[PATCH] KVM: x86/mmu: Rename the special lm_root to pml4_root

From: Sean Christopherson
Date: Thu Mar 18 2021 - 16:12:23 EST


Rename the lm_root pointer, which is used when shadowing 32-bit L1 NPT
with 64-bit L0 NPT, to pml4_root. KVM uses dedicated logic to configure
the levels that do not exist in L1's page tables, and to bypass them when
walking the shadow page tables. That dedicated logic assumes 4-level
paging and will need to be updated if AMD ever gains 5-level paging.

No functional change intended.

Suggested-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
arch/x86/include/asm/kvm_host.h | 2 +-
arch/x86/kvm/mmu/mmu.c | 20 ++++++++++----------
2 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index a52f973bdff6..890ada926387 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -396,7 +396,7 @@ struct kvm_mmu {
u32 pkru_mask;

u64 *pae_root;
- u64 *lm_root;
+ u64 *pml4_root;

/*
* check zero bits on shadow page table entries, these
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index c6ed633594a2..a535fe249cd1 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -3324,10 +3324,10 @@ static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu)
if (mmu->shadow_root_level == PT64_ROOT_4LEVEL) {
pm_mask |= PT_ACCESSED_MASK | PT_WRITABLE_MASK | PT_USER_MASK;

- if (WARN_ON_ONCE(!mmu->lm_root))
+ if (WARN_ON_ONCE(!mmu->pml4_root))
return -EIO;

- mmu->lm_root[0] = __pa(mmu->pae_root) | pm_mask;
+ mmu->pml4_root[0] = __pa(mmu->pae_root) | pm_mask;
}

for (i = 0; i < 4; ++i) {
@@ -3347,7 +3347,7 @@ static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu)
}

if (mmu->shadow_root_level == PT64_ROOT_4LEVEL)
- mmu->root_hpa = __pa(mmu->lm_root);
+ mmu->root_hpa = __pa(mmu->pml4_root);
else
mmu->root_hpa = __pa(mmu->pae_root);

@@ -3360,7 +3360,7 @@ static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu)
static int mmu_alloc_special_roots(struct kvm_vcpu *vcpu)
{
struct kvm_mmu *mmu = vcpu->arch.mmu;
- u64 *lm_root, *pae_root;
+ u64 *pml4_root, *pae_root;

/*
* When shadowing 32-bit or PAE NPT with 64-bit NPT, the PML4 and PDP
@@ -3379,14 +3379,14 @@ static int mmu_alloc_special_roots(struct kvm_vcpu *vcpu)
if (WARN_ON_ONCE(mmu->shadow_root_level != PT64_ROOT_4LEVEL))
return -EIO;

- if (mmu->pae_root && mmu->lm_root)
+ if (mmu->pae_root && mmu->pml4_root)
return 0;

/*
* The special roots should always be allocated in concert. Yell and
* bail if KVM ends up in a state where only one of the roots is valid.
*/
- if (WARN_ON_ONCE(!tdp_enabled || mmu->pae_root || mmu->lm_root))
+ if (WARN_ON_ONCE(!tdp_enabled || mmu->pae_root || mmu->pml4_root))
return -EIO;

/*
@@ -3397,14 +3397,14 @@ static int mmu_alloc_special_roots(struct kvm_vcpu *vcpu)
if (!pae_root)
return -ENOMEM;

- lm_root = (void *)get_zeroed_page(GFP_KERNEL_ACCOUNT);
- if (!lm_root) {
+ pml4_root = (void *)get_zeroed_page(GFP_KERNEL_ACCOUNT);
+ if (!pml4_root) {
free_page((unsigned long)pae_root);
return -ENOMEM;
}

mmu->pae_root = pae_root;
- mmu->lm_root = lm_root;
+ mmu->pml4_root = pml4_root;

return 0;
}
@@ -5281,7 +5281,7 @@ static void free_mmu_pages(struct kvm_mmu *mmu)
if (!tdp_enabled && mmu->pae_root)
set_memory_encrypted((unsigned long)mmu->pae_root, 1);
free_page((unsigned long)mmu->pae_root);
- free_page((unsigned long)mmu->lm_root);
+ free_page((unsigned long)mmu->pml4_root);
}

static int __kvm_mmu_create(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu)
--
2.31.0.rc2.261.g7f71774620-goog