arm: KVM: fix possible misalignment of PGDs and bounce page
The kvm/mmu code shared by arm and arm64 uses kalloc() to allocate
a bounce page (if hypervisor init code crosses page boundary) and
hypervisor PGDs. The problem is that kalloc() does not guarantee
the proper alignment. In the case of the bounce page, the page sized
buffer allocated may also cross a page boundary negating the purpose
and leading to a hang during kvm initialization. Likewise the PGDs
allocated may not meet the minimum alignment requirements of the
underlying MMU. This patch uses __get_free_page() to guarantee the
worst case alignment needs of the bounce page and PGDs on both arm
and arm64.
Cc: <stable@vger.kernel.org> # 3.10+
Signed-off-by: Mark Salter <msalter@redhat.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
index 80bb1e6..16f8049 100644
--- a/arch/arm/kvm/mmu.c
+++ b/arch/arm/kvm/mmu.c
@@ -42,6 +42,8 @@
static unsigned long hyp_idmap_end;
static phys_addr_t hyp_idmap_vector;
+#define pgd_order get_order(PTRS_PER_PGD * sizeof(pgd_t))
+
#define kvm_pmd_huge(_x) (pmd_huge(_x) || pmd_trans_huge(_x))
static void kvm_tlb_flush_vmid_ipa(struct kvm *kvm, phys_addr_t ipa)
@@ -293,14 +295,14 @@
if (boot_hyp_pgd) {
unmap_range(NULL, boot_hyp_pgd, hyp_idmap_start, PAGE_SIZE);
unmap_range(NULL, boot_hyp_pgd, TRAMPOLINE_VA, PAGE_SIZE);
- kfree(boot_hyp_pgd);
+ free_pages((unsigned long)boot_hyp_pgd, pgd_order);
boot_hyp_pgd = NULL;
}
if (hyp_pgd)
unmap_range(NULL, hyp_pgd, TRAMPOLINE_VA, PAGE_SIZE);
- kfree(init_bounce_page);
+ free_page((unsigned long)init_bounce_page);
init_bounce_page = NULL;
mutex_unlock(&kvm_hyp_pgd_mutex);
@@ -330,7 +332,7 @@
for (addr = VMALLOC_START; is_vmalloc_addr((void*)addr); addr += PGDIR_SIZE)
unmap_range(NULL, hyp_pgd, KERN_TO_HYP(addr), PGDIR_SIZE);
- kfree(hyp_pgd);
+ free_pages((unsigned long)hyp_pgd, pgd_order);
hyp_pgd = NULL;
}
@@ -1024,7 +1026,7 @@
size_t len = __hyp_idmap_text_end - __hyp_idmap_text_start;
phys_addr_t phys_base;
- init_bounce_page = kmalloc(PAGE_SIZE, GFP_KERNEL);
+ init_bounce_page = (void *)__get_free_page(GFP_KERNEL);
if (!init_bounce_page) {
kvm_err("Couldn't allocate HYP init bounce page\n");
err = -ENOMEM;
@@ -1050,8 +1052,9 @@
(unsigned long)phys_base);
}
- hyp_pgd = kzalloc(PTRS_PER_PGD * sizeof(pgd_t), GFP_KERNEL);
- boot_hyp_pgd = kzalloc(PTRS_PER_PGD * sizeof(pgd_t), GFP_KERNEL);
+ hyp_pgd = (pgd_t *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, pgd_order);
+ boot_hyp_pgd = (pgd_t *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, pgd_order);
+
if (!hyp_pgd || !boot_hyp_pgd) {
kvm_err("Hyp mode PGD not allocated\n");
err = -ENOMEM;