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[34.140.204.24]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3a0b0dffaa1sm1179414f8f.31.2025.05.06.03.36.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 06 May 2025 03:36:40 -0700 (PDT) Date: Tue, 6 May 2025 11:36:35 +0100 From: Vincent Donnefort To: Sebastian Ott Cc: Marc Zyngier , Oliver Upton , 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, stable@vger.kernel.org Subject: Re: [PATCH] KVM: arm64: Fix uninitialized memcache pointer in user_mem_abort() Message-ID: References: <20250505173148.33900-1-sebott@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250505173148.33900-1-sebott@redhat.com> On Mon, May 05, 2025 at 07:31:48PM +0200, Sebastian Ott wrote: > 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@redhat.com/ > --- > 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, phys_addr_t fault_ipa, > return -EFAULT; > } > > + if (!is_protected_kvm_enabled()) > + memcache = &vcpu->arch.mmu_page_cache; > + else > + memcache = &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, phys_addr_t fault_ipa, > if (!fault_is_perm || (logging_active && write_fault)) { > int min_pages = kvm_mmu_cache_min_pages(vcpu->arch.hw_mmu); > > - if (!is_protected_kvm_enabled()) { > - memcache = &vcpu->arch.mmu_page_cache; > + if (!is_protected_kvm_enabled()) > ret = kvm_mmu_topup_memory_cache(memcache, min_pages); > - } else { > - memcache = &vcpu->arch.pkvm_memcache; > + else > ret = topup_hyp_memcache(memcache, min_pages); > - } > + > if (ret) > return ret; > } > > base-commit: 92a09c47464d040866cf2b4cd052bc60555185fb > -- > 2.49.0 > > For the pKVM part Reviewed-by: Vincent Donnefort Thanks