Messages in this thread Patch in this message | | | Date | Wed, 25 Jun 2014 19:45:51 -0500 | From | Kim Phillips <> | Subject | [PATCH 2/2 v2] ARM: KVM: user_mem_abort: support stage 2 MMIO page mapping |
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From: Kim Phillips <kim.phillips@linaro.org>
A userspace process can map device MMIO memory via VFIO or /dev/mem, e.g., for platform device passthrough support in QEMU.
During early development, we found the PAGE_S2 memory type being used for MMIO mappings. This patch corrects that by using the more strongly ordered memory type for device MMIO mappings: PAGE_S2_DEVICE.
Signed-off-by: Kim Phillips <kim.phillips@linaro.org> Acked-by: Christoffer Dall <christoffer.dall@linaro.org> --- Hi, here's a v2, upon request:
- rebased onto today's mainline ToT - mmu.o-build tested only (ToT build doesn't complete) - made commit text less terse - added Christoffer's ack
Cheers,
Kim
arch/arm/kvm/mmu.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c index 16f8049..69af021 100644 --- a/arch/arm/kvm/mmu.c +++ b/arch/arm/kvm/mmu.c @@ -748,6 +748,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache; struct vm_area_struct *vma; pfn_t pfn; + pgprot_t mem_type = PAGE_S2; write_fault = kvm_is_write_fault(kvm_vcpu_get_hsr(vcpu)); if (fault_status == FSC_PERM && !write_fault) { @@ -798,6 +799,9 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, if (is_error_pfn(pfn)) return -EFAULT; + if (kvm_is_mmio_pfn(pfn)) + mem_type = PAGE_S2_DEVICE; + spin_lock(&kvm->mmu_lock); if (mmu_notifier_retry(kvm, mmu_seq)) goto out_unlock; @@ -805,7 +809,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, hugetlb = transparent_hugepage_adjust(&pfn, &fault_ipa); if (hugetlb) { - pmd_t new_pmd = pfn_pmd(pfn, PAGE_S2); + pmd_t new_pmd = pfn_pmd(pfn, mem_type); new_pmd = pmd_mkhuge(new_pmd); if (writable) { kvm_set_s2pmd_writable(&new_pmd); @@ -814,13 +818,14 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, coherent_cache_guest_page(vcpu, hva & PMD_MASK, PMD_SIZE); ret = stage2_set_pmd_huge(kvm, memcache, fault_ipa, &new_pmd); } else { - pte_t new_pte = pfn_pte(pfn, PAGE_S2); + pte_t new_pte = pfn_pte(pfn, mem_type); if (writable) { kvm_set_s2pte_writable(&new_pte); kvm_set_pfn_dirty(pfn); } coherent_cache_guest_page(vcpu, hva, PAGE_SIZE); - ret = stage2_set_pte(kvm, memcache, fault_ipa, &new_pte, false); + ret = stage2_set_pte(kvm, memcache, fault_ipa, &new_pte, + mem_type == PAGE_S2_DEVICE); } -- 2.0.0
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