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KVM: arm64: Use fallback mapping sizes for contiguous huge page sizes 

Although huge pages can be created out of multiple contiguous PMDs
or PTEs, the corresponding sizes are not supported at Stage-2 yet.

Instead of failing the mapping, fall back to the nearer supported
mapping size (CONT_PMD to PMD and CONT_PTE to PTE respectively).

Suggested-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Gavin Shan <gshan@redhat.com>
[maz: rewritten commit message]
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201025230626.18501-1-gshan@redhat.com
zero-sugar-mainline-defconfig
Gavin Shan 2020-10-26 10:06:26 +11:00 committed by Marc Zyngier
parent e2fc6a9f68
commit 2f40c46021
1 changed files with 19 additions and 7 deletions
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26
arch/arm64/kvm/mmu.c
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@ -787,14 +787,26 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
vma_shift = PAGE_SHIFT;
}
if (vma_shift == PUD_SHIFT &&
!fault_supports_stage2_huge_mapping(memslot, hva, PUD_SIZE))
vma_shift = PMD_SHIFT;
if (vma_shift == PMD_SHIFT &&
!fault_supports_stage2_huge_mapping(memslot, hva, PMD_SIZE)) {
force_pte = true;
switch (vma_shift) {
case PUD_SHIFT:
if (fault_supports_stage2_huge_mapping(memslot, hva, PUD_SIZE))
break;
fallthrough;
case CONT_PMD_SHIFT:
vma_shift = PMD_SHIFT;
fallthrough;
case PMD_SHIFT:
if (fault_supports_stage2_huge_mapping(memslot, hva, PMD_SIZE))
break;
fallthrough;
case CONT_PTE_SHIFT:
vma_shift = PAGE_SHIFT;
force_pte = true;
fallthrough;
case PAGE_SHIFT:
break;
default:
WARN_ONCE(1, "Unknown vma_shift %d", vma_shift);
}
vma_pagesize = 1UL << vma_shift;