From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 809B9C433EF for ; Tue, 14 Dec 2021 17:28:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236385AbhLNR2V (ORCPT ); Tue, 14 Dec 2021 12:28:21 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47006 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236396AbhLNR2S (ORCPT ); Tue, 14 Dec 2021 12:28:18 -0500 Received: from mail-il1-x149.google.com (mail-il1-x149.google.com [IPv6:2607:f8b0:4864:20::149]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8F0BBC06173F for ; Tue, 14 Dec 2021 09:28:17 -0800 (PST) Received: by mail-il1-x149.google.com with SMTP id y15-20020a056e02174f00b002a4222f24a5so18351459ill.3 for ; Tue, 14 Dec 2021 09:28:17 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:message-id:mime-version:subject:from:to:cc; bh=zk8b273QnCh6EBKHsBLZCwm7phsH1qXNNxAFMztBRMQ=; b=Z1p6iB38u4qCLN3DR6XCPMSeigD1Z90OlOv79x1GPPrkP/Zle4CFrX7F1AkqkyLyv7 pTfAm2sxx5KBGsVYl56DkuvF8sus9B08ph5GevUidg2bCb2erwD34UEBUPgQOLv2mcgR ttlLQ+aDL8Y+RBNggNyu2CUQAdU88fB6nPfi8d7KDMjMMZQ8uVCn5U/6ZJr8yehKvQq0 YK4s3ktTyMmfdGY1232w6DsMQ2PcXxxJkoJxHs+J6kv9Z3xtxkjSTBPdaELbVMwVRRj6 Vpp1uDVLDs+pDeM0HqOS9PL1A9Jajy0DfNyDpiCp0whq9oBBQx135HKMKyhmTo12gaXb NmRA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=zk8b273QnCh6EBKHsBLZCwm7phsH1qXNNxAFMztBRMQ=; b=TsDkcKCvyoRIoLarK6lV53WokKT8yBT8uDNYHY4ajhOVLqeD94hAQcOSK3u+aagKSM V6tLwukY5FeSCeKumWCsUG2hmMXAmoU2gtLh5Tr1lDCnJQh3NAoSCEmfZqwWTOi6ZYD+ ZLRrn/K9kaP9dfiShtvh31LckIgBTILhQvPZFnTIIDFysrRgHmMa2hp9aI/qV51wMP+O Gs07BJHKBZs1BwxzAUa/80/S5UY6dXNXmCkdhctpbQyElZy/49xBtm76SSITAz4yun1U WR2xfkJTnGye99R4qYET0TcLJi4XnksP0sADTx/pt+m6DkVdZK6wBf2XCeLd+WqML+KK Wg/g== X-Gm-Message-State: AOAM533nkZiylEaJNItGKvdpBbeQ/KcVUGsg4LdyHVrR8ZZD0pSs11SF +I8xW2Qikjmaf81q5KV0ElRA2rSeMZs= X-Google-Smtp-Source: ABdhPJwm2kW1tWIdTafhk7By1Qz8hjfZFCojXCQPPWKGX9iyHrDuiA02tnU4jkY+2HaL5PjwP1IH8HpANww= X-Received: from oupton.c.googlers.com ([fda3:e722:ac3:cc00:2b:ff92:c0a8:404]) (user=oupton job=sendgmr) by 2002:a92:8747:: with SMTP id d7mr4479540ilm.203.1639502896974; Tue, 14 Dec 2021 09:28:16 -0800 (PST) Date: Tue, 14 Dec 2021 17:28:06 +0000 Message-Id: <20211214172812.2894560-1-oupton@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.34.1.173.g76aa8bc2d0-goog Subject: [PATCH v4 0/6] KVM: arm64: Emulate the OS Lock From: Oliver Upton To: kvmarm@lists.cs.columbia.edu Cc: kvm@vger.kernel.org, Marc Zyngier , James Morse , Alexandru Elisei , Suzuki K Poulose , linux-arm-kernel@lists.infradead.org, Andrew Jones , Peter Shier , Ricardo Koller , Reiji Watanabe , Oliver Upton Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org KVM does not implement the debug architecture to the letter of the specification. One such issue is the fact that KVM treats the OS Lock as RAZ/WI, rather than emulating its behavior on hardware. This series adds emulation support for the OS Lock to KVM. Emulation is warranted as the OS Lock affects debug exceptions taken from all ELs, and is not limited to only the context of the guest. The 1st patch is a correctness fix for the OSLSR register, ensuring the trap handler actually is written to suggest WO behavior. Note that the changed code should never be reached on a correct implementation, as hardware should generate the undef, not KVM. The 2nd patch adds the necessary context to track guest values of the OS Lock bit and exposes the value to userspace for the sake of migration. The 3rd patch makes the OSLK bit writable in OSLAR_EL1 (from the guest) and OSLSR_EL1 (from userspace), but does nothing with its value. The 4th patch actually implements the OS Lock behavior, disabling all debug exceptions (except breakpoint instructions) from the perspective of the guest. This is done by disabling MDE and SS in MDSCR_EL1. The 5th patch asserts that OSLSR_EL1 is exposed by KVM to userspace through the KVM_GET_REG_LIST ioctl. Lastly, the 6th patch asserts that no debug exceptions are routed to the guest when the OSLK bit is set. This series applies cleanly to 5.16-rc4. Tested on an Ampere Altra machine with the included selftests patches. Oliver Upton (6): KVM: arm64: Correctly treat writes to OSLSR_EL1 as undefined KVM: arm64: Stash OSLSR_EL1 in the cpu context KVM: arm64: Allow guest to set the OSLK bit KVM: arm64: Emulate the OS Lock selftests: KVM: Add OSLSR_EL1 to the list of blessed regs selftests: KVM: Test OS lock behavior arch/arm64/include/asm/kvm_host.h | 6 ++ arch/arm64/include/asm/sysreg.h | 9 +++ arch/arm64/kvm/debug.c | 26 ++++++- arch/arm64/kvm/sys_regs.c | 74 ++++++++++++++----- .../selftests/kvm/aarch64/debug-exceptions.c | 58 ++++++++++++++- .../selftests/kvm/aarch64/get-reg-list.c | 1 + 6 files changed, 151 insertions(+), 23 deletions(-) -- 2.34.1.173.g76aa8bc2d0-goog