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authorLinus Torvalds <torvalds@linux-foundation.org>2011-10-30 15:36:45 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-10-30 15:36:45 -0700
commit1bc87b00556e8f7ba30a1010471951c5b8f71114 (patch)
treee73c2d187e2dff0df97ed82e32b45e362b923117 /Documentation/virtual
parentacff987d94cbdb4049f3706bed1f1792f8ef6837 (diff)
parentf1c1da2bde712812a3e0f9a7a7ebe7a916a4b5f4 (diff)
downloadop-kernel-dev-1bc87b00556e8f7ba30a1010471951c5b8f71114.zip
op-kernel-dev-1bc87b00556e8f7ba30a1010471951c5b8f71114.tar.gz
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.txt71
1 files changed, 69 insertions, 2 deletions
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index b0e4b9c..7945b0b 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.
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