On 06.07.2018 15:55, Janosch Frank wrote:
> If the host invalidates a pmd, we also have to invalidate the
> corresponding gmap pmds, as well as flush them from the TLB. This is
> necessary, as we don't share the pmd tables between host and guest as
> we do with ptes.
>
> The clearing part of these three new functions sets a guest pmd entry
> to _SEGMENT_ENTRY_EMPTY, so the guest will fault on it and we will
> re-link it.
>
> Flushing the gmap is not necessary in the host's lazy local and csp
> cases. Both purge the TLB completely.
>
> Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxxxxxxx>
> Reviewed-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
> ---
> arch/s390/include/asm/pgtable.h | 4 ++
> arch/s390/mm/gmap.c | 114 ++++++++++++++++++++++++++++++++++++++++
> arch/s390/mm/pgtable.c | 17 ++++--
> 3 files changed, 132 insertions(+), 3 deletions(-)
>
> diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
> index 7c9ccd180e75..7f51e33f6456 100644
> --- a/arch/s390/include/asm/pgtable.h
> +++ b/arch/s390/include/asm/pgtable.h
> @@ -1119,6 +1119,10 @@ int set_pgste_bits(struct mm_struct *mm, unsigned long addr,
> int get_pgste(struct mm_struct *mm, unsigned long hva, unsigned long *pgstep);
> int pgste_perform_essa(struct mm_struct *mm, unsigned long hva, int orc,
> unsigned long *oldpte, unsigned long *oldpgste);
> +void gmap_pmdp_csp(struct mm_struct *mm, unsigned long vmaddr);
> +void gmap_pmdp_invalidate(struct mm_struct *mm, unsigned long vmaddr);
> +void gmap_pmdp_idte_local(struct mm_struct *mm, unsigned long vmaddr);
> +void gmap_pmdp_idte_global(struct mm_struct *mm, unsigned long vmaddr);
>
> /*
> * Certain architectures need to do special things when PTEs
> diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
> index 3140f9084c8b..75d50dadd59f 100644
> --- a/arch/s390/mm/gmap.c
> +++ b/arch/s390/mm/gmap.c
> @@ -2276,6 +2276,120 @@ static void gmap_pmdp_xchg(struct gmap *gmap, pmd_t *pmdp, pmd_t new,
> *pmdp = new;
> }
>
> +static void gmap_pmdp_clear(struct mm_struct *mm, unsigned long vmaddr,
> + int purge)
> +{
> + pmd_t *pmdp;
> + struct gmap *gmap;
> +
> + rcu_read_lock();
> + list_for_each_entry_rcu(gmap, &mm->context.gmap_list, list) {
> + spin_lock(&gmap->guest_table_lock);
> + pmdp = (pmd_t *)radix_tree_delete(&gmap->host_to_guest,
> + vmaddr >> PMD_SHIFT);
> + if (pmdp) {
> + if (purge)
> + __pmdp_csp(pmdp);
> + pmd_val(*pmdp) = _SEGMENT_ENTRY_EMPTY;
Just wondering if we actually call notifiers on all possible paths?
Should be add a WARN_ON() in case the GMAP PMDP still has a notifier bit
set?
> + }
> + spin_unlock(&gmap->guest_table_lock);
> + }
> + rcu_read_unlock();
> +}
> +
> +/**
> + * gmap_pmdp_invalidate - invalidate all affected guest pmd entries without
> + * flushing
> + * @mm: pointer to the process mm_struct
> + * @vmaddr: virtual address in the process address space
> + */
> +void gmap_pmdp_invalidate(struct mm_struct *mm, unsigned long vmaddr)
> +{
> + gmap_pmdp_clear(mm, vmaddr, 0);
> +}
> +EXPORT_SYMBOL_GPL(gmap_pmdp_invalidate);
> +
> +/**
> + * gmap_pmdp_csp - csp all affected guest pmd entries
> + * @mm: pointer to the process mm_struct
> + * @vmaddr: virtual address in the process address space
> + */
> +void gmap_pmdp_csp(struct mm_struct *mm, unsigned long vmaddr)
> +{
> + gmap_pmdp_clear(mm, vmaddr, 1);
> +}
> +EXPORT_SYMBOL_GPL(gmap_pmdp_csp);
> +
> +/**
> + * gmap_pmdp_idte_local - invalidate and clear a guest pmd entry
> + * @mm: pointer to the process mm_struct
> + * @vmaddr: virtual address in the process address space
> + */
> +void gmap_pmdp_idte_local(struct mm_struct *mm, unsigned long vmaddr)
> +{
> + unsigned long *entry, gaddr;
> + struct gmap *gmap;
> + pmd_t *pmdp;
> +
> + rcu_read_lock();
> + list_for_each_entry_rcu(gmap, &mm->context.gmap_list, list) {
> + spin_lock(&gmap->guest_table_lock);
> + entry = radix_tree_delete(&gmap->host_to_guest,
> + vmaddr >> PMD_SHIFT);
> + if (entry) {
> + pmdp = (pmd_t *)entry;
> + gaddr = __gmap_segment_gaddr(entry);
> + if (MACHINE_HAS_TLB_GUEST)
> + __pmdp_idte(gaddr, pmdp,
> + IDTE_GUEST_ASCE,
> + gmap->asce, IDTE_LOCAL);
> + else if (MACHINE_HAS_IDTE)
> + __pmdp_idte(gaddr, pmdp, 0, 0,
> + IDTE_LOCAL);
> + *entry = _SEGMENT_ENTRY_EMPTY;
> + }
> + spin_unlock(&gmap->guest_table_lock);
> + }
> + rcu_read_unlock();
> +}
> +EXPORT_SYMBOL_GPL(gmap_pmdp_idte_local);
> +
> +/**
> + * gmap_pmdp_idte_global - invalidate and clear a guest pmd entry
> + * @mm: pointer to the process mm_struct
> + * @vmaddr: virtual address in the process address space
> + */
> +void gmap_pmdp_idte_global(struct mm_struct *mm, unsigned long vmaddr)
> +{
> + unsigned long *entry, gaddr;
> + struct gmap *gmap;
> + pmd_t *pmdp;
> +
> + rcu_read_lock();
> + list_for_each_entry_rcu(gmap, &mm->context.gmap_list, list) {
> + spin_lock(&gmap->guest_table_lock);
> + entry = radix_tree_delete(&gmap->host_to_guest,
> + vmaddr >> PMD_SHIFT);
> + if (entry) {
> + pmdp = (pmd_t *)entry;
> + gaddr = __gmap_segment_gaddr(entry);
> + if (MACHINE_HAS_TLB_GUEST)
> + __pmdp_idte(gaddr, pmdp,
> + IDTE_GUEST_ASCE,
> + gmap->asce, IDTE_GLOBAL);
> + else if (MACHINE_HAS_IDTE)
> + __pmdp_idte(gaddr, pmdp, 0, 0,
> + IDTE_GLOBAL);
> + else
> + __pmdp_csp(pmdp);
> + *entry = _SEGMENT_ENTRY_EMPTY;
> + }
> + spin_unlock(&gmap->guest_table_lock);
> + }
> + rcu_read_unlock();
> +}
> +EXPORT_SYMBOL_GPL(gmap_pmdp_idte_global);
> +
> static inline void thp_split_mm(struct mm_struct *mm)
> {
> #ifdef CONFIG_TRANSPARENT_HUGEPAGE
> diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
> index 7e1c17b1a24a..7bdb15fc5487 100644
> --- a/arch/s390/mm/pgtable.c
> +++ b/arch/s390/mm/pgtable.c
> @@ -347,18 +347,27 @@ static inline void pmdp_idte_local(struct mm_struct *mm,
> mm->context.asce, IDTE_LOCAL);
> else
> __pmdp_idte(addr, pmdp, 0, 0, IDTE_LOCAL);
> + if (mm_has_pgste(mm))
> + gmap_pmdp_idte_local(mm, addr);
> }
>
> static inline void pmdp_idte_global(struct mm_struct *mm,
> unsigned long addr, pmd_t *pmdp)
> {
> - if (MACHINE_HAS_TLB_GUEST)
> + if (MACHINE_HAS_TLB_GUEST) {
> __pmdp_idte(addr, pmdp, IDTE_NODAT | IDTE_GUEST_ASCE,
> mm->context.asce, IDTE_GLOBAL);
> - else if (MACHINE_HAS_IDTE)
> + if (mm_has_pgste(mm))
> + gmap_pmdp_idte_global(mm, addr);
> + } else if (MACHINE_HAS_IDTE) {
> __pmdp_idte(addr, pmdp, 0, 0, IDTE_GLOBAL);
> - else
> + if (mm_has_pgste(mm))
> + gmap_pmdp_idte_global(mm, addr);
> + } else {
> __pmdp_csp(pmdp);
> + if (mm_has_pgste(mm))
> + gmap_pmdp_csp(mm, addr);
> + }
> }
>
> static inline pmd_t pmdp_flush_direct(struct mm_struct *mm,
> @@ -392,6 +401,8 @@ static inline pmd_t pmdp_flush_lazy(struct mm_struct *mm,
> cpumask_of(smp_processor_id()))) {
> pmd_val(*pmdp) |= _SEGMENT_ENTRY_INVALID;
> mm->context.flush_mm = 1;
> + if (mm_has_pgste(mm))
> + gmap_pmdp_invalidate(mm, addr);
> } else {
> pmdp_idte_global(mm, addr, pmdp);
> }
>
--
Thanks,
David / dhildenb
