From patchwork Tue Jul 12 00:10:44 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Aaron Lewis X-Patchwork-Id: 12914388 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 5F1F2C433EF for ; Tue, 12 Jul 2022 00:10:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231182AbiGLAKy (ORCPT ); Mon, 11 Jul 2022 20:10:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46078 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229716AbiGLAKx (ORCPT ); Mon, 11 Jul 2022 20:10:53 -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 AF7ED41D2C for ; Mon, 11 Jul 2022 17:10:52 -0700 (PDT) Received: by mail-pl1-x649.google.com with SMTP id m5-20020a170902768500b0016a1c410f6cso4651358pll.13 for ; Mon, 11 Jul 2022 17:10:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=rkL0rI7YYkksMhFhqsYdPkoMpCHhDlCfTv9yglLwc+k=; b=rNQWOy/f/nHCM16uCxYeWL6CR3adPm28PwG7nOyHJHo9V+KiSte5mfrKg3x4RhVweK s71CNmaLzSdcWDw6w1gdZRNuRyx05CfRo17Py0ONfbBmfBghpQDh65qlKB2ca3WDWDKs zW/h8vdTNxJSC1cBaZ/W+/5Ybu+5Q5E4Fd22pV1K+8fh7wPdaXqF5XnTAjw9np//p93+ LypjNN1M2CViUpSMC0kNxOfzZ6sulQ3XQ2JQASB7DXNH3Fw5aja7LrBmobBpJzTi+uJm OJ6+jf8m1JzVtT2z1XBVhZ2wOVhoDvmYNNVQBoton/xSbwMX+RZljEuXvHKZewirMyaI l0Zg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=rkL0rI7YYkksMhFhqsYdPkoMpCHhDlCfTv9yglLwc+k=; b=HP0cVyRmkwzGuKeE+fB5yQ47R0aZwCyEo+5PPTihuL1AvBFfL4CUiywJCHiZuX7Hzm 9QToMgJN3e4W2d8r/a6TzIT2A+bX1yOfbVXUhYmb54hoBSw/2gHv60MXMxpMNiBW6pgJ MJnWIr7zbHJvZDVcch3jVHfJCq6zYHLb9QNi/Z1mWMDMH1sNoEq1Gw9WmWNIqtDvlWXI CXBfpVEBHf9rxMNm31rDlt2Bz5pgE7r/zcWjdUDGBl4syRirz+6P+JRQtC1FKgOI6AsR Sy2OteaaNJ7APEgCkMpcouB+SPluEO86OnwcKaO5k/maJ35N9Naei1OBUd1xqhXviKZu Il+g== X-Gm-Message-State: AJIora930pcgOzyPcua5GsOZu/gRuSXYyK6U6Gd43kvINNDNZtNS0Sk3 NI0vYOyNEEyRvpzHDPIaAyGbky3lS/TyReLbyOGctJOIWDpdldNjS3v8CF6djh4c6d874iegCA7 BSxJiKfk4LvTZDdYEn0pj4FEDivv50fqHZpMxUeWK23uEqCz1R/W4JyPU3jxwacdS0oLD X-Google-Smtp-Source: AGRyM1teM9wvEko26Po9aADbWJbDearNWus55TOLyjPzTpxWLXxny9Jgmsmesj68Ke2NiTBDGcPnRSkMIK159soD X-Received: from aaronlewis.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:2675]) (user=aaronlewis job=sendgmr) by 2002:a05:6a00:170a:b0:52a:d3d4:3852 with SMTP id h10-20020a056a00170a00b0052ad3d43852mr6794332pfc.19.1657584652097; Mon, 11 Jul 2022 17:10:52 -0700 (PDT) Date: Tue, 12 Jul 2022 00:10:44 +0000 In-Reply-To: <20220712001045.2364298-1-aaronlewis@google.com> Message-Id: <20220712001045.2364298-2-aaronlewis@google.com> Mime-Version: 1.0 References: <20220712001045.2364298-1-aaronlewis@google.com> X-Mailer: git-send-email 2.37.0.144.g8ac04bfd2-goog Subject: [PATCH v2 1/2] KVM: x86: fix documentation for KVM_X86_SET_MSR_FILTER From: Aaron Lewis To: kvm@vger.kernel.org Cc: pbonzini@redhat.com, jmattson@google.com, seanjc@google.com, Aaron Lewis Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Two copies of KVM_X86_SET_MSR_FILTER somehow managed to make it's way into the documentation. Remove one copy and merge the difference from the removed copy into the copy that's being kept. Fixes: fd49e8ee70b3 ("Merge branch 'kvm-sev-cgroup' into HEAD") Signed-off-by: Aaron Lewis --- Documentation/virt/kvm/api.rst | 115 +++------------------------------ 1 file changed, 8 insertions(+), 107 deletions(-) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index bafaeedd455c..5c651a4e4e2c 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -4074,7 +4074,7 @@ Queues an SMI on the thread's vcpu. 4.97 KVM_X86_SET_MSR_FILTER ---------------------------- -:Capability: KVM_X86_SET_MSR_FILTER +:Capability: KVM_CAP_X86_MSR_FILTER :Architectures: x86 :Type: vm ioctl :Parameters: struct kvm_msr_filter @@ -4173,8 +4173,12 @@ If an MSR access is not permitted through the filtering, it generates a allows user space to deflect and potentially handle various MSR accesses into user space. -If a vCPU is in running state while this ioctl is invoked, the vCPU may -experience inconsistent filtering behavior on MSR accesses. +Note, invoking this ioctl while a vCPU is running is inherently racy. However, +KVM does guarantee that vCPUs will see either the previous filter or the new +filter, e.g. MSRs with identical settings in both the old and new filter will +have deterministic behavior. + + 4.98 KVM_CREATE_SPAPR_TCE_64 ---------------------------- @@ -5287,110 +5291,7 @@ KVM_PV_DUMP authentication tag all of which are needed to decrypt the dump at a later time. - -4.126 KVM_X86_SET_MSR_FILTER ----------------------------- - -:Capability: KVM_CAP_X86_MSR_FILTER -:Architectures: x86 -:Type: vm ioctl -:Parameters: struct kvm_msr_filter -:Returns: 0 on success, < 0 on error - -:: - - struct kvm_msr_filter_range { - #define KVM_MSR_FILTER_READ (1 << 0) - #define KVM_MSR_FILTER_WRITE (1 << 1) - __u32 flags; - __u32 nmsrs; /* number of msrs in bitmap */ - __u32 base; /* MSR index the bitmap starts at */ - __u8 *bitmap; /* a 1 bit allows the operations in flags, 0 denies */ - }; - - #define KVM_MSR_FILTER_MAX_RANGES 16 - struct kvm_msr_filter { - #define KVM_MSR_FILTER_DEFAULT_ALLOW (0 << 0) - #define KVM_MSR_FILTER_DEFAULT_DENY (1 << 0) - __u32 flags; - struct kvm_msr_filter_range ranges[KVM_MSR_FILTER_MAX_RANGES]; - }; - -flags values for ``struct kvm_msr_filter_range``: - -``KVM_MSR_FILTER_READ`` - - Filter read accesses to MSRs using the given bitmap. A 0 in the bitmap - indicates that a read should immediately fail, while a 1 indicates that - a read for a particular MSR should be handled regardless of the default - filter action. - -``KVM_MSR_FILTER_WRITE`` - - Filter write accesses to MSRs using the given bitmap. A 0 in the bitmap - indicates that a write should immediately fail, while a 1 indicates that - a write for a particular MSR should be handled regardless of the default - filter action. - -``KVM_MSR_FILTER_READ | KVM_MSR_FILTER_WRITE`` - - Filter both read and write accesses to MSRs using the given bitmap. A 0 - in the bitmap indicates that both reads and writes should immediately fail, - while a 1 indicates that reads and writes for a particular MSR are not - filtered by this range. - -flags values for ``struct kvm_msr_filter``: - -``KVM_MSR_FILTER_DEFAULT_ALLOW`` - - If no filter range matches an MSR index that is getting accessed, KVM will - fall back to allowing access to the MSR. - -``KVM_MSR_FILTER_DEFAULT_DENY`` - - If no filter range matches an MSR index that is getting accessed, KVM will - fall back to rejecting access to the MSR. In this mode, all MSRs that should - be processed by KVM need to explicitly be marked as allowed in the bitmaps. - -This ioctl allows user space to define up to 16 bitmaps of MSR ranges to -specify whether a certain MSR access should be explicitly filtered for or not. - -If this ioctl has never been invoked, MSR accesses are not guarded and the -default KVM in-kernel emulation behavior is fully preserved. - -Calling this ioctl with an empty set of ranges (all nmsrs == 0) disables MSR -filtering. In that mode, ``KVM_MSR_FILTER_DEFAULT_DENY`` is invalid and causes -an error. - -As soon as the filtering is in place, every MSR access is processed through -the filtering except for accesses to the x2APIC MSRs (from 0x800 to 0x8ff); -x2APIC MSRs are always allowed, independent of the ``default_allow`` setting, -and their behavior depends on the ``X2APIC_ENABLE`` bit of the APIC base -register. - -If a bit is within one of the defined ranges, read and write accesses are -guarded by the bitmap's value for the MSR index if the kind of access -is included in the ``struct kvm_msr_filter_range`` flags. If no range -cover this particular access, the behavior is determined by the flags -field in the kvm_msr_filter struct: ``KVM_MSR_FILTER_DEFAULT_ALLOW`` -and ``KVM_MSR_FILTER_DEFAULT_DENY``. - -Each bitmap range specifies a range of MSRs to potentially allow access on. -The range goes from MSR index [base .. base+nmsrs]. The flags field -indicates whether reads, writes or both reads and writes are filtered -by setting a 1 bit in the bitmap for the corresponding MSR index. - -If an MSR access is not permitted through the filtering, it generates a -#GP inside the guest. When combined with KVM_CAP_X86_USER_SPACE_MSR, that -allows user space to deflect and potentially handle various MSR accesses -into user space. - -Note, invoking this ioctl with a vCPU is running is inherently racy. However, -KVM does guarantee that vCPUs will see either the previous filter or the new -filter, e.g. MSRs with identical settings in both the old and new filter will -have deterministic behavior. - -4.127 KVM_XEN_HVM_SET_ATTR +4.126 KVM_XEN_HVM_SET_ATTR -------------------------- :Capability: KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_SHARED_INFO