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| author | Carsten Otte <cotte@de.ibm.com> | 2012-01-04 10:25:26 +0100 |
|---|---|---|
| committer | Avi Kivity <avi@redhat.com> | 2012-03-05 13:52:20 +0100 |
| commit | ccc7910fe564d99415def7c041fa261e62a43011 (patch) | |
| tree | 8895fd2463f7b4e48c4510284c37e84a1753ee0d /Documentation | |
| parent | KVM: s390: ucontrol: disable in-kernel irq stack (diff) | |
| download | linux-ccc7910fe564d99415def7c041fa261e62a43011.tar.xz linux-ccc7910fe564d99415def7c041fa261e62a43011.zip | |
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>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/virtual/kvm/api.txt | 16 |
1 files changed, 16 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 |