From a9d23e71d7716e394a772686bfd994f4e181b235 Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Tue, 8 Mar 2016 12:21:41 +0100 Subject: [PATCH] s390/mm: shadow pages with real guest requested protection We really want to avoid manually handling protection for nested virtualization. By shadowing pages with the protection the guest asked us for, the SIE can handle most protection-related actions for us (e.g. special handling for MVPG) and we can directly forward protection exceptions to the guest. PTEs will now always be shadowed with the correct _PAGE_PROTECT flag. Unshadowing will take care of any guest changes to the parent PTE and any host changes to the host PTE. If the host PTE doesn't have the fitting access rights or is not available, we have to fix it up. Acked-by: Martin Schwidefsky Signed-off-by: David Hildenbrand Signed-off-by: Christian Borntraeger --- arch/s390/include/asm/gmap.h | 3 +-- arch/s390/include/asm/pgtable.h | 2 +- arch/s390/kvm/gaccess.c | 2 +- arch/s390/mm/gmap.c | 12 +++++------- arch/s390/mm/pgtable.c | 16 +++++++--------- 5 files changed, 15 insertions(+), 20 deletions(-) diff --git a/arch/s390/include/asm/gmap.h b/arch/s390/include/asm/gmap.h index 58e65ee5b2d2..4a47055f58d7 100644 --- a/arch/s390/include/asm/gmap.h +++ b/arch/s390/include/asm/gmap.h @@ -110,8 +110,7 @@ int gmap_shadow_sgt(struct gmap *sg, unsigned long saddr, unsigned long sgt); int gmap_shadow_pgt(struct gmap *sg, unsigned long saddr, unsigned long pgt); int gmap_shadow_pgt_lookup(struct gmap *sg, unsigned long saddr, unsigned long *pgt, int *dat_protection); -int gmap_shadow_page(struct gmap *sg, unsigned long saddr, - unsigned long paddr, int write); +int gmap_shadow_page(struct gmap *sg, unsigned long saddr, pte_t pte); void gmap_register_pte_notifier(struct gmap_notifier *); void gmap_unregister_pte_notifier(struct gmap_notifier *); diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h index a6e7fc8f5b49..c7ebba483f09 100644 --- a/arch/s390/include/asm/pgtable.h +++ b/arch/s390/include/asm/pgtable.h @@ -895,7 +895,7 @@ void ptep_zap_unused(struct mm_struct *mm, unsigned long addr, pte_t *ptep , int reset); void ptep_zap_key(struct mm_struct *mm, unsigned long addr, pte_t *ptep); int ptep_shadow_pte(struct mm_struct *mm, unsigned long saddr, - pte_t *sptep, pte_t *tptep, int write); + pte_t *sptep, pte_t *tptep, pte_t pte); void ptep_unshadow_pte(struct mm_struct *mm, unsigned long saddr, pte_t *ptep); bool test_and_clear_guest_dirty(struct mm_struct *mm, unsigned long address); diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c index ba4985262bce..c5f79c1205cf 100644 --- a/arch/s390/kvm/gaccess.c +++ b/arch/s390/kvm/gaccess.c @@ -1109,7 +1109,7 @@ int kvm_s390_shadow_fault(struct gmap *sg, unsigned long saddr, int write) dat_protection |= pte.p; if (write && dat_protection) return PGM_PROTECTION; - rc = gmap_shadow_page(sg, saddr, pte.pfra * 4096, write); + rc = gmap_shadow_page(sg, saddr, __pte(pte.val)); if (rc) return rc; return 0; diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c index b02d0d0cc641..a57a87bfeb27 100644 --- a/arch/s390/mm/gmap.c +++ b/arch/s390/mm/gmap.c @@ -1743,8 +1743,7 @@ EXPORT_SYMBOL_GPL(gmap_shadow_pgt); * gmap_shadow_page - create a shadow page mapping * @sg: pointer to the shadow guest address space structure * @saddr: faulting address in the shadow gmap - * @paddr: parent gmap address to get mapped at @saddr - * @write: =1 map r/w, =0 map r/o + * @pte: pte in parent gmap address space to get shadowed * * Returns 0 if successfully shadowed or already shadowed, -EAGAIN if the * shadow table structure is incomplete, -ENOMEM if out of memory and @@ -1752,12 +1751,11 @@ EXPORT_SYMBOL_GPL(gmap_shadow_pgt); * * Called with sg->mm->mmap_sem in read. */ -int gmap_shadow_page(struct gmap *sg, unsigned long saddr, - unsigned long paddr, int write) +int gmap_shadow_page(struct gmap *sg, unsigned long saddr, pte_t pte) { struct gmap *parent; struct gmap_rmap *rmap; - unsigned long vmaddr; + unsigned long vmaddr, paddr; spinlock_t *ptl; pte_t *sptep, *tptep; int rc; @@ -1771,6 +1769,7 @@ int gmap_shadow_page(struct gmap *sg, unsigned long saddr, rmap->raddr = (saddr & PAGE_MASK) | _SHADOW_RMAP_PGTABLE; while (1) { + paddr = pte_val(pte) & PAGE_MASK; vmaddr = __gmap_translate(parent, paddr); if (IS_ERR_VALUE(vmaddr)) { rc = vmaddr; @@ -1791,8 +1790,7 @@ int gmap_shadow_page(struct gmap *sg, unsigned long saddr, radix_tree_preload_end(); break; } - rc = ptep_shadow_pte(sg->mm, saddr, - sptep, tptep, write); + rc = ptep_shadow_pte(sg->mm, saddr, sptep, tptep, pte); if (rc > 0) { /* Success and a new mapping */ gmap_insert_rmap(sg, vmaddr, rmap); diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c index 5b02583fbf4c..293130b5aee7 100644 --- a/arch/s390/mm/pgtable.c +++ b/arch/s390/mm/pgtable.c @@ -463,29 +463,27 @@ int ptep_force_prot(struct mm_struct *mm, unsigned long addr, } int ptep_shadow_pte(struct mm_struct *mm, unsigned long saddr, - pte_t *sptep, pte_t *tptep, int write) + pte_t *sptep, pte_t *tptep, pte_t pte) { pgste_t spgste, tpgste; pte_t spte, tpte; int rc = -EAGAIN; + if (!(pte_val(*tptep) & _PAGE_INVALID)) + return 0; /* already shadowed */ spgste = pgste_get_lock(sptep); spte = *sptep; if (!(pte_val(spte) & _PAGE_INVALID) && - !(pte_val(spte) & _PAGE_PROTECT)) { - rc = 0; - if (!(pte_val(*tptep) & _PAGE_INVALID)) - /* Update existing mapping */ - ptep_flush_direct(mm, saddr, tptep); - else - rc = 1; + !((pte_val(spte) & _PAGE_PROTECT) && + !(pte_val(pte) & _PAGE_PROTECT))) { pgste_val(spgste) |= PGSTE_VSIE_BIT; tpgste = pgste_get_lock(tptep); pte_val(tpte) = (pte_val(spte) & PAGE_MASK) | - (write ? 0 : _PAGE_PROTECT); + (pte_val(pte) & _PAGE_PROTECT); /* don't touch the storage key - it belongs to parent pgste */ tpgste = pgste_set_pte(tptep, tpgste, tpte); pgste_set_unlock(tptep, tpgste); + rc = 1; } pgste_set_unlock(sptep, spgste); return rc;