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| author | Konstantin Weitz <WEITZKON@de.ibm.com> | 2012-04-25 15:30:38 +0200 |
|---|---|---|
| committer | Marcelo Tosatti <mtosatti@redhat.com> | 2012-04-30 21:38:31 -0300 |
| commit | 41628d334361670d825fb03c04568f5ef9f084dc (patch) | |
| tree | 88b2eadd0f7de12f1d8b226e4491532b8783ee94 /arch/s390 | |
| parent | b6ddf05ff68d81a7c1736717faf492b70e9bf4f9 (diff) | |
| download | linux-41628d334361670d825fb03c04568f5ef9f084dc.tar.gz linux-41628d334361670d825fb03c04568f5ef9f084dc.tar.bz2 linux-41628d334361670d825fb03c04568f5ef9f084dc.zip | |
KVM: s390: Implement the directed yield (diag 9c) hypervisor call for KVM
This patch implements the directed yield hypercall found on other
System z hypervisors. It delegates execution time to the virtual cpu
specified in the instruction's parameter.
Useful to avoid long spinlock waits in the guest.
Christian Borntraeger: moved common code in virt/kvm/
Signed-off-by: Konstantin Weitz <WEITZKON@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Diffstat (limited to 'arch/s390')
| -rw-r--r-- | arch/s390/include/asm/kvm_host.h | 1 | ||||
| -rw-r--r-- | arch/s390/kvm/diag.c | 25 | ||||
| -rw-r--r-- | arch/s390/kvm/kvm-s390.c | 1 |
3 files changed, 27 insertions, 0 deletions
diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h index 7343872890a2..dd17537b9a9d 100644 --- a/arch/s390/include/asm/kvm_host.h +++ b/arch/s390/include/asm/kvm_host.h @@ -148,6 +148,7 @@ struct kvm_vcpu_stat { u32 instruction_sigp_restart; u32 diagnose_10; u32 diagnose_44; + u32 diagnose_9c; }; struct kvm_s390_io_info { diff --git a/arch/s390/kvm/diag.c b/arch/s390/kvm/diag.c index a353f0ea45c2..2d2ae327b747 100644 --- a/arch/s390/kvm/diag.c +++ b/arch/s390/kvm/diag.c @@ -53,6 +53,29 @@ static int __diag_time_slice_end(struct kvm_vcpu *vcpu) return 0; } +static int __diag_time_slice_end_directed(struct kvm_vcpu *vcpu) +{ + struct kvm *kvm = vcpu->kvm; + struct kvm_vcpu *tcpu; + int tid; + int i; + + tid = vcpu->run->s.regs.gprs[(vcpu->arch.sie_block->ipa & 0xf0) >> 4]; + vcpu->stat.diagnose_9c++; + VCPU_EVENT(vcpu, 5, "diag time slice end directed to %d", tid); + + if (tid == vcpu->vcpu_id) + return 0; + + kvm_for_each_vcpu(i, tcpu, kvm) + if (tcpu->vcpu_id == tid) { + kvm_vcpu_yield_to(tcpu); + break; + } + + return 0; +} + static int __diag_ipl_functions(struct kvm_vcpu *vcpu) { unsigned int reg = vcpu->arch.sie_block->ipa & 0xf; @@ -89,6 +112,8 @@ int kvm_s390_handle_diag(struct kvm_vcpu *vcpu) return diag_release_pages(vcpu); case 0x44: return __diag_time_slice_end(vcpu); + case 0x9c: + return __diag_time_slice_end_directed(vcpu); case 0x308: return __diag_ipl_functions(vcpu); default: diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index d30c8350b949..fd98914a36f1 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -74,6 +74,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = { { "instruction_sigp_restart", VCPU_STAT(instruction_sigp_restart) }, { "diagnose_10", VCPU_STAT(diagnose_10) }, { "diagnose_44", VCPU_STAT(diagnose_44) }, + { "diagnose_9c", VCPU_STAT(diagnose_9c) }, { NULL } }; |