From patchwork Wed Apr 8 05:03:22 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ankur Arora X-Patchwork-Id: 11479331 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id E0E291894 for ; Wed, 8 Apr 2020 05:05:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BFDD92082F for ; Wed, 8 Apr 2020 05:05:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="PlrYMSP2" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726819AbgDHFFs (ORCPT ); Wed, 8 Apr 2020 01:05:48 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:38234 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726798AbgDHFFr (ORCPT ); Wed, 8 Apr 2020 01:05:47 -0400 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 03852xa5179539; Wed, 8 Apr 2020 05:05:36 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding; s=corp-2020-01-29; bh=7Qqvi8ilezudja6Xt6TMpZeT8QAYzWIZNCTpskFpIKg=; b=PlrYMSP2h6k1ZitVeuybm/+AYAE+sB8vRMB0+kQOvow5oszNXceJgjEAAvFiIlmk8dfT 43T9eS07CTuXT5UodAkvV/QFJS1fQXtS2c29x/cctBkqEX6jmAfoJcWHJC0DTzKAUQWR iUbfgYI6KmSYNMk70LnKGdaOG/+UOyrjPqDPs2t9xMboURdOeol/NYZGkwptOCiG14T0 sbJWNxq07XmOG8CdPD29AbXQVHyC/cFAqZVn9RBzyVvGYcPANFGGd78XxPiAgZ4dOBxM VvAY06D+9EnXtAWkr8uALBZMh621nLJ+hx8OYkjVKw5z/RXOjk5BS3CqcxHaLinqXVoO jQ== Received: from aserp3030.oracle.com (aserp3030.oracle.com [141.146.126.71]) by userp2120.oracle.com with ESMTP id 3091mnh158-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 08 Apr 2020 05:05:36 +0000 Received: from pps.filterd (aserp3030.oracle.com [127.0.0.1]) by aserp3030.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 03852gSb148301; Wed, 8 Apr 2020 05:05:35 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by aserp3030.oracle.com with ESMTP id 3091kgj7qp-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 08 Apr 2020 05:05:35 +0000 Received: from abhmp0012.oracle.com (abhmp0012.oracle.com [141.146.116.18]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id 03855Xes022191; Wed, 8 Apr 2020 05:05:33 GMT Received: from monad.ca.oracle.com (/10.156.75.81) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Tue, 07 Apr 2020 22:05:33 -0700 From: Ankur Arora To: linux-kernel@vger.kernel.org, x86@kernel.org Cc: peterz@infradead.org, hpa@zytor.com, jpoimboe@redhat.com, namit@vmware.com, mhiramat@kernel.org, jgross@suse.com, bp@alien8.de, vkuznets@redhat.com, pbonzini@redhat.com, boris.ostrovsky@oracle.com, mihai.carabas@oracle.com, kvm@vger.kernel.org, xen-devel@lists.xenproject.org, virtualization@lists.linux-foundation.org, Ankur Arora Subject: [RFC PATCH 25/26] x86/kvm: Guest support for dynamic hints Date: Tue, 7 Apr 2020 22:03:22 -0700 Message-Id: <20200408050323.4237-26-ankur.a.arora@oracle.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200408050323.4237-1-ankur.a.arora@oracle.com> References: <20200408050323.4237-1-ankur.a.arora@oracle.com> MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9584 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxscore=0 bulkscore=0 suspectscore=0 spamscore=0 malwarescore=0 adultscore=0 phishscore=0 mlxlogscore=999 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2004080037 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9584 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 mlxlogscore=999 mlxscore=0 priorityscore=1501 bulkscore=0 adultscore=0 impostorscore=0 phishscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2004080037 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org If the hypervisor supports KVM_FEATURE_DYNAMIC_HINTS, then register a callback vector (currently chosen to be HYPERVISOR_CALLBACK_VECTOR.) The callback triggers on a change in the active hints which are are exported via KVM CPUID in %ecx. Trigger re-evaluation of KVM_HINTS based on change in their active status. Signed-off-by: Ankur Arora --- arch/x86/Kconfig | 1 + arch/x86/entry/entry_64.S | 5 +++ arch/x86/include/asm/kvm_para.h | 7 ++++ arch/x86/kernel/kvm.c | 58 ++++++++++++++++++++++++++++++--- include/asm-generic/kvm_para.h | 4 +++ include/linux/kvm_para.h | 5 +++ 6 files changed, 76 insertions(+), 4 deletions(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index e0629558b6b5..23b239d184fc 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -810,6 +810,7 @@ config KVM_GUEST select PARAVIRT_CLOCK select ARCH_CPUIDLE_HALTPOLL select PARAVIRT_RUNTIME + select X86_HV_CALLBACK_VECTOR default y ---help--- This option enables various optimizations for running under the KVM diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 0e9504fabe52..96b2a243c54f 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -1190,6 +1190,11 @@ apicinterrupt3 HYPERVISOR_CALLBACK_VECTOR \ acrn_hv_callback_vector acrn_hv_vector_handler #endif +#if IS_ENABLED(CONFIG_KVM_GUEST) +apicinterrupt3 HYPERVISOR_CALLBACK_VECTOR \ + kvm_callback_vector kvm_do_callback +#endif + idtentry debug do_debug has_error_code=0 paranoid=1 shift_ist=IST_INDEX_DB ist_offset=DB_STACK_OFFSET idtentry int3 do_int3 has_error_code=0 create_gap=1 idtentry stack_segment do_stack_segment has_error_code=1 diff --git a/arch/x86/include/asm/kvm_para.h b/arch/x86/include/asm/kvm_para.h index 9b4df6eaa11a..5a7ca5639c2e 100644 --- a/arch/x86/include/asm/kvm_para.h +++ b/arch/x86/include/asm/kvm_para.h @@ -88,11 +88,13 @@ static inline long kvm_hypercall4(unsigned int nr, unsigned long p1, bool kvm_para_available(void); unsigned int kvm_arch_para_features(void); unsigned int kvm_arch_para_hints(void); +unsigned int kvm_arch_para_active_hints(void); void kvm_async_pf_task_wait(u32 token, int interrupt_kernel); void kvm_async_pf_task_wake(u32 token); u32 kvm_read_and_reset_pf_reason(void); extern void kvm_disable_steal_time(void); void do_async_page_fault(struct pt_regs *regs, unsigned long error_code, unsigned long address); +void kvm_callback_vector(struct pt_regs *regs); #ifdef CONFIG_PARAVIRT_SPINLOCKS void __init kvm_spinlock_init(void); @@ -121,6 +123,11 @@ static inline unsigned int kvm_arch_para_hints(void) return 0; } +static inline unsigned int kvm_arch_para_active_hints(void) +{ + return 0; +} + static inline u32 kvm_read_and_reset_pf_reason(void) { return 0; diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c index 1cb7eab805a6..163b7a7ec5f9 100644 --- a/arch/x86/kernel/kvm.c +++ b/arch/x86/kernel/kvm.c @@ -25,6 +25,8 @@ #include #include #include +#include +#include #include #include #include @@ -438,7 +440,7 @@ static void __init sev_map_percpu_data(void) static bool pv_tlb_flush_supported(void) { return (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH) && - !kvm_para_has_hint(KVM_HINTS_REALTIME) && + !kvm_para_has_active_hint(KVM_HINTS_REALTIME) && kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)); } @@ -463,7 +465,7 @@ static bool pv_ipi_supported(void) static bool pv_sched_yield_supported(void) { return (kvm_para_has_feature(KVM_FEATURE_PV_SCHED_YIELD) && - !kvm_para_has_hint(KVM_HINTS_REALTIME) && + !kvm_para_has_active_hint(KVM_HINTS_REALTIME) && kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)); } @@ -568,7 +570,7 @@ static void kvm_smp_send_call_func_ipi(const struct cpumask *mask) static void __init kvm_smp_prepare_cpus(unsigned int max_cpus) { native_smp_prepare_cpus(max_cpus); - if (kvm_para_has_hint(KVM_HINTS_REALTIME)) + if (kvm_para_has_active_hint(KVM_HINTS_REALTIME)) static_branch_disable(&virt_spin_lock_key); } @@ -654,6 +656,13 @@ static bool kvm_pv_tlb(void) return cond; } +#ifdef CONFIG_PARAVIRT_RUNTIME +static bool has_dynamic_hint; +static void __init kvm_register_callback_vector(void); +#else +#define has_dynamic_hint false +#endif /* CONFIG_PARAVIRT_RUNTIME */ + static void __init kvm_guest_init(void) { int i; @@ -674,6 +683,12 @@ static void __init kvm_guest_init(void) if (kvm_para_has_feature(KVM_FEATURE_PV_EOI)) apic_set_eoi_write(kvm_guest_apic_eoi_write); + if (IS_ENABLED(CONFIG_PARAVIRT_RUNTIME) && + kvm_para_has_feature(KVM_FEATURE_DYNAMIC_HINTS)) { + kvm_register_callback_vector(); + has_dynamic_hint = true; + } + #ifdef CONFIG_SMP smp_ops.smp_prepare_cpus = kvm_smp_prepare_cpus; smp_ops.smp_prepare_boot_cpu = kvm_smp_prepare_boot_cpu; @@ -729,12 +744,27 @@ unsigned int kvm_arch_para_features(void) return cpuid_eax(kvm_cpuid_base() | KVM_CPUID_FEATURES); } +/* + * Universe of hints that's ever been given to this guest. + */ unsigned int kvm_arch_para_hints(void) { return cpuid_edx(kvm_cpuid_base() | KVM_CPUID_FEATURES); } EXPORT_SYMBOL_GPL(kvm_arch_para_hints); +/* + * Currently active set of hints. Reading can race with modifications. + */ +unsigned int kvm_arch_para_active_hints(void) +{ + if (has_dynamic_hint) + return cpuid_ecx(kvm_cpuid_base() | KVM_CPUID_FEATURES); + else + return kvm_arch_para_hints(); +} +EXPORT_SYMBOL_GPL(kvm_arch_para_active_hints); + static uint32_t __init kvm_detect(void) { return kvm_cpuid_base(); @@ -878,7 +908,7 @@ static inline bool kvm_para_lock_ops(void) { /* Does host kernel support KVM_FEATURE_PV_UNHALT? */ return kvm_para_has_feature(KVM_FEATURE_PV_UNHALT) && - !kvm_para_has_hint(KVM_HINTS_REALTIME); + !kvm_para_has_active_hint(KVM_HINTS_REALTIME); } static bool kvm_pv_spinlock(void) @@ -975,4 +1005,24 @@ void kvm_trigger_reprobe_cpuid(struct work_struct *work) mutex_unlock(&text_mutex); } + +static DECLARE_WORK(trigger_reprobe, kvm_trigger_reprobe_cpuid); + +void __irq_entry kvm_do_callback(struct pt_regs *regs) +{ + struct pt_regs *old_regs = set_irq_regs(regs); + + irq_enter(); + inc_irq_stat(irq_hv_callback_count); + + schedule_work(&trigger_reprobe); + irq_exit(); + set_irq_regs(old_regs); +} + +static void __init kvm_register_callback_vector(void) +{ + alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, kvm_callback_vector); + wrmsrl(MSR_KVM_HINT_VECTOR, HYPERVISOR_CALLBACK_VECTOR); +} #endif /* CONFIG_PARAVIRT_RUNTIME */ diff --git a/include/asm-generic/kvm_para.h b/include/asm-generic/kvm_para.h index 728e5c5706c4..4a575299ad62 100644 --- a/include/asm-generic/kvm_para.h +++ b/include/asm-generic/kvm_para.h @@ -24,6 +24,10 @@ static inline unsigned int kvm_arch_para_hints(void) return 0; } +static inline unsigned int kvm_arch_para_active_hints(void) +{ + return 0; +} static inline bool kvm_para_available(void) { return false; diff --git a/include/linux/kvm_para.h b/include/linux/kvm_para.h index f23b90b02898..c98d3944d25a 100644 --- a/include/linux/kvm_para.h +++ b/include/linux/kvm_para.h @@ -14,4 +14,9 @@ static inline bool kvm_para_has_hint(unsigned int feature) { return !!(kvm_arch_para_hints() & (1UL << feature)); } + +static inline bool kvm_para_has_active_hint(unsigned int feature) +{ + return !!(kvm_arch_para_active_hints() & BIT(feature)); +} #endif /* __LINUX_KVM_PARA_H */