linux-kernel - [PATCH v2 15/18] KVM: x86/mmu: rename kvm_mmu_new_pgd, introduce variant that calls get_guest

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Date:   Thu, 17 Feb 2022 16:03:37 -0500
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     seanjc@...gle.com
Subject: [PATCH v2 15/18] KVM: x86/mmu: rename kvm_mmu_new_pgd, introduce variant that calls get_guest_pgd

In the common case, the argument to kvm_mmu_new_pgd is already in
vcpu->arch.cr3, but that does not work when the guest_mmu is in use.
In that case, the root for L1 TDP tables needs to be retrieved via vendor
code.  Besides, kvm_mmu_new_pgd is a bad name: it can be used also when
the role bits change, not just when the PGD changes.

Kill two birds with one stone by renaming the old kvm_mmu_new_pgd
to __kvm_mmu_update_root.  The non-__ version, kvm_mmu_update_root,
covers the common case, including nested TDP, by calling the
get_guest_pgd callback to retrieve the desired PGD pointer.

Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
 arch/x86/include/asm/kvm_host.h |  2 +-
 arch/x86/kvm/mmu/mmu.c          | 15 +++++++++++----
 arch/x86/kvm/svm/nested.c       |  2 +-
 arch/x86/kvm/vmx/nested.c       |  2 +-
 arch/x86/kvm/x86.c              |  2 +-
 5 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 79f37ccc8726..319ac0918aa2 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1808,7 +1808,7 @@ void kvm_mmu_invlpg(struct kvm_vcpu *vcpu, gva_t gva);
 void kvm_mmu_invalidate_gva(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
 			    gva_t gva, hpa_t root_hpa);
 void kvm_mmu_invpcid_gva(struct kvm_vcpu *vcpu, gva_t gva, unsigned long pcid);
-void kvm_mmu_new_pgd(struct kvm_vcpu *vcpu, gpa_t new_pgd);
+void kvm_mmu_update_root(struct kvm_vcpu *vcpu);
 
 void kvm_configure_mmu(bool enable_tdp, int tdp_forced_root_level,
 		       int tdp_max_root_level, int tdp_huge_page_level);
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index d422d0d2adf8..c44b5114f947 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4189,7 +4189,7 @@ static bool fast_pgd_switch(struct kvm *kvm, struct kvm_mmu *mmu,
 		return cached_root_find_without_current(kvm, mmu, new_pgd, new_role);
 }
 
-void kvm_mmu_new_pgd(struct kvm_vcpu *vcpu, gpa_t new_pgd)
+static void __kvm_mmu_update_root(struct kvm_vcpu *vcpu, gpa_t new_pgd)
 {
 	struct kvm_mmu *mmu = vcpu->arch.mmu;
 	union kvm_mmu_page_role new_role = mmu->mmu_role.base;
@@ -4228,7 +4228,14 @@ 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));
 }
-EXPORT_SYMBOL_GPL(kvm_mmu_new_pgd);
+
+void kvm_mmu_update_root(struct kvm_vcpu *vcpu)
+{
+	gpa_t new_pgd = kvm_mmu_get_guest_pgd(vcpu);
+
+	__kvm_mmu_update_root(vcpu, new_pgd);
+}
+EXPORT_SYMBOL_GPL(kvm_mmu_update_root);
 
 static bool sync_mmio_spte(struct kvm_vcpu *vcpu, u64 *sptep, gfn_t gfn,
 			   unsigned int access)
@@ -4892,7 +4899,7 @@ void kvm_init_shadow_npt_mmu(struct kvm_vcpu *vcpu, unsigned long cr0,
 	new_role = kvm_calc_shadow_npt_root_page_role(vcpu, &regs);
 
 	shadow_mmu_init_context(vcpu, context, &regs, new_role);
-	kvm_mmu_new_pgd(vcpu, nested_cr3);
+	__kvm_mmu_update_root(vcpu, nested_cr3);
 }
 EXPORT_SYMBOL_GPL(kvm_init_shadow_npt_mmu);
 
@@ -4948,7 +4955,7 @@ 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);
+	__kvm_mmu_update_root(vcpu, new_eptp);
 }
 EXPORT_SYMBOL_GPL(kvm_init_shadow_ept_mmu);
 
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index 96bab464967f..2386fadae9ed 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -498,7 +498,7 @@ static int nested_svm_load_cr3(struct kvm_vcpu *vcpu, unsigned long cr3,
 	kvm_init_mmu(vcpu);
 
 	if (!nested_npt)
-		kvm_mmu_new_pgd(vcpu, cr3);
+		kvm_mmu_update_root(vcpu);
 
 	return 0;
 }
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 1dfe23963a9e..2dbd7a9ada84 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -1133,7 +1133,7 @@ static int nested_vmx_load_cr3(struct kvm_vcpu *vcpu, unsigned long cr3,
 	kvm_init_mmu(vcpu);
 
 	if (!nested_ept)
-		kvm_mmu_new_pgd(vcpu, cr3);
+		kvm_mmu_update_root(vcpu);
 
 	return 0;
 }
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index adcee7c305ca..9800c8883a48 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1189,7 +1189,7 @@ int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
 		return 1;
 
 	if (cr3 != kvm_read_cr3(vcpu))
-		kvm_mmu_new_pgd(vcpu, cr3);
+		kvm_mmu_update_root(vcpu);
 
 	vcpu->arch.cr3 = cr3;
 	kvm_register_mark_dirty(vcpu, VCPU_EXREG_CR3);
-- 
2.31.1