[PATCH v5 33/51] x86/xen/time: NOP-ify x86_platform's sched_clock save/restore hooks
From: Sean Christopherson <seanjc@google.com>
Date: 2026-07-01 19:33:08
Also in:
kvm, linux-coco, linux-hyperv, lkml, virtualization, xen-devel
Subsystem:
the rest, x86 architecture (32-bit and 64-bit), xen hypervisor x86 · Maintainers:
Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, Juergen Gross
NOP-ify the x86_platform sched_clock save/restore hooks when setting up Xen's PV clock to make it somewhat obvious the hooks aren't used when running as a Xen guest (Xen uses a paravirtualized suspend/resume flow). Reviewed-by: David Woodhouse <redacted> Signed-off-by: Sean Christopherson <seanjc@google.com> --- arch/x86/xen/time.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c
index 487ad838c441..477441752f40 100644
--- a/arch/x86/xen/time.c
+++ b/arch/x86/xen/time.c@@ -567,6 +567,12 @@ static void __init xen_init_time_common(void) xen_sched_clock_offset = xen_clocksource_read(); static_call_update(pv_steal_clock, xen_steal_clock); paravirt_set_sched_clock(xen_sched_clock); + /* + * Xen has paravirtualized suspend/resume and so doesn't use the common + * x86 sched_clock save/restore hooks. + */ + x86_platform.save_sched_clock_state = x86_init_noop; + x86_platform.restore_sched_clock_state = x86_init_noop; x86_init.hyper.get_tsc_khz = xen_tsc_khz; x86_platform.get_wallclock = xen_get_wallclock;
--
2.55.0.rc0.799.gd6f94ed593-goog