From: Ankit Agrawal <ankita@nvidia.com> mainline inclusion from mainline-v6.9-rc1 commit 8c47ce3e1d2c285349edf426b98e8460ce3e2f33 category: bugfix bugzilla: https://atomgit.com/openeuler/kernel/issues/9340 CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- To provide VM with the ability to get device IO memory with NormalNC property, map device MMIO in KVM for ARM64 at stage2 as NormalNC. Having NormalNC S2 default puts guests in control (based on [1], "Combining stage 1 and stage 2 memory type attributes") of device MMIO regions memory mappings. The rules are summarized below: ([(S1) - stage1], [(S2) - stage 2]) S1 | S2 | Result NORMAL-WB | NORMAL-NC | NORMAL-NC NORMAL-WT | NORMAL-NC | NORMAL-NC NORMAL-NC | NORMAL-NC | NORMAL-NC DEVICE<attr> | NORMAL-NC | DEVICE<attr> Still this cannot be generalized to non PCI devices such as GICv2. There is insufficient information and uncertainity in the behavior of non PCI driver. A driver must indicate support using the new flag VM_ALLOW_ANY_UNCACHED. Adapt KVM to make use of the flag VM_ALLOW_ANY_UNCACHED as indicator to activate the S2 setting to NormalNc. [1] section D8.5.5 of DDI0487J_a_a-profile_architecture_reference_manual.pdf Suggested-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Jason Gunthorpe <jgg@nvidia.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Ankit Agrawal <ankita@nvidia.com> Signed-off-by: Tian Zheng <zhengtian10@huawei.com> --- arch/arm64/kvm/mmu.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index fbc62b27adc8..e4fe5c7785e2 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -1476,7 +1476,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, int ret = 0; bool write_fault, writable, force_pte = false; bool exec_fault, mte_allowed; - bool device = false; + bool device = false, vfio_allow_any_uc = false; unsigned long mmu_seq; struct kvm *kvm = vcpu->kvm; struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache; @@ -1583,6 +1583,8 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, gfn = kvm_gpa_from_fault(kvm, fault_ipa) >> PAGE_SHIFT; mte_allowed = kvm_vma_mte_allowed(vma); + vfio_allow_any_uc = vma->vm_flags & VM_ALLOW_ANY_UNCACHED; + /* Don't use the VMA after the unlock -- it may have vanished */ vma = NULL; @@ -1686,10 +1688,14 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, if (exec_fault) prot |= KVM_PGTABLE_PROT_X; - if (device) - prot |= KVM_PGTABLE_PROT_DEVICE; - else if (cpus_have_const_cap(ARM64_HAS_CACHE_DIC)) + if (device) { + if (vfio_allow_any_uc) + prot |= KVM_PGTABLE_PROT_NORMAL_NC; + else + prot |= KVM_PGTABLE_PROT_DEVICE; + } else if (cpus_have_const_cap(ARM64_HAS_CACHE_DIC)) { prot |= KVM_PGTABLE_PROT_X; + } /* * Under the premise of getting a FSC_PERM fault, we just need to relax -- 2.33.0