[PATCH v3 2/6] KVM: x86/mmu: Move round_gfn_for_level() helper into mmu_internal.h

From: Hou Wenlong
Date: Fri Sep 23 2022 - 06:52:49 EST


Rounding down the GFN to a huge page size is a common pattern
throughout KVM, so move round_gfn_for_level() helper in
tdp_iter.c to mmu_internal.h for common usage. Also rename
it as gfn_round_for_level() to use gfn_* prefix and clean
up the other call site.

Signed-off-by: Hou Wenlong <houwenlong.hwl@xxxxxxxxxxxx>
---
arch/x86/kvm/mmu/mmu.c | 5 +++--
arch/x86/kvm/mmu/mmu_internal.h | 5 +++++
arch/x86/kvm/mmu/paging_tmpl.h | 2 +-
arch/x86/kvm/mmu/tdp_iter.c | 11 +++--------
4 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index ae9f84b0fc64..70c57ed166c7 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -3110,7 +3110,7 @@ static int __direct_map(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
if (fault->nx_huge_page_workaround_enabled)
disallowed_hugepage_adjust(fault, *it.sptep, it.level);

- base_gfn = fault->gfn & ~(KVM_PAGES_PER_HPAGE(it.level) - 1);
+ base_gfn = gfn_round_for_level(fault->gfn, it.level);
if (it.level == fault->goal_level)
break;

@@ -4333,7 +4333,8 @@ int kvm_tdp_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
if (shadow_memtype_mask && kvm_arch_has_noncoherent_dma(vcpu->kvm)) {
for ( ; fault->max_level > PG_LEVEL_4K; --fault->max_level) {
int page_num = KVM_PAGES_PER_HPAGE(fault->max_level);
- gfn_t base = (fault->addr >> PAGE_SHIFT) & ~(page_num - 1);
+ gfn_t base = gfn_round_for_level(fault->addr >> PAGE_SHIFT,
+ fault->max_level);

if (kvm_mtrr_check_gfn_range_consistency(vcpu, base, page_num))
break;
diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h
index 6651c154f2e0..249bfcd502b4 100644
--- a/arch/x86/kvm/mmu/mmu_internal.h
+++ b/arch/x86/kvm/mmu/mmu_internal.h
@@ -155,6 +155,11 @@ static inline bool kvm_mmu_page_ad_need_write_protect(struct kvm_mmu_page *sp)
return kvm_x86_ops.cpu_dirty_log_size && sp->role.guest_mode;
}

+static inline gfn_t gfn_round_for_level(gfn_t gfn, int level)
+{
+ return gfn & -KVM_PAGES_PER_HPAGE(level);
+}
+
int mmu_try_to_unsync_pages(struct kvm *kvm, const struct kvm_memory_slot *slot,
gfn_t gfn, bool can_unsync, bool prefetch);

diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
index 39e0205e7300..4e9f992474cb 100644
--- a/arch/x86/kvm/mmu/paging_tmpl.h
+++ b/arch/x86/kvm/mmu/paging_tmpl.h
@@ -701,7 +701,7 @@ static int FNAME(fetch)(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault,
if (fault->nx_huge_page_workaround_enabled)
disallowed_hugepage_adjust(fault, *it.sptep, it.level);

- base_gfn = fault->gfn & ~(KVM_PAGES_PER_HPAGE(it.level) - 1);
+ base_gfn = gfn_round_for_level(fault->gfn, it.level);
if (it.level == fault->goal_level)
break;

diff --git a/arch/x86/kvm/mmu/tdp_iter.c b/arch/x86/kvm/mmu/tdp_iter.c
index 39b48e7d7d1a..c4bb4abed6d0 100644
--- a/arch/x86/kvm/mmu/tdp_iter.c
+++ b/arch/x86/kvm/mmu/tdp_iter.c
@@ -15,11 +15,6 @@ static void tdp_iter_refresh_sptep(struct tdp_iter *iter)
iter->old_spte = kvm_tdp_mmu_read_spte(iter->sptep);
}

-static gfn_t round_gfn_for_level(gfn_t gfn, int level)
-{
- return gfn & -KVM_PAGES_PER_HPAGE(level);
-}
-
/*
* Return the TDP iterator to the root PT and allow it to continue its
* traversal over the paging structure from there.
@@ -30,7 +25,7 @@ void tdp_iter_restart(struct tdp_iter *iter)
iter->yielded_gfn = iter->next_last_level_gfn;
iter->level = iter->root_level;

- iter->gfn = round_gfn_for_level(iter->next_last_level_gfn, iter->level);
+ iter->gfn = gfn_round_for_level(iter->next_last_level_gfn, iter->level);
tdp_iter_refresh_sptep(iter);

iter->valid = true;
@@ -97,7 +92,7 @@ static bool try_step_down(struct tdp_iter *iter)

iter->level--;
iter->pt_path[iter->level - 1] = child_pt;
- iter->gfn = round_gfn_for_level(iter->next_last_level_gfn, iter->level);
+ iter->gfn = gfn_round_for_level(iter->next_last_level_gfn, iter->level);
tdp_iter_refresh_sptep(iter);

return true;
@@ -139,7 +134,7 @@ static bool try_step_up(struct tdp_iter *iter)
return false;

iter->level++;
- iter->gfn = round_gfn_for_level(iter->gfn, iter->level);
+ iter->gfn = gfn_round_for_level(iter->gfn, iter->level);
tdp_iter_refresh_sptep(iter);

return true;
--
2.31.1