linux-dev/arch/s390/mm/gmap.c, branch linus/master

Merge tag 's390-5.19-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

2022-06-03T20:57:50Z

Pull more s390 updates from Heiko Carstens: "Just a couple of small improvements, bug fixes and cleanups: - Add Eric Farman as maintainer for s390 virtio drivers. - Improve machine check handling, and avoid incorrectly injecting a machine check into a kvm guest. - Add cond_resched() call to gmap page table walker in order to avoid possible huge latencies. Also use non-quiesing sske instruction to speed up storage key handling. - Add __GFP_NORETRY to KEXEC_CONTROL_MEMORY_GFP so s390 behaves similar like common code. - Get sie control block address from correct stack slot in perf event code. This fixes potential random memory accesses. - Change uaccess code so that the exception handler sets the result of get_user() and __get_kernel_nofault() to zero in case of a fault. Until now this was done via input parameters for inline assemblies. Doing it via fault handling is what most or even all other architectures are doing. - Couple of other small cleanups and fixes" * tag 's390-5.19-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: s390/stack: add union to reflect kvm stack slot usages s390/stack: merge empty stack frame slots s390/uaccess: whitespace cleanup s390/uaccess: use __noreturn instead of __attribute__((noreturn)) s390/uaccess: use exception handler to zero result on get_user() failure s390/uaccess: use symbolic names for inline assembler operands s390/mcck: isolate SIE instruction when setting CIF_MCCK_GUEST flag s390/mm: use non-quiescing sske for KVM switch to keyed guest s390/gmap: voluntarily schedule during key setting MAINTAINERS: Update s390 virtio-ccw s390/kexec: add __GFP_NORETRY to KEXEC_CONTROL_MEMORY_GFP s390/Kconfig.debug: fix indentation s390/Kconfig: fix indentation s390/perf: obtain sie_block from the right address s390: generate register offsets into pt_regs automatically s390: simplify early program check handler s390/crypto: fix scatterwalk_unmap() callers in AES-GCM

s390/gmap: voluntarily schedule during key setting

2022-06-01T10:03:16Z

With large and many guest with storage keys it is possible to create large latencies or stalls during initial key setting: rcu: INFO: rcu_sched self-detected stall on CPU rcu: 18-....: (2099 ticks this GP) idle=54e/1/0x4000000000000002 softirq=35598716/35598716 fqs=998 (t=2100 jiffies g=155867385 q=20879) Task dump for CPU 18: CPU 1/KVM R running task 0 1030947 256019 0x06000004 Call Trace: sched_show_task rcu_dump_cpu_stacks rcu_sched_clock_irq update_process_times tick_sched_handle tick_sched_timer __hrtimer_run_queues hrtimer_interrupt do_IRQ ext_int_handler ptep_zap_key The mmap lock is held during the page walking but since this is a semaphore scheduling is still possible. Same for the kvm srcu. To minimize overhead do this on every segment table entry or large page. Signed-off-by: Christian Borntraeger Reviewed-by: Alexander Gordeev Reviewed-by: Claudio Imbrenda Link: https://lore.kernel.org/r/20220530092706.11637-2-borntraeger@linux.ibm.com Signed-off-by: Christian Borntraeger Signed-off-by: Heiko Carstens

KVM: s390: vsie/gmap: reduce gmap_rmap overhead

2022-05-03T13:15:44Z

there are cases that trigger a 2nd shadow event for the same vmaddr/raddr combination. (prefix changes, reboots, some known races) This will increase memory usages and it will result in long latencies when cleaning up, e.g. on shutdown. To avoid cases with a list that has hundreds of identical raddrs we check existing entries at insert time. As this measurably reduces the list length this will be faster than traversing the list at shutdown time. In the long run several places will be optimized to create less entries and a shrinker might be necessary. Fixes: 4be130a08420 ("s390/mm: add shadow gmap support") Signed-off-by: Christian Borntraeger Acked-by: David Hildenbrand Link: https://lore.kernel.org/r/20220429151526.1560-1-borntraeger@linux.ibm.com Signed-off-by: Heiko Carstens

s390: convert ".insn" encoding to instruction names

2022-03-10T14:58:17Z

With z10 as minimum supported machine generation many ".insn" encodings could be now converted to instruction names. There are couple of exceptions - stfle is used from the als code built for z900 and cannot be converted - few ".insn" directives encode unsupported instruction formats The generated code is identical before/after this change. Acked-by: Ilya Leoshkevich Reviewed-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390/mm,gmap: don't use pte_val()/pXd_val() as lvalue

2022-03-01T20:05:10Z

Convert pgtable code so pte_val()/pXd_val() aren't used as lvalue anymore. This allows in later step to convert pte_val()/pXd_val() to functions, which in turn makes it impossible to use these macros to modify page table entries like they have been used before. Therefore a construct like this: pte_val(*pte) = __pa(addr) | prot; which would directly write into a page table, isn't possible anymore with the last step of this series. Reviewed-by: Claudio Imbrenda Reviewed-by: Alexander Gordeev Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390/mm: use set_pXd()/set_pte() helper functions everywhere

2022-03-01T20:05:10Z

Use the new set_pXd()/set_pte() helper functions at all places where page table entries are modified. Reviewed-by: Alexander Gordeev Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik

KVM: s390: pv: properly handle page flags for protected guests

2021-10-27T05:55:53Z

Introduce variants of the convert and destroy page functions that also clear the PG_arch_1 bit used to mark them as secure pages. The PG_arch_1 flag is always allowed to overindicate; using the new functions introduced here allows to reduce the extent of overindication and thus improve performance. These new functions can only be called on pages for which a reference is already being held. Signed-off-by: Claudio Imbrenda Reviewed-by: Janosch Frank Reviewed-by: Christian Borntraeger Link: https://lore.kernel.org/r/20210920132502.36111-7-imbrenda@linux.ibm.com Signed-off-by: Christian Borntraeger

s390/gmap: don't unconditionally call pte_unmap_unlock() in __gmap_zap()

2021-10-25T07:20:38Z

... otherwise we will try unlocking a spinlock that was never locked via a garbage pointer. At the time we reach this code path, we usually successfully looked up a PGSTE already; however, evil user space could have manipulated the VMA layout in the meantime and triggered removal of the page table. Fixes: 1e133ab296f3 ("s390/mm: split arch/s390/mm/pgtable.c") Signed-off-by: David Hildenbrand Reviewed-by: Claudio Imbrenda Acked-by: Heiko Carstens Link: https://lore.kernel.org/r/20210909162248.14969-3-david@redhat.com Signed-off-by: Christian Borntraeger

s390/gmap: validate VMA in __gmap_zap()

2021-10-25T07:20:38Z

We should not walk/touch page tables outside of VMA boundaries when holding only the mmap sem in read mode. Evil user space can modify the VMA layout just before this function runs and e.g., trigger races with page table removal code since commit dd2283f2605e ("mm: mmap: zap pages with read mmap_sem in munmap"). The pure prescence in our guest_to_host radix tree does not imply that there is a VMA. Further, we should not allocate page tables (via get_locked_pte()) outside of VMA boundaries: if evil user space decides to map hugetlbfs to these ranges, bad things will happen because we suddenly have PTE or PMD page tables where we shouldn't have them. Similarly, we have to check if we suddenly find a hugetlbfs VMA, before calling get_locked_pte(). Note that gmap_discard() is different: zap_page_range()->unmap_single_vma() makes sure to stay within VMA boundaries. Fixes: b31288fa83b2 ("s390/kvm: support collaborative memory management") Signed-off-by: David Hildenbrand Reviewed-by: Claudio Imbrenda Acked-by: Heiko Carstens Link: https://lore.kernel.org/r/20210909162248.14969-2-david@redhat.com Signed-off-by: Christian Borntraeger

s390/mm: fix kernel doc comments

2021-09-07T11:38:41Z

Signed-off-by: Heiko Carstens