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arm/arm64: KVM: Add KVM_GET/SET_VCPU_EVENTS

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For the migrating VMs, user space may need to know the exception
state. For example, in the machine A, KVM make an SError pending,
when migrate to B, KVM also needs to pend an SError.

This new IOCTL exports user-invisible states related to SError.
Together with appropriate user space changes, user space can get/set
the SError exception state to do migrate/snapshot/suspend.

Signed-off-by: Dongjiu Geng <gengdongjiu@huawei.com>
Reviewed-by: James Morse <james.morse@arm.com>
[expanded documentation wording]
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
This commit is contained in:
Dongjiu Geng
2018-07-19 16:24:22 +01:00
committed by Marc Zyngier
parent 327432c246
commit b7b27facc7
8 changed files with 146 additions and 7 deletions
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54
Documentation/virtual/kvm/api.txt
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@@ -835,11 +835,13 @@ struct kvm_clock_data {
Capability: KVM_CAP_VCPU_EVENTS
Extended by: KVM_CAP_INTR_SHADOW
Architectures: x86
Type: vm ioctl
Architectures: x86, arm64
Type: vcpu ioctl
Parameters: struct kvm_vcpu_event (out)
Returns: 0 on success, -1 on error
X86:
Gets currently pending exceptions, interrupts, and NMIs as well as related
states of the vcpu.
@@ -881,15 +883,52 @@ Only two fields are defined in the flags field:
- KVM_VCPUEVENT_VALID_SMM may be set in the flags field to signal that
smi contains a valid state.
ARM64:
If the guest accesses a device that is being emulated by the host kernel in
such a way that a real device would generate a physical SError, KVM may make
a virtual SError pending for that VCPU. This system error interrupt remains
pending until the guest takes the exception by unmasking PSTATE.A.
Running the VCPU may cause it to take a pending SError, or make an access that
causes an SError to become pending. The event's description is only valid while
the VPCU is not running.
This API provides a way to read and write the pending 'event' state that is not
visible to the guest. To save, restore or migrate a VCPU the struct representing
the state can be read then written using this GET/SET API, along with the other
guest-visible registers. It is not possible to 'cancel' an SError that has been
made pending.
A device being emulated in user-space may also wish to generate an SError. To do
this the events structure can be populated by user-space. The current state
should be read first, to ensure no existing SError is pending. If an existing
SError is pending, the architecture's 'Multiple SError interrupts' rules should
be followed. (2.5.3 of DDI0587.a "ARM Reliability, Availability, and
Serviceability (RAS) Specification").
struct kvm_vcpu_events {
struct {
__u8 serror_pending;
__u8 serror_has_esr;
/* Align it to 8 bytes */
__u8 pad[6];
__u64 serror_esr;
} exception;
__u32 reserved[12];
};
4.32 KVM_SET_VCPU_EVENTS
Capability: KVM_CAP_VCPU_EVENTS
Extended by: KVM_CAP_INTR_SHADOW
Architectures: x86
Type: vm ioctl
Architectures: x86, arm64
Type: vcpu ioctl
Parameters: struct kvm_vcpu_event (in)
Returns: 0 on success, -1 on error
X86:
Set pending exceptions, interrupts, and NMIs as well as related states of the
vcpu.
@@ -910,6 +949,13 @@ shall be written into the VCPU.
KVM_VCPUEVENT_VALID_SMM can only be set if KVM_CAP_X86_SMM is available.
ARM64:
Set the pending SError exception state for this VCPU. It is not possible to
'cancel' an Serror that has been made pending.
See KVM_GET_VCPU_EVENTS for the data structure.
4.33 KVM_GET_DEBUGREGS