Commit d0c04a9a authored by Will Deacon's avatar Will Deacon Committed by ZhangPeng
Browse files

KVM: arm64: Don't defer TLB invalidation when zapping table entries 

stable inclusion
from stable-v6.6.47
commit 2c770086e0792eddb40e82067179586e90dc9c23
bugzilla: https://gitee.com/openeuler/kernel/issues/IAHMJO

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=2c770086e0792eddb40e82067179586e90dc9c23



--------------------------------

commit f62d4c3eb687d87b616b4279acec7862553bda77 upstream.

Commit 7657ea92 ("KVM: arm64: Use TLBI range-based instructions for
unmap") introduced deferred TLB invalidation for the stage-2 page-table
so that range-based invalidation can be used for the accumulated
addresses. This works fine if the structure of the page-tables remains
unchanged, but if entire tables are zapped and subsequently freed then
we transiently leave the hardware page-table walker with a reference
to freed memory thanks to the translation walk caches. For example,
stage2_unmap_walker() will free page-table pages:

	if (childp)
		mm_ops->put_page(childp);

and issue the TLB invalidation later in kvm_pgtable_stage2_unmap():

	if (stage2_unmap_defer_tlb_flush(pgt))
		/* Perform the deferred TLB invalidations */
		kvm_tlb_flush_vmid_range(pgt->mmu, addr, size);

For now, take the conservative approach and invalidate the TLB eagerly
when we clear a table entry. Note, however, that the existing level
hint passed to __kvm_tlb_flush_vmid_ipa() is incorrect and will be
fixed in a subsequent patch.

Cc: Raghavendra Rao Ananta <rananta@google.com>
Cc: Shaoqin Huang <shahuang@redhat.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Oliver Upton <oliver.upton@linux.dev>
Reviewed-by: default avatarShaoqin Huang <shahuang@redhat.com>
Reviewed-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240327124853.11206-2-will@kernel.org


Signed-off-by: default avatarOliver Upton <oliver.upton@linux.dev>
Cc: <stable@vger.kernel.org> # 6.6.y only
Signed-off-by: default avatarWill Deacon <will@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarZhangPeng <zhangpeng362@huawei.com>
parent 2b8c8a47

arch/arm64/kvm/hyp/pgtable.c

+3 −1
Original line number Diff line number Diff line
@@ -861,10 +861,12 @@ static void stage2_unmap_put_pte(const struct kvm_pgtable_visit_ctx *ctx, 
	if (kvm_pte_valid(ctx->old)) {

		kvm_clear_pte(ctx->ptep);



		if (!stage2_unmap_defer_tlb_flush(pgt))

		if (!stage2_unmap_defer_tlb_flush(pgt) ||

		    kvm_pte_table(ctx->old, ctx->level)) {

			kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, mmu,

					ctx->addr, ctx->level);

		}

	}



	mm_ops->put_page(ctx->ptep);

}