linux-kernel - [PATCH 51/54] KVM: x86/mmu: Drop redundant rsvd bits reset for nested NPT

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]

Date:   Tue, 22 Jun 2021 10:57:36 -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,
        Yu Zhang <yu.c.zhang@...ux.intel.com>,
        Maxim Levitsky <mlevitsk@...hat.com>
Subject: [PATCH 51/54] KVM: x86/mmu: Drop redundant rsvd bits reset for nested NPT

Drop the extra reset of shadow_zero_bits in the nested NPT flow now
that shadow_mmu_init_context computes the correct level for nested NPT.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/mmu/mmu.c | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 7849f53fd874..d4969ac98a4b 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4693,12 +4693,6 @@ void kvm_init_shadow_npt_mmu(struct kvm_vcpu *vcpu, unsigned long cr0,
 	__kvm_mmu_new_pgd(vcpu, nested_cr3, new_role.base);
 
 	shadow_mmu_init_context(vcpu, context, &regs, new_role);
-
-	/*
-	 * Redo the shadow bits, the reset done by shadow_mmu_init_context()
-	 * (above) may use the wrong shadow_root_level.
-	 */
-	reset_shadow_zero_bits_mask(vcpu, context);
 }
 EXPORT_SYMBOL_GPL(kvm_init_shadow_npt_mmu);
 
-- 
2.32.0.288.g62a8d224e6-goog