diff options
author | Carsten Otte <cotte@de.ibm.com> | 2012-01-04 04:25:26 -0500 |
---|---|---|
committer | Avi Kivity <avi@redhat.com> | 2012-03-05 07:52:20 -0500 |
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 | |||
1539 | "vcpu_addr" with the length "length". The field "user_addr" is ignored. | 1539 | "vcpu_addr" with the length "length". The field "user_addr" is ignored. |
1540 | All parameters need to be alligned by 1 megabyte. | 1540 | All parameters need to be alligned by 1 megabyte. |
1541 | 1541 | ||
1542 | 4.66 KVM_S390_VCPU_FAULT | ||
1543 | |||
1544 | Capability: KVM_CAP_S390_UCONTROL | ||
1545 | Architectures: s390 | ||
1546 | Type: vcpu ioctl | ||
1547 | Parameters: vcpu absolute address (in) | ||
1548 | Returns: 0 in case of success | ||
1549 | |||
1550 | This call creates a page table entry on the virtual cpu's address space | ||
1551 | (for user controlled virtual machines) or the virtual machine's address | ||
1552 | space (for regular virtual machines). This only works for minor faults, | ||
1553 | thus it's recommended to access subject memory page via the user page | ||
1554 | table upfront. This is useful to handle validity intercepts for user | ||
1555 | controlled virtual machines to fault in the virtual cpu's lowcore pages | ||
1556 | prior to calling the KVM_RUN ioctl. | ||
1557 | |||
1542 | 5. The kvm_run structure | 1558 | 5. The kvm_run structure |
1543 | 1559 | ||
1544 | Application code obtains a pointer to the kvm_run structure by | 1560 | 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, | |||
761 | break; | 761 | break; |
762 | } | 762 | } |
763 | #endif | 763 | #endif |
764 | case KVM_S390_VCPU_FAULT: { | ||
765 | r = gmap_fault(arg, vcpu->arch.gmap); | ||
766 | if (!IS_ERR_VALUE(r)) | ||
767 | r = 0; | ||
768 | break; | ||
769 | } | ||
764 | default: | 770 | default: |
765 | r = -EINVAL; | 771 | r = -EINVAL; |
766 | } | 772 | } |
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 { | |||
675 | }; | 675 | }; |
676 | #define KVM_S390_UCAS_MAP _IOW(KVMIO, 0x50, struct kvm_s390_ucas_mapping) | 676 | #define KVM_S390_UCAS_MAP _IOW(KVMIO, 0x50, struct kvm_s390_ucas_mapping) |
677 | #define KVM_S390_UCAS_UNMAP _IOW(KVMIO, 0x51, struct kvm_s390_ucas_mapping) | 677 | #define KVM_S390_UCAS_UNMAP _IOW(KVMIO, 0x51, struct kvm_s390_ucas_mapping) |
678 | #define KVM_S390_VCPU_FAULT _IOW(KVMIO, 0x52, unsigned long) | ||
678 | 679 | ||
679 | /* Device model IOC */ | 680 | /* Device model IOC */ |
680 | #define KVM_CREATE_IRQCHIP _IO(KVMIO, 0x60) | 681 | #define KVM_CREATE_IRQCHIP _IO(KVMIO, 0x60) |