When slot->base_gfn and userspace_addr are not aligned wrt each other,
large page support is disabled for the entire memslot.
This patch applies the same logic for when slot->base_gfn and
gmem.pgoff are not aligned wrt each other.
Change-Id: Iab21b8995e77beae6dbadc3b623a1e9e07e6dce6
Signed-off-by: Ackerley Tng <ackerleytng@xxxxxxxxxx>
---
arch/x86/kvm/x86.c | 53 ++++++++++++++++++++++++++++++++++++++--------
1 file changed, 44 insertions(+), 9 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 12433b1e755b..ee0e3420cc17 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -12950,6 +12950,46 @@ int memslot_rmap_alloc(struct kvm_memory_slot *slot, unsigned long npages)
return 0;
}
+static inline bool kvm_is_level_aligned(u64 value, int level)
+{
+ return IS_ALIGNED(value, KVM_PAGES_PER_HPAGE(level));
+}
+
+static inline bool
+kvm_should_allow_lpage_for_slot(struct kvm_memory_slot *slot, int level)
+{
+ bool gfn_and_userspace_addr_aligned;
+ unsigned long ugfn;
+
+ ugfn = slot->userspace_addr >> PAGE_SHIFT;
+
+ /*
+ * If addresses are not aligned wrt each other, then large page mapping
+ * cannot be allowed for the slot since page tables only allow guest to
+ * host translations to function at fixed levels.
+ */
+ gfn_and_userspace_addr_aligned =
+ kvm_is_level_aligned(slot->base_gfn ^ ugfn, level);
+
+ /*
+ * If slot->userspace_addr is 0 (disabled), 0 is always aligned so the
+ * check is deferred to gmem.pgoff.
+ */
+ if (!gfn_and_userspace_addr_aligned)
+ return false;
+
+ if (kvm_slot_has_gmem(slot)) {
+ bool gfn_and_gmem_pgoff_aligned;
+
+ gfn_and_gmem_pgoff_aligned = kvm_is_level_aligned(
+ slot->base_gfn ^ slot->gmem.pgoff, level);
+
+ return gfn_and_gmem_pgoff_aligned;
+ }
+
+ return true;
+}
+
static int kvm_alloc_memslot_metadata(struct kvm *kvm,
struct kvm_memory_slot *slot)
{
@@ -12971,7 +13011,6 @@ static int kvm_alloc_memslot_metadata(struct kvm *kvm,
for (i = 1; i < KVM_NR_PAGE_SIZES; ++i) {
struct kvm_lpage_info *linfo;
- unsigned long ugfn;
int lpages;
int level = i + 1;
@@ -12983,16 +13022,12 @@ static int kvm_alloc_memslot_metadata(struct kvm *kvm,
slot->arch.lpage_info[i - 1] = linfo;
- if (slot->base_gfn & (KVM_PAGES_PER_HPAGE(level) - 1))
+ if (!kvm_is_level_aligned(slot->base_gfn, level))
linfo[0].disallow_lpage = 1;
- if ((slot->base_gfn + npages) & (KVM_PAGES_PER_HPAGE(level) - 1))
+ if (!kvm_is_level_aligned(slot->base_gfn + npages, level))
linfo[lpages - 1].disallow_lpage = 1;
- ugfn = slot->userspace_addr >> PAGE_SHIFT;
- /*
- * If the gfn and userspace address are not aligned wrt each
- * other, disable large page support for this slot.
- */
- if ((slot->base_gfn ^ ugfn) & (KVM_PAGES_PER_HPAGE(level) - 1)) {
+
+ if (!kvm_should_allow_lpage_for_slot(slot, level)) {
unsigned long j;
for (j = 0; j < lpages; ++j)
--
2.49.0.1045.g170613ef41-goog
