From: Sean Christopherson <seanjc@google.com>
To: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Sean Christopherson <seanjc@google.com>,
Juergen Gross <jgross@suse.com>,
"K. Y. Srinivasan" <kys@microsoft.com>,
Haiyang Zhang <haiyangz@microsoft.com>,
Wei Liu <wei.liu@kernel.org>, Dexuan Cui <decui@microsoft.com>,
Ajay Kaher <ajay.kaher@broadcom.com>,
Jan Kiszka <jan.kiszka@siemens.com>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
John Stultz <jstultz@google.com>
Cc: linux-kernel@vger.kernel.org, linux-coco@lists.linux.dev,
kvm@vger.kernel.org, virtualization@lists.linux.dev,
linux-hyperv@vger.kernel.org, xen-devel@lists.xenproject.org,
Tom Lendacky <thomas.lendacky@amd.com>,
Nikunj A Dadhania <nikunj@amd.com>
Subject: [PATCH v2 03/38] x86/tsc: Add helper to register CPU and TSC freq calibration routines
Date: Wed, 26 Feb 2025 18:18:19 -0800 [thread overview]
Message-ID: <20250227021855.3257188-4-seanjc@google.com> (raw)
In-Reply-To: <20250227021855.3257188-1-seanjc@google.com>
Add a helper to register non-native, i.e. PV and CoCo, CPU and TSC
frequency calibration routines. This will allow consolidating handling
of common TSC properties that are forced by hypervisor (PV routines),
and will also allow adding sanity checks to guard against overriding a
TSC calibration routine with a routine that is less robust/trusted.
Make the CPU calibration routine optional, as Xen (very sanely) doesn't
assume the CPU runs as the same frequency as the TSC.
Wrap the helper in an #ifdef to document that the kernel overrides
the native routines when running as a VM, and to guard against unwanted
usage. Add a TODO to call out that AMD_MEM_ENCRYPT is a mess and doesn't
depend on HYPERVISOR_GUEST because it gates both guest and host code.
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/coco/sev/core.c | 4 ++--
arch/x86/include/asm/tsc.h | 4 ++++
arch/x86/kernel/cpu/acrn.c | 4 ++--
arch/x86/kernel/cpu/mshyperv.c | 3 +--
arch/x86/kernel/cpu/vmware.c | 4 ++--
arch/x86/kernel/jailhouse.c | 4 ++--
arch/x86/kernel/kvmclock.c | 4 ++--
arch/x86/kernel/tsc.c | 17 +++++++++++++++++
arch/x86/xen/time.c | 2 +-
9 files changed, 33 insertions(+), 13 deletions(-)
diff --git a/arch/x86/coco/sev/core.c b/arch/x86/coco/sev/core.c
index 82492efc5d94..684cef70edc1 100644
--- a/arch/x86/coco/sev/core.c
+++ b/arch/x86/coco/sev/core.c
@@ -3291,6 +3291,6 @@ void __init snp_secure_tsc_init(void)
rdmsrl(MSR_AMD64_GUEST_TSC_FREQ, tsc_freq_mhz);
snp_tsc_freq_khz = (unsigned long)(tsc_freq_mhz * 1000);
- x86_platform.calibrate_cpu = securetsc_get_tsc_khz;
- x86_platform.calibrate_tsc = securetsc_get_tsc_khz;
+ tsc_register_calibration_routines(securetsc_get_tsc_khz,
+ securetsc_get_tsc_khz);
}
diff --git a/arch/x86/include/asm/tsc.h b/arch/x86/include/asm/tsc.h
index c3a14df46327..9318c74e8d13 100644
--- a/arch/x86/include/asm/tsc.h
+++ b/arch/x86/include/asm/tsc.h
@@ -40,6 +40,10 @@ extern int cpuid_get_cpu_freq(unsigned int *cpu_khz);
extern void tsc_early_init(void);
extern void tsc_init(void);
+#if defined(CONFIG_HYPERVISOR_GUEST) || defined(CONFIG_AMD_MEM_ENCRYPT)
+extern void tsc_register_calibration_routines(unsigned long (*calibrate_tsc)(void),
+ unsigned long (*calibrate_cpu)(void));
+#endif
extern void mark_tsc_unstable(char *reason);
extern int unsynchronized_tsc(void);
extern int check_tsc_unstable(void);
diff --git a/arch/x86/kernel/cpu/acrn.c b/arch/x86/kernel/cpu/acrn.c
index 2c5b51aad91a..c1506cb87d8c 100644
--- a/arch/x86/kernel/cpu/acrn.c
+++ b/arch/x86/kernel/cpu/acrn.c
@@ -29,8 +29,8 @@ static void __init acrn_init_platform(void)
/* Install system interrupt handler for ACRN hypervisor callback */
sysvec_install(HYPERVISOR_CALLBACK_VECTOR, sysvec_acrn_hv_callback);
- x86_platform.calibrate_tsc = acrn_get_tsc_khz;
- x86_platform.calibrate_cpu = acrn_get_tsc_khz;
+ tsc_register_calibration_routines(acrn_get_tsc_khz,
+ acrn_get_tsc_khz);
}
static bool acrn_x2apic_available(void)
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index f285757618fc..aa60491bf738 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -478,8 +478,7 @@ static void __init ms_hyperv_init_platform(void)
if (ms_hyperv.features & HV_ACCESS_FREQUENCY_MSRS &&
ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) {
- x86_platform.calibrate_tsc = hv_get_tsc_khz;
- x86_platform.calibrate_cpu = hv_get_tsc_khz;
+ tsc_register_calibration_routines(hv_get_tsc_khz, hv_get_tsc_khz);
setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ);
}
diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c
index 00189cdeb775..d6f079a75f05 100644
--- a/arch/x86/kernel/cpu/vmware.c
+++ b/arch/x86/kernel/cpu/vmware.c
@@ -416,8 +416,8 @@ static void __init vmware_platform_setup(void)
}
vmware_tsc_khz = tsc_khz;
- x86_platform.calibrate_tsc = vmware_get_tsc_khz;
- x86_platform.calibrate_cpu = vmware_get_tsc_khz;
+ tsc_register_calibration_routines(vmware_get_tsc_khz,
+ vmware_get_tsc_khz);
#ifdef CONFIG_X86_LOCAL_APIC
/* Skip lapic calibration since we know the bus frequency. */
diff --git a/arch/x86/kernel/jailhouse.c b/arch/x86/kernel/jailhouse.c
index cd8ed1edbf9e..b0a053692161 100644
--- a/arch/x86/kernel/jailhouse.c
+++ b/arch/x86/kernel/jailhouse.c
@@ -209,8 +209,6 @@ static void __init jailhouse_init_platform(void)
x86_init.mpparse.parse_smp_cfg = jailhouse_parse_smp_config;
x86_init.pci.arch_init = jailhouse_pci_arch_init;
- x86_platform.calibrate_cpu = jailhouse_get_tsc;
- x86_platform.calibrate_tsc = jailhouse_get_tsc;
x86_platform.get_wallclock = jailhouse_get_wallclock;
x86_platform.legacy.rtc = 0;
x86_platform.legacy.warm_reset = 0;
@@ -220,6 +218,8 @@ static void __init jailhouse_init_platform(void)
machine_ops.emergency_restart = jailhouse_no_restart;
+ tsc_register_calibration_routines(jailhouse_get_tsc, jailhouse_get_tsc);
+
while (pa_data) {
mapping = early_memremap(pa_data, sizeof(header));
memcpy(&header, mapping, sizeof(header));
diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
index 5b2c15214a6b..b898b95a7d50 100644
--- a/arch/x86/kernel/kvmclock.c
+++ b/arch/x86/kernel/kvmclock.c
@@ -320,8 +320,8 @@ void __init kvmclock_init(void)
flags = pvclock_read_flags(&hv_clock_boot[0].pvti);
kvm_sched_clock_init(flags & PVCLOCK_TSC_STABLE_BIT);
- x86_platform.calibrate_tsc = kvm_get_tsc_khz;
- x86_platform.calibrate_cpu = kvm_get_tsc_khz;
+ tsc_register_calibration_routines(kvm_get_tsc_khz, kvm_get_tsc_khz);
+
x86_platform.get_wallclock = kvm_get_wallclock;
x86_platform.set_wallclock = kvm_set_wallclock;
#ifdef CONFIG_X86_LOCAL_APIC
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index bb4619148161..d65e85929d3e 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -1294,6 +1294,23 @@ static void __init check_system_tsc_reliable(void)
tsc_disable_clocksource_watchdog();
}
+/*
+ * TODO: Disentangle AMD_MEM_ENCRYPT and make SEV guest support depend on
+ * HYPERVISOR_GUEST.
+ */
+#if defined(CONFIG_HYPERVISOR_GUEST) || defined(CONFIG_AMD_MEM_ENCRYPT)
+void tsc_register_calibration_routines(unsigned long (*calibrate_tsc)(void),
+ unsigned long (*calibrate_cpu)(void))
+{
+ if (WARN_ON_ONCE(!calibrate_tsc))
+ return;
+
+ x86_platform.calibrate_tsc = calibrate_tsc;
+ if (calibrate_cpu)
+ x86_platform.calibrate_cpu = calibrate_cpu;
+}
+#endif
+
/*
* Make an educated guess if the TSC is trustworthy and synchronized
* over all CPUs.
diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c
index 96521b1874ac..9e2e900dc0c7 100644
--- a/arch/x86/xen/time.c
+++ b/arch/x86/xen/time.c
@@ -566,7 +566,7 @@ static void __init xen_init_time_common(void)
static_call_update(pv_steal_clock, xen_steal_clock);
paravirt_set_sched_clock(xen_sched_clock);
- x86_platform.calibrate_tsc = xen_tsc_khz;
+ tsc_register_calibration_routines(xen_tsc_khz, NULL);
x86_platform.get_wallclock = xen_get_wallclock;
}
--
2.48.1.711.g2feabab25a-goog
next prev parent reply other threads:[~2025-02-27 2:19 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-02-27 2:18 [PATCH v2 00/38] x86: Try to wrangle PV clocks vs. TSC Sean Christopherson
2025-02-27 2:18 ` [PATCH v2 01/38] x86/tsc: Add a standalone helpers for getting TSC info from CPUID.0x15 Sean Christopherson
2025-02-27 2:18 ` [PATCH v2 02/38] x86/tsc: Add standalone helper for getting CPU frequency from CPUID Sean Christopherson
2025-02-27 2:18 ` Sean Christopherson [this message]
2025-03-04 4:17 ` [PATCH v2 03/38] x86/tsc: Add helper to register CPU and TSC freq calibration routines Michael Kelley
2025-02-27 2:18 ` [PATCH v2 04/38] x86/sev: Mark TSC as reliable when configuring Secure TSC Sean Christopherson
2025-02-27 2:18 ` [PATCH v2 05/38] x86/sev: Move check for SNP Secure TSC support to tsc_early_init() Sean Christopherson
2025-02-27 2:18 ` [PATCH v2 06/38] x86/tdx: Override PV calibration routines with CPUID-based calibration Sean Christopherson
2025-02-27 13:15 ` Kirill A. Shutemov
2025-02-27 2:18 ` [PATCH v2 07/38] x86/acrn: Mark TSC frequency as known when using ACRN for calibration Sean Christopherson
2025-02-27 2:18 ` [PATCH v2 08/38] clocksource: hyper-v: Register sched_clock save/restore iff it's necessary Sean Christopherson
2025-03-04 4:17 ` Michael Kelley
2025-03-04 17:39 ` Sean Christopherson
2025-02-27 2:18 ` [PATCH v2 09/38] clocksource: hyper-v: Drop wrappers to sched_clock save/restore helpers Sean Christopherson
2025-03-04 4:17 ` Michael Kelley
2025-02-27 2:18 ` [PATCH v2 10/38] clocksource: hyper-v: Don't save/restore TSC offset when using HV sched_clock Sean Christopherson
2025-03-04 4:17 ` Michael Kelley
2025-02-27 2:18 ` [PATCH v2 11/38] x86/kvmclock: Setup kvmclock for secondary CPUs iff CONFIG_SMP=y Sean Christopherson
2025-02-27 2:18 ` [PATCH v2 12/38] x86/kvm: Don't disable kvmclock on BSP in syscore_suspend() Sean Christopherson
2025-02-27 2:18 ` [PATCH v2 13/38] x86/paravirt: Move handling of unstable PV clocks into paravirt_set_sched_clock() Sean Christopherson
2025-02-27 2:18 ` [PATCH v2 14/38] x86/kvmclock: Move sched_clock save/restore helpers up in kvmclock.c Sean Christopherson
2025-02-27 2:18 ` [PATCH v2 15/38] x86/xen/time: Nullify x86_platform's sched_clock save/restore hooks Sean Christopherson
2025-02-27 2:18 ` [PATCH v2 16/38] x86/vmware: Nullify save/restore hooks when using VMware's sched_clock Sean Christopherson
2025-02-27 2:18 ` [PATCH v2 17/38] x86/tsc: WARN if TSC sched_clock save/restore used with PV sched_clock Sean Christopherson
2025-02-27 2:18 ` [PATCH v2 18/38] x86/paravirt: Pass sched_clock save/restore helpers during registration Sean Christopherson
2025-02-27 2:18 ` [PATCH v2 19/38] x86/kvmclock: Move kvm_sched_clock_init() down in kvmclock.c Sean Christopherson
2025-02-27 2:18 ` [PATCH v2 20/38] x86/xen/time: Mark xen_setup_vsyscall_time_info() as __init Sean Christopherson
2025-02-27 2:18 ` [PATCH v2 21/38] x86/pvclock: Mark setup helpers and related various as __init/__ro_after_init Sean Christopherson
2025-02-27 2:18 ` [PATCH v2 22/38] x86/pvclock: WARN if pvclock's valid_flags are overwritten Sean Christopherson
2025-02-27 2:18 ` [PATCH v2 23/38] x86/kvmclock: Refactor handling of PVCLOCK_TSC_STABLE_BIT during kvmclock_init() Sean Christopherson
2025-02-27 2:18 ` [PATCH v2 24/38] timekeeping: Resume clocksources before reading persistent clock Sean Christopherson
2025-02-27 7:48 ` Thomas Gleixner
2025-02-27 2:18 ` [PATCH v2 25/38] x86/kvmclock: Hook clocksource.suspend/resume when kvmclock isn't sched_clock Sean Christopherson
2025-02-27 2:18 ` [PATCH v2 26/38] x86/kvmclock: WARN if wall clock is read while kvmclock is suspended Sean Christopherson
2025-02-27 2:18 ` [PATCH v2 27/38] x86/kvmclock: Enable kvmclock on APs during onlining if kvmclock isn't sched_clock Sean Christopherson
2025-02-27 2:18 ` [PATCH v2 28/38] x86/paravirt: Mark __paravirt_set_sched_clock() as __init Sean Christopherson
2025-02-27 2:18 ` [PATCH v2 29/38] x86/paravirt: Plumb a return code into __paravirt_set_sched_clock() Sean Christopherson
2025-02-27 2:18 ` [PATCH v2 30/38] x86/paravirt: Don't use a PV sched_clock in CoCo guests with trusted TSC Sean Christopherson
2025-02-27 13:17 ` Kirill A. Shutemov
2025-02-27 2:18 ` [PATCH v2 31/38] x86/tsc: Pass KNOWN_FREQ and RELIABLE as params to registration Sean Christopherson
2025-03-04 4:18 ` Michael Kelley
2025-02-27 2:18 ` [PATCH v2 32/38] x86/tsc: Rejects attempts to override TSC calibration with lesser routine Sean Christopherson
2025-02-27 2:18 ` [PATCH v2 33/38] x86/kvmclock: Mark TSC as reliable when it's constant and nonstop Sean Christopherson
2025-02-27 2:18 ` [PATCH v2 34/38] x86/kvmclock: Get CPU base frequency from CPUID when it's available Sean Christopherson
2025-02-27 2:18 ` [PATCH v2 35/38] x86/kvmclock: Get TSC frequency from CPUID when its available Sean Christopherson
2025-02-27 2:18 ` [PATCH v2 36/38] x86/kvmclock: Stuff local APIC bus period when core crystal freq comes from CPUID Sean Christopherson
2025-02-27 2:18 ` [PATCH v2 37/38] x86/kvmclock: Use TSC for sched_clock if it's constant and non-stop Sean Christopherson
2025-02-27 2:18 ` [PATCH v2 38/38] x86/paravirt: kvmclock: Setup kvmclock early iff it's sched_clock Sean Christopherson
2025-02-28 11:23 ` [PATCH v2 00/38] x86: Try to wrangle PV clocks vs. TSC David Woodhouse
2025-03-03 20:53 ` Sean Christopherson
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