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authorMarc Zyngier <marc.zyngier@arm.com>2016-06-30 18:40:50 +0100
committerChristoffer Dall <christoffer.dall@linaro.org>2016-07-03 23:41:27 +0200
commiteac378a9ceb7196b776a965d915e02995fb8ba55 (patch)
tree207965331a3cb620ebcd081ac61b1580a2a7cf90
parentf7bec68d2faed8180d7172cdbd69d99e3cad1387 (diff)
arm/arm64: KVM: Check that IDMAP doesn't intersect with VA range
This is more of a safety measure than anything else: If we end-up with an idmap page that intersect with the range picked for the the HYP VA space, abort the KVM setup, as it is unsafe to go further. I cannot imagine it happening on 64bit (we have a mechanism to work around it), but could potentially occur on a 32bit system with the kernel loaded high enough in memory so that in conflicts with the kernel VA. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
-rw-r--r--arch/arm/kvm/mmu.c15
1 files changed, 15 insertions, 0 deletions
diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
index 0b36dd52af62..8a0aa37605c5 100644
--- a/arch/arm/kvm/mmu.c
+++ b/arch/arm/kvm/mmu.c
@@ -1709,6 +1709,21 @@ int kvm_mmu_init(void)
*/
BUG_ON((hyp_idmap_start ^ (hyp_idmap_end - 1)) & PAGE_MASK);
+ kvm_info("IDMAP page: %lx\n", hyp_idmap_start);
+ kvm_info("HYP VA range: %lx:%lx\n",
+ KERN_TO_HYP(PAGE_OFFSET), KERN_TO_HYP(~0UL));
+
+ if (hyp_idmap_start >= KERN_TO_HYP(PAGE_OFFSET) &&
+ hyp_idmap_start < KERN_TO_HYP(~0UL)) {
+ /*
+ * The idmap page is intersecting with the VA space,
+ * it is not safe to continue further.
+ */
+ kvm_err("IDMAP intersecting with HYP VA, unable to continue\n");
+ err = -EINVAL;
+ goto out;
+ }
+
hyp_pgd = (pgd_t *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, hyp_pgd_order);
if (!hyp_pgd) {
kvm_err("Hyp mode PGD not allocated\n");