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authorRadim Krčmář <rkrcmar@redhat.com>2018-02-01 15:04:17 +0100
committerRadim Krčmář <rkrcmar@redhat.com>2018-02-01 15:04:17 +0100
commit7bf14c28ee776be567855bd39ed8ff795ea19f55 (patch)
tree6113748c673e85fccc2c56c050697789c00c6bc2 /Documentation/virtual
parentkvm: x86: remove efer_reload entry in kvm_vcpu_stat (diff)
parentx86/kvm: Make it compile on 32bit and with HYPYERVISOR_GUEST=n (diff)
downloadlinux-7bf14c28ee776be567855bd39ed8ff795ea19f55.tar.xz
linux-7bf14c28ee776be567855bd39ed8ff795ea19f55.zip
Merge branch 'x86/hyperv' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Topic branch for stable KVM clockource under Hyper-V. Thanks to Christoffer Dall for resolving the ARM conflict.
Diffstat (limited to 'Documentation/virtual')
-rw-r--r--Documentation/virtual/kvm/api.txt53
1 files changed, 50 insertions, 3 deletions
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index e5f1743e0b3e..70d3368adba9 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -3403,7 +3403,53 @@ invalid, if invalid pages are written to (e.g. after the end of memory)
or if no page table is present for the addresses (e.g. when using
hugepages).
-4.109 KVM_MEMORY_ENCRYPT_OP
+4.109 KVM_PPC_GET_CPU_CHAR
+
+Capability: KVM_CAP_PPC_GET_CPU_CHAR
+Architectures: powerpc
+Type: vm ioctl
+Parameters: struct kvm_ppc_cpu_char (out)
+Returns: 0 on successful completion
+ -EFAULT if struct kvm_ppc_cpu_char cannot be written
+
+This ioctl gives userspace information about certain characteristics
+of the CPU relating to speculative execution of instructions and
+possible information leakage resulting from speculative execution (see
+CVE-2017-5715, CVE-2017-5753 and CVE-2017-5754). The information is
+returned in struct kvm_ppc_cpu_char, which looks like this:
+
+struct kvm_ppc_cpu_char {
+ __u64 character; /* characteristics of the CPU */
+ __u64 behaviour; /* recommended software behaviour */
+ __u64 character_mask; /* valid bits in character */
+ __u64 behaviour_mask; /* valid bits in behaviour */
+};
+
+For extensibility, the character_mask and behaviour_mask fields
+indicate which bits of character and behaviour have been filled in by
+the kernel. If the set of defined bits is extended in future then
+userspace will be able to tell whether it is running on a kernel that
+knows about the new bits.
+
+The character field describes attributes of the CPU which can help
+with preventing inadvertent information disclosure - specifically,
+whether there is an instruction to flash-invalidate the L1 data cache
+(ori 30,30,0 or mtspr SPRN_TRIG2,rN), whether the L1 data cache is set
+to a mode where entries can only be used by the thread that created
+them, whether the bcctr[l] instruction prevents speculation, and
+whether a speculation barrier instruction (ori 31,31,0) is provided.
+
+The behaviour field describes actions that software should take to
+prevent inadvertent information disclosure, and thus describes which
+vulnerabilities the hardware is subject to; specifically whether the
+L1 data cache should be flushed when returning to user mode from the
+kernel, and whether a speculation barrier should be placed between an
+array bounds check and the array access.
+
+These fields use the same bit definitions as the new
+H_GET_CPU_CHARACTERISTICS hypercall.
+
+4.110 KVM_MEMORY_ENCRYPT_OP
Capability: basic
Architectures: x86
@@ -3419,7 +3465,7 @@ Currently, this ioctl is used for issuing Secure Encrypted Virtualization
(SEV) commands on AMD Processors. The SEV commands are defined in
Documentation/virtual/kvm/amd-memory-encryption.txt.
-4.110 KVM_MEMORY_ENCRYPT_REG_REGION
+4.111 KVM_MEMORY_ENCRYPT_REG_REGION
Capability: basic
Architectures: x86
@@ -3442,7 +3488,7 @@ Note: The current SEV key management spec does not provide commands to
swap or migrate (move) ciphertext pages. Hence, for now we pin the guest
memory region registered with the ioctl.
-4.111 KVM_MEMORY_ENCRYPT_UNREG_REGION
+4.112 KVM_MEMORY_ENCRYPT_UNREG_REGION
Capability: basic
Architectures: x86
@@ -3453,6 +3499,7 @@ Returns: 0 on success; -1 on error
This ioctl can be used to unregister the guest memory region registered
with KVM_MEMORY_ENCRYPT_REG_REGION ioctl above.
+
5. The kvm_run structure
------------------------