diff options
Diffstat (limited to 'arch/powerpc/kvm/book3s_hv_builtin.c')
| -rw-r--r-- | arch/powerpc/kvm/book3s_hv_builtin.c | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/arch/powerpc/kvm/book3s_hv_builtin.c b/arch/powerpc/kvm/book3s_hv_builtin.c index 1786bf80bf00..3e43f815ac5d 100644 --- a/arch/powerpc/kvm/book3s_hv_builtin.c +++ b/arch/powerpc/kvm/book3s_hv_builtin.c @@ -17,6 +17,7 @@ #include <linux/memblock.h> #include <linux/sizes.h> #include <linux/cma.h> +#include <linux/bitops.h> #include <asm/cputable.h> #include <asm/kvm_ppc.h> @@ -97,6 +98,37 @@ void __init kvm_cma_reserve(void) } /* + * Real-mode H_CONFER implementation. + * We check if we are the only vcpu out of this virtual core + * still running in the guest and not ceded. If so, we pop up + * to the virtual-mode implementation; if not, just return to + * the guest. + */ +long int kvmppc_rm_h_confer(struct kvm_vcpu *vcpu, int target, + unsigned int yield_count) +{ + struct kvmppc_vcore *vc = vcpu->arch.vcore; + int threads_running; + int threads_ceded; + int threads_conferring; + u64 stop = get_tb() + 10 * tb_ticks_per_usec; + int rv = H_SUCCESS; /* => don't yield */ + + set_bit(vcpu->arch.ptid, &vc->conferring_threads); + while ((get_tb() < stop) && (VCORE_EXIT_COUNT(vc) == 0)) { + threads_running = VCORE_ENTRY_COUNT(vc); + threads_ceded = hweight32(vc->napping_threads); + threads_conferring = hweight32(vc->conferring_threads); + if (threads_ceded + threads_conferring >= threads_running) { + rv = H_TOO_HARD; /* => do yield */ + break; + } + } + clear_bit(vcpu->arch.ptid, &vc->conferring_threads); + return rv; +} + +/* * When running HV mode KVM we need to block certain operations while KVM VMs * exist in the system. We use a counter of VMs to track this. * |