3.16.55-rc1 review patch. If anyone has any objections, please let me know.
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From: Marc Zyngier marc.zyngier@arm.com
commit 7839c672e58bf62da8f2f0197fefb442c02ba1dd upstream.
When we unmap the HYP memory, we try to be clever and unmap one PGD at a time. If we start with a non-PGD aligned address and try to unmap a whole PGD, things go horribly wrong in unmap_hyp_range (addr and end can never match, and it all goes really badly as we keep incrementing pgd and parse random memory as page tables...).
The obvious fix is to let unmap_hyp_range do what it does best, which is to iterate over a range.
The size of the linear mapping, which begins at PAGE_OFFSET, can be easily calculated by subtracting PAGE_OFFSET form high_memory, because high_memory is defined as the linear map address of the last byte of DRAM, plus one.
The size of the vmalloc region is given trivially by VMALLOC_END - VMALLOC_START.
Reported-by: Andre Przywara andre.przywara@arm.com Tested-by: Andre Przywara andre.przywara@arm.com Reviewed-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 [bwh: Backported to 3.16: adjust filename, context] Signed-off-by: Ben Hutchings ben@decadent.org.uk --- arch/arm/kvm/mmu.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-)
--- a/arch/arm/kvm/mmu.c +++ b/arch/arm/kvm/mmu.c @@ -345,17 +345,15 @@ void free_boot_hyp_pgd(void) */ void free_hyp_pgds(void) { - unsigned long addr; - free_boot_hyp_pgd();
mutex_lock(&kvm_hyp_pgd_mutex);
if (hyp_pgd) { - for (addr = PAGE_OFFSET; virt_addr_valid(addr); addr += PGDIR_SIZE) - unmap_range(NULL, hyp_pgd, KERN_TO_HYP(addr), PGDIR_SIZE); - for (addr = VMALLOC_START; is_vmalloc_addr((void*)addr); addr += PGDIR_SIZE) - unmap_range(NULL, hyp_pgd, KERN_TO_HYP(addr), PGDIR_SIZE); + unmap_range(NULL, hyp_pgd, KERN_TO_HYP(PAGE_OFFSET), + (uintptr_t)high_memory - PAGE_OFFSET); + unmap_range(NULL, hyp_pgd, KERN_TO_HYP(VMALLOC_START), + VMALLOC_END - VMALLOC_START);
free_pages((unsigned long)hyp_pgd, pgd_order); hyp_pgd = NULL;