diff mbox

[PULL,1/2] arm: KVM: Fix idmap overlap detection when the kernel is idmap'ed

Message ID 20160909105456.8585-2-christoffer.dall@linaro.org (mailing list archive)
State New, archived
Headers show

Commit Message

Christoffer Dall Sept. 9, 2016, 10:54 a.m. UTC 
From: Marc Zyngier <marc.zyngier@arm.com>

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 <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
---
 arch/arm/kvm/mmu.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
diff mbox

Patch

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.