kvm: limit virtual address space to 47-bit on amd64 #12398
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* There are no known use cases requiring the extended address space.
* By restricting the size, we avoid the overhead of:
a) Aligning the virtual address space size to the physical
address space size.
b) Creating unnecessary page table entries for the unused
extended range.
* The memory slot size is currently configured only to cover
the default 47-bit address space.
* 5-level page table support was primarily introduced to workaround
a specific kernel bug where VDSO could be mapped above the 47-bit
boundary (v6.9-rc1~186^2~7).
Updates #12308
PiperOrigin-RevId: 845852358
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kvm: limit virtual address space to 47-bit on amd64
a) Aligning the virtual address space size to the physical
address space size.
b) Creating unnecessary page table entries for the unused
extended range.
the default 47-bit address space.
a specific kernel bug where VDSO could be mapped above the 47-bit
boundary (v6.9-rc1
186^27).Updates #12308