diff options
| author | Carsten Otte <cotte@de.ibm.com> | 2012-01-04 10:25:26 +0100 |
|---|---|---|
| committer | Avi Kivity <avi@redhat.com> | 2012-03-05 14:52:20 +0200 |
| commit | ccc7910fe564d99415def7c041fa261e62a43011 (patch) | |
| tree | 8895fd2463f7b4e48c4510284c37e84a1753ee0d | |
| parent | d6b6d166864fa97ca3b1ed1a5c62fd3b53d4606f (diff) | |
KVM: s390: ucontrol: interface to inject faults on a vcpu page table
This patch allows the user to fault in pages on a virtual cpus
address space for user controlled virtual machines. Typically this
is superfluous because userspace can just create a mapping and
let the kernel's page fault logic take are of it. There is one
exception: SIE won't start if the lowcore is not present. Normally
the kernel takes care of this [handle_validity() in
arch/s390/kvm/intercept.c] but since the kernel does not handle
intercepts for user controlled virtual machines, userspace needs to
be able to handle this condition.
Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
| -rw-r--r-- | Documentation/virtual/kvm/api.txt | 16 | ||||
| -rw-r--r-- | arch/s390/kvm/kvm-s390.c | 6 | ||||
| -rw-r--r-- | include/linux/kvm.h | 1 |
3 files changed, 23 insertions, 0 deletions
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index 5ebf47d99e56..a67fb35993fa 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -1539,6 +1539,22 @@ This ioctl unmaps the memory in the vcpu's address space starting at "vcpu_addr" with the length "length". The field "user_addr" is ignored. All parameters need to be alligned by 1 megabyte. +4.66 KVM_S390_VCPU_FAULT + +Capability: KVM_CAP_S390_UCONTROL +Architectures: s390 +Type: vcpu ioctl +Parameters: vcpu absolute address (in) +Returns: 0 in case of success + +This call creates a page table entry on the virtual cpu's address space +(for user controlled virtual machines) or the virtual machine's address +space (for regular virtual machines). This only works for minor faults, +thus it's recommended to access subject memory page via the user page +table upfront. This is useful to handle validity intercepts for user +controlled virtual machines to fault in the virtual cpu's lowcore pages +prior to calling the KVM_RUN ioctl. + 5. The kvm_run structure Application code obtains a pointer to the kvm_run structure by diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 5b5c28e471df..8489edf80c89 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -761,6 +761,12 @@ long kvm_arch_vcpu_ioctl(struct file *filp, break; } #endif + case KVM_S390_VCPU_FAULT: { + r = gmap_fault(arg, vcpu->arch.gmap); + if (!IS_ERR_VALUE(r)) + r = 0; + break; + } default: r = -EINVAL; } diff --git a/include/linux/kvm.h b/include/linux/kvm.h index 8f888df206a2..778e748927b4 100644 --- a/include/linux/kvm.h +++ b/include/linux/kvm.h @@ -675,6 +675,7 @@ struct kvm_s390_ucas_mapping { }; #define KVM_S390_UCAS_MAP _IOW(KVMIO, 0x50, struct kvm_s390_ucas_mapping) #define KVM_S390_UCAS_UNMAP _IOW(KVMIO, 0x51, struct kvm_s390_ucas_mapping) +#define KVM_S390_VCPU_FAULT _IOW(KVMIO, 0x52, unsigned long) /* Device model IOC */ #define KVM_CREATE_IRQCHIP _IO(KVMIO, 0x60) |