = true;
-		mmap_read_lock(mm);
-		return 0;
-	}
-	/* the mm lock has not been dropped */
-	if (fault & VM_FAULT_ERROR) {
-		rc = vm_fault_to_errno(fault, 0);
-		BUG_ON(!rc);
-		return rc;
-	}
-	/* the mm lock has not been dropped because of FAULT_FLAG_RETRY_NOWAIT */
-	if (fault & VM_FAULT_RETRY)
-		return -EAGAIN;
-	/* nothing needed to be done and the mm lock has not been dropped */
-	return 0;
-}
-
-/**
- * __gmap_fault - resolve a fault on a guest address
- * @gmap: pointer to guest mapping meta data structure
- * @gaddr: guest address
- * @fault_flags: flags to pass down to handle_mm_fault()
- *
- * Context: Needs to be called with mm->mmap_lock held in read mode. Might
- * drop and re-acquire the lock. Will always return with the lock held.
- */
-static int __gmap_fault(struct gmap *gmap, unsigned long gaddr, unsigned int fault_flags)
-{
-	unsigned long vmaddr;
-	bool unlocked;
-	int rc = 0;
-
-retry:
-	unlocked = false;
-
-	vmaddr = __gmap_translate(gmap, gaddr);
-	if (IS_ERR_VALUE(vmaddr))
-		return vmaddr;
-
-	if (fault_flags & FAULT_FLAG_RETRY_NOWAIT)
-		rc = fixup_user_fault_nowait(gmap->mm, vmaddr, fault_flags, &unlocked);
-	else
-		rc = fixup_user_fault(gmap->mm, vmaddr, fault_flags, &unlocked);
-	if (rc)
-		return rc;
-	/*
-	 * In the case that fixup_user_fault unlocked the mmap_lock during
-	 * fault-in, redo __gmap_translate() to avoid racing with a
-	 * map/unmap_segment.
-	 * In particular, __gmap_translate(), fixup_user_fault{,_nowait}(),
-	 * and __gmap_link() must all be called atomically in one go; if the
-	 * lock had been dropped in between, a retry is needed.
-	 */
-	if (unlocked)
-		goto retry;
-
-	return __gmap_link(gmap, gaddr, vmaddr);
-}
-
-/**
- * gmap_fault - resolve a fault on a guest address
- * @gmap: pointer to guest mapping meta data structure
- * @gaddr: guest address
- * @fault_flags: flags to pass down to handle_mm_fault()
- *
- * Returns 0 on success, -ENOMEM for out of memory conditions, -EFAULT if the
- * vm address is already mapped to a different guest segment, and -EAGAIN if
- * FAULT_FLAG_RETRY_NOWAIT was specified and the fault could not be processed
- * immediately.
- */
-int gmap_fault(struct gmap *gmap, unsigned long gaddr, unsigned int fault_flags)
-{
-	int rc;
-
-	mmap_read_lock(gmap->mm);
-	rc = __gmap_fault(gmap, gaddr, fault_flags);
-	mmap_read_unlock(gmap->mm);
-	return rc;
-}
-EXPORT_SYMBOL_GPL(gmap_fault);
-
 /*
  * this function is assumed to be called with mmap_lock held
  */
-- 
2.47.1