diff options
| -rw-r--r-- | arch/s390/include/asm/gmap.h | 37 | ||||
| -rw-r--r-- | arch/s390/kvm/pv.c | 12 | ||||
| -rw-r--r-- | arch/s390/mm/gmap.c | 99 |
3 files changed, 116 insertions, 32 deletions
diff --git a/arch/s390/include/asm/gmap.h b/arch/s390/include/asm/gmap.h index f4073106e1f3..5cc46e0dde62 100644 --- a/arch/s390/include/asm/gmap.h +++ b/arch/s390/include/asm/gmap.h @@ -147,7 +147,42 @@ int gmap_mprotect_notify(struct gmap *, unsigned long start, void gmap_sync_dirty_log_pmd(struct gmap *gmap, unsigned long dirty_bitmap[4], unsigned long gaddr, unsigned long vmaddr); int gmap_mark_unmergeable(void); -void s390_reset_acc(struct mm_struct *mm); void s390_unlist_old_asce(struct gmap *gmap); int s390_replace_asce(struct gmap *gmap); +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); + +/** + * s390_uv_destroy_range - Destroy a range of pages in the given mm. + * @mm: the mm on which to operate on + * @start: the start of the range + * @end: the end of the range + * + * This function will call cond_sched, so it should not generate stalls, but + * it will otherwise only return when it completed. + */ +static inline void s390_uv_destroy_range(struct mm_struct *mm, unsigned long start, + unsigned long end) +{ + (void)__s390_uv_destroy_range(mm, start, end, false); +} + +/** + * s390_uv_destroy_range_interruptible - Destroy a range of pages in the + * given mm, but stop when a fatal signal is received. + * @mm: the mm on which to operate on + * @start: the start of the range + * @end: the end of the range + * + * This function will call cond_sched, so it should not generate stalls. If + * a fatal signal is received, it will return with -EINTR immediately, + * without finishing destroying the whole range. Upon successful + * completion, 0 is returned. + */ +static inline int s390_uv_destroy_range_interruptible(struct mm_struct *mm, unsigned long start, + unsigned long end) +{ + return __s390_uv_destroy_range(mm, start, end, true); +} #endif /* _ASM_S390_GMAP_H */ diff --git a/arch/s390/kvm/pv.c b/arch/s390/kvm/pv.c index f1733812a263..a556db3912a1 100644 --- a/arch/s390/kvm/pv.c +++ b/arch/s390/kvm/pv.c @@ -13,6 +13,8 @@ #include <asm/gmap.h> #include <asm/uv.h> #include <asm/mman.h> +#include <linux/pagewalk.h> +#include <linux/sched/mm.h> #include "kvm-s390.h" int kvm_s390_pv_destroy_cpu(struct kvm_vcpu *vcpu, u16 *rc, u16 *rrc) @@ -153,8 +155,14 @@ int kvm_s390_pv_deinit_vm(struct kvm *kvm, u16 *rc, u16 *rrc) { int cc; - /* make all pages accessible before destroying the guest */ - s390_reset_acc(kvm->mm); + /* + * if the mm still has a mapping, make all its pages accessible + * before destroying the guest + */ + if (mmget_not_zero(kvm->mm)) { + s390_uv_destroy_range(kvm->mm, 0, TASK_SIZE); + mmput(kvm->mm); + } cc = uv_cmd_nodata(kvm_s390_pv_get_handle(kvm), UVC_CMD_DESTROY_SEC_CONF, rc, rrc); diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c index 85cab61d87a9..62758cb5872f 100644 --- a/arch/s390/mm/gmap.c +++ b/arch/s390/mm/gmap.c @@ -2697,44 +2697,85 @@ void s390_reset_cmma(struct mm_struct *mm) } EXPORT_SYMBOL_GPL(s390_reset_cmma); -/* - * make inaccessible pages accessible again - */ -static int __s390_reset_acc(pte_t *ptep, unsigned long addr, - unsigned long next, struct mm_walk *walk) +#define GATHER_GET_PAGES 32 + +struct reset_walk_state { + unsigned long next; + unsigned long count; + unsigned long pfns[GATHER_GET_PAGES]; +}; + +static int s390_gather_pages(pte_t *ptep, unsigned long addr, + unsigned long next, struct mm_walk *walk) { + struct reset_walk_state *p = walk->private; pte_t pte = READ_ONCE(*ptep); - /* There is a reference through the mapping */ - if (pte_present(pte)) - WARN_ON_ONCE(uv_destroy_owned_page(pte_val(pte) & PAGE_MASK)); - - return 0; + if (pte_present(pte)) { + /* we have a reference from the mapping, take an extra one */ + get_page(phys_to_page(pte_val(pte))); + p->pfns[p->count] = phys_to_pfn(pte_val(pte)); + p->next = next; + p->count++; + } + return p->count >= GATHER_GET_PAGES; } -static const struct mm_walk_ops reset_acc_walk_ops = { - .pte_entry = __s390_reset_acc, +static const struct mm_walk_ops gather_pages_ops = { + .pte_entry = s390_gather_pages, }; -#include <linux/sched/mm.h> -void s390_reset_acc(struct mm_struct *mm) +/* + * Call the Destroy secure page UVC on each page in the given array of PFNs. + * Each page needs to have an extra reference, which will be released here. + */ +void s390_uv_destroy_pfns(unsigned long count, unsigned long *pfns) { - if (!mm_is_protected(mm)) - return; - /* - * we might be called during - * reset: we walk the pages and clear - * close of all kvm file descriptors: we walk the pages and clear - * exit of process on fd closure: vma already gone, do nothing - */ - if (!mmget_not_zero(mm)) - return; - mmap_read_lock(mm); - walk_page_range(mm, 0, TASK_SIZE, &reset_acc_walk_ops, NULL); - mmap_read_unlock(mm); - mmput(mm); + unsigned long i; + + for (i = 0; i < count; i++) { + /* we always have an extra reference */ + uv_destroy_owned_page(pfn_to_phys(pfns[i])); + /* get rid of the extra reference */ + put_page(pfn_to_page(pfns[i])); + cond_resched(); + } +} +EXPORT_SYMBOL_GPL(s390_uv_destroy_pfns); + +/** + * __s390_uv_destroy_range - Call the destroy secure page UVC on each page + * in the given range of the given address space. + * @mm: the mm to operate on + * @start: the start of the range + * @end: the end of the range + * @interruptible: if not 0, stop when a fatal signal is received + * + * Walk the given range of the given address space and call the destroy + * secure page UVC on each page. Optionally exit early if a fatal signal is + * pending. + * + * Return: 0 on success, -EINTR if the function stopped before completing + */ +int __s390_uv_destroy_range(struct mm_struct *mm, unsigned long start, + unsigned long end, bool interruptible) +{ + struct reset_walk_state state = { .next = start }; + int r = 1; + + while (r > 0) { + state.count = 0; + mmap_read_lock(mm); + r = walk_page_range(mm, state.next, end, &gather_pages_ops, &state); + mmap_read_unlock(mm); + cond_resched(); + s390_uv_destroy_pfns(state.count, state.pfns); + if (interruptible && fatal_signal_pending(current)) + return -EINTR; + } + return 0; } -EXPORT_SYMBOL_GPL(s390_reset_acc); +EXPORT_SYMBOL_GPL(__s390_uv_destroy_range); /** * s390_unlist_old_asce - Remove the topmost level of page tables from the |