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| author | Paul Mackerras <paulus@ozlabs.org> | 2017-06-21 09:01:27 +0300 |
|---|---|---|
| committer | Paul Mackerras <paulus@ozlabs.org> | 2017-06-22 04:25:31 +0300 |
| commit | 2ed4f9dd19c0f76f7fb56c4b201696d29149325c (patch) | |
| tree | dc386c28edb9885280d62e1fb51fe2dd5b693a94 | |
| parent | e20bbd3d8d5c4432db8fd6f091b096963236064f (diff) | |
| download | linux-2ed4f9dd19c0f76f7fb56c4b201696d29149325c.tar.xz | |
KVM: PPC: Book3S HV: Add capability to report possible virtual SMT modes
Now that userspace can set the virtual SMT mode by enabling the
KVM_CAP_PPC_SMT capability, it is useful for userspace to be able
to query the set of possible virtual SMT modes. This provides a
new capability, KVM_CAP_PPC_SMT_POSSIBLE, to provide this
information. The return value is a bitmap of possible modes, with
bit N set if virtual SMT mode 2^N is available. That is, 1 indicates
SMT1 is available, 2 indicates that SMT2 is available, 3 indicates
that both SMT1 and SMT2 are available, and so on.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
| -rw-r--r-- | Documentation/virtual/kvm/api.txt | 11 | ||||
| -rw-r--r-- | arch/powerpc/kvm/powerpc.c | 10 | ||||
| -rw-r--r-- | include/uapi/linux/kvm.h | 1 |
3 files changed, 22 insertions, 0 deletions
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index 1531a3cd548f..63875dbb6ef5 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -4010,6 +4010,8 @@ be 0. A successful call to enable this capability will result in vsmt_mode being returned when the KVM_CAP_PPC_SMT capability is subsequently queried for the VM. This capability is only supported by HV KVM, and can only be set before any VCPUs have been created. +The KVM_CAP_PPC_SMT_POSSIBLE capability indicates which virtual SMT +modes are available. 7.12 KVM_CAP_PPC_FWNMI @@ -4183,3 +4185,12 @@ Currently the following bits are defined for the device_irq_level bitmap: Future versions of kvm may implement additional events. These will get indicated by returning a higher number from KVM_CHECK_EXTENSION and will be listed above. + +8.10 KVM_CAP_PPC_SMT_POSSIBLE + +Architectures: ppc + +Querying this capability returns a bitmap indicating the possible +virtual SMT modes that can be set using KVM_CAP_PPC_SMT. If bit N +(counting from the right) is set, then a virtual SMT mode of 2^N is +available. diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c index ccaa7a407c15..b14736f3870b 100644 --- a/arch/powerpc/kvm/powerpc.c +++ b/arch/powerpc/kvm/powerpc.c @@ -566,6 +566,16 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) r = threads_per_subcore; } break; + case KVM_CAP_PPC_SMT_POSSIBLE: + r = 1; + if (hv_enabled) { + if (!cpu_has_feature(CPU_FTR_ARCH_300)) + r = ((threads_per_subcore << 1) - 1); + else + /* P9 can emulate dbells, so allow any mode */ + r = 8 | 4 | 2 | 1; + } + break; case KVM_CAP_PPC_RMA: r = 0; break; diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 89bc145b4051..36ea74aa3422 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -896,6 +896,7 @@ struct kvm_ppc_resize_hpt { #define KVM_CAP_X86_GUEST_MWAIT 143 #define KVM_CAP_ARM_USER_IRQ 144 #define KVM_CAP_PPC_FWNMI 145 +#define KVM_CAP_PPC_SMT_POSSIBLE 146 #ifdef KVM_CAP_IRQ_ROUTING |