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Message-ID: <20250227021855.3257188-19-seanjc@google.com>
Date: Wed, 26 Feb 2025 18:18:34 -0800
From: Sean Christopherson <seanjc@...gle.com>
To: Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>, Paolo Bonzini <pbonzini@...hat.com>,
Sean Christopherson <seanjc@...gle.com>, Juergen Gross <jgross@...e.com>,
"K. Y. Srinivasan" <kys@...rosoft.com>, Haiyang Zhang <haiyangz@...rosoft.com>, Wei Liu <wei.liu@...nel.org>,
Dexuan Cui <decui@...rosoft.com>, Ajay Kaher <ajay.kaher@...adcom.com>,
Jan Kiszka <jan.kiszka@...mens.com>, Andy Lutomirski <luto@...nel.org>,
Peter Zijlstra <peterz@...radead.org>, Daniel Lezcano <daniel.lezcano@...aro.org>,
John Stultz <jstultz@...gle.com>
Cc: linux-kernel@...r.kernel.org, linux-coco@...ts.linux.dev,
kvm@...r.kernel.org, virtualization@...ts.linux.dev,
linux-hyperv@...r.kernel.org, xen-devel@...ts.xenproject.org,
Tom Lendacky <thomas.lendacky@....com>, Nikunj A Dadhania <nikunj@....com>
Subject: [PATCH v2 18/38] x86/paravirt: Pass sched_clock save/restore helpers
during registration
Pass in a PV clock's save/restore helpers when configuring sched_clock
instead of relying on each PV clock to manually set the save/restore hooks.
In addition to bringing sanity to the code, this will allow gracefully
"rejecting" a PV sched_clock, e.g. when running as a CoCo guest that has
access to a "secure" TSC.
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
arch/x86/include/asm/paravirt.h | 8 +++++---
arch/x86/kernel/cpu/vmware.c | 7 ++-----
arch/x86/kernel/kvmclock.c | 5 ++---
arch/x86/kernel/paravirt.c | 5 ++++-
arch/x86/xen/time.c | 5 ++---
drivers/clocksource/hyperv_timer.c | 6 ++----
6 files changed, 17 insertions(+), 19 deletions(-)
diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index cfceabd5f7e1..dc26a3c26527 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -28,11 +28,13 @@ u64 dummy_sched_clock(void);
DECLARE_STATIC_CALL(pv_steal_clock, dummy_steal_clock);
DECLARE_STATIC_CALL(pv_sched_clock, dummy_sched_clock);
-void __paravirt_set_sched_clock(u64 (*func)(void), bool stable);
+void __paravirt_set_sched_clock(u64 (*func)(void), bool stable,
+ void (*save)(void), void (*restore)(void));
-static inline void paravirt_set_sched_clock(u64 (*func)(void))
+static inline void paravirt_set_sched_clock(u64 (*func)(void),
+ void (*save)(void), void (*restore)(void))
{
- __paravirt_set_sched_clock(func, true);
+ __paravirt_set_sched_clock(func, true, save, restore);
}
static __always_inline u64 paravirt_sched_clock(void)
diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c
index d6eadb5b37fd..399cf3286a60 100644
--- a/arch/x86/kernel/cpu/vmware.c
+++ b/arch/x86/kernel/cpu/vmware.c
@@ -344,11 +344,8 @@ static void __init vmware_paravirt_ops_setup(void)
vmware_cyc2ns_setup();
- if (vmw_sched_clock) {
- paravirt_set_sched_clock(vmware_sched_clock);
- x86_platform.save_sched_clock_state = NULL;
- x86_platform.restore_sched_clock_state = NULL;
- }
+ if (vmw_sched_clock)
+ paravirt_set_sched_clock(vmware_sched_clock, NULL, NULL);
if (vmware_is_stealclock_available()) {
has_steal_clock = true;
diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
index c78db52ae399..1ad3878cc1d9 100644
--- a/arch/x86/kernel/kvmclock.c
+++ b/arch/x86/kernel/kvmclock.c
@@ -136,7 +136,8 @@ static void kvm_restore_sched_clock_state(void)
static inline void kvm_sched_clock_init(bool stable)
{
kvm_sched_clock_offset = kvm_clock_read();
- __paravirt_set_sched_clock(kvm_sched_clock_read, stable);
+ __paravirt_set_sched_clock(kvm_sched_clock_read, stable,
+ kvm_save_sched_clock_state, kvm_restore_sched_clock_state);
pr_info("kvm-clock: using sched offset of %llu cycles",
kvm_sched_clock_offset);
@@ -343,8 +344,6 @@ void __init kvmclock_init(void)
#ifdef CONFIG_SMP
x86_cpuinit.early_percpu_clock_init = kvm_setup_secondary_clock;
#endif
- x86_platform.save_sched_clock_state = kvm_save_sched_clock_state;
- x86_platform.restore_sched_clock_state = kvm_restore_sched_clock_state;
kvm_get_preset_lpj();
/*
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index 55c819673a9d..9673cd3a3f0a 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -86,12 +86,15 @@ static u64 native_steal_clock(int cpu)
DEFINE_STATIC_CALL(pv_steal_clock, native_steal_clock);
DEFINE_STATIC_CALL(pv_sched_clock, native_sched_clock);
-void __paravirt_set_sched_clock(u64 (*func)(void), bool stable)
+void __paravirt_set_sched_clock(u64 (*func)(void), bool stable,
+ void (*save)(void), void (*restore)(void))
{
if (!stable)
clear_sched_clock_stable();
static_call_update(pv_sched_clock, func);
+ x86_platform.save_sched_clock_state = save;
+ x86_platform.restore_sched_clock_state = restore;
}
/* These are in entry.S */
diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c
index 51eba986cd18..3179f850352d 100644
--- a/arch/x86/xen/time.c
+++ b/arch/x86/xen/time.c
@@ -564,13 +564,12 @@ 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 = NULL;
- x86_platform.restore_sched_clock_state = NULL;
+ paravirt_set_sched_clock(xen_sched_clock, NULL, NULL);
tsc_register_calibration_routines(xen_tsc_khz, NULL);
x86_platform.get_wallclock = xen_get_wallclock;
diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c
index 4a21874e91b9..1c4ed9995cb2 100644
--- a/drivers/clocksource/hyperv_timer.c
+++ b/drivers/clocksource/hyperv_timer.c
@@ -550,10 +550,8 @@ static void hv_restore_sched_clock_state(void)
static __always_inline void hv_setup_sched_clock(void *sched_clock)
{
/* We're on x86/x64 *and* using PV ops */
- paravirt_set_sched_clock(sched_clock);
-
- x86_platform.save_sched_clock_state = hv_save_sched_clock_state;
- x86_platform.restore_sched_clock_state = hv_restore_sched_clock_state;
+ paravirt_set_sched_clock(sched_clock, hv_save_sched_clock_state,
+ hv_restore_sched_clock_state);
}
#else /* !CONFIG_GENERIC_SCHED_CLOCK && !CONFIG_PARAVIRT */
static __always_inline void hv_setup_sched_clock(void *sched_clock) {}
--
2.48.1.711.g2feabab25a-goog
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