From 59ac15326ed8c936459c8163cf264e9fd35a18ba Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Wed, 3 Dec 2014 15:38:31 +0100 Subject: [PATCH] s390x/kvm: avoid syscalls by syncing registers with kvm_run We can avoid loads of syscalls when dropping to user space by storing the values of more registers directly within kvm_run. Support is added for: - ARCH0: CPU timer, clock comparator, TOD programmable register, guest breaking-event register, program parameter - PFAULT: pfault parameters (token, select, compare) Signed-off-by: David Hildenbrand Signed-off-by: Jens Freimann Reviewed-by: Cornelia Huck Acked-by: Christian Borntraeger Signed-off-by: Cornelia Huck --- target-s390x/kvm.c | 72 +++++++++++++++++++++++++++++++++++++----------------- 1 file changed, 50 insertions(+), 22 deletions(-) diff --git a/target-s390x/kvm.c b/target-s390x/kvm.c index 1483082a78..d188c8ba50 100644 --- a/target-s390x/kvm.c +++ b/target-s390x/kvm.c @@ -252,18 +252,33 @@ int kvm_arch_put_registers(CPUState *cs, int level) return 0; } - /* - * These ONE_REGS are not protected by a capability. As they are only - * necessary for migration we just trace a possible error, but don't - * return with an error return code. - */ - kvm_set_one_reg(cs, KVM_REG_S390_CPU_TIMER, &env->cputm); - kvm_set_one_reg(cs, KVM_REG_S390_CLOCK_COMP, &env->ckc); - kvm_set_one_reg(cs, KVM_REG_S390_TODPR, &env->todpr); - kvm_set_one_reg(cs, KVM_REG_S390_GBEA, &env->gbea); - kvm_set_one_reg(cs, KVM_REG_S390_PP, &env->pp); + if (can_sync_regs(cs, KVM_SYNC_ARCH0)) { + cs->kvm_run->s.regs.cputm = env->cputm; + cs->kvm_run->s.regs.ckc = env->ckc; + cs->kvm_run->s.regs.todpr = env->todpr; + cs->kvm_run->s.regs.gbea = env->gbea; + cs->kvm_run->s.regs.pp = env->pp; + cs->kvm_run->kvm_dirty_regs |= KVM_SYNC_ARCH0; + } else { + /* + * These ONE_REGS are not protected by a capability. As they are only + * necessary for migration we just trace a possible error, but don't + * return with an error return code. + */ + kvm_set_one_reg(cs, KVM_REG_S390_CPU_TIMER, &env->cputm); + kvm_set_one_reg(cs, KVM_REG_S390_CLOCK_COMP, &env->ckc); + kvm_set_one_reg(cs, KVM_REG_S390_TODPR, &env->todpr); + kvm_set_one_reg(cs, KVM_REG_S390_GBEA, &env->gbea); + kvm_set_one_reg(cs, KVM_REG_S390_PP, &env->pp); + } - if (cap_async_pf) { + /* pfault parameters */ + if (can_sync_regs(cs, KVM_SYNC_PFAULT)) { + cs->kvm_run->s.regs.pft = env->pfault_token; + cs->kvm_run->s.regs.pfs = env->pfault_select; + cs->kvm_run->s.regs.pfc = env->pfault_compare; + cs->kvm_run->kvm_dirty_regs |= KVM_SYNC_PFAULT; + } else if (cap_async_pf) { r = kvm_set_one_reg(cs, KVM_REG_S390_PFTOKEN, &env->pfault_token); if (r < 0) { return r; @@ -367,18 +382,31 @@ int kvm_arch_get_registers(CPUState *cs) env->psa = cs->kvm_run->s.regs.prefix; } - /* - * These ONE_REGS are not protected by a capability. As they are only - * necessary for migration we just trace a possible error, but don't - * return with an error return code. - */ - kvm_get_one_reg(cs, KVM_REG_S390_CPU_TIMER, &env->cputm); - kvm_get_one_reg(cs, KVM_REG_S390_CLOCK_COMP, &env->ckc); - kvm_get_one_reg(cs, KVM_REG_S390_TODPR, &env->todpr); - kvm_get_one_reg(cs, KVM_REG_S390_GBEA, &env->gbea); - kvm_get_one_reg(cs, KVM_REG_S390_PP, &env->pp); + if (can_sync_regs(cs, KVM_SYNC_ARCH0)) { + env->cputm = cs->kvm_run->s.regs.cputm; + env->ckc = cs->kvm_run->s.regs.ckc; + env->todpr = cs->kvm_run->s.regs.todpr; + env->gbea = cs->kvm_run->s.regs.gbea; + env->pp = cs->kvm_run->s.regs.pp; + } else { + /* + * These ONE_REGS are not protected by a capability. As they are only + * necessary for migration we just trace a possible error, but don't + * return with an error return code. + */ + kvm_get_one_reg(cs, KVM_REG_S390_CPU_TIMER, &env->cputm); + kvm_get_one_reg(cs, KVM_REG_S390_CLOCK_COMP, &env->ckc); + kvm_get_one_reg(cs, KVM_REG_S390_TODPR, &env->todpr); + kvm_get_one_reg(cs, KVM_REG_S390_GBEA, &env->gbea); + kvm_get_one_reg(cs, KVM_REG_S390_PP, &env->pp); + } - if (cap_async_pf) { + /* pfault parameters */ + if (can_sync_regs(cs, KVM_SYNC_PFAULT)) { + env->pfault_token = cs->kvm_run->s.regs.pft; + env->pfault_select = cs->kvm_run->s.regs.pfs; + env->pfault_compare = cs->kvm_run->s.regs.pfc; + } else if (cap_async_pf) { r = kvm_get_one_reg(cs, KVM_REG_S390_PFTOKEN, &env->pfault_token); if (r < 0) { return r; -- 2.11.4.GIT