This is a note to let you know that I've just added the patch titled
ARM: KVM: user_mem_abort: support stage 2 MMIO page mapping
to the 3.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
arm-kvm-user_mem_abort-support-stage-2-mmio-page-mapping.patch
and it can be found in the queue-3.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From b88657674d39fc2127d62d0de9ca142e166443c8 Mon Sep 17 00:00:00 2001
From: Kim Phillips <kim.phillips@xxxxxxxxxx>
Date: Thu, 26 Jun 2014 01:45:51 +0100
Subject: ARM: KVM: user_mem_abort: support stage 2 MMIO page mapping
From: Kim Phillips <kim.phillips@xxxxxxxxxx>
commit b88657674d39fc2127d62d0de9ca142e166443c8 upstream.
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@xxxxxxxxxx>
Acked-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
Acked-by: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Signed-off-by: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm/kvm/mmu.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
--- a/arch/arm/kvm/mmu.c
+++ b/arch/arm/kvm/mmu.c
@@ -759,6 +759,7 @@ static int user_mem_abort(struct kvm_vcp
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) {
@@ -809,6 +810,9 @@ static int user_mem_abort(struct kvm_vcp
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;
@@ -816,7 +820,7 @@ static int user_mem_abort(struct kvm_vcp
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);
@@ -825,13 +829,14 @@ static int user_mem_abort(struct kvm_vcp
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);
}
Patches currently in stable-queue which might be from kim.phillips@xxxxxxxxxx are
queue-3.14/arm-kvm-user_mem_abort-support-stage-2-mmio-page-mapping.patch
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