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author | Aaron Lewis <aaronlewis@google.com> | 2022-07-12 03:10:44 +0300 |
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committer | Paolo Bonzini <pbonzini@redhat.com> | 2022-09-26 19:02:29 +0300 |
commit | b5cb32b16ce7f757b53f14586bbdd05c3b7ebc29 (patch) | |
tree | 71e43e2040d2859b7cdf65ac3ed814bd742418f6 /Documentation/virt/kvm/api.rst | |
parent | db25eb87ad42f6eb3dcc045e760fc9e23df3e845 (diff) | |
download | linux-b5cb32b16ce7f757b53f14586bbdd05c3b7ebc29.tar.xz |
KVM: x86: Delete duplicate documentation for KVM_X86_SET_MSR_FILTER
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 <aaronlewis@google.com>
Link: https://lore.kernel.org/r/20220712001045.2364298-2-aaronlewis@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'Documentation/virt/kvm/api.rst')
-rw-r--r-- | Documentation/virt/kvm/api.rst | 113 |
1 files changed, 6 insertions, 107 deletions
diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index abd7c32126ce..236a797be71c 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 +4173,10 @@ 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 +5289,7 @@ 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 |