KVM: s390: move gmap_shadow_pgt_lookup() into kvm

Claudio Imbrenda · Claudio Imbrenda · commit 43656f774a4b · 2025-01-31T12:03:53.000+01:00
Move gmap_shadow_pgt_lookup() from mm/gmap.c into kvm/gaccess.c . Reviewed-by: Steffen Eiden <seiden@linux.ibm.com> Reviewed-by: Janosch Frank <frankja@linux.ibm.com> Reviewed-by: Christoph Schlameuss <schlameuss@linux.ibm.com> Link: https://lore.kernel.org/r/20250123144627.312456-13-imbrenda@linux.ibm.com Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com> Message-ID: <20250123144627.312456-13-imbrenda@linux.ibm.com>
diff --git a/arch/s390/include/asm/gmap.h b/arch/s390/include/asm/gmap.h
@@ -125,8 +125,6 @@ int gmap_shadow_sgt(struct gmap *sg, unsigned long saddr, unsigned long sgt,
 		    int fake);
 int gmap_shadow_pgt(struct gmap *sg, unsigned long saddr, unsigned long pgt,
 		    int fake);
-int gmap_shadow_pgt_lookup(struct gmap *sg, unsigned long saddr,
-			   unsigned long *pgt, int *dat_protection, int *fake);
 int gmap_shadow_page(struct gmap *sg, unsigned long saddr, pte_t pte);
 
 void gmap_register_pte_notifier(struct gmap_notifier *);
@@ -142,6 +140,7 @@ void s390_uv_destroy_pfns(unsigned long count, unsigned long *pfns);
 int __s390_uv_destroy_range(struct mm_struct *mm, unsigned long start,
 			    unsigned long end, bool interruptible);
 int kvm_s390_wiggle_split_folio(struct mm_struct *mm, struct folio *folio, bool split);
+unsigned long *gmap_table_walk(struct gmap *gmap, unsigned long gaddr, int level);
 
 /**
  * s390_uv_destroy_range - Destroy a range of pages in the given mm.
diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c
@@ -16,6 +16,7 @@
 #include <asm/gmap.h>
 #include <asm/dat-bits.h>
 #include "kvm-s390.h"
+#include "gmap.h"
 #include "gaccess.h"
 
 /*
@@ -1392,6 +1393,42 @@ static int kvm_s390_shadow_tables(struct gmap *sg, unsigned long saddr,
 	return 0;
 }
 
+/**
+ * shadow_pgt_lookup() - find a shadow page table
+ * @sg: pointer to the shadow guest address space structure
+ * @saddr: the address in the shadow aguest address space
+ * @pgt: parent gmap address of the page table to get shadowed
+ * @dat_protection: if the pgtable is marked as protected by dat
+ * @fake: pgt references contiguous guest memory block, not a pgtable
+ *
+ * Returns 0 if the shadow page table was found and -EAGAIN if the page
+ * table was not found.
+ *
+ * Called with sg->mm->mmap_lock in read.
+ */
+static int shadow_pgt_lookup(struct gmap *sg, unsigned long saddr, unsigned long *pgt,
+			     int *dat_protection, int *fake)
+{
+	unsigned long *table;
+	struct page *page;
+	int rc;
+
+	spin_lock(&sg->guest_table_lock);
+	table = gmap_table_walk(sg, saddr, 1); /* get segment pointer */
+	if (table && !(*table & _SEGMENT_ENTRY_INVALID)) {
+		/* Shadow page tables are full pages (pte+pgste) */
+		page = pfn_to_page(*table >> PAGE_SHIFT);
+		*pgt = page->index & ~GMAP_SHADOW_FAKE_TABLE;
+		*dat_protection = !!(*table & _SEGMENT_ENTRY_PROTECT);
+		*fake = !!(page->index & GMAP_SHADOW_FAKE_TABLE);
+		rc = 0;
+	} else  {
+		rc = -EAGAIN;
+	}
+	spin_unlock(&sg->guest_table_lock);
+	return rc;
+}
+
 /**
  * kvm_s390_shadow_fault - handle fault on a shadow page table
  * @vcpu: virtual cpu
@@ -1415,6 +1452,9 @@ int kvm_s390_shadow_fault(struct kvm_vcpu *vcpu, struct gmap *sg,
 	int dat_protection, fake;
 	int rc;
 
+	if (KVM_BUG_ON(!gmap_is_shadow(sg), vcpu->kvm))
+		return -EFAULT;
+
 	mmap_read_lock(sg->mm);
 	/*
 	 * We don't want any guest-2 tables to change - so the parent
@@ -1423,7 +1463,7 @@ int kvm_s390_shadow_fault(struct kvm_vcpu *vcpu, struct gmap *sg,
 	 */
 	ipte_lock(vcpu->kvm);
 
-	rc = gmap_shadow_pgt_lookup(sg, saddr, &pgt, &dat_protection, &fake);
+	rc = shadow_pgt_lookup(sg, saddr, &pgt, &dat_protection, &fake);
 	if (rc)
 		rc = kvm_s390_shadow_tables(sg, saddr, &pgt, &dat_protection,
 					    &fake);
diff --git a/arch/s390/kvm/gmap.h b/arch/s390/kvm/gmap.h
@@ -10,6 +10,8 @@
 #ifndef ARCH_KVM_S390_GMAP_H
 #define ARCH_KVM_S390_GMAP_H
 
+#define GMAP_SHADOW_FAKE_TABLE 1ULL
+
 int gmap_make_secure(struct gmap *gmap, unsigned long gaddr, void *uvcb);
 int gmap_convert_to_secure(struct gmap *gmap, unsigned long gaddr);
 int gmap_destroy_page(struct gmap *gmap, unsigned long gaddr);
diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
@@ -36,8 +36,6 @@
 
 #define GMAP_SHADOW_FAKE_TABLE 1ULL
 
-static inline unsigned long *gmap_table_walk(struct gmap *gmap, unsigned long gaddr, int level);
-
 static struct page *gmap_alloc_crst(void)
 {
 	struct page *page;
@@ -738,8 +736,7 @@ static void gmap_call_notifier(struct gmap *gmap, unsigned long start,
  *
  * Note: Can also be called for shadow gmaps.
  */
-static inline unsigned long *gmap_table_walk(struct gmap *gmap,
-					     unsigned long gaddr, int level)
+unsigned long *gmap_table_walk(struct gmap *gmap, unsigned long gaddr, int level)
 {
 	const int asce_type = gmap->asce & _ASCE_TYPE_MASK;
 	unsigned long *table = gmap->table;
@@ -790,6 +787,7 @@ static inline unsigned long *gmap_table_walk(struct gmap *gmap,
 	}
 	return table;
 }
+EXPORT_SYMBOL(gmap_table_walk);
 
 /**
  * gmap_pte_op_walk - walk the gmap page table, get the page table lock
@@ -1744,46 +1742,6 @@ int gmap_shadow_sgt(struct gmap *sg, unsigned long saddr, unsigned long sgt,
 }
 EXPORT_SYMBOL_GPL(gmap_shadow_sgt);
 
-/**
- * gmap_shadow_pgt_lookup - find a shadow page table
- * @sg: pointer to the shadow guest address space structure
- * @saddr: the address in the shadow aguest address space
- * @pgt: parent gmap address of the page table to get shadowed
- * @dat_protection: if the pgtable is marked as protected by dat
- * @fake: pgt references contiguous guest memory block, not a pgtable
- *
- * Returns 0 if the shadow page table was found and -EAGAIN if the page
- * table was not found.
- *
- * Called with sg->mm->mmap_lock in read.
- */
-int gmap_shadow_pgt_lookup(struct gmap *sg, unsigned long saddr,
-			   unsigned long *pgt, int *dat_protection,
-			   int *fake)
-{
-	unsigned long *table;
-	struct page *page;
-	int rc;
-
-	BUG_ON(!gmap_is_shadow(sg));
-	spin_lock(&sg->guest_table_lock);
-	table = gmap_table_walk(sg, saddr, 1); /* get segment pointer */
-	if (table && !(*table & _SEGMENT_ENTRY_INVALID)) {
-		/* Shadow page tables are full pages (pte+pgste) */
-		page = pfn_to_page(*table >> PAGE_SHIFT);
-		*pgt = page->index & ~GMAP_SHADOW_FAKE_TABLE;
-		*dat_protection = !!(*table & _SEGMENT_ENTRY_PROTECT);
-		*fake = !!(page->index & GMAP_SHADOW_FAKE_TABLE);
-		rc = 0;
-	} else  {
-		rc = -EAGAIN;
-	}
-	spin_unlock(&sg->guest_table_lock);
-	return rc;
-
-}
-EXPORT_SYMBOL_GPL(gmap_shadow_pgt_lookup);
-
 /**
  * gmap_shadow_pgt - instantiate a shadow page table
  * @sg: pointer to the shadow guest address space structure
