Re: [PATCH 2/2] ARM: KVM: user_mem_abort: support stage 2 MMIO page mapping

Christoffer Dall
2014-05-06T18:04:54Z

On Tue, Mar 25, 2014 at 05:08:14PM -0500, Kim Phillips wrote:
> Use the correct memory type for device MMIO mappings: PAGE_S2_DEVICE.
>
> Signed-off-by: Kim Phillips <kim.phillips@linaro.org>
> ---
> 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 7789857..a354610 100644
> --- a/arch/arm/kvm/mmu.c
> +++ b/arch/arm/kvm/mmu.c
> @@ -652,6 +652,7 @@ 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) {
> @@ -702,6 +703,9 @@ 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;
> @@ -709,7 +713,7 @@ 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);
> @@ -718,13 +722,14 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
> coherent_icache_guest_page(kvm, 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_icache_guest_page(kvm, 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);
> }
>
>
> --
> 1.9.1
>

I think this looks reasonable.

Acked-by: Christoffer Dall <christoffer.dall@linaro.org>