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Subject[PATCH 06/16] KVM: x86/mmu: Refactor the per-slot level calculation in mapping_level()
Date
Invert the loop which adjusts the allowed page level based on what's
compatible with the associated memslot to use a largest-to-smallest
page size walk. This paves the way for passing around a "max level"
variable instead of having redundant checks and/or multiple booleans.

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
arch/x86/kvm/mmu/mmu.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index e4a96236aa14..bd1711201181 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -1326,7 +1326,7 @@ gfn_to_memslot_dirty_bitmap(struct kvm_vcpu *vcpu, gfn_t gfn,
static int mapping_level(struct kvm_vcpu *vcpu, gfn_t large_gfn,
bool *force_pt_level)
{
- int host_level, level, max_level;
+ int host_level, max_level;
struct kvm_memory_slot *slot;

if (unlikely(*force_pt_level))
@@ -1343,12 +1343,12 @@ static int mapping_level(struct kvm_vcpu *vcpu, gfn_t large_gfn,
return host_level;

max_level = min(kvm_x86_ops->get_lpage_level(), host_level);
-
- for (level = PT_DIRECTORY_LEVEL; level <= max_level; ++level)
- if (__mmu_gfn_lpage_is_disallowed(large_gfn, level, slot))
+ for ( ; max_level > PT_PAGE_TABLE_LEVEL; max_level--) {
+ if (!__mmu_gfn_lpage_is_disallowed(large_gfn, max_level, slot))
break;
+ }

- return level - 1;
+ return max_level;
}

/*
--
2.24.0
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