From patchwork Fri Apr 30 14:37:49 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Aaron Lewis X-Patchwork-Id: 12233567 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-21.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT, USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A529EC433ED for ; Fri, 30 Apr 2021 14:37:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 69664613D9 for ; Fri, 30 Apr 2021 14:37:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230379AbhD3Oin (ORCPT ); Fri, 30 Apr 2021 10:38:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49140 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230297AbhD3Oim (ORCPT ); Fri, 30 Apr 2021 10:38:42 -0400 Received: from mail-pl1-x649.google.com (mail-pl1-x649.google.com [IPv6:2607:f8b0:4864:20::649]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AC7D9C06174A for ; Fri, 30 Apr 2021 07:37:54 -0700 (PDT) Received: by mail-pl1-x649.google.com with SMTP id m10-20020a170902f20ab02900ed7e32ff42so3716260plc.19 for ; Fri, 30 Apr 2021 07:37:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:message-id:mime-version:subject:from:to:cc; bh=v5lYu1w+irOCEZJQl/ANzvss1KKbzTlcUMWMr3wEwIU=; b=hLsvwn8xKe2dyxS2t6qKV/Q5tQNoF5Y92f3eXV85RZYbprYcxDuoixMIirnaU19+Pi yxN6SbDbHnyJGrriQBg0ozX//CtWauQqON9Xk0LZj8V7/TaFOCV7Kcl+ElSf3XFdDZPw Q5qF9Qc2H/Z3m1Sn+HRsAI4N3H66VEHQdWsfbAHg6hryDlRXeM2CJy3ceo0qi2I5H1vs e12eLUE7BpEX4C/ZYeXheUA8N6/qzt+lQxFhtbMnU+jVUfMvcXQSEpw/rBvSnQo1YB4R KnBAYHDU2XDG98RlzRvz3FGcfA+nEvp35M7scYViD9BZGyTUTdd7de6BShISlmr7V4yJ R2cA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=v5lYu1w+irOCEZJQl/ANzvss1KKbzTlcUMWMr3wEwIU=; b=O/ixPkF8BNu5TOn8A6lK1/u/8zv2PkIv+cXC+rx4wwAADZbHUzaIkrPU4/jqDbMB5T d6hT+kESAfK+z1gGFlWWPmx7CmoPnpcfg1svDZN1Chj+7LPFuuFmHKsXNsgi39JepoJj nDSM8uAvrWFYZYnbqZ832yxBvvELWLrgkBT4KDdfhacTj6dj4LJTUsHEPumOLy+6RPay kZgAuFTH/Zkc1JlB3uX6+X7+f/UC4gA6aKqUsa85jP52UALmsRnWCwBKhIeN+SeiiAdy LbQ1+KeCBPgdpHrSzhBscAATwK+B7XHmcEhGdrLVgFtc6NUs1lmyuOUJUh7glfdWuwXY xjOg== X-Gm-Message-State: AOAM533Dh9nFjcmdrjemofBqTcNSS+XW/qGMXMIss1xafMHOX9CelBXJ jiHEEh+qNpd6nZ/tGt5SdH6af/kyXlZNjZDn X-Google-Smtp-Source: ABdhPJzVyxCwumdlhXSDRDRuTJTfZ+CAdxm11+hy0w667BUJnxcocTjfduwCPFou+asw+4qL+IEq9wDv0xHGVjBg X-Received: from aaronlewis1.sea.corp.google.com ([2620:15c:100:202:250e:2425:2e40:acc]) (user=aaronlewis job=sendgmr) by 2002:a17:902:ec84:b029:ea:b28d:e53e with SMTP id x4-20020a170902ec84b02900eab28de53emr5327690plg.77.1619793474194; Fri, 30 Apr 2021 07:37:54 -0700 (PDT) Date: Fri, 30 Apr 2021 07:37:49 -0700 Message-Id: <20210430143751.1693253-1-aaronlewis@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.31.1.527.g47e6f16901-goog Subject: [PATCH v5 0/2] fallback for emulation errors From: Aaron Lewis To: david.edmondson@oracle.com, seanjc@google.com, jmattson@google.com Cc: kvm@vger.kernel.org, Aaron Lewis Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org This patchset allows userspace to be a fallback for handling emulation errors. v1 -> v2: - Added additional documentation for KVM_CAP_EXIT_ON_EMULATION_FAILURE. - In prepare_emulation_failure_exit(): - Created a local variable for vcpu->run. - Cleared the flags, emulation_failure.flags. - Or'd the instruction bytes flag on to emulation_failure.flags. - Updated the comment for KVM_INTERNAL_ERROR_EMULATION flags on how they are to be used. - Updated the comment for struct emulation_failure. v2 -> v3: - Update documentation for KVM_CAP_EXIT_ON_EMULATION_FAILURE. - Fix spacing in prepare_emulation_failure_exit(). v3 -> v4: - In prepare_emulation_failure_exit(): - Clear instruction bytes to 0x90. - Copy over insn_size bytes rather than sizeof(ctxt->fetch.data). - set_page_table_entry() takes a pte rather than mask. - In _vm_get_page_table_entry(): - Removed check for page aligned addresses only. - Added canonical check. - Added a check to make sure no reserved bits are set along the walk except for the final pte (the pte cannot have the reserved bits checked otherwise the test would fail). - Added check to ensure superpage bits are clear. - Added check in test for 'allow_smaller_maxphyaddr' module parameter. - If the is_flds() check fails, only look at the first byte. - Don't use labels to increment the RIP. Decode the instruction well enough to ensure it is only 2-bytes. v4 -> v5: - Switch 'insn_size' to u32. - Add documentation for how the flags are used. - Remove 'max_insn_size' and use 'sizeof(run->emulation_failure.insn_bytes)' instead. - Fix typos. - Fix canonical check. - Add reserved check for bit-7 of PML4E. - Add reserved check for bit-63 of all page table levels if EFER.NXE = 0. - Remove opcode check (it might be a prefix). - Remove labels. - Remove detritus (rogue cpuid entry in the test). Aaron Lewis (2): kvm: x86: Allow userspace to handle emulation errors selftests: kvm: Allows userspace to handle emulation errors. Documentation/virt/kvm/api.rst | 21 ++ arch/x86/include/asm/kvm_host.h | 6 + arch/x86/kvm/x86.c | 37 ++- include/uapi/linux/kvm.h | 23 ++ tools/include/uapi/linux/kvm.h | 23 ++ tools/testing/selftests/kvm/.gitignore | 1 + tools/testing/selftests/kvm/Makefile | 1 + .../selftests/kvm/include/x86_64/processor.h | 4 + .../selftests/kvm/lib/x86_64/processor.c | 94 ++++++++ .../kvm/x86_64/emulator_error_test.c | 219 ++++++++++++++++++ 10 files changed, 425 insertions(+), 4 deletions(-) create mode 100644 tools/testing/selftests/kvm/x86_64/emulator_error_test.c