Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
KVM: s390: Add alignment checks for hugepages
When backing a guest page with a large page, check that the alignment
of the guest page matches the alignment of the host physical page
backing it within the large page.
Also check that the memslot is large enough to fit the large page.
Those checks are currently not needed, because memslots are guaranteed
to be 1m-aligned, but this will change.
Reviewed-by: Steffen Eiden <seiden@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
+29
-8
+1
-1
arch/s390/kvm/faultin.c
+1
-1
arch/s390/kvm/faultin.c
···
109
109
scoped_guard(read_lock, &kvm->mmu_lock) {
110
110
if (!mmu_invalidate_retry_gfn(kvm, inv_seq, f->gfn)) {
111
111
f->valid = true;
112
-
rc = gmap_link(mc, kvm->arch.gmap, f);
112
+
rc = gmap_link(mc, kvm->arch.gmap, f, slot);
113
113
kvm_release_faultin_page(kvm, f->page, !!rc, f->write_attempt);
114
114
f->page = NULL;
115
115
}
+26
-6
arch/s390/kvm/gmap.c
+26
-6
arch/s390/kvm/gmap.c
···
613
613
return rc;
614
614
}
615
615
616
-
static inline bool gmap_2g_allowed(struct gmap *gmap, gfn_t gfn)
616
+
static inline bool gmap_2g_allowed(struct gmap *gmap, struct guest_fault *f,
617
+
struct kvm_memory_slot *slot)
617
618
{
618
619
return false;
619
620
}
620
621
621
-
static inline bool gmap_1m_allowed(struct gmap *gmap, gfn_t gfn)
622
+
/**
623
+
* gmap_1m_allowed() - Check whether a 1M hugepage is allowed.
624
+
* @gmap: The gmap of the guest.
625
+
* @f: Describes the fault that is being resolved.
626
+
* @slot: The memslot the faulting address belongs to.
627
+
*
628
+
* The function checks whether the GMAP_FLAG_ALLOW_HPAGE_1M flag is set for
629
+
* @gmap, whether the offset of the address in the 1M virtual frame is the
630
+
* same as the offset in the physical 1M frame, and finally whether the whole
631
+
* 1M page would fit in the given memslot.
632
+
*
633
+
* Return: true if a 1M hugepage is allowed to back the faulting address, false
634
+
* otherwise.
635
+
*/
636
+
static inline bool gmap_1m_allowed(struct gmap *gmap, struct guest_fault *f,
637
+
struct kvm_memory_slot *slot)
622
638
{
623
-
return test_bit(GMAP_FLAG_ALLOW_HPAGE_1M, &gmap->flags);
639
+
return test_bit(GMAP_FLAG_ALLOW_HPAGE_1M, &gmap->flags) &&
640
+
!((f->gfn ^ f->pfn) & ~_SEGMENT_FR_MASK) &&
641
+
slot->base_gfn <= ALIGN_DOWN(f->gfn, _PAGES_PER_SEGMENT) &&
642
+
slot->base_gfn + slot->npages >= ALIGN(f->gfn + 1, _PAGES_PER_SEGMENT);
624
643
}
625
644
626
-
int gmap_link(struct kvm_s390_mmu_cache *mc, struct gmap *gmap, struct guest_fault *f)
645
+
int gmap_link(struct kvm_s390_mmu_cache *mc, struct gmap *gmap, struct guest_fault *f,
646
+
struct kvm_memory_slot *slot)
627
647
{
628
648
unsigned int order;
629
649
int rc, level;
···
653
633
level = TABLE_TYPE_PAGE_TABLE;
654
634
if (f->page) {
655
635
order = folio_order(page_folio(f->page));
656
-
if (order >= get_order(_REGION3_SIZE) && gmap_2g_allowed(gmap, f->gfn))
636
+
if (order >= get_order(_REGION3_SIZE) && gmap_2g_allowed(gmap, f, slot))
657
637
level = TABLE_TYPE_REGION3;
658
-
else if (order >= get_order(_SEGMENT_SIZE) && gmap_1m_allowed(gmap, f->gfn))
638
+
else if (order >= get_order(_SEGMENT_SIZE) && gmap_1m_allowed(gmap, f, slot))
659
639
level = TABLE_TYPE_SEGMENT;
660
640
}
661
641
rc = dat_link(mc, gmap->asce, level, uses_skeys(gmap), f);
+2
-1
arch/s390/kvm/gmap.h
+2
-1
arch/s390/kvm/gmap.h
···
90
90
struct gmap *gmap_new_child(struct gmap *parent, gfn_t limit);
91
91
void gmap_remove_child(struct gmap *child);
92
92
void gmap_dispose(struct gmap *gmap);
93
-
int gmap_link(struct kvm_s390_mmu_cache *mc, struct gmap *gmap, struct guest_fault *fault);
93
+
int gmap_link(struct kvm_s390_mmu_cache *mc, struct gmap *gmap, struct guest_fault *fault,
94
+
struct kvm_memory_slot *slot);
94
95
void gmap_sync_dirty_log(struct gmap *gmap, gfn_t start, gfn_t end);
95
96
int gmap_set_limit(struct gmap *gmap, gfn_t limit);
96
97
int gmap_ucas_translate(struct kvm_s390_mmu_cache *mc, struct gmap *gmap, gpa_t *gaddr);