| Message ID | 20200207113958.7320-12-borntraeger@de.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: s390: Add support for protected VMs | expand |
On 07.02.20 12:39, Christian Borntraeger wrote: > Before we destroy the secure configuration, we better make all > pages accessible again. This also happens during reboot, where we reboot > into a non-secure guest that then can go again into secure mode. As > this "new" secure guest will have a new ID we cannot reuse the old page > state. > > Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> > Reviewed-by: Thomas Huth <thuth@redhat.com> > Reviewed-by: Cornelia Huck <cohuck@redhat.com> > --- > arch/s390/include/asm/pgtable.h | 1 + > arch/s390/kvm/pv.c | 2 ++ > arch/s390/mm/gmap.c | 35 +++++++++++++++++++++++++++++++++ > 3 files changed, 38 insertions(+) > > diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h > index dbd1453e6924..3e2ea997c334 100644 > --- a/arch/s390/include/asm/pgtable.h > +++ b/arch/s390/include/asm/pgtable.h > @@ -1669,6 +1669,7 @@ extern int vmem_remove_mapping(unsigned long start, unsigned long size); > extern int s390_enable_sie(void); > extern int s390_enable_skey(void); > extern void s390_reset_cmma(struct mm_struct *mm); > +extern void s390_reset_acc(struct mm_struct *mm); > > /* s390 has a private copy of get unmapped area to deal with cache synonyms */ > #define HAVE_ARCH_UNMAPPED_AREA > diff --git a/arch/s390/kvm/pv.c b/arch/s390/kvm/pv.c > index 4795e61f4e16..392795a92bd9 100644 > --- a/arch/s390/kvm/pv.c > +++ b/arch/s390/kvm/pv.c > @@ -66,6 +66,8 @@ int kvm_s390_pv_destroy_vm(struct kvm *kvm) > int rc; > u32 ret; > > + /* make all pages accessible before destroying the guest */ > + s390_reset_acc(kvm->mm); > rc = uv_cmd_nodata(kvm_s390_pv_handle(kvm), > UVC_CMD_DESTROY_SEC_CONF, &ret); > WRITE_ONCE(kvm->arch.gmap->guest_handle, 0); > diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c > index 7291452fe5f0..27926a06df32 100644 > --- a/arch/s390/mm/gmap.c > +++ b/arch/s390/mm/gmap.c > @@ -2650,3 +2650,38 @@ void s390_reset_cmma(struct mm_struct *mm) > up_write(&mm->mmap_sem); > } > 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) > +{ > + pte_t pte = READ_ONCE(*ptep); > + > + if (pte_present(pte)) > + WARN_ON_ONCE(uv_convert_from_secure(pte_val(pte) & PAGE_MASK)); > + return 0; > +} > + > +static const struct mm_walk_ops reset_acc_walk_ops = { > + .pte_entry = __s390_reset_acc, > +}; > + > +#include <linux/sched/mm.h> > +void s390_reset_acc(struct mm_struct *mm) > +{ > + /* > + * 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; > + down_read(&mm->mmap_sem); > + walk_page_range(mm, 0, TASK_SIZE, &reset_acc_walk_ops, NULL); > + up_read(&mm->mmap_sem); > + mmput(mm); > +} > +EXPORT_SYMBOL_GPL(s390_reset_acc); > Reviewed-by: David Hildenbrand <david@redhat.com>
diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h index dbd1453e6924..3e2ea997c334 100644 --- a/arch/s390/include/asm/pgtable.h +++ b/arch/s390/include/asm/pgtable.h @@ -1669,6 +1669,7 @@ extern int vmem_remove_mapping(unsigned long start, unsigned long size); extern int s390_enable_sie(void); extern int s390_enable_skey(void); extern void s390_reset_cmma(struct mm_struct *mm); +extern void s390_reset_acc(struct mm_struct *mm); /* s390 has a private copy of get unmapped area to deal with cache synonyms */ #define HAVE_ARCH_UNMAPPED_AREA diff --git a/arch/s390/kvm/pv.c b/arch/s390/kvm/pv.c index 4795e61f4e16..392795a92bd9 100644 --- a/arch/s390/kvm/pv.c +++ b/arch/s390/kvm/pv.c @@ -66,6 +66,8 @@ int kvm_s390_pv_destroy_vm(struct kvm *kvm) int rc; u32 ret; + /* make all pages accessible before destroying the guest */ + s390_reset_acc(kvm->mm); rc = uv_cmd_nodata(kvm_s390_pv_handle(kvm), UVC_CMD_DESTROY_SEC_CONF, &ret); WRITE_ONCE(kvm->arch.gmap->guest_handle, 0); diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c index 7291452fe5f0..27926a06df32 100644 --- a/arch/s390/mm/gmap.c +++ b/arch/s390/mm/gmap.c @@ -2650,3 +2650,38 @@ void s390_reset_cmma(struct mm_struct *mm) up_write(&mm->mmap_sem); } 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) +{ + pte_t pte = READ_ONCE(*ptep); + + if (pte_present(pte)) + WARN_ON_ONCE(uv_convert_from_secure(pte_val(pte) & PAGE_MASK)); + return 0; +} + +static const struct mm_walk_ops reset_acc_walk_ops = { + .pte_entry = __s390_reset_acc, +}; + +#include <linux/sched/mm.h> +void s390_reset_acc(struct mm_struct *mm) +{ + /* + * 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; + down_read(&mm->mmap_sem); + walk_page_range(mm, 0, TASK_SIZE, &reset_acc_walk_ops, NULL); + up_read(&mm->mmap_sem); + mmput(mm); +} +EXPORT_SYMBOL_GPL(s390_reset_acc);