linux-kernel - [PATCH] KVM: x86: Deplete Paolo's brown paper bag supply by one

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-next>] [day] [month] [year] [list]

Message-Id: <20220406225106.55471-1-seanjc@google.com>
Date:   Wed,  6 Apr 2022 22:51:06 +0000
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
Subject: [PATCH] KVM: x86: Deplete Paolo's brown paper bag supply by one

Fix an inverted check on CR0.PG when computing the cpu_role, the MMU is
direct and all CR4 bits ignored if paging is disabled, not enabled.

Fixes: d73678dc11ec ("KVM: x86/mmu: split cpu_role from mmu_role")
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---

I haven't done much testing on the rest of the MMU role patches, this just
popped up in very, very basic testing ;-)  I assume this will be squashed,
hence the snarky shortlog.

 arch/x86/kvm/mmu/mmu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index e41d7bba7a65..ab24fc161bac 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4699,7 +4699,7 @@ kvm_calc_cpu_role(struct kvm_vcpu *vcpu, const struct kvm_mmu_role_regs *regs)
 	role.base.smm = is_smm(vcpu);
 	role.base.guest_mode = is_guest_mode(vcpu);
 
-	if (____is_cr0_pg(regs)) {
+	if (!____is_cr0_pg(regs)) {
 		role.base.direct = 1;
 		return role;
 	}

base-commit: 56ba4b488353a8925b30367d72e41d1996c23554
-- 
2.35.1.1094.g7c7d902a7c-goog