linux-kernel - [PATCH 07/23] KVM: MMU: remove kvm_mmu_calc_root_page

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Date:   Fri,  4 Feb 2022 06:57:02 -0500
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     dmatlack@...gle.com, seanjc@...gle.com, vkuznets@...hat.com
Subject: [PATCH 07/23] KVM: MMU: remove kvm_mmu_calc_root_page_role

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@...hat.com>
---
 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