Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754055Ab2BTCYJ (ORCPT ); Sun, 19 Feb 2012 21:24:09 -0500 Received: from oz.csail.mit.edu ([128.30.30.239]:55817 "EHLO mail.mgebm.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753500Ab2BTCXC (ORCPT ); Sun, 19 Feb 2012 21:23:02 -0500 From: Eric B Munson To: avi@redhat.com Cc: Eric B Munson , mingo@redhat.com, hpa@zytor.com, ryanh@linux.vnet.ibm.com, aliguori@us.ibm.com, mtosatti@redhat.com, kvm@vger.kernel.org, linux-arch@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 3/4 V15] Add ioctl for KVM_KVMCLOCK_CTRL Date: Sun, 19 Feb 2012 21:22:56 -0500 Message-Id: <1329704577-6329-4-git-send-email-emunson@mgebm.net> X-Mailer: git-send-email 1.7.5.4 In-Reply-To: <1329704577-6329-1-git-send-email-emunson@mgebm.net> References: <1329704577-6329-1-git-send-email-emunson@mgebm.net> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5924 Lines: 165 Now that we have a flag that will tell the guest it was suspended, create an interface for that communication using a KVM ioctl. Signed-off-by: Eric B Munson Cc: mingo@redhat.com Cc: hpa@zytor.com Cc: ryanh@linux.vnet.ibm.com Cc: aliguori@us.ibm.com Cc: mtosatti@redhat.com Cc: kvm@vger.kernel.org Cc: linux-arch@vger.kernel.org Cc: x86@kernel.org Cc: linux-kernel@vger.kernel.org --- Changes from V14: Add description of flags bit used for host->guest communication Changes from V13: Expand the ioctl documentation Changes from V12: Rename KVM_CAP and KVM ioctl Changes from V11: Correct typo in api.txt Add kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu) call to kvm_set_guest_paused() Changes from V10: Return the ioctl to per vcpu instead of per vm Changes from V9: Use kvm_for_each_vcpu to iterate online vcpu's Changes from V8: Make KVM_GUEST_PAUSED a per vm ioctl instead of per vcpu Changes from V7: Define KVM_CAP_GUEST_PAUSED and support check Call mark_page_dirty () after setting PVCLOCK_GUEST_STOPPED Changes from V4: Rename KVM_GUEST_PAUSED to KVMCLOCK_GUEST_PAUSED Add new ioctl description to api.txt Documentation/virtual/kvm/api.txt | 20 ++++++++++++++++++++ Documentation/virtual/kvm/msr.txt | 4 ++++ arch/x86/kvm/x86.c | 22 ++++++++++++++++++++++ include/linux/kvm.h | 3 +++ 4 files changed, 49 insertions(+), 0 deletions(-) diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index 59a3826..c9617b3 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -1628,6 +1628,26 @@ at the memory location pointed to by "addr". The list of registers accessible using this interface is identical to the list in 4.64. +4.70 KVM_KVMCLOCK_CTRL + +Capability: KVM_CAP_KVMCLOCK_CTRL +Architectures: Any that implement pvclocks (currently x86 only) +Type: vcpu ioctl +Parameters: None +Returns: 0 on success, -1 on error + +This signals to the host kernel that the specified guest is being paused by +userspace. The host will set a flag in the pvclock structure that is checked +from the soft lockup watchdog. The flag is part of the pvclock structure that +is shared between guest and host, specifically the second bit of the flags +field of the pvclock_vcpu_time_info structure. It will be set exclusively by +the host and read/cleared exclusively by the guest. The guest operation of +checking and clearing the flag must an atomic operation so +load-link/store-conditional, or equivalent must be used. There are two cases +where the guest will clear the flag: when the soft lockup watchdog timer resets +itself or when a soft lockup is detected. This ioctl can be called any time +after pausing the vcpu, but before it is resumed. + 5. The kvm_run structure Application code obtains a pointer to the kvm_run structure by diff --git a/Documentation/virtual/kvm/msr.txt b/Documentation/virtual/kvm/msr.txt index 5031780..96b41bd 100644 --- a/Documentation/virtual/kvm/msr.txt +++ b/Documentation/virtual/kvm/msr.txt @@ -109,6 +109,10 @@ MSR_KVM_SYSTEM_TIME_NEW: 0x4b564d01 0 | 24 | multiple cpus are guaranteed to | | be monotonic ------------------------------------------------------------- + | | guest vcpu has been paused by + 1 | N/A | the host + | | See 4.70 in api.txt + ------------------------------------------------------------- Availability of this MSR must be checked via bit 3 in 0x4000001 cpuid leaf prior to usage. diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index c9d99e5..7ba8213 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2143,6 +2143,7 @@ int kvm_dev_ioctl_check_extension(long ext) case KVM_CAP_XSAVE: case KVM_CAP_ASYNC_PF: case KVM_CAP_GET_TSC_KHZ: + case KVM_CAP_KVMCLOCK_CTRL: r = 1; break; case KVM_CAP_COALESCED_MMIO: @@ -2593,6 +2594,23 @@ static int kvm_vcpu_ioctl_x86_set_xcrs(struct kvm_vcpu *vcpu, return r; } +/* + * kvm_set_guest_paused() indicates to the guest kernel that it has been + * stopped by the hypervisor. This function will be called from the host only. + * EINVAL is returned when the host attempts to set the flag for a guest that + * does not support pv clocks. + */ +static int kvm_set_guest_paused(struct kvm_vcpu *vcpu) +{ + struct pvclock_vcpu_time_info *src = &vcpu->arch.hv_clock; + if (!vcpu->arch.time_page) + return -EINVAL; + src->flags |= PVCLOCK_GUEST_STOPPED; + mark_page_dirty(vcpu->kvm, vcpu->arch.time >> PAGE_SHIFT); + kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu); + return 0; +} + long kvm_arch_vcpu_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg) { @@ -2869,6 +2887,10 @@ long kvm_arch_vcpu_ioctl(struct file *filp, r = vcpu->arch.virtual_tsc_khz; goto out; } + case KVM_KVMCLOCK_CTRL: { + r = kvm_set_guest_paused(vcpu); + goto out; + } default: r = -EINVAL; } diff --git a/include/linux/kvm.h b/include/linux/kvm.h index acbe429..a90db11 100644 --- a/include/linux/kvm.h +++ b/include/linux/kvm.h @@ -588,6 +588,7 @@ struct kvm_ppc_pvinfo { #define KVM_CAP_TSC_DEADLINE_TIMER 72 #define KVM_CAP_S390_UCONTROL 73 #define KVM_CAP_SYNC_REGS 74 +#define KVM_CAP_KVMCLOCK_CTRL 75 #ifdef KVM_CAP_IRQ_ROUTING @@ -855,6 +856,8 @@ struct kvm_s390_ucas_mapping { /* Available with KVM_CAP_ONE_REG */ #define KVM_GET_ONE_REG _IOW(KVMIO, 0xab, struct kvm_one_reg) #define KVM_SET_ONE_REG _IOW(KVMIO, 0xac, struct kvm_one_reg) +/* VM is being stopped by host */ +#define KVM_KVMCLOCK_CTRL _IO(KVMIO, 0xad) #define KVM_DEV_ASSIGN_ENABLE_IOMMU (1 << 0) -- 1.7.5.4 -- 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/