From a8cf291bdac5d415eadb55e79df1fca8c3f0dfef Mon Sep 17 00:00:00 2001 From: Jianyong Wu Date: Wed, 9 Dec 2020 14:09:26 +0800 Subject: ptp: Reorganize ptp_kvm.c to make it arch-independent Currently, the ptp_kvm module contains a lot of x86-specific code. Let's move this code into a new arch-specific file in the same directory, and rename the arch-independent file to ptp_kvm_common.c. Acked-by: Richard Cochran Reviewed-by: Andre Przywara Signed-off-by: Jianyong Wu Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20201209060932.212364-4-jianyong.wu@arm.com --- drivers/ptp/Makefile | 1 + drivers/ptp/ptp_kvm.c | 197 ------------------------------------------- drivers/ptp/ptp_kvm_common.c | 157 ++++++++++++++++++++++++++++++++++ drivers/ptp/ptp_kvm_x86.c | 97 +++++++++++++++++++++ 4 files changed, 255 insertions(+), 197 deletions(-) delete mode 100644 drivers/ptp/ptp_kvm.c create mode 100644 drivers/ptp/ptp_kvm_common.c create mode 100644 drivers/ptp/ptp_kvm_x86.c (limited to 'drivers/ptp') diff --git a/drivers/ptp/Makefile b/drivers/ptp/Makefile index db5aef3bddc6..d11eeb5811d1 100644 --- a/drivers/ptp/Makefile +++ b/drivers/ptp/Makefile @@ -4,6 +4,7 @@ # ptp-y := ptp_clock.o ptp_chardev.o ptp_sysfs.o +ptp_kvm-$(CONFIG_X86) := ptp_kvm_x86.o ptp_kvm_common.o obj-$(CONFIG_PTP_1588_CLOCK) += ptp.o obj-$(CONFIG_PTP_1588_CLOCK_DTE) += ptp_dte.o obj-$(CONFIG_PTP_1588_CLOCK_INES) += ptp_ines.o diff --git a/drivers/ptp/ptp_kvm.c b/drivers/ptp/ptp_kvm.c deleted file mode 100644 index 658d33fc3195..000000000000 --- a/drivers/ptp/ptp_kvm.c +++ /dev/null @@ -1,197 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0-or-later -/* - * Virtual PTP 1588 clock for use with KVM guests - * - * Copyright (C) 2017 Red Hat Inc. - */ -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include - -#include - -struct kvm_ptp_clock { - struct ptp_clock *ptp_clock; - struct ptp_clock_info caps; -}; - -static DEFINE_SPINLOCK(kvm_ptp_lock); - -static struct pvclock_vsyscall_time_info *hv_clock; - -static struct kvm_clock_pairing clock_pair; -static phys_addr_t clock_pair_gpa; - -static int ptp_kvm_get_time_fn(ktime_t *device_time, - struct system_counterval_t *system_counter, - void *ctx) -{ - unsigned long ret; - struct timespec64 tspec; - unsigned version; - int cpu; - struct pvclock_vcpu_time_info *src; - - spin_lock(&kvm_ptp_lock); - - preempt_disable_notrace(); - cpu = smp_processor_id(); - src = &hv_clock[cpu].pvti; - - do { - /* - * We are using a TSC value read in the hosts - * kvm_hc_clock_pairing handling. - * So any changes to tsc_to_system_mul - * and tsc_shift or any other pvclock - * data invalidate that measurement. - */ - version = pvclock_read_begin(src); - - ret = kvm_hypercall2(KVM_HC_CLOCK_PAIRING, - clock_pair_gpa, - KVM_CLOCK_PAIRING_WALLCLOCK); - if (ret != 0) { - pr_err_ratelimited("clock pairing hypercall ret %lu\n", ret); - spin_unlock(&kvm_ptp_lock); - preempt_enable_notrace(); - return -EOPNOTSUPP; - } - - tspec.tv_sec = clock_pair.sec; - tspec.tv_nsec = clock_pair.nsec; - ret = __pvclock_read_cycles(src, clock_pair.tsc); - } while (pvclock_read_retry(src, version)); - - preempt_enable_notrace(); - - system_counter->cycles = ret; - system_counter->cs = &kvm_clock; - - *device_time = timespec64_to_ktime(tspec); - - spin_unlock(&kvm_ptp_lock); - - return 0; -} - -static int ptp_kvm_getcrosststamp(struct ptp_clock_info *ptp, - struct system_device_crosststamp *xtstamp) -{ - return get_device_system_crosststamp(ptp_kvm_get_time_fn, NULL, - NULL, xtstamp); -} - -/* - * PTP clock operations - */ - -static int ptp_kvm_adjfreq(struct ptp_clock_info *ptp, s32 ppb) -{ - return -EOPNOTSUPP; -} - -static int ptp_kvm_adjtime(struct ptp_clock_info *ptp, s64 delta) -{ - return -EOPNOTSUPP; -} - -static int ptp_kvm_settime(struct ptp_clock_info *ptp, - const struct timespec64 *ts) -{ - return -EOPNOTSUPP; -} - -static int ptp_kvm_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts) -{ - unsigned long ret; - struct timespec64 tspec; - - spin_lock(&kvm_ptp_lock); - - ret = kvm_hypercall2(KVM_HC_CLOCK_PAIRING, - clock_pair_gpa, - KVM_CLOCK_PAIRING_WALLCLOCK); - if (ret != 0) { - pr_err_ratelimited("clock offset hypercall ret %lu\n", ret); - spin_unlock(&kvm_ptp_lock); - return -EOPNOTSUPP; - } - - tspec.tv_sec = clock_pair.sec; - tspec.tv_nsec = clock_pair.nsec; - spin_unlock(&kvm_ptp_lock); - - memcpy(ts, &tspec, sizeof(struct timespec64)); - - return 0; -} - -static int ptp_kvm_enable(struct ptp_clock_info *ptp, - struct ptp_clock_request *rq, int on) -{ - return -EOPNOTSUPP; -} - -static const struct ptp_clock_info ptp_kvm_caps = { - .owner = THIS_MODULE, - .name = "KVM virtual PTP", - .max_adj = 0, - .n_ext_ts = 0, - .n_pins = 0, - .pps = 0, - .adjfreq = ptp_kvm_adjfreq, - .adjtime = ptp_kvm_adjtime, - .gettime64 = ptp_kvm_gettime, - .settime64 = ptp_kvm_settime, - .enable = ptp_kvm_enable, - .getcrosststamp = ptp_kvm_getcrosststamp, -}; - -/* module operations */ - -static struct kvm_ptp_clock kvm_ptp_clock; - -static void __exit ptp_kvm_exit(void) -{ - ptp_clock_unregister(kvm_ptp_clock.ptp_clock); -} - -static int __init ptp_kvm_init(void) -{ - long ret; - - if (!kvm_para_available()) - return -ENODEV; - - clock_pair_gpa = slow_virt_to_phys(&clock_pair); - hv_clock = pvclock_get_pvti_cpu0_va(); - - if (!hv_clock) - return -ENODEV; - - ret = kvm_hypercall2(KVM_HC_CLOCK_PAIRING, clock_pair_gpa, - KVM_CLOCK_PAIRING_WALLCLOCK); - if (ret == -KVM_ENOSYS || ret == -KVM_EOPNOTSUPP) - return -ENODEV; - - kvm_ptp_clock.caps = ptp_kvm_caps; - - kvm_ptp_clock.ptp_clock = ptp_clock_register(&kvm_ptp_clock.caps, NULL); - - return PTR_ERR_OR_ZERO(kvm_ptp_clock.ptp_clock); -} - -module_init(ptp_kvm_init); -module_exit(ptp_kvm_exit); - -MODULE_AUTHOR("Marcelo Tosatti "); -MODULE_DESCRIPTION("PTP clock using KVMCLOCK"); -MODULE_LICENSE("GPL"); diff --git a/drivers/ptp/ptp_kvm_common.c b/drivers/ptp/ptp_kvm_common.c new file mode 100644 index 000000000000..721ddcede5e1 --- /dev/null +++ b/drivers/ptp/ptp_kvm_common.c @@ -0,0 +1,157 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Virtual PTP 1588 clock for use with KVM guests + * + * Copyright (C) 2017 Red Hat Inc. + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +struct kvm_ptp_clock { + struct ptp_clock *ptp_clock; + struct ptp_clock_info caps; +}; + +static DEFINE_SPINLOCK(kvm_ptp_lock); + +static int ptp_kvm_get_time_fn(ktime_t *device_time, + struct system_counterval_t *system_counter, + void *ctx) +{ + long ret; + u64 cycle; + struct timespec64 tspec; + struct clocksource *cs; + + spin_lock(&kvm_ptp_lock); + + preempt_disable_notrace(); + ret = kvm_arch_ptp_get_crosststamp(&cycle, &tspec, &cs); + if (ret) { + spin_unlock(&kvm_ptp_lock); + preempt_enable_notrace(); + return ret; + } + + preempt_enable_notrace(); + + system_counter->cycles = cycle; + system_counter->cs = cs; + + *device_time = timespec64_to_ktime(tspec); + + spin_unlock(&kvm_ptp_lock); + + return 0; +} + +static int ptp_kvm_getcrosststamp(struct ptp_clock_info *ptp, + struct system_device_crosststamp *xtstamp) +{ + return get_device_system_crosststamp(ptp_kvm_get_time_fn, NULL, + NULL, xtstamp); +} + +/* + * PTP clock operations + */ + +static int ptp_kvm_adjfreq(struct ptp_clock_info *ptp, s32 ppb) +{ + return -EOPNOTSUPP; +} + +static int ptp_kvm_adjtime(struct ptp_clock_info *ptp, s64 delta) +{ + return -EOPNOTSUPP; +} + +static int ptp_kvm_settime(struct ptp_clock_info *ptp, + const struct timespec64 *ts) +{ + return -EOPNOTSUPP; +} + +static int ptp_kvm_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts) +{ + long ret; + struct timespec64 tspec; + + spin_lock(&kvm_ptp_lock); + + ret = kvm_arch_ptp_get_clock(&tspec); + if (ret) { + spin_unlock(&kvm_ptp_lock); + return ret; + } + + spin_unlock(&kvm_ptp_lock); + + memcpy(ts, &tspec, sizeof(struct timespec64)); + + return 0; +} + +static int ptp_kvm_enable(struct ptp_clock_info *ptp, + struct ptp_clock_request *rq, int on) +{ + return -EOPNOTSUPP; +} + +static const struct ptp_clock_info ptp_kvm_caps = { + .owner = THIS_MODULE, + .name = "KVM virtual PTP", + .max_adj = 0, + .n_ext_ts = 0, + .n_pins = 0, + .pps = 0, + .adjfreq = ptp_kvm_adjfreq, + .adjtime = ptp_kvm_adjtime, + .gettime64 = ptp_kvm_gettime, + .settime64 = ptp_kvm_settime, + .enable = ptp_kvm_enable, + .getcrosststamp = ptp_kvm_getcrosststamp, +}; + +/* module operations */ + +static struct kvm_ptp_clock kvm_ptp_clock; + +static void __exit ptp_kvm_exit(void) +{ + ptp_clock_unregister(kvm_ptp_clock.ptp_clock); +} + +static int __init ptp_kvm_init(void) +{ + long ret; + + ret = kvm_arch_ptp_init(); + if (ret) { + pr_err("fail to initialize ptp_kvm"); + return ret; + } + + kvm_ptp_clock.caps = ptp_kvm_caps; + + kvm_ptp_clock.ptp_clock = ptp_clock_register(&kvm_ptp_clock.caps, NULL); + + return PTR_ERR_OR_ZERO(kvm_ptp_clock.ptp_clock); +} + +module_init(ptp_kvm_init); +module_exit(ptp_kvm_exit); + +MODULE_AUTHOR("Marcelo Tosatti "); +MODULE_DESCRIPTION("PTP clock using KVMCLOCK"); +MODULE_LICENSE("GPL"); diff --git a/drivers/ptp/ptp_kvm_x86.c b/drivers/ptp/ptp_kvm_x86.c new file mode 100644 index 000000000000..3dd519dfc473 --- /dev/null +++ b/drivers/ptp/ptp_kvm_x86.c @@ -0,0 +1,97 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Virtual PTP 1588 clock for use with KVM guests + * + * Copyright (C) 2017 Red Hat Inc. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +struct pvclock_vsyscall_time_info *hv_clock; + +static phys_addr_t clock_pair_gpa; +static struct kvm_clock_pairing clock_pair; + +int kvm_arch_ptp_init(void) +{ + long ret; + + if (!kvm_para_available()) + return -ENODEV; + + clock_pair_gpa = slow_virt_to_phys(&clock_pair); + hv_clock = pvclock_get_pvti_cpu0_va(); + if (!hv_clock) + return -ENODEV; + + ret = kvm_hypercall2(KVM_HC_CLOCK_PAIRING, clock_pair_gpa, + KVM_CLOCK_PAIRING_WALLCLOCK); + if (ret == -KVM_ENOSYS || ret == -KVM_EOPNOTSUPP) + return -ENODEV; + + return 0; +} + +int kvm_arch_ptp_get_clock(struct timespec64 *ts) +{ + long ret; + + ret = kvm_hypercall2(KVM_HC_CLOCK_PAIRING, + clock_pair_gpa, + KVM_CLOCK_PAIRING_WALLCLOCK); + if (ret != 0) { + pr_err_ratelimited("clock offset hypercall ret %lu\n", ret); + return -EOPNOTSUPP; + } + + ts->tv_sec = clock_pair.sec; + ts->tv_nsec = clock_pair.nsec; + + return 0; +} + +int kvm_arch_ptp_get_crosststamp(u64 *cycle, struct timespec64 *tspec, + struct clocksource **cs) +{ + struct pvclock_vcpu_time_info *src; + unsigned int version; + long ret; + int cpu; + + cpu = smp_processor_id(); + src = &hv_clock[cpu].pvti; + + do { + /* + * We are using a TSC value read in the hosts + * kvm_hc_clock_pairing handling. + * So any changes to tsc_to_system_mul + * and tsc_shift or any other pvclock + * data invalidate that measurement. + */ + version = pvclock_read_begin(src); + + ret = kvm_hypercall2(KVM_HC_CLOCK_PAIRING, + clock_pair_gpa, + KVM_CLOCK_PAIRING_WALLCLOCK); + if (ret != 0) { + pr_err_ratelimited("clock pairing hypercall ret %lu\n", ret); + return -EOPNOTSUPP; + } + tspec->tv_sec = clock_pair.sec; + tspec->tv_nsec = clock_pair.nsec; + *cycle = __pvclock_read_cycles(src, clock_pair.tsc); + } while (pvclock_read_retry(src, version)); + + *cs = &kvm_clock; + + return 0; +} -- cgit v1.2.3 From 300bb1fe767183a1ca1dadf691409c53c4ecff4b Mon Sep 17 00:00:00 2001 From: Jianyong Wu Date: Wed, 9 Dec 2020 14:09:30 +0800 Subject: ptp: arm/arm64: Enable ptp_kvm for arm/arm64 Currently, there is no mechanism to keep time sync between guest and host in arm/arm64 virtualization environment. Time in guest will drift compared with host after boot up as they may both use third party time sources to correct their time respectively. The time deviation will be in order of milliseconds. But in some scenarios,like in cloud environment, we ask for higher time precision. kvm ptp clock, which chooses the host clock source as a reference clock to sync time between guest and host, has been adopted by x86 which takes the time sync order from milliseconds to nanoseconds. This patch enables kvm ptp clock for arm/arm64 and improves clock sync precision significantly. Test result comparisons between with kvm ptp clock and without it in arm/arm64 are as follows. This test derived from the result of command 'chronyc sources'. we should take more care of the last sample column which shows the offset between the local clock and the source at the last measurement. no kvm ptp in guest: MS Name/IP address Stratum Poll Reach LastRx Last sample ======================================================================== ^* dns1.synet.edu.cn 2 6 377 13 +1040us[+1581us] +/- 21ms ^* dns1.synet.edu.cn 2 6 377 21 +1040us[+1581us] +/- 21ms ^* dns1.synet.edu.cn 2 6 377 29 +1040us[+1581us] +/- 21ms ^* dns1.synet.edu.cn 2 6 377 37 +1040us[+1581us] +/- 21ms ^* dns1.synet.edu.cn 2 6 377 45 +1040us[+1581us] +/- 21ms ^* dns1.synet.edu.cn 2 6 377 53 +1040us[+1581us] +/- 21ms ^* dns1.synet.edu.cn 2 6 377 61 +1040us[+1581us] +/- 21ms ^* dns1.synet.edu.cn 2 6 377 4 -130us[ +796us] +/- 21ms ^* dns1.synet.edu.cn 2 6 377 12 -130us[ +796us] +/- 21ms ^* dns1.synet.edu.cn 2 6 377 20 -130us[ +796us] +/- 21ms in host: MS Name/IP address Stratum Poll Reach LastRx Last sample ======================================================================== ^* 120.25.115.20 2 7 377 72 -470us[ -603us] +/- 18ms ^* 120.25.115.20 2 7 377 92 -470us[ -603us] +/- 18ms ^* 120.25.115.20 2 7 377 112 -470us[ -603us] +/- 18ms ^* 120.25.115.20 2 7 377 2 +872ns[-6808ns] +/- 17ms ^* 120.25.115.20 2 7 377 22 +872ns[-6808ns] +/- 17ms ^* 120.25.115.20 2 7 377 43 +872ns[-6808ns] +/- 17ms ^* 120.25.115.20 2 7 377 63 +872ns[-6808ns] +/- 17ms ^* 120.25.115.20 2 7 377 83 +872ns[-6808ns] +/- 17ms ^* 120.25.115.20 2 7 377 103 +872ns[-6808ns] +/- 17ms ^* 120.25.115.20 2 7 377 123 +872ns[-6808ns] +/- 17ms The dns1.synet.edu.cn is the network reference clock for guest and 120.25.115.20 is the network reference clock for host. we can't get the clock error between guest and host directly, but a roughly estimated value will be in order of hundreds of us to ms. with kvm ptp in guest: chrony has been disabled in host to remove the disturb by network clock. MS Name/IP address Stratum Poll Reach LastRx Last sample ======================================================================== * PHC0 0 3 377 8 -7ns[ +1ns] +/- 3ns * PHC0 0 3 377 8 +1ns[ +16ns] +/- 3ns * PHC0 0 3 377 6 -4ns[ -0ns] +/- 6ns * PHC0 0 3 377 6 -8ns[ -12ns] +/- 5ns * PHC0 0 3 377 5 +2ns[ +4ns] +/- 4ns * PHC0 0 3 377 13 +2ns[ +4ns] +/- 4ns * PHC0 0 3 377 12 -4ns[ -6ns] +/- 4ns * PHC0 0 3 377 11 -8ns[ -11ns] +/- 6ns * PHC0 0 3 377 10 -14ns[ -20ns] +/- 4ns * PHC0 0 3 377 8 +4ns[ +5ns] +/- 4ns The PHC0 is the ptp clock which choose the host clock as its source clock. So we can see that the clock difference between host and guest is in order of ns. Cc: Mark Rutland Acked-by: Richard Cochran Signed-off-by: Jianyong Wu Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20201209060932.212364-8-jianyong.wu@arm.com --- drivers/clocksource/arm_arch_timer.c | 34 ++++++++++++++++++++++++++++++++++ drivers/ptp/Kconfig | 2 +- drivers/ptp/Makefile | 1 + drivers/ptp/ptp_kvm_arm.c | 28 ++++++++++++++++++++++++++++ 4 files changed, 64 insertions(+), 1 deletion(-) create mode 100644 drivers/ptp/ptp_kvm_arm.c (limited to 'drivers/ptp') diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index 8f12e223703f..e0f167e5e792 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -25,6 +25,8 @@ #include #include #include +#include +#include #include #include @@ -1659,3 +1661,35 @@ static int __init arch_timer_acpi_init(struct acpi_table_header *table) } TIMER_ACPI_DECLARE(arch_timer, ACPI_SIG_GTDT, arch_timer_acpi_init); #endif + +int kvm_arch_ptp_get_crosststamp(u64 *cycle, struct timespec64 *ts, + struct clocksource **cs) +{ + struct arm_smccc_res hvc_res; + u32 ptp_counter; + ktime_t ktime; + + if (!IS_ENABLED(CONFIG_HAVE_ARM_SMCCC_DISCOVERY)) + return -EOPNOTSUPP; + + if (arch_timer_uses_ppi == ARCH_TIMER_VIRT_PPI) + ptp_counter = KVM_PTP_VIRT_COUNTER; + else + ptp_counter = KVM_PTP_PHYS_COUNTER; + + arm_smccc_1_1_invoke(ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID, + ptp_counter, &hvc_res); + + if ((int)(hvc_res.a0) < 0) + return -EOPNOTSUPP; + + ktime = (u64)hvc_res.a0 << 32 | hvc_res.a1; + *ts = ktime_to_timespec64(ktime); + if (cycle) + *cycle = (u64)hvc_res.a2 << 32 | hvc_res.a3; + if (cs) + *cs = &clocksource_counter; + + return 0; +} +EXPORT_SYMBOL_GPL(kvm_arch_ptp_get_crosststamp); diff --git a/drivers/ptp/Kconfig b/drivers/ptp/Kconfig index f2edef0df40f..8c20e524e9ad 100644 --- a/drivers/ptp/Kconfig +++ b/drivers/ptp/Kconfig @@ -108,7 +108,7 @@ config PTP_1588_CLOCK_PCH config PTP_1588_CLOCK_KVM tristate "KVM virtual PTP clock" depends on PTP_1588_CLOCK - depends on KVM_GUEST && X86 + depends on (KVM_GUEST && X86) || (HAVE_ARM_SMCCC_DISCOVERY && ARM_ARCH_TIMER) default y help This driver adds support for using kvm infrastructure as a PTP diff --git a/drivers/ptp/Makefile b/drivers/ptp/Makefile index d11eeb5811d1..8673d1743faa 100644 --- a/drivers/ptp/Makefile +++ b/drivers/ptp/Makefile @@ -5,6 +5,7 @@ ptp-y := ptp_clock.o ptp_chardev.o ptp_sysfs.o ptp_kvm-$(CONFIG_X86) := ptp_kvm_x86.o ptp_kvm_common.o +ptp_kvm-$(CONFIG_HAVE_ARM_SMCCC) := ptp_kvm_arm.o ptp_kvm_common.o obj-$(CONFIG_PTP_1588_CLOCK) += ptp.o obj-$(CONFIG_PTP_1588_CLOCK_DTE) += ptp_dte.o obj-$(CONFIG_PTP_1588_CLOCK_INES) += ptp_ines.o diff --git a/drivers/ptp/ptp_kvm_arm.c b/drivers/ptp/ptp_kvm_arm.c new file mode 100644 index 000000000000..b7d28c8dfb84 --- /dev/null +++ b/drivers/ptp/ptp_kvm_arm.c @@ -0,0 +1,28 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Virtual PTP 1588 clock for use with KVM guests + * Copyright (C) 2019 ARM Ltd. + * All Rights Reserved + */ + +#include +#include + +#include +#include + +int kvm_arch_ptp_init(void) +{ + int ret; + + ret = kvm_arm_hyp_service_available(ARM_SMCCC_KVM_FUNC_PTP); + if (ret <= 0) + return -EOPNOTSUPP; + + return 0; +} + +int kvm_arch_ptp_get_clock(struct timespec64 *ts) +{ + return kvm_arch_ptp_get_crosststamp(NULL, ts, NULL); +} -- cgit v1.2.3 From a86ed2cfa13c5175eb082c50a644f6bf29ac65cc Mon Sep 17 00:00:00 2001 From: Jon Hunter Date: Tue, 20 Apr 2021 14:24:19 +0100 Subject: ptp: Don't print an error if ptp_kvm is not supported Commit 300bb1fe7671 ("ptp: arm/arm64: Enable ptp_kvm for arm/arm64") enable ptp_kvm support for ARM platforms and for any ARM platform that does not support this, the following error message is displayed ... ERR KERN fail to initialize ptp_kvm For platforms that do not support ptp_kvm this error is a bit misleading and so fix this by only printing this message if the error returned by kvm_arch_ptp_init() is not -EOPNOTSUPP. Note that -EOPNOTSUPP is only returned by ARM platforms today if ptp_kvm is not supported. Fixes: 300bb1fe7671 ("ptp: arm/arm64: Enable ptp_kvm for arm/arm64") Signed-off-by: Jon Hunter Acked-by: Richard Cochran Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20210420132419.1318148-1-jonathanh@nvidia.com --- drivers/ptp/ptp_kvm_common.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'drivers/ptp') diff --git a/drivers/ptp/ptp_kvm_common.c b/drivers/ptp/ptp_kvm_common.c index 721ddcede5e1..fcae32f56f25 100644 --- a/drivers/ptp/ptp_kvm_common.c +++ b/drivers/ptp/ptp_kvm_common.c @@ -138,7 +138,8 @@ static int __init ptp_kvm_init(void) ret = kvm_arch_ptp_init(); if (ret) { - pr_err("fail to initialize ptp_kvm"); + if (ret != -EOPNOTSUPP) + pr_err("fail to initialize ptp_kvm"); return ret; } -- cgit v1.2.3