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| author | David Woodhouse <dwmw@amazon.co.uk> | 2021-03-01 15:53:09 +0300 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2021-03-02 22:30:54 +0300 |
| commit | 30b5c851af7991ad08abe90c1e7c31615fa98a1a (patch) | |
| tree | b8596021030db95f8825f0f947da71e004450491 /Documentation/security | |
| parent | 7d7c5f76e54131ed05b057103b5278b6b852148b (diff) | |
| download | linux-30b5c851af7991ad08abe90c1e7c31615fa98a1a.tar.xz | |
KVM: x86/xen: Add support for vCPU runstate information
This is how Xen guests do steal time accounting. The hypervisor records
the amount of time spent in each of running/runnable/blocked/offline
states.
In the Xen accounting, a vCPU is still in state RUNSTATE_running while
in Xen for a hypercall or I/O trap, etc. Only if Xen explicitly schedules
does the state become RUNSTATE_blocked. In KVM this means that even when
the vCPU exits the kvm_run loop, the state remains RUNSTATE_running.
The VMM can explicitly set the vCPU to RUNSTATE_blocked by using the
KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_CURRENT attribute, and can also use
KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADJUST to retrospectively add a given
amount of time to the blocked state and subtract it from the running
state.
The state_entry_time corresponds to get_kvmclock_ns() at the time the
vCPU entered the current state, and the total times of all four states
should always add up to state_entry_time.
Co-developed-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <20210301125309.874953-2-dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'Documentation/security')
0 files changed, 0 insertions, 0 deletions