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| author | Marc Zyngier <marc.zyngier@arm.com> | 2016-04-28 16:16:31 +0100 |
|---|---|---|
| committer | Sasha Levin <sasha.levin@oracle.com> | 2016-06-03 19:15:37 -0400 |
| commit | 660cd2235c5ac7a4d3aa5c3370b63124fb50cf81 (patch) | |
| tree | eec474844593582a972635b3ed871b196c7a86ac /arch | |
| parent | 788da6ee7dc349b45047212f7dbce31e3fdc82b0 (diff) | |
| download | lwn-660cd2235c5ac7a4d3aa5c3370b63124fb50cf81.tar.gz lwn-660cd2235c5ac7a4d3aa5c3370b63124fb50cf81.zip | |
arm/arm64: KVM: Enforce Break-Before-Make on Stage-2 page tables
[ Upstream commit d4b9e0790aa764c0b01e18d4e8d33e93ba36d51f ]
The ARM architecture mandates that when changing a page table entry
from a valid entry to another valid entry, an invalid entry is first
written, TLB invalidated, and only then the new entry being written.
The current code doesn't respect this, directly writing the new
entry and only then invalidating TLBs. Let's fix it up.
Cc: <stable@vger.kernel.org>
Reported-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm/kvm/mmu.c | 17 |
1 files changed, 11 insertions, 6 deletions
diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c index da09ddcfcc00..691ea94897fd 100644 --- a/arch/arm/kvm/mmu.c +++ b/arch/arm/kvm/mmu.c @@ -886,11 +886,14 @@ static int stage2_set_pmd_huge(struct kvm *kvm, struct kvm_mmu_memory_cache VM_BUG_ON(pmd_present(*pmd) && pmd_pfn(*pmd) != pmd_pfn(*new_pmd)); old_pmd = *pmd; - kvm_set_pmd(pmd, *new_pmd); - if (pmd_present(old_pmd)) + if (pmd_present(old_pmd)) { + pmd_clear(pmd); kvm_tlb_flush_vmid_ipa(kvm, addr); - else + } else { get_page(virt_to_page(pmd)); + } + + kvm_set_pmd(pmd, *new_pmd); return 0; } @@ -939,12 +942,14 @@ static int stage2_set_pte(struct kvm *kvm, struct kvm_mmu_memory_cache *cache, /* Create 2nd stage page table mapping - Level 3 */ old_pte = *pte; - kvm_set_pte(pte, *new_pte); - if (pte_present(old_pte)) + if (pte_present(old_pte)) { + kvm_set_pte(pte, __pte(0)); kvm_tlb_flush_vmid_ipa(kvm, addr); - else + } else { get_page(virt_to_page(pte)); + } + kvm_set_pte(pte, *new_pte); return 0; } |