diff mbox

[v6,09/12] s390/mm: Add huge pmd storage key handling

Message ID 20180713063702.54628-10-frankja@linux.ibm.com (mailing list archive)
State New, archived
Headers show

Commit Message

Janosch Frank July 13, 2018, 6:36 a.m. UTC 
From: Janosch Frank <frankja@linux.vnet.ibm.com>

Storage keys for guests with huge page mappings have to be managed in
hardware. There are no PGSTEs for PMDs that we could use to retain the
guests's logical view of the key.

Signed-off-by: Janosch Frank <frankja@linux.vnet.ibm.com>
---
 arch/s390/mm/pgtable.c | 87 +++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 76 insertions(+), 11 deletions(-)

Comments

David Hildenbrand July 13, 2018, 8:58 a.m. UTC | #1 
On 13.07.2018 08:36, Janosch Frank wrote:
> From: Janosch Frank <frankja@linux.vnet.ibm.com>
> 
> Storage keys for guests with huge page mappings have to be managed in
> hardware. There are no PGSTEs for PMDs that we could use to retain the
> guests's logical view of the key.
> 
> Signed-off-by: Janosch Frank <frankja@linux.vnet.ibm.com>
> ---
>  arch/s390/mm/pgtable.c | 87 +++++++++++++++++++++++++++++++++++++++++++-------
>  1 file changed, 76 insertions(+), 11 deletions(-)
> 
> diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
> index 6550ed56fcdf..161e08437681 100644
> --- a/arch/s390/mm/pgtable.c
> +++ b/arch/s390/mm/pgtable.c
> @@ -18,6 +18,7 @@
>  #include <linux/sysctl.h>
>  #include <linux/ksm.h>
>  #include <linux/mman.h>
> +#include <linux/hugetlb.h>
>  
>  #include <asm/pgtable.h>
>  #include <asm/pgalloc.h>
> @@ -782,12 +783,35 @@ EXPORT_SYMBOL_GPL(test_and_clear_guest_dirty);
>  int set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
>  			  unsigned char key, bool nq)
>  {
> -	unsigned long keyul;
> +	unsigned long keyul, paddr;
>  	spinlock_t *ptl;
>  	pgste_t old, new;
> +	pmd_t *pmdp;
>  	pte_t *ptep;
>  
> -	ptep = get_locked_pte(mm, addr, &ptl);
> +	pmdp = (pmd_t *)huge_pte_offset(mm, addr, HPAGE_SIZE);
> +	if (!pmdp)
> +		return -EFAULT;
> +
> +	ptl = pmd_lock(mm, pmdp);
> +	if (!pmd_present(*pmdp)) {
> +		spin_unlock(ptl);
> +		return -EFAULT;
> +	}
> +	if (pmd_large(*pmdp)) {
> +		paddr = pmd_val(*pmdp) & HPAGE_MASK;
> +		paddr |= addr & ~HPAGE_MASK;
> +		/*
> +		 * Huge pmds need quiescing operations, they are
> +		 * always mapped.
> +		 */
> +		page_set_storage_key(paddr, key, 1);
> +		spin_unlock(ptl);
> +		return 0;
> +	}
> +	spin_unlock(ptl);
> +
> +	ptep = pte_alloc_map_lock(mm, pmdp, addr, &ptl);
>  	if (unlikely(!ptep))
>  		return -EFAULT;
>  
> @@ -798,14 +822,14 @@ int set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
>  	pgste_val(new) |= (keyul & (_PAGE_CHANGED | _PAGE_REFERENCED)) << 48;
>  	pgste_val(new) |= (keyul & (_PAGE_ACC_BITS | _PAGE_FP_BIT)) << 56;
>  	if (!(pte_val(*ptep) & _PAGE_INVALID)) {
> -		unsigned long address, bits, skey;
> +		unsigned long bits, skey;
>  
> -		address = pte_val(*ptep) & PAGE_MASK;
> -		skey = (unsigned long) page_get_storage_key(address);
> +		paddr = pte_val(*ptep) & PAGE_MASK;
> +		skey = (unsigned long) page_get_storage_key(paddr);
>  		bits = skey & (_PAGE_CHANGED | _PAGE_REFERENCED);
>  		skey = key & (_PAGE_ACC_BITS | _PAGE_FP_BIT);
>  		/* Set storage key ACC and FP */
> -		page_set_storage_key(address, skey, !nq);
> +		page_set_storage_key(paddr, skey, !nq);
>  		/* Merge host changed & referenced into pgste  */
>  		pgste_val(new) |= bits << 52;
>  	}
> @@ -861,20 +885,40 @@ EXPORT_SYMBOL(cond_set_guest_storage_key);
>  int reset_guest_reference_bit(struct mm_struct *mm, unsigned long addr)
>  {
>  	spinlock_t *ptl;
> +	unsigned long paddr;
>  	pgste_t old, new;
> +	pmd_t *pmdp;
>  	pte_t *ptep;
>  	int cc = 0;
>  
> -	ptep = get_locked_pte(mm, addr, &ptl);
> -	if (unlikely(!ptep))
> +	pmdp = (pmd_t *)huge_pte_offset(mm, addr, HPAGE_SIZE);
> +	if (!pmdp)
>  		return -EFAULT;
>  
> +	ptl = pmd_lock(mm, pmdp);
> +	if (!pmd_present(*pmdp)) {
> +		spin_unlock(ptl);
> +		return -EFAULT;
> +	}
> +	if (pmd_large(*pmdp)) {
> +		paddr = pmd_val(*pmdp) & HPAGE_MASK;
> +		paddr |= addr & ~HPAGE_MASK;
> +		cc = page_reset_referenced(paddr);
> +		spin_unlock(ptl);
> +		return cc;
> +	}
> +	spin_unlock(ptl);
> +
> +	ptep = pte_alloc_map_lock(mm, pmdp, addr, &ptl);
> +	if (unlikely(!ptep))
> +		return -EFAULT;
>  	new = old = pgste_get_lock(ptep);
>  	/* Reset guest reference bit only */
>  	pgste_val(new) &= ~PGSTE_GR_BIT;
>  
>  	if (!(pte_val(*ptep) & _PAGE_INVALID)) {
> -		cc = page_reset_referenced(pte_val(*ptep) & PAGE_MASK);
> +		paddr = pte_val(*ptep) & PAGE_MASK;
> +		cc = page_reset_referenced(paddr);
>  		/* Merge real referenced bit into host-set */
>  		pgste_val(new) |= ((unsigned long) cc << 53) & PGSTE_HR_BIT;
>  	}
> @@ -893,18 +937,39 @@ EXPORT_SYMBOL(reset_guest_reference_bit);
>  int get_guest_storage_key(struct mm_struct *mm, unsigned long addr,
>  			  unsigned char *key)
>  {
> +	unsigned long paddr;
>  	spinlock_t *ptl;
>  	pgste_t pgste;
> +	pmd_t *pmdp;
>  	pte_t *ptep;
>  
> -	ptep = get_locked_pte(mm, addr, &ptl);
> +	pmdp = (pmd_t *)huge_pte_offset(mm, addr, HPAGE_SIZE);
> +	if (!pmdp)
> +		return -EFAULT;
> +
> +	ptl = pmd_lock(mm, pmdp);
> +	if (!pmd_present(*pmdp)) {
> +		spin_unlock(ptl);
> +		return -EFAULT;
> +	}
> +	if (pmd_large(*pmdp)) {
> +		paddr = pmd_val(*pmdp) & HPAGE_MASK;
> +		paddr |= addr & ~HPAGE_MASK;
> +		*key = page_get_storage_key(paddr);
> +		spin_unlock(ptl);
> +		return 0;
> +	}
> +	spin_unlock(ptl);
> +
> +	ptep = pte_alloc_map_lock(mm, pmdp, addr, &ptl);
>  	if (unlikely(!ptep))
>  		return -EFAULT;
>  
>  	pgste = pgste_get_lock(ptep);
>  	*key = (pgste_val(pgste) & (PGSTE_ACC_BITS | PGSTE_FP_BIT)) >> 56;
> +	paddr = pte_val(*ptep) & PAGE_MASK;
>  	if (!(pte_val(*ptep) & _PAGE_INVALID))
> -		*key = page_get_storage_key(pte_val(*ptep) & PAGE_MASK);
> +		*key = page_get_storage_key(paddr);
>  	/* Reflect guest's logical view, not physical */
>  	*key |= (pgste_val(pgste) & (PGSTE_GR_BIT | PGSTE_GC_BIT)) >> 48;
>  	pgste_set_unlock(ptep, pgste);
> 


From what I can tell, this looks good to me.
diff mbox

Patch

diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
index 6550ed56fcdf..161e08437681 100644
--- a/arch/s390/mm/pgtable.c
+++ b/arch/s390/mm/pgtable.c
@@ -18,6 +18,7 @@ 
 #include <linux/sysctl.h>
 #include <linux/ksm.h>
 #include <linux/mman.h>
+#include <linux/hugetlb.h>
 
 #include <asm/pgtable.h>
 #include <asm/pgalloc.h>
@@ -782,12 +783,35 @@  EXPORT_SYMBOL_GPL(test_and_clear_guest_dirty);
 int set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
 			  unsigned char key, bool nq)
 {
-	unsigned long keyul;
+	unsigned long keyul, paddr;
 	spinlock_t *ptl;
 	pgste_t old, new;
+	pmd_t *pmdp;
 	pte_t *ptep;
 
-	ptep = get_locked_pte(mm, addr, &ptl);
+	pmdp = (pmd_t *)huge_pte_offset(mm, addr, HPAGE_SIZE);
+	if (!pmdp)
+		return -EFAULT;
+
+	ptl = pmd_lock(mm, pmdp);
+	if (!pmd_present(*pmdp)) {
+		spin_unlock(ptl);
+		return -EFAULT;
+	}
+	if (pmd_large(*pmdp)) {
+		paddr = pmd_val(*pmdp) & HPAGE_MASK;
+		paddr |= addr & ~HPAGE_MASK;
+		/*
+		 * Huge pmds need quiescing operations, they are
+		 * always mapped.
+		 */
+		page_set_storage_key(paddr, key, 1);
+		spin_unlock(ptl);
+		return 0;
+	}
+	spin_unlock(ptl);
+
+	ptep = pte_alloc_map_lock(mm, pmdp, addr, &ptl);
 	if (unlikely(!ptep))
 		return -EFAULT;
 
@@ -798,14 +822,14 @@  int set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
 	pgste_val(new) |= (keyul & (_PAGE_CHANGED | _PAGE_REFERENCED)) << 48;
 	pgste_val(new) |= (keyul & (_PAGE_ACC_BITS | _PAGE_FP_BIT)) << 56;
 	if (!(pte_val(*ptep) & _PAGE_INVALID)) {
-		unsigned long address, bits, skey;
+		unsigned long bits, skey;
 
-		address = pte_val(*ptep) & PAGE_MASK;
-		skey = (unsigned long) page_get_storage_key(address);
+		paddr = pte_val(*ptep) & PAGE_MASK;
+		skey = (unsigned long) page_get_storage_key(paddr);
 		bits = skey & (_PAGE_CHANGED | _PAGE_REFERENCED);
 		skey = key & (_PAGE_ACC_BITS | _PAGE_FP_BIT);
 		/* Set storage key ACC and FP */
-		page_set_storage_key(address, skey, !nq);
+		page_set_storage_key(paddr, skey, !nq);
 		/* Merge host changed & referenced into pgste  */
 		pgste_val(new) |= bits << 52;
 	}
@@ -861,20 +885,40 @@  EXPORT_SYMBOL(cond_set_guest_storage_key);
 int reset_guest_reference_bit(struct mm_struct *mm, unsigned long addr)
 {
 	spinlock_t *ptl;
+	unsigned long paddr;
 	pgste_t old, new;
+	pmd_t *pmdp;
 	pte_t *ptep;
 	int cc = 0;
 
-	ptep = get_locked_pte(mm, addr, &ptl);
-	if (unlikely(!ptep))
+	pmdp = (pmd_t *)huge_pte_offset(mm, addr, HPAGE_SIZE);
+	if (!pmdp)
 		return -EFAULT;
 
+	ptl = pmd_lock(mm, pmdp);
+	if (!pmd_present(*pmdp)) {
+		spin_unlock(ptl);
+		return -EFAULT;
+	}
+	if (pmd_large(*pmdp)) {
+		paddr = pmd_val(*pmdp) & HPAGE_MASK;
+		paddr |= addr & ~HPAGE_MASK;
+		cc = page_reset_referenced(paddr);
+		spin_unlock(ptl);
+		return cc;
+	}
+	spin_unlock(ptl);
+
+	ptep = pte_alloc_map_lock(mm, pmdp, addr, &ptl);
+	if (unlikely(!ptep))
+		return -EFAULT;
 	new = old = pgste_get_lock(ptep);
 	/* Reset guest reference bit only */
 	pgste_val(new) &= ~PGSTE_GR_BIT;
 
 	if (!(pte_val(*ptep) & _PAGE_INVALID)) {
-		cc = page_reset_referenced(pte_val(*ptep) & PAGE_MASK);
+		paddr = pte_val(*ptep) & PAGE_MASK;
+		cc = page_reset_referenced(paddr);
 		/* Merge real referenced bit into host-set */
 		pgste_val(new) |= ((unsigned long) cc << 53) & PGSTE_HR_BIT;
 	}
@@ -893,18 +937,39 @@  EXPORT_SYMBOL(reset_guest_reference_bit);
 int get_guest_storage_key(struct mm_struct *mm, unsigned long addr,
 			  unsigned char *key)
 {
+	unsigned long paddr;
 	spinlock_t *ptl;
 	pgste_t pgste;
+	pmd_t *pmdp;
 	pte_t *ptep;
 
-	ptep = get_locked_pte(mm, addr, &ptl);
+	pmdp = (pmd_t *)huge_pte_offset(mm, addr, HPAGE_SIZE);
+	if (!pmdp)
+		return -EFAULT;
+
+	ptl = pmd_lock(mm, pmdp);
+	if (!pmd_present(*pmdp)) {
+		spin_unlock(ptl);
+		return -EFAULT;
+	}
+	if (pmd_large(*pmdp)) {
+		paddr = pmd_val(*pmdp) & HPAGE_MASK;
+		paddr |= addr & ~HPAGE_MASK;
+		*key = page_get_storage_key(paddr);
+		spin_unlock(ptl);
+		return 0;
+	}
+	spin_unlock(ptl);
+
+	ptep = pte_alloc_map_lock(mm, pmdp, addr, &ptl);
 	if (unlikely(!ptep))
 		return -EFAULT;
 
 	pgste = pgste_get_lock(ptep);
 	*key = (pgste_val(pgste) & (PGSTE_ACC_BITS | PGSTE_FP_BIT)) >> 56;
+	paddr = pte_val(*ptep) & PAGE_MASK;
 	if (!(pte_val(*ptep) & _PAGE_INVALID))
-		*key = page_get_storage_key(pte_val(*ptep) & PAGE_MASK);
+		*key = page_get_storage_key(paddr);
 	/* Reflect guest's logical view, not physical */
 	*key |= (pgste_val(pgste) & (PGSTE_GR_BIT | PGSTE_GC_BIT)) >> 48;
 	pgste_set_unlock(ptep, pgste);