redonkable
/
alistair23-linux
1
0
Fork 0
Code Releases Activity

KVM: arm64: Update page shift if stage 2 block mapping not supported 

Commit 196f878a7a (" KVM: arm/arm64: Signal SIGBUS when stage2 discovers
hwpoison memory") modifies user_mem_abort() to send a SIGBUS signal when
the fault IPA maps to a hwpoisoned page. Commit 1559b7583f ("KVM:
arm/arm64: Re-check VMA on detecting a poisoned page") changed
kvm_send_hwpoison_signal() to use the page shift instead of the VMA because
at that point the code had already released the mmap lock, which means
userspace could have modified the VMA.

If userspace uses hugetlbfs for the VM memory, user_mem_abort() tries to
map the guest fault IPA using block mappings in stage 2. That is not always
possible, if, for example, userspace uses dirty page logging for the VM.
Update the page shift appropriately in those cases when we downgrade the
stage 2 entry from a block mapping to a page.

Fixes: 1559b7583f ("KVM: arm/arm64: Re-check VMA on detecting a poisoned page")
Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Link: https://lore.kernel.org/r/20200901133357.52640-2-alexandru.elisei@arm.com
zero-sugar-mainline-defconfig
Alexandru Elisei 2020-09-01 14:33:56 +01:00 committed by Marc Zyngier
parent 376426b1a9
commit 7b75cd5128
1 changed files with 1 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/arm64/kvm/mmu.c
View File

@ -1871,6 +1871,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
!fault_supports_stage2_huge_mapping(memslot, hva, vma_pagesize)) {
force_pte = true;
vma_pagesize = PAGE_SIZE;
vma_shift = PAGE_SHIFT;
}
/*