diff options
| author | Sean Christopherson <seanjc@google.com> | 2026-06-30 15:56:12 -0700 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2026-07-08 13:41:10 -0700 |
| commit | 32d7943e51798c26072d88ff84f68c566a6e2184 (patch) | |
| tree | 322d3d35c6a98308adeaf5a7bef546b370774d59 | |
| parent | e4ffb0ceb9f47f3797de69c2b81b501ba447515f (diff) | |
KVM: x86/xen: Consolidate checks on Xen vCPU ID for singleshot timer hypercalls
Hoist the checks on the Xen vCPU ID when handling set_singleshot_timer and
stop_singleshot_timer hypercalls out of their individual if-statements,
so that both checks on the ID are in common code. kvm_xen_hcall_vcpu_op()
is already doubly committed to handling only singleshot timer hypercalls,
and even if that were to change in the future, the function could simply
be renamed and turned into a helper specifically for timer hypercalls.
Opportunistically add a comment to explain why the check exists; the code
looks rather nonsensical without the knowledge that @vcpu_id is a common
param for all per-vCPU hypercalls.
No functional change intended.
Reviewed-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Philippe Mathieu-Daudé <philmd@oss.qualcomm.com>
Link: https://patch.msgid.link/20260630225619.511632-6-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
| -rw-r--r-- | arch/x86/kvm/xen.c | 20 |
1 files changed, 11 insertions, 9 deletions
diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c index 3ed6686e0a1a..7a0d89faca85 100644 --- a/arch/x86/kvm/xen.c +++ b/arch/x86/kvm/xen.c @@ -1614,12 +1614,18 @@ static bool kvm_xen_hcall_vcpu_op(struct kvm_vcpu *vcpu, bool longmode, int cmd, if (!kvm_xen_timer_enabled(vcpu)) return false; - if (cmd == VCPUOP_set_singleshot_timer) { - if (vcpu->arch.xen.vcpu_id != vcpu_id) { - *r = -EINVAL; - return true; - } + /* + * Reject the hypercall if the guest is trying to start/stop the timer + * for a different vCPU. Xen per-vCPU hypercalls take a target vCPU as + * a common parameter, as all per-vCPU hypercalls *except* single-shot + * timer updates can be cross-vCPU. + */ + if (vcpu->arch.xen.vcpu_id != vcpu_id) { + *r = -EINVAL; + return true; + } + if (cmd == VCPUOP_set_singleshot_timer) { /* * The only difference for 32-bit compat is the 4 bytes of * padding after the interesting part of the structure. So @@ -1644,10 +1650,6 @@ static bool kvm_xen_hcall_vcpu_op(struct kvm_vcpu *vcpu, bool longmode, int cmd, kvm_xen_start_timer(vcpu, oneshot.timeout_abs_ns, false); } else { - if (vcpu->arch.xen.vcpu_id != vcpu_id) { - *r = -EINVAL; - return true; - } kvm_xen_stop_timer(vcpu); } |