tree: https://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm.git queue head: 0c4011a2150b6d177cdd06c887615594a4693179 commit: 3c780d1840b62d9b5f2abffad6cc1373033ed6ea [26/31] KVM: arm/arm64: Fix unintended stage 2 PMD mappings config: arm-axm55xx_defconfig (attached as .config) compiler: arm-linux-gnueabi-gcc (Debian 7.2.0-11) 7.2.0 reproduce: wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross git checkout 3c780d1840b62d9b5f2abffad6cc1373033ed6ea # save the attached .config to linux build tree GCC_VERSION=7.2.0 make.cross ARCH=arm All error/warnings (new ones prefixed by >>): arch/arm/kvm/../../../virt/kvm/arm/mmu.c: In function 'fault_supports_stage2_pmd_mappings': >> arch/arm/kvm/../../../virt/kvm/arm/mmu.c:1636:20: error: 'S2_PMD_MASK' undeclared (first use in this function); did you mean 'PMD_MASK'? if ((gpa_start & ~S2_PMD_MASK) != (uaddr_start & ~S2_PMD_MASK)) ^~~~~~~~~~~ PMD_MASK arch/arm/kvm/../../../virt/kvm/arm/mmu.c:1636:20: note: each undeclared identifier is reported only once for each function it appears in >> arch/arm/kvm/../../../virt/kvm/arm/mmu.c:1652:31: error: 'S2_PMD_SIZE' undeclared (first use in this function); did you mean 'PMD_SIZE'? (hva & S2_PMD_MASK) + S2_PMD_SIZE <= uaddr_end; ^~~~~~~~~~~ PMD_SIZE >> arch/arm/kvm/../../../virt/kvm/arm/mmu.c:1653:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ vim +1636 arch/arm/kvm/../../../virt/kvm/arm/mmu.c 1597 1598 static bool fault_supports_stage2_pmd_mappings(struct kvm_memory_slot *memslot, 1599 unsigned long hva) 1600 { 1601 gpa_t gpa_start, gpa_end; 1602 hva_t uaddr_start, uaddr_end; 1603 size_t size; 1604 1605 size = memslot->npages * PAGE_SIZE; 1606 1607 gpa_start = memslot->base_gfn << PAGE_SHIFT; 1608 gpa_end = gpa_start + size; 1609 1610 uaddr_start = memslot->userspace_addr; 1611 uaddr_end = uaddr_start + size; 1612 1613 /* 1614 * Pages belonging to memslots that don't have the same alignment 1615 * within a PMD for userspace and IPA cannot be mapped with stage-2 1616 * PMD entries, because we'll end up mapping the wrong pages. 1617 * 1618 * Consider a layout like the following: 1619 * 1620 * memslot->userspace_addr: 1621 * +-----+--------------------+--------------------+---+ 1622 * |abcde|fgh Stage-1 PMD | Stage-1 PMD tv|xyz| 1623 * +-----+--------------------+--------------------+---+ 1624 * 1625 * memslot->base_gfn << PAGE_SIZE: 1626 * +---+--------------------+--------------------+-----+ 1627 * |abc|def Stage-2 PMD | Stage-2 PMD |tvxyz| 1628 * +---+--------------------+--------------------+-----+ 1629 * 1630 * If we create those stage-2 PMDs, we'll end up with this incorrect 1631 * mapping: 1632 * d -> f 1633 * e -> g 1634 * f -> h 1635 */ > 1636 if ((gpa_start & ~S2_PMD_MASK) != (uaddr_start & ~S2_PMD_MASK)) 1637 return false; 1638 1639 /* 1640 * Next, let's make sure we're not trying to map anything not covered 1641 * by the memslot. This means we have to prohibit PMD size mappings 1642 * for the beginning and end of a non-PMD aligned and non-PMD sized 1643 * memory slot (illustrated by the head and tail parts of the 1644 * userspace view above containing pages 'abcde' and 'xyz', 1645 * respectively). 1646 * 1647 * Note that it doesn't matter if we do the check using the 1648 * userspace_addr or the base_gfn, as both are equally aligned (per 1649 * the check above) and equally sized. 1650 */ 1651 return (hva & S2_PMD_MASK) >= uaddr_start && > 1652 (hva & S2_PMD_MASK) + S2_PMD_SIZE <= uaddr_end; > 1653 } 1654 --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation
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