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KVM: arm64: Do not try to map PUDs when they are folded into PMD 

commit 3fb884ffe9 upstream.

For the obscure cases where PMD and PUD are the same size
(64kB pages with 42bit VA, for example, which results in only
two levels of page tables), we can't map anything as a PUD,
because there is... erm... no PUD to speak of. Everything is
either a PMD or a PTE.

So let's only try and map a PUD when its size is different from
that of a PMD.

Cc: stable@vger.kernel.org
Fixes: b8e0ba7c8b ("KVM: arm64: Add support for creating PUD hugepages at stage 2")
Reported-by: Gavin Shan <gshan@redhat.com>
Reported-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Tested-by: Gavin Shan <gshan@redhat.com>
Tested-by: Eric Auger <eric.auger@redhat.com>
Tested-by: Alexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
5.4-rM2-2.2.x-imx-squashed
Marc Zyngier 2020-09-02 11:18:29 +01:00 committed by Greg Kroah-Hartman
parent a86743ebe6
commit d334a67d3e
1 changed files with 6 additions and 1 deletions
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7
virt/kvm/arm/mmu.c
View File

@ -1814,7 +1814,12 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
(fault_status == FSC_PERM &&
stage2_is_exec(kvm, fault_ipa, vma_pagesize));
if (vma_pagesize == PUD_SIZE) {
/*
* If PUD_SIZE == PMD_SIZE, there is no real PUD level, and
* all we have is a 2-level page table. Trying to map a PUD in
* this case would be fatally wrong.
*/
if (PUD_SIZE != PMD_SIZE && vma_pagesize == PUD_SIZE) {
pud_t new_pud = kvm_pfn_pud(pfn, mem_type);
new_pud = kvm_pud_mkhuge(new_pud);