From d2896d4b55b2e32b423072a4124d7da4dc1e6cb1 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Mon, 22 Aug 2016 09:01:17 +0100 Subject: [PATCH] arm: KVM: Fix idmap overlap detection when the kernel is idmap'ed We're trying hard to detect when the HYP idmap overlaps with the HYP va, as it makes the teardown of a cpu dangerous. But there is one case where an overlap is completely safe, which is when the whole of the kernel is idmap'ed, which is likely to happen on 32bit when RAM is at 0x8000000 and we're using a 2G/2G VA split. In that case, we can proceed safely. Reported-by: Christoffer Dall Signed-off-by: Marc Zyngier Signed-off-by: Christoffer Dall --- arch/arm/kvm/mmu.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c index 29d0b23..a3faafe 100644 --- a/arch/arm/kvm/mmu.c +++ b/arch/arm/kvm/mmu.c @@ -1714,7 +1714,8 @@ int kvm_mmu_init(void) kern_hyp_va(PAGE_OFFSET), kern_hyp_va(~0UL)); if (hyp_idmap_start >= kern_hyp_va(PAGE_OFFSET) && - hyp_idmap_start < kern_hyp_va(~0UL)) { + hyp_idmap_start < kern_hyp_va(~0UL) && + hyp_idmap_start != (unsigned long)__hyp_idmap_text_start) { /* * The idmap page is intersecting with the VA space, * it is not safe to continue further. -- 2.7.4