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Commit 2ed4f9dd authored by Paul Mackerras's avatar Paul Mackerras
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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: default avatarPaul Mackerras <paulus@ozlabs.org>
parent e20bbd3d

Documentation/virtual/kvm/api.txt

+11 −0
Original line number Diff line number Diff line
@@ -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.

arch/powerpc/kvm/powerpc.c

+10 −0
Original line number Diff line number Diff line
@@ -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;

include/uapi/linux/kvm.h

+1 −0
Original line number Diff line number Diff line
@@ -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