Hi James, On 20/06/17 17:11, James Morse wrote: > Once we enable ARCH_SUPPORTS_MEMORY_FAILURE on arm64, notifications for > broken memory can call memory_failure() in mm/memory-failure.c to offline > pages of memory, possibly signalling user space processes and notifying all > the in-kernel users. > > memory_failure() has two modes, early and late. Early is used by > machine-managers like Qemu to receive a notification when a memory error is > notified to the host. These can then be relayed to the guest before the > affected page is accessed. To enable this, the process must set > PR_MCE_KILL_EARLY in PR_MCE_KILL_SET using the prctl() syscall. > > Once the early notification has been handled, nothing stops the > machine-manager or guest from accessing the affected page. If the > machine-manager does this the page will fail to be mapped and SIGBUS will > be sent. This patch adds the equivalent path for when the guest accesses > the page, sending SIGBUS to the machine-manager. > > These two signals can be distinguished by the machine-manager using their > si_code: BUS_MCEERR_AO for 'action optional' early notifications, and > BUS_MCEERR_AR for 'action required' synchronous/late notifications. > > Do as x86 does, and deliver the SIGBUS when we discover pfn == > KVM_PFN_ERR_HWPOISON. Use the hugepage size as si_addr_lsb if this vma was > allocated as a hugepage. Transparent hugepages will be split by > memory_failure() before we see them here. > > Cc: Punit Agrawal <punit.agrawal@xxxxxxx> > Signed-off-by: James Morse <james.morse@xxxxxxx> > > --- > arm64 has ARCH_SUPPORTS_MEMORY_FAILURE in linux-next, so can enable > MEMORY_FAILURE. This patch will build without those changes as > KVM_PFN_ERR_HWPOISON is always defined. > > Changes since v2: > * Just the commit message. > > Changes since v1: > * Pass the vma to kvm_send_hwpoison_signal(), used Punit's huge_page_shift() > calculation to find the block size. > * ... tested against hugepage not transparent huge page ... Applied to -next. Thanks, M. -- Jazz is not dead. It just smells funny... _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
