Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751880AbdIULns (ORCPT ); Thu, 21 Sep 2017 07:43:48 -0400 Received: from mx1.redhat.com ([209.132.183.28]:56586 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751818AbdIULni (ORCPT ); Thu, 21 Sep 2017 07:43:38 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 2BF5C7EA8F Authentication-Results: ext-mx04.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx04.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=mtosatti@redhat.com Message-Id: <20170921114039.466130276@redhat.com> User-Agent: quilt/0.60-1 Date: Thu, 21 Sep 2017 08:38:38 -0300 From: Marcelo Tosatti To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Marcelo Tosatti Subject: [patch 3/3] x86: kvm guest side support for KVM_HC_RT_PRIO hypercall References: <20170921113835.031375194@redhat.com> Content-Disposition: inline; filename=03-kvm-hv-fifo-guest-support X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Thu, 21 Sep 2017 11:43:38 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3174 Lines: 111 Add hypercalls to spinlock/unlock to set/unset FIFO priority for the vcpu, protected by a static branch to avoid performance increase in the normal kernels. Enable option by "kvmfifohc" kernel command line parameter (disabled by default). Signed-off-by: Marcelo Tosatti --- arch/x86/kernel/kvm.c | 31 +++++++++++++++++++++++++++++++ include/linux/spinlock.h | 2 +- include/linux/spinlock_api_smp.h | 17 +++++++++++++++++ 3 files changed, 49 insertions(+), 1 deletion(-) Index: kvm.fifopriohc-submit/arch/x86/kernel/kvm.c =================================================================== --- kvm.fifopriohc-submit.orig/arch/x86/kernel/kvm.c +++ kvm.fifopriohc-submit/arch/x86/kernel/kvm.c @@ -37,6 +37,7 @@ #include #include #include +#include #include #include #include @@ -321,6 +322,36 @@ static notrace void kvm_guest_apic_eoi_w apic->native_eoi_write(APIC_EOI, APIC_EOI_ACK); } +static int kvmfifohc; + +static int parse_kvmfifohc(char *arg) +{ + kvmfifohc = 1; + return 0; +} + +early_param("kvmfifohc", parse_kvmfifohc); + +DEFINE_STATIC_KEY_FALSE(kvm_fifo_hc_key); + +static void kvm_init_fifo_hc(void) +{ + long ret; + + ret = kvm_hypercall1(KVM_HC_RT_PRIO, 0); + + if (ret == 0 && kvmfifohc == 1) + static_branch_enable(&kvm_fifo_hc_key); +} + +static __init int kvmguest_late_init(void) +{ + kvm_init_fifo_hc(); + return 0; +} + +late_initcall(kvmguest_late_init); + static void kvm_guest_cpu_init(void) { if (!kvm_para_available()) Index: kvm.fifopriohc-submit/include/linux/spinlock_api_smp.h =================================================================== --- kvm.fifopriohc-submit.orig/include/linux/spinlock_api_smp.h +++ kvm.fifopriohc-submit/include/linux/spinlock_api_smp.h @@ -136,11 +136,28 @@ static inline void __raw_spin_lock_bh(ra LOCK_CONTENDED(lock, do_raw_spin_trylock, do_raw_spin_lock); } +#ifdef CONFIG_KVM_GUEST +DECLARE_STATIC_KEY_FALSE(kvm_fifo_hc_key); +#endif + static inline void __raw_spin_lock(raw_spinlock_t *lock) { preempt_disable(); + +#if defined(CONFIG_KVM_GUEST) && defined(CONFIG_SMP) + /* enable FIFO priority */ + if (static_branch_unlikely(&kvm_fifo_hc_key)) + kvm_hypercall1(KVM_HC_RT_PRIO, 0x1); +#endif + spin_acquire(&lock->dep_map, 0, 0, _RET_IP_); LOCK_CONTENDED(lock, do_raw_spin_trylock, do_raw_spin_lock); + +#if defined(CONFIG_KVM_GUEST) && defined(CONFIG_SMP) + /* disable FIFO priority */ + if (static_branch_unlikely(&kvm_fifo_hc_key)) + kvm_hypercall1(KVM_HC_RT_PRIO, 0); +#endif } #endif /* !CONFIG_GENERIC_LOCKBREAK || CONFIG_DEBUG_LOCK_ALLOC */ Index: kvm.fifopriohc-submit/include/linux/spinlock.h =================================================================== --- kvm.fifopriohc-submit.orig/include/linux/spinlock.h +++ kvm.fifopriohc-submit/include/linux/spinlock.h @@ -56,7 +56,7 @@ #include #include #include - +#include /* * Must define these before including other files, inline functions need them