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author | Linus Torvalds <torvalds@linux-foundation.org> | 2011-10-31 02:36:45 +0400 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-10-31 02:36:45 +0400 |
commit | 1bc87b00556e8f7ba30a1010471951c5b8f71114 (patch) | |
tree | e73c2d187e2dff0df97ed82e32b45e362b923117 /Documentation/virtual | |
parent | acff987d94cbdb4049f3706bed1f1792f8ef6837 (diff) | |
parent | f1c1da2bde712812a3e0f9a7a7ebe7a916a4b5f4 (diff) | |
download | linux-1bc87b00556e8f7ba30a1010471951c5b8f71114.tar.xz |
Merge branch 'kvm-updates/3.2' of git://git.kernel.org/pub/scm/linux/kernel/git/avi/kvm
* 'kvm-updates/3.2' of git://git.kernel.org/pub/scm/linux/kernel/git/avi/kvm: (75 commits)
KVM: SVM: Keep intercepting task switching with NPT enabled
KVM: s390: implement sigp external call
KVM: s390: fix register setting
KVM: s390: fix return value of kvm_arch_init_vm
KVM: s390: check cpu_id prior to using it
KVM: emulate lapic tsc deadline timer for guest
x86: TSC deadline definitions
KVM: Fix simultaneous NMIs
KVM: x86 emulator: convert push %sreg/pop %sreg to direct decode
KVM: x86 emulator: switch lds/les/lss/lfs/lgs to direct decode
KVM: x86 emulator: streamline decode of segment registers
KVM: x86 emulator: simplify OpMem64 decode
KVM: x86 emulator: switch src decode to decode_operand()
KVM: x86 emulator: qualify OpReg inhibit_byte_regs hack
KVM: x86 emulator: switch OpImmUByte decode to decode_imm()
KVM: x86 emulator: free up some flag bits near src, dst
KVM: x86 emulator: switch src2 to generic decode_operand()
KVM: x86 emulator: expand decode flags to 64 bits
KVM: x86 emulator: split dst decode to a generic decode_operand()
KVM: x86 emulator: move memop, memopp into emulation context
...
Diffstat (limited to 'Documentation/virtual')
-rw-r--r-- | Documentation/virtual/kvm/api.txt | 71 |
1 files changed, 69 insertions, 2 deletions
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index b0e4b9cd6a66..7945b0bd35e2 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -175,10 +175,30 @@ Parameters: vcpu id (apic id on x86) Returns: vcpu fd on success, -1 on error This API adds a vcpu to a virtual machine. The vcpu id is a small integer -in the range [0, max_vcpus). You can use KVM_CAP_NR_VCPUS of the -KVM_CHECK_EXTENSION ioctl() to determine the value for max_vcpus at run-time. +in the range [0, max_vcpus). + +The recommended max_vcpus value can be retrieved using the KVM_CAP_NR_VCPUS of +the KVM_CHECK_EXTENSION ioctl() at run-time. +The maximum possible value for max_vcpus can be retrieved using the +KVM_CAP_MAX_VCPUS of the KVM_CHECK_EXTENSION ioctl() at run-time. + If the KVM_CAP_NR_VCPUS does not exist, you should assume that max_vcpus is 4 cpus max. +If the KVM_CAP_MAX_VCPUS does not exist, you should assume that max_vcpus is +same as the value returned from KVM_CAP_NR_VCPUS. + +On powerpc using book3s_hv mode, the vcpus are mapped onto virtual +threads in one or more virtual CPU cores. (This is because the +hardware requires all the hardware threads in a CPU core to be in the +same partition.) The KVM_CAP_PPC_SMT capability indicates the number +of vcpus per virtual core (vcore). The vcore id is obtained by +dividing the vcpu id by the number of vcpus per vcore. The vcpus in a +given vcore will always be in the same physical core as each other +(though that might be a different physical core from time to time). +Userspace can control the threading (SMT) mode of the guest by its +allocation of vcpu ids. For example, if userspace wants +single-threaded guest vcpus, it should make all vcpu ids be a multiple +of the number of vcpus per vcore. On powerpc using book3s_hv mode, the vcpus are mapped onto virtual threads in one or more virtual CPU cores. (This is because the @@ -1633,3 +1653,50 @@ developer registration required to access it). char padding[256]; }; }; + +6. Capabilities that can be enabled + +There are certain capabilities that change the behavior of the virtual CPU when +enabled. To enable them, please see section 4.37. Below you can find a list of +capabilities and what their effect on the vCPU is when enabling them. + +The following information is provided along with the description: + + Architectures: which instruction set architectures provide this ioctl. + x86 includes both i386 and x86_64. + + Parameters: what parameters are accepted by the capability. + + Returns: the return value. General error numbers (EBADF, ENOMEM, EINVAL) + are not detailed, but errors with specific meanings are. + +6.1 KVM_CAP_PPC_OSI + +Architectures: ppc +Parameters: none +Returns: 0 on success; -1 on error + +This capability enables interception of OSI hypercalls that otherwise would +be treated as normal system calls to be injected into the guest. OSI hypercalls +were invented by Mac-on-Linux to have a standardized communication mechanism +between the guest and the host. + +When this capability is enabled, KVM_EXIT_OSI can occur. + +6.2 KVM_CAP_PPC_PAPR + +Architectures: ppc +Parameters: none +Returns: 0 on success; -1 on error + +This capability enables interception of PAPR hypercalls. PAPR hypercalls are +done using the hypercall instruction "sc 1". + +It also sets the guest privilege level to "supervisor" mode. Usually the guest +runs in "hypervisor" privilege mode with a few missing features. + +In addition to the above, it changes the semantics of SDR1. In this mode, the +HTAB address part of SDR1 contains an HVA instead of a GPA, as PAPR keeps the +HTAB invisible to the guest. + +When this capability is enabled, KVM_EXIT_PAPR_HCALL can occur. |