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| author | Marek Majtyka <marek.majtyka@tieto.com> | 2015-09-16 12:04:55 +0200 |
|---|---|---|
| committer | Marc Zyngier <marc.zyngier@arm.com> | 2015-09-16 14:50:45 +0100 |
| commit | ca09f02f122b2ecb0f5ddfc5fd47b29ed657d4fd (patch) | |
| tree | 5af4246ef7b215b3e689be3812cd197b410fc185 /arch/arm | |
| parent | 1713e5aa05fff3951e747548b373bd2c81be4e7a (diff) | |
| download | lwn-ca09f02f122b2ecb0f5ddfc5fd47b29ed657d4fd.tar.gz lwn-ca09f02f122b2ecb0f5ddfc5fd47b29ed657d4fd.zip | |
arm: KVM: Fix incorrect device to IPA mapping
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]
Cc: stable@vger.kernel.org
Signed-off-by: Marek Majtyka <marek.majtyka@tieto.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Diffstat (limited to 'arch/arm')
| -rw-r--r-- | arch/arm/kvm/mmu.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c index 7b4201294187..6984342da13d 100644 --- a/arch/arm/kvm/mmu.c +++ b/arch/arm/kvm/mmu.c @@ -1792,8 +1792,10 @@ 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; /* IO region dirty page logging not allowed */ if (memslot->flags & KVM_MEM_LOG_DIRTY_PAGES) |