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[2003:f6:af1b:ce00:e6fe:5f11:c0a7:f4a1]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3a099ae0c3dsm11343310f8f.12.2025.05.05.10.32.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 05 May 2025 10:32:14 -0700 (PDT) From: Sebastian Ott To: Marc Zyngier , Oliver Upton Cc: Quentin Perret , Fuad Tabba , Catalin Marinas , Will Deacon , Mark Brown , Mark Rutland , linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org, Sebastian Ott , stable@vger.kernel.org Subject: [PATCH] KVM: arm64: Fix uninitialized memcache pointer in user_mem_abort() Date: Mon, 5 May 2025 19:31:48 +0200 Message-ID: <20250505173148.33900-1-sebott@redhat.com> X-Mailer: git-send-email 2.49.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Commit fce886a60207 ("KVM: arm64: Plumb the pKVM MMU in KVM") made the initialization of the local memcache variable in user_mem_abort() conditional, leaving a codepath where it is used uninitialized via kvm_pgtable_stage2_map(). This can fail on any path that requires a stage-2 allocation without transition via a permission fault or dirty logging. Fix this by making sure that memcache is always valid. Fixes: fce886a60207 ("KVM: arm64: Plumb the pKVM MMU in KVM") Signed-off-by: Sebastian Ott Reviewed-by: Marc Zyngier Cc: stable@vger.kernel.org Link: https://lore.kernel.org/kvmarm/3f5db4c7-ccce-fb95-595c-692fa7aad227@r= edhat.com/ Reviewed-by: Vincent Donnefort --- arch/arm64/kvm/mmu.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index 754f2fe0cc67..eeda92330ade 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -1501,6 +1501,11 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phy= s_addr_t fault_ipa, return -EFAULT; } =20 + if (!is_protected_kvm_enabled()) + memcache =3D &vcpu->arch.mmu_page_cache; + else + memcache =3D &vcpu->arch.pkvm_memcache; + /* * Permission faults just need to update the existing leaf entry, * and so normally don't require allocations from the memcache. The @@ -1510,13 +1515,11 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, ph= ys_addr_t fault_ipa, if (!fault_is_perm || (logging_active && write_fault)) { int min_pages =3D kvm_mmu_cache_min_pages(vcpu->arch.hw_mmu); =20 - if (!is_protected_kvm_enabled()) { - memcache =3D &vcpu->arch.mmu_page_cache; + if (!is_protected_kvm_enabled()) ret =3D kvm_mmu_topup_memory_cache(memcache, min_pages); - } else { - memcache =3D &vcpu->arch.pkvm_memcache; + else ret =3D topup_hyp_memcache(memcache, min_pages); - } + if (ret) return ret; } base-commit: 92a09c47464d040866cf2b4cd052bc60555185fb --=20 2.49.0