| From | Kamal Mostafa <> | Subject | [PATCH 3.19.y-ckt 33/86] arm: KVM: Fix incorrect device to IPA mapping | Date | Tue, 27 Oct 2015 14:29:33 -0700 |
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3.19.8-ckt9 -stable review patch. If anyone has any objections, please let me know.
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From: Marek Majtyka <marek.majtyka@tieto.com>
commit ca09f02f122b2ecb0f5ddfc5fd47b29ed657d4fd upstream.
A critical bug has been found in device memory stage1 translation for VMs with more then 4GB of address space. Once vm_pgoff size is smaller then pa (which is true for LPAE case, u32 and u64 respectively) some more significant bits of pa may be lost as a shift operation is performed on u32 and later cast onto u64.
Example: vm_pgoff(u32)=0x00210030, PAGE_SHIFT=12 expected pa(u64): 0x0000002010030000 produced pa(u64): 0x0000000010030000
The fix is to change the order of operations (casting first onto phys_addr_t and then shifting).
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> [maz: fixed changelog and patch formatting] Signed-off-by: Marek Majtyka <marek.majtyka@tieto.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- arch/arm/kvm/mmu.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c index 9ec6dfe..0512ed4 100644 --- a/arch/arm/kvm/mmu.c +++ b/arch/arm/kvm/mmu.c @@ -1439,8 +1439,10 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm, if (vma->vm_flags & VM_PFNMAP) { gpa_t gpa = mem->guest_phys_addr + (vm_start - mem->userspace_addr); - phys_addr_t pa = (vma->vm_pgoff << PAGE_SHIFT) + - vm_start - vma->vm_start; + phys_addr_t pa; + + pa = (phys_addr_t)vma->vm_pgoff << PAGE_SHIFT; + pa += vm_start - vma->vm_start; ret = kvm_phys_addr_ioremap(kvm, gpa, pa, vm_end - vm_start, -- 1.9.1
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