[PATCH 07/23] KVM: MMU: remove kvm_mmu_calc_root_page_role

From: Paolo Bonzini
Date: Fri Feb 04 2022 - 06:57:56 EST


Since the guest PGD is now loaded after the MMU has been set up
completely, the desired role for a cache hit is simply the current
mmu_role. There is no need to compute it again, so __kvm_mmu_new_pgd
can be folded in kvm_mmu_new_pgd.

As an aside, the !tdp_enabled case in the function was dead code,
and that also gets mopped up as a side effect.

Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
arch/x86/kvm/mmu/mmu.c | 29 ++++-------------------------
1 file changed, 4 insertions(+), 25 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index b8ab16323629..42475e4c2a48 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -190,8 +190,6 @@ struct kmem_cache *mmu_page_header_cache;
static struct percpu_counter kvm_total_used_mmu_pages;

static void mmu_spte_set(u64 *sptep, u64 spte);
-static union kvm_mmu_page_role
-kvm_mmu_calc_root_page_role(struct kvm_vcpu *vcpu);

struct kvm_mmu_role_regs {
const unsigned long cr0;
@@ -4159,9 +4157,9 @@ static bool fast_pgd_switch(struct kvm_vcpu *vcpu, gpa_t new_pgd,
return false;
}

-static void __kvm_mmu_new_pgd(struct kvm_vcpu *vcpu, gpa_t new_pgd,
- union kvm_mmu_page_role new_role)
+void kvm_mmu_new_pgd(struct kvm_vcpu *vcpu, gpa_t new_pgd)
{
+ union kvm_mmu_page_role new_role = vcpu->arch.mmu->mmu_role.base;
if (!fast_pgd_switch(vcpu, new_pgd, new_role)) {
kvm_mmu_free_roots(vcpu, vcpu->arch.mmu, KVM_MMU_ROOT_CURRENT);
return;
@@ -4196,11 +4194,6 @@ static void __kvm_mmu_new_pgd(struct kvm_vcpu *vcpu, gpa_t new_pgd,
__clear_sp_write_flooding_count(
to_shadow_page(vcpu->arch.mmu->root_hpa));
}
-
-void kvm_mmu_new_pgd(struct kvm_vcpu *vcpu, gpa_t new_pgd)
-{
- __kvm_mmu_new_pgd(vcpu, new_pgd, kvm_mmu_calc_root_page_role(vcpu));
-}
EXPORT_SYMBOL_GPL(kvm_mmu_new_pgd);

static unsigned long get_cr3(struct kvm_vcpu *vcpu)
@@ -4871,7 +4864,7 @@ void kvm_init_shadow_npt_mmu(struct kvm_vcpu *vcpu, unsigned long cr0,

shadow_mmu_init_context(vcpu, context, &regs, new_role);
reset_shadow_zero_bits_mask(vcpu, context, is_efer_nx(context));
- __kvm_mmu_new_pgd(vcpu, nested_cr3, new_role.base);
+ kvm_mmu_new_pgd(vcpu, nested_cr3);
}
EXPORT_SYMBOL_GPL(kvm_init_shadow_npt_mmu);

@@ -4923,7 +4916,7 @@ void kvm_init_shadow_ept_mmu(struct kvm_vcpu *vcpu, bool execonly,
reset_ept_shadow_zero_bits_mask(context, execonly);
}

- __kvm_mmu_new_pgd(vcpu, new_eptp, new_role.base);
+ kvm_mmu_new_pgd(vcpu, new_eptp);
}
EXPORT_SYMBOL_GPL(kvm_init_shadow_ept_mmu);

@@ -5009,20 +5002,6 @@ void kvm_init_mmu(struct kvm_vcpu *vcpu)
}
EXPORT_SYMBOL_GPL(kvm_init_mmu);

-static union kvm_mmu_page_role
-kvm_mmu_calc_root_page_role(struct kvm_vcpu *vcpu)
-{
- struct kvm_mmu_role_regs regs = vcpu_to_role_regs(vcpu);
- union kvm_mmu_role role;
-
- if (tdp_enabled)
- role = kvm_calc_tdp_mmu_root_page_role(vcpu, &regs, true);
- else
- role = kvm_calc_shadow_mmu_root_page_role(vcpu, &regs, true);
-
- return role.base;
-}
-
void kvm_mmu_after_set_cpuid(struct kvm_vcpu *vcpu)
{
/*
--
2.31.1