linux-kernel - [PATCH 13/15] KVM: x86: Drop pointless @reset_roots from kvm_init

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20210609234235.1244004-14-seanjc@google.com>
Date:   Wed,  9 Jun 2021 16:42:33 -0700
From:   Sean Christopherson <seanjc@...gle.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Sean Christopherson <seanjc@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, Junaid Shahid <junaids@...gle.com>,
        Maxim Levitsky <mlevitsk@...hat.com>,
        Lai Jiangshan <laijs@...ux.alibaba.com>
Subject: [PATCH 13/15] KVM: x86: Drop pointless @reset_roots from kvm_init_mmu()

Remove the @reset_roots param from kvm_init_mmu(), the one user,
kvm_mmu_reset_context() has already unloaded the MMU and thus freed and
invalidated all roots.  This also happens to be why the reset_roots=true
paths doesn't leak roots; they're already invalid.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/mmu.h        |  2 +-
 arch/x86/kvm/mmu/mmu.c    | 13 ++-----------
 arch/x86/kvm/svm/nested.c |  2 +-
 arch/x86/kvm/vmx/nested.c |  2 +-
 arch/x86/kvm/x86.c        |  2 +-
 5 files changed, 6 insertions(+), 15 deletions(-)

diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h
index 88d0ed5225a4..63b49725fb24 100644
--- a/arch/x86/kvm/mmu.h
+++ b/arch/x86/kvm/mmu.h
@@ -65,7 +65,7 @@ void kvm_mmu_set_ept_masks(bool has_ad_bits, bool has_exec_only);
 void
 reset_shadow_zero_bits_mask(struct kvm_vcpu *vcpu, struct kvm_mmu *context);
 
-void kvm_init_mmu(struct kvm_vcpu *vcpu, bool reset_roots);
+void kvm_init_mmu(struct kvm_vcpu *vcpu);
 void kvm_init_shadow_npt_mmu(struct kvm_vcpu *vcpu, u32 cr0, u32 cr4, u32 efer,
 			     gpa_t nested_cr3);
 void kvm_init_shadow_ept_mmu(struct kvm_vcpu *vcpu, bool execonly,
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index f987f2ea4a01..b4fa8ec8afce 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4817,17 +4817,8 @@ static void init_kvm_nested_mmu(struct kvm_vcpu *vcpu)
 	update_last_nonleaf_level(vcpu, g_context);
 }
 
-void kvm_init_mmu(struct kvm_vcpu *vcpu, bool reset_roots)
+void kvm_init_mmu(struct kvm_vcpu *vcpu)
 {
-	if (reset_roots) {
-		uint i;
-
-		vcpu->arch.mmu->root_hpa = INVALID_PAGE;
-
-		for (i = 0; i < KVM_MMU_NUM_PREV_ROOTS; i++)
-			vcpu->arch.mmu->prev_roots[i] = KVM_MMU_ROOT_INFO_INVALID;
-	}
-
 	if (mmu_is_nested(vcpu))
 		init_kvm_nested_mmu(vcpu);
 	else if (tdp_enabled)
@@ -4853,7 +4844,7 @@ kvm_mmu_calc_root_page_role(struct kvm_vcpu *vcpu)
 void kvm_mmu_reset_context(struct kvm_vcpu *vcpu)
 {
 	kvm_mmu_unload(vcpu);
-	kvm_init_mmu(vcpu, true);
+	kvm_init_mmu(vcpu);
 }
 EXPORT_SYMBOL_GPL(kvm_mmu_reset_context);
 
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index ccd90ea93acd..8a4276d8753d 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -421,7 +421,7 @@ static int nested_svm_load_cr3(struct kvm_vcpu *vcpu, unsigned long cr3,
 	vcpu->arch.cr3 = cr3;
 	kvm_register_mark_available(vcpu, VCPU_EXREG_CR3);
 
-	kvm_init_mmu(vcpu, false);
+	kvm_init_mmu(vcpu);
 
 	return 0;
 }
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 4b8f5dca49ac..f686618d9ede 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -1094,7 +1094,7 @@ static int nested_vmx_load_cr3(struct kvm_vcpu *vcpu, unsigned long cr3, bool ne
 	vcpu->arch.cr3 = cr3;
 	kvm_register_mark_available(vcpu, VCPU_EXREG_CR3);
 
-	kvm_init_mmu(vcpu, false);
+	kvm_init_mmu(vcpu);
 
 	return 0;
 }
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index d3a2a3375541..32e93492273f 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -10409,7 +10409,7 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
 	kvm_vcpu_mtrr_init(vcpu);
 	vcpu_load(vcpu);
 	kvm_vcpu_reset(vcpu, false);
-	kvm_init_mmu(vcpu, false);
+	kvm_init_mmu(vcpu);
 	vcpu_put(vcpu);
 	return 0;
 
-- 
2.32.0.rc1.229.g3e70b5a671-goog