From 338679f7ba4a81906b3fdfa6507824fdf704be80 Mon Sep 17 00:00:00 2001 From: Christian Borntraeger Date: Tue, 4 Jun 2013 09:53:59 +0200 Subject: s390/pgtable: Fix guest overindication for change bit When doing the transition invalid->valid in the host page table for a guest, then the guest view of C/R is in the pgste. After validation the view is pgste OR real key. We must zero out the real key C/R to avoid guest over-indication for change (and reference). Touching the real key is ok also for the host: The change bit is tracked via write protection and the reference bit is also ok because set_pte_at was called and the page will be touched anyway soon. Furthermore architecture defines reference as "substantially accurate", over- and underindication are ok. Signed-off-by: Christian Borntraeger Signed-off-by: Martin Schwidefsky --- arch/s390/include/asm/pgtable.h | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) (limited to 'arch/s390/include/asm/pgtable.h') diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h index ac01463038f1..391e592356d0 100644 --- a/arch/s390/include/asm/pgtable.h +++ b/arch/s390/include/asm/pgtable.h @@ -704,17 +704,19 @@ static inline void pgste_set_key(pte_t *ptep, pgste_t pgste, pte_t entry) { #ifdef CONFIG_PGSTE unsigned long address; - unsigned long okey, nkey; + unsigned long nkey; if (pte_val(entry) & _PAGE_INVALID) return; + VM_BUG_ON(!(pte_val(*ptep) & _PAGE_INVALID)); address = pte_val(entry) & PAGE_MASK; - okey = nkey = page_get_storage_key(address); - nkey &= ~(_PAGE_ACC_BITS | _PAGE_FP_BIT); - /* Set page access key and fetch protection bit from pgste */ - nkey |= (pgste_val(pgste) & (RCP_ACC_BITS | RCP_FP_BIT)) >> 56; - if (okey != nkey) - page_set_storage_key(address, nkey, 0); + /* + * Set page access key and fetch protection bit from pgste. + * The guest C/R information is still in the PGSTE, set real + * key C/R to 0. + */ + nkey = (pgste_val(pgste) & (RCP_ACC_BITS | RCP_FP_BIT)) >> 56; + page_set_storage_key(address, nkey, 0); #endif } -- cgit v1.2.3-70-g09d2 From 3a82603be4f5523ce21dd468a323aa36ff845f6d Mon Sep 17 00:00:00 2001 From: Christian Borntraeger Date: Wed, 5 Jun 2013 09:22:33 +0200 Subject: s390/pgtable: Save pgste during modify_prot_start/commit In modify_prot_start we update the pgste value but never store it back into the original location. Lets save the calculated result, since modify_prot_commit will use the value of the pgste. Signed-off-by: Christian Borntraeger Signed-off-by: Martin Schwidefsky --- arch/s390/include/asm/pgtable.h | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) (limited to 'arch/s390/include/asm/pgtable.h') diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h index 391e592356d0..f9a0a70dc936 100644 --- a/arch/s390/include/asm/pgtable.h +++ b/arch/s390/include/asm/pgtable.h @@ -640,6 +640,13 @@ static inline void pgste_set_unlock(pte_t *ptep, pgste_t pgste) #endif } +static inline void pgste_set(pte_t *ptep, pgste_t pgste) +{ +#ifdef CONFIG_PGSTE + *(pgste_t *)(ptep + PTRS_PER_PTE) = pgste; +#endif +} + static inline pgste_t pgste_update_all(pte_t *ptep, pgste_t pgste) { #ifdef CONFIG_PGSTE @@ -1101,8 +1108,10 @@ static inline pte_t ptep_modify_prot_start(struct mm_struct *mm, if (!mm_exclusive(mm)) __ptep_ipte(address, ptep); - if (mm_has_pgste(mm)) + if (mm_has_pgste(mm)) { pgste = pgste_update_all(&pte, pgste); + pgste_set(ptep, pgste); + } return pte; } -- cgit v1.2.3-70-g09d2 From a8f6e7f7953d1baa05a346bf7cee44f1d022c63d Mon Sep 17 00:00:00 2001 From: Christian Borntraeger Date: Wed, 5 Jun 2013 09:25:34 +0200 Subject: s390/pgtable: make pgste lock an explicit barrier Getting and Releasing the pgste lock has lock semantics. Make the code an explicit barrier. Signed-off-by: Christian Borntraeger Signed-off-by: Martin Schwidefsky --- arch/s390/include/asm/pgtable.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'arch/s390/include/asm/pgtable.h') diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h index f9a0a70dc936..e8b6e5b8932c 100644 --- a/arch/s390/include/asm/pgtable.h +++ b/arch/s390/include/asm/pgtable.h @@ -623,7 +623,7 @@ static inline pgste_t pgste_get_lock(pte_t *ptep) " csg %0,%1,%2\n" " jl 0b\n" : "=&d" (old), "=&d" (new), "=Q" (ptep[PTRS_PER_PTE]) - : "Q" (ptep[PTRS_PER_PTE]) : "cc"); + : "Q" (ptep[PTRS_PER_PTE]) : "cc", "memory"); #endif return __pgste(new); } @@ -635,7 +635,8 @@ static inline void pgste_set_unlock(pte_t *ptep, pgste_t pgste) " nihh %1,0xff7f\n" /* clear RCP_PCL_BIT */ " stg %1,%0\n" : "=Q" (ptep[PTRS_PER_PTE]) - : "d" (pgste_val(pgste)), "Q" (ptep[PTRS_PER_PTE]) : "cc"); + : "d" (pgste_val(pgste)), "Q" (ptep[PTRS_PER_PTE]) + : "cc", "memory"); preempt_enable(); #endif } -- cgit v1.2.3-70-g09d2