Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932378AbbHNKLv (ORCPT ); Fri, 14 Aug 2015 06:11:51 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59152 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932327AbbHNKLr (ORCPT ); Fri, 14 Aug 2015 06:11:47 -0400 From: =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= To: linux-kernel@vger.kernel.org Cc: kvm@vger.kernel.org, Paolo Bonzini , Christian Borntraeger Subject: [PATCH v3 4/5] KVM: add KVM_USER_EXIT vcpu ioctl for userspace exit Date: Fri, 14 Aug 2015 12:08:36 +0200 Message-Id: <1439546917-17391-5-git-send-email-rkrcmar@redhat.com> In-Reply-To: <1439546917-17391-1-git-send-email-rkrcmar@redhat.com> References: <1439546917-17391-1-git-send-email-rkrcmar@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4688 Lines: 146 The guest can use KVM_USER_EXIT instead of a signal-based exiting to userspace. Availability depends on KVM_CAP_USER_EXIT. Only x86 is implemented so far. Signed-off-by: Radim Krčmář --- v3: * use ioctl argument directly (unsigned long as flags) [Paolo] v2: * use vcpu ioctl instead of vm one [Paolo] * shrink kvm_user_exit from 64 to 32 bytes Documentation/virtual/kvm/api.txt | 25 +++++++++++++++++++++++++ arch/x86/kvm/x86.c | 15 +++++++++++++++ include/uapi/linux/kvm.h | 3 +++ virt/kvm/kvm_main.c | 5 +++-- 4 files changed, 46 insertions(+), 2 deletions(-) diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index 3c714d43a717..df087ff3c5b6 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -3020,6 +3020,31 @@ Returns: 0 on success, -1 on error Queues an SMI on the thread's vcpu. + +4.97 KVM_USER_EXIT + +Capability: KVM_CAP_USER_EXIT +Architectures: x86 +Type: vcpu ioctl +Parameters: unsigned long flags (in) +Returns: 0 on success, + -EINVAL if flags is not 0 + +The ioctl is asynchronous to VCPU execution and can be issued from all threads. + +Make vcpu_id exit to userspace as soon as possible. If the VCPU is not running +in kernel at the time, it will exit early on the next call to KVM_RUN. +If the VCPU was going to exit because of other reasons when KVM_USER_EXIT was +issued, it will keep the original exit reason without exiting early on next +KVM_RUN. +If VCPU exited because of KVM_USER_EXIT, the exit reason is KVM_EXIT_REQUEST. + +This ioctl has very similar effect (same sans some races on userspace exit) as +sending a signal (that is blocked in userspace and set in KVM_SET_SIGNAL_MASK) +to the VCPU thread. + + + 5. The kvm_run structure ------------------------ diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 37db1b32684a..d985806b17b1 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2467,6 +2467,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) case KVM_CAP_ASSIGN_DEV_IRQ: case KVM_CAP_PCI_2_3: #endif + case KVM_CAP_USER_EXIT: r = 1; break; case KVM_CAP_X86_SMM: @@ -3078,6 +3079,17 @@ static int kvm_set_guest_paused(struct kvm_vcpu *vcpu) return 0; } +static int kvm_vcpu_ioctl_user_exit(struct kvm_vcpu *vcpu, unsigned long flags) +{ + if (flags != 0) + return -EINVAL; + + kvm_make_request(KVM_REQ_EXIT, vcpu); + kvm_vcpu_kick(vcpu); + + return 0; +} + long kvm_arch_vcpu_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg) { @@ -3342,6 +3354,9 @@ long kvm_arch_vcpu_ioctl(struct file *filp, r = kvm_set_guest_paused(vcpu); goto out; } + case KVM_USER_EXIT: + r = kvm_vcpu_ioctl_user_exit(vcpu, arg); + break; default: r = -EINVAL; } diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index d996a7cdb4d2..58b3a07adc81 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -826,6 +826,7 @@ struct kvm_ppc_smmu_info { #define KVM_CAP_X86_SMM 117 #define KVM_CAP_MULTI_ADDRESS_SPACE 118 #define KVM_CAP_SPLIT_IRQCHIP 119 +#define KVM_CAP_USER_EXIT 120 #ifdef KVM_CAP_IRQ_ROUTING @@ -1213,6 +1214,8 @@ struct kvm_s390_ucas_mapping { #define KVM_S390_GET_IRQ_STATE _IOW(KVMIO, 0xb6, struct kvm_s390_irq_state) /* Available with KVM_CAP_X86_SMM */ #define KVM_SMI _IO(KVMIO, 0xb7) +/* Available with KVM_CAP_USER_EXIT */ +#define KVM_USER_EXIT _IO(KVMIO, 0xb8) #define KVM_DEV_ASSIGN_ENABLE_IOMMU (1 << 0) #define KVM_DEV_ASSIGN_PCI_2_3 (1 << 1) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 347899966178..dfa2d5f27713 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -2251,15 +2251,16 @@ static long kvm_vcpu_ioctl(struct file *filp, if (unlikely(_IOC_TYPE(ioctl) != KVMIO)) return -EINVAL; -#if defined(CONFIG_S390) || defined(CONFIG_PPC) || defined(CONFIG_MIPS) /* * Special cases: vcpu ioctls that are asynchronous to vcpu execution, * so vcpu_load() would break it. */ +#if defined(CONFIG_S390) || defined(CONFIG_PPC) || defined(CONFIG_MIPS) if (ioctl == KVM_S390_INTERRUPT || ioctl == KVM_S390_IRQ || ioctl == KVM_INTERRUPT) return kvm_arch_vcpu_ioctl(filp, ioctl, arg); #endif - + if (ioctl == KVM_USER_EXIT) + return kvm_arch_vcpu_ioctl(filp, ioctl, arg); r = vcpu_load(vcpu); if (r) -- 2.5.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/