path: root/Documentation
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authorChristoffer Dall <christoffer.dall@linaro.org>2014-10-16 16:40:53 +0200
committerChristoffer Dall <christoffer.dall@linaro.org>2014-12-13 14:15:26 +0100
commitf7fa034dc8559c7d7326bfc8bd1a26175abd931a (patch)
treeaa0458365535fcc65662a40fef2dec95a43a47a0 /Documentation
parentarm/arm64: KVM: Reset the HCR on each vcpu when resetting the vcpu (diff)
arm/arm64: KVM: Clarify KVM_ARM_VCPU_INIT ABI
It is not clear that this ioctl can be called multiple times for a given vcpu. Userspace already does this, so clarify the ABI. Also specify that userspace is expected to always make secondary and subsequent calls to the ioctl with the same parameters for the VCPU as the initial call (which userspace also already does). Add code to check that userspace doesn't violate that ABI in the future, and move the kvm_vcpu_set_target() function which is currently duplicated between the 32-bit and 64-bit versions in guest.c to a common static function in arm.c, shared between both architectures. Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Diffstat (limited to 'Documentation')
1 files changed, 5 insertions, 0 deletions
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index bb82a906e51e..81f1b974c06a 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -2453,6 +2453,11 @@ return ENOEXEC for that vcpu.
Note that because some registers reflect machine topology, all vcpus
should be created before this ioctl is invoked.
+Userspace can call this function multiple times for a given vcpu, including
+after the vcpu has been run. This will reset the vcpu to its initial
+state. All calls to this function after the initial call must use the same
+target and same set of feature flags, otherwise EINVAL will be returned.
Possible features:
- KVM_ARM_VCPU_POWER_OFF: Starts the CPU in a power-off state.
Depends on KVM_CAP_ARM_PSCI. If not set, the CPU will be powered on