On 2012-01-17 19:04, Eric B Munson wrote:
> 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 <emun...@mgebm.net>
>
> Cc: mi...@redhat.com
> Cc: h...@zytor.com
> Cc: ry...@linux.vnet.ibm.com
> Cc: aligu...@us.ibm.com
> Cc: mtosa...@redhat.com
> Cc: jeremy.fitzhardi...@citrix.com
> Cc: kvm@vger.kernel.org
> Cc: linux-a...@vger.kernel.org
> Cc: x...@kernel.org
> Cc: linux-ker...@vger.kernel.org
> ---
> 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 | 13 +++++++++++++
> arch/x86/kvm/x86.c | 26 ++++++++++++++++++++++++++
> include/linux/kvm.h | 3 +++
> 3 files changed, 42 insertions(+), 0 deletions(-)
>
> diff --git a/Documentation/virtual/kvm/api.txt
> b/Documentation/virtual/kvm/api.txt
> index e1d94bf..1931e5c 100644
> --- a/Documentation/virtual/kvm/api.txt
> +++ b/Documentation/virtual/kvm/api.txt
> @@ -1491,6 +1491,19 @@ following algorithm:
> Some guests configure the LINT1 NMI input to cause a panic, aiding in
> debugging.
>
> +4.65 KVMCLOCK_GUEST_PAUSED
> +
> +Capability: KVM_CAP_GUEST_PAUSED
> +Architechtures: 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. This ioctl can be called during pause or
> +unpause.
> +
> 5. The kvm_run structure
>
> Application code obtains a pointer to the kvm_run structure by
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 14d6cad..4661abe 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -2056,6 +2056,7 @@ int kvm_dev_ioctl_check_extension(long ext)
> case KVM_CAP_X86_ROBUST_SINGLESTEP:
> case KVM_CAP_XSAVE:
> case KVM_CAP_ASYNC_PF:
> + case KVM_CAP_GUEST_PAUSED:
> case KVM_CAP_GET_TSC_KHZ:
> r = 1;
> break;
> @@ -3061,6 +3062,27 @@ out:
> 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.
> + */
> +static int kvm_set_guest_paused(struct kvm *kvm)
> +{
> + struct kvm_vcpu *vcpu;
> + struct pvclock_vcpu_time_info *src;
> + int i;
> +
> + for (i = 0; i < atomic_read(&kvm->online_vcpus); i++) {
> + vcpu = kvm->vcpus[i];
kvm_for_each_vcpu?
> + if (!vcpu->arch.time_page)
> + continue;
> + src = &vcpu->arch.hv_clock;
> + src->flags |= PVCLOCK_GUEST_STOPPED;
> + mark_page_dirty(vcpu->kvm, vcpu->arch.time >> PAGE_SHIFT);
> + }
> + return 0;
> +}
> +
> long kvm_arch_vm_ioctl(struct file *filp,
> unsigned int ioctl, unsigned long arg)
> {
> @@ -3351,6 +3373,10 @@ long kvm_arch_vm_ioctl(struct file *filp,
> r = 0;
> break;
> }
> + case KVMCLOCK_GUEST_PAUSED: {
> + r = kvm_set_guest_paused(kvm);
> + break;
> + }
>
> default:
> ;
> diff --git a/include/linux/kvm.h b/include/linux/kvm.h
> index 68e67e5..4ffe0df 100644
> --- a/include/linux/kvm.h
> +++ b/include/linux/kvm.h
> @@ -558,6 +558,7 @@ struct kvm_ppc_pvinfo {
> #define KVM_CAP_PPC_PAPR 68
> #define KVM_CAP_S390_GMAP 71
> #define KVM_CAP_TSC_DEADLINE_TIMER 72
> +#define KVM_CAP_GUEST_PAUSED 73
>
> #ifdef KVM_CAP_IRQ_ROUTING
>
> @@ -763,6 +764,8 @@ struct kvm_clock_data {
> #define KVM_CREATE_SPAPR_TCE _IOW(KVMIO, 0xa8, struct
> kvm_create_spapr_tce)
> /* Available with KVM_CAP_RMA */
> #define KVM_ALLOCATE_RMA _IOR(KVMIO, 0xa9, struct kvm_allocate_rma)
> +/* VM is being stopped by host */
> +#define KVMCLOCK_GUEST_PAUSED _IO(KVMIO, 0xaa)
>
> #define KVM_DEV_ASSIGN_ENABLE_IOMMU (1 << 0)
>
Jan
--
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux
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