| Message ID | 20201111062211.33144-8-jianyong.wu@arm.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | Enable ptp_kvm for arm/arm64 | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Not a local patch |
Hi Jianyong,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on linus/master]
[also build test WARNING on v5.10-rc3 next-20201110]
[cannot apply to tip/timers/core kvmarm/next kvm/linux-next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/0day-ci/linux/commits/Jianyong-Wu/Enable-ptp_kvm-for-arm-arm64/20201111-142600
base: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git eccc876724927ff3b9ff91f36f7b6b159e948f0c
config: arm64-randconfig-r016-20201111 (attached as .config)
compiler: aarch64-linux-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/0day-ci/linux/commit/94d44d1bc7bec0d91d4c4851dd935a752bffe07d
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Jianyong-Wu/Enable-ptp_kvm-for-arm-arm64/20201111-142600
git checkout 94d44d1bc7bec0d91d4c4851dd935a752bffe07d
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=arm64
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
All warnings (new ones prefixed by >>):
>> drivers/clocksource/arm_arch_timer.c:1655:5: warning: no previous prototype for 'kvm_arch_ptp_get_crosststamp' [-Wmissing-prototypes]
1655 | int kvm_arch_ptp_get_crosststamp(u64 *cycle, struct timespec64 *ts,
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
--
>> drivers/ptp/ptp_kvm_arm.c:19:5: warning: no previous prototype for 'kvm_arch_ptp_init' [-Wmissing-prototypes]
19 | int kvm_arch_ptp_init(void)
| ^~~~~~~~~~~~~~~~~
>> drivers/ptp/ptp_kvm_arm.c:30:5: warning: no previous prototype for 'kvm_arch_ptp_get_clock' [-Wmissing-prototypes]
30 | int kvm_arch_ptp_get_clock(struct timespec64 *ts)
| ^~~~~~~~~~~~~~~~~~~~~~
vim +/kvm_arch_ptp_get_crosststamp +1655 drivers/clocksource/arm_arch_timer.c
1654
> 1655 int kvm_arch_ptp_get_crosststamp(u64 *cycle, struct timespec64 *ts,
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
Hi Jianyong,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on linus/master]
[also build test ERROR on v5.10-rc3 next-20201111]
[cannot apply to tip/timers/core kvmarm/next kvm/linux-next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/0day-ci/linux/commits/Jianyong-Wu/Enable-ptp_kvm-for-arm-arm64/20201111-142600
base: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git eccc876724927ff3b9ff91f36f7b6b159e948f0c
config: arm-milbeaut_m10v_defconfig (attached as .config)
compiler: arm-linux-gnueabi-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/0day-ci/linux/commit/94d44d1bc7bec0d91d4c4851dd935a752bffe07d
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Jianyong-Wu/Enable-ptp_kvm-for-arm-arm64/20201111-142600
git checkout 94d44d1bc7bec0d91d4c4851dd935a752bffe07d
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=arm
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
All errors (new ones prefixed by >>):
arch/arm/vfp/vfphw.o: in function `vfp_support_entry':
(.text+0xa): relocation truncated to fit: R_ARM_THM_JUMP19 against symbol `vfp_kmode_exception' defined in .text.unlikely section in arch/arm/vfp/vfpmodule.o
arm-linux-gnueabi-ld: arch/arm/kernel/setup.o: in function `setup_arch':
setup.c:(.init.text+0xaa2): undefined reference to `kvm_init_hyp_services'
arm-linux-gnueabi-ld: drivers/clocksource/arm_arch_timer.o: in function `kvm_arch_ptp_get_crosststamp':
>> arm_arch_timer.c:(.text+0x202): undefined reference to `arm_smccc_1_1_get_conduit'
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
On 2020-11-11 06:22, Jianyong Wu wrote: > 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 envirenment, we > ask environment > 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 > precison 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. > > Signed-off-by: Jianyong Wu <jianyong.wu@arm.com> > --- > drivers/clocksource/arm_arch_timer.c | 28 ++++++++++++++++++ > drivers/ptp/Kconfig | 2 +- > drivers/ptp/Makefile | 1 + > drivers/ptp/ptp_kvm_arm.c | 44 ++++++++++++++++++++++++++++ > 4 files changed, 74 insertions(+), 1 deletion(-) > create mode 100644 drivers/ptp/ptp_kvm_arm.c > > diff --git a/drivers/clocksource/arm_arch_timer.c > b/drivers/clocksource/arm_arch_timer.c > index d55acffb0b90..b33c5a663d30 100644 > --- a/drivers/clocksource/arm_arch_timer.c > +++ b/drivers/clocksource/arm_arch_timer.c > @@ -25,6 +25,7 @@ > #include <linux/sched/clock.h> > #include <linux/sched_clock.h> > #include <linux/acpi.h> > +#include <linux/arm-smccc.h> > > #include <asm/arch_timer.h> > #include <asm/virt.h> > @@ -1650,3 +1651,30 @@ 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; > + ktime_t ktime; > + u32 ptp_counter; > + > + if (arch_timer_uses_ppi == ARCH_TIMER_VIRT_PPI) > + ptp_counter = ARM_PTP_VIRT_COUNTER; > + else > + ptp_counter = ARM_PTP_PHY_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); > + *cycle = (u64)hvc_res.a2 << 32 | hvc_res.a3; Endianness. > + *cs = &clocksource_counter; > + > + return 0; > +} > +EXPORT_SYMBOL_GPL(kvm_arch_ptp_get_crosststamp); > diff --git a/drivers/ptp/Kconfig b/drivers/ptp/Kconfig > index 942f72d8151d..677c7f696b70 100644 > --- a/drivers/ptp/Kconfig > +++ b/drivers/ptp/Kconfig > @@ -106,7 +106,7 @@ 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 699a4e4d19c2..9fa5ede44b2b 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..2212827c0384 > --- /dev/null > +++ b/drivers/ptp/ptp_kvm_arm.c > @@ -0,0 +1,44 @@ > +// 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 <linux/kernel.h> > +#include <linux/err.h> > +#include <asm/hypervisor.h> > +#include <linux/module.h> > +#include <linux/psci.h> > +#include <linux/arm-smccc.h> > +#include <linux/timecounter.h> > +#include <linux/sched/clock.h> > +#include <asm/arch_timer.h> > +#include <asm/hypervisor.h> > + > +int kvm_arch_ptp_init(void) > +{ > + int ret; > + > + ret = kvm_arm_hyp_service_available(ARM_SMCCC_KVM_FUNC_KVM_PTP); > + if (ret <= 0) > + return -EOPNOTSUPP; > + > + return 0; > +} > + > +int kvm_arch_ptp_get_clock(struct timespec64 *ts) > +{ > + ktime_t ktime; > + struct arm_smccc_res hvc_res; > + > + arm_smccc_1_1_invoke(ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID, > + ARM_PTP_NONE_COUNTER, &hvc_res); I really don't see the need to use a non-architectural counter ID. Using the virtual counter ID should just be fine, and shouldn't lead to any issue. Am I missing something? > + if ((int)(hvc_res.a0) < 0) > + return -EOPNOTSUPP; > + > + ktime = (u64)hvc_res.a0 << 32 | hvc_res.a1; Endianness. > + *ts = ktime_to_timespec64(ktime); > + > + return 0; > +} Thanks, M.
Hi Marc, > -----Original Message----- > From: Marc Zyngier <maz@kernel.org> > Sent: Monday, November 23, 2020 6:49 PM > To: Jianyong Wu <Jianyong.Wu@arm.com> > Cc: netdev@vger.kernel.org; yangbo.lu@nxp.com; john.stultz@linaro.org; > tglx@linutronix.de; pbonzini@redhat.com; sean.j.christopherson@intel.com; > richardcochran@gmail.com; Mark Rutland <Mark.Rutland@arm.com>; > will@kernel.org; Suzuki Poulose <Suzuki.Poulose@arm.com>; Andre > Przywara <Andre.Przywara@arm.com>; Steven Price > <Steven.Price@arm.com>; linux-kernel@vger.kernel.org; linux-arm- > kernel@lists.infradead.org; kvmarm@lists.cs.columbia.edu; > kvm@vger.kernel.org; Steve Capper <Steve.Capper@arm.com>; Justin He > <Justin.He@arm.com>; nd <nd@arm.com> > Subject: Re: [PATCH v15 7/9] ptp: arm/arm64: Enable ptp_kvm for > arm/arm64 > > On 2020-11-11 06:22, Jianyong Wu wrote: > > 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 > > envirenment, we ask > > environment > OK > > 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 > > precison > > precision > OK > > 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. > > > > Signed-off-by: Jianyong Wu <jianyong.wu@arm.com> > > --- > > drivers/clocksource/arm_arch_timer.c | 28 ++++++++++++++++++ > > drivers/ptp/Kconfig | 2 +- > > drivers/ptp/Makefile | 1 + > > drivers/ptp/ptp_kvm_arm.c | 44 > ++++++++++++++++++++++++++++ > > 4 files changed, 74 insertions(+), 1 deletion(-) create mode 100644 > > drivers/ptp/ptp_kvm_arm.c > > > > diff --git a/drivers/clocksource/arm_arch_timer.c > > b/drivers/clocksource/arm_arch_timer.c > > index d55acffb0b90..b33c5a663d30 100644 > > --- a/drivers/clocksource/arm_arch_timer.c > > +++ b/drivers/clocksource/arm_arch_timer.c > > @@ -25,6 +25,7 @@ > > #include <linux/sched/clock.h> > > #include <linux/sched_clock.h> > > #include <linux/acpi.h> > > +#include <linux/arm-smccc.h> > > > > #include <asm/arch_timer.h> > > #include <asm/virt.h> > > @@ -1650,3 +1651,30 @@ 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; > > + ktime_t ktime; > > + u32 ptp_counter; > > + > > + if (arch_timer_uses_ppi == ARCH_TIMER_VIRT_PPI) > > + ptp_counter = ARM_PTP_VIRT_COUNTER; > > + else > > + ptp_counter = ARM_PTP_PHY_COUNTER; > > + > > + > arm_smccc_1_1_invoke(ARM_SMCCC_VENDOR_HYP_KVM_PTP_FU > NC_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); > > + *cycle = (u64)hvc_res.a2 << 32 | hvc_res.a3; > > Endianness. > > > + *cs = &clocksource_counter; > > + > > + return 0; > > +} > > +EXPORT_SYMBOL_GPL(kvm_arch_ptp_get_crosststamp); > > diff --git a/drivers/ptp/Kconfig b/drivers/ptp/Kconfig index > > 942f72d8151d..677c7f696b70 100644 > > --- a/drivers/ptp/Kconfig > > +++ b/drivers/ptp/Kconfig > > @@ -106,7 +106,7 @@ 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 > > 699a4e4d19c2..9fa5ede44b2b 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..2212827c0384 > > --- /dev/null > > +++ b/drivers/ptp/ptp_kvm_arm.c > > @@ -0,0 +1,44 @@ > > +// 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 <linux/kernel.h> > > +#include <linux/err.h> > > +#include <asm/hypervisor.h> > > +#include <linux/module.h> > > +#include <linux/psci.h> > > +#include <linux/arm-smccc.h> > > +#include <linux/timecounter.h> > > +#include <linux/sched/clock.h> > > +#include <asm/arch_timer.h> > > +#include <asm/hypervisor.h> > > + > > +int kvm_arch_ptp_init(void) > > +{ > > + int ret; > > + > > + ret = > kvm_arm_hyp_service_available(ARM_SMCCC_KVM_FUNC_KVM_PTP); > > + if (ret <= 0) > > + return -EOPNOTSUPP; > > + > > + return 0; > > +} > > + > > +int kvm_arch_ptp_get_clock(struct timespec64 *ts) { > > + ktime_t ktime; > > + struct arm_smccc_res hvc_res; > > + > > + > arm_smccc_1_1_invoke(ARM_SMCCC_VENDOR_HYP_KVM_PTP_FU > NC_ID, > > + ARM_PTP_NONE_COUNTER, &hvc_res); > > I really don't see the need to use a non-architectural counter ID. > Using the virtual counter ID should just be fine, and shouldn't lead to any > issue. > > Am I missing something? In this function, no counter data is needed. If virtual counter ID is used here, user may be confused with why we get virtual counter data and do nothing with it. So I explicitly add a new "NONE" counter ID to make it clear. WDYT? Thanks Jianyong > > > + if ((int)(hvc_res.a0) < 0) > > + return -EOPNOTSUPP; > > + > > + ktime = (u64)hvc_res.a0 << 32 | hvc_res.a1; > > Endianness. > > > + *ts = ktime_to_timespec64(ktime); > > + > > + return 0; > > +} > > Thanks, > > M. > -- > Jazz is not dead. It just smells funny...
Jianyong, On 2020-11-24 05:37, Jianyong Wu wrote: > Hi Marc, [...] >> > + >> arm_smccc_1_1_invoke(ARM_SMCCC_VENDOR_HYP_KVM_PTP_FU >> NC_ID, >> > + ARM_PTP_NONE_COUNTER, &hvc_res); >> >> I really don't see the need to use a non-architectural counter ID. >> Using the virtual counter ID should just be fine, and shouldn't lead >> to any >> issue. >> > >> Am I missing something? > > In this function, no counter data is needed. If virtual counter ID is > used here, user may be confused with why we get virtual counter > data and do nothing with it. So I explicitly add a new "NONE" counter > ID to make it clear. > > WDYT? ITIABI (I Think It's A Bad Idea). There are two counters, and the API allows to retrieve the data for any of these two. If the "user" doesn't want to do anything with the data, that's their problem. Here, you can just sue the virtual counter, and that will give you the exact same semantic, without inventing non-architectural state. Thanks, M.
Hi Marc, > -----Original Message----- > From: Marc Zyngier <maz@kernel.org> > Sent: Tuesday, November 24, 2020 5:05 PM > To: Jianyong Wu <Jianyong.Wu@arm.com> > Cc: netdev@vger.kernel.org; yangbo.lu@nxp.com; john.stultz@linaro.org; > tglx@linutronix.de; pbonzini@redhat.com; sean.j.christopherson@intel.com; > richardcochran@gmail.com; Mark Rutland <Mark.Rutland@arm.com>; > will@kernel.org; Suzuki Poulose <Suzuki.Poulose@arm.com>; Andre > Przywara <Andre.Przywara@arm.com>; Steven Price > <Steven.Price@arm.com>; linux-kernel@vger.kernel.org; linux-arm- > kernel@lists.infradead.org; kvmarm@lists.cs.columbia.edu; > kvm@vger.kernel.org; Steve Capper <Steve.Capper@arm.com>; Justin He > <Justin.He@arm.com>; nd <nd@arm.com> > Subject: Re: [PATCH v15 7/9] ptp: arm/arm64: Enable ptp_kvm for > arm/arm64 > > Jianyong, > > On 2020-11-24 05:37, Jianyong Wu wrote: > > Hi Marc, > > [...] > > >> > + > >> arm_smccc_1_1_invoke(ARM_SMCCC_VENDOR_HYP_KVM_PTP_FU > >> NC_ID, > >> > + ARM_PTP_NONE_COUNTER, &hvc_res); > >> > >> I really don't see the need to use a non-architectural counter ID. > >> Using the virtual counter ID should just be fine, and shouldn't lead > >> to any issue. > >> > > > >> Am I missing something? > > > > In this function, no counter data is needed. If virtual counter ID is > > used here, user may be confused with why we get virtual counter > > data and do nothing with it. So I explicitly add a new "NONE" counter > > ID to make it clear. > > > > WDYT? > > ITIABI (I Think It's A Bad Idea). There are two counters, and the API > allows to retrieve the data for any of these two. If the "user" doesn't > want to do anything with the data, that's their problem. > > Here, you can just sue the virtual counter, and that will give you the > exact same semantic, without inventing non-architectural state. > OK, that's it. Thanks Jianyong Wu > Thanks, > > M. > -- > Jazz is not dead. It just smells funny...
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index d55acffb0b90..b33c5a663d30 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -25,6 +25,7 @@ #include <linux/sched/clock.h> #include <linux/sched_clock.h> #include <linux/acpi.h> +#include <linux/arm-smccc.h> #include <asm/arch_timer.h> #include <asm/virt.h> @@ -1650,3 +1651,30 @@ 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; + ktime_t ktime; + u32 ptp_counter; + + if (arch_timer_uses_ppi == ARCH_TIMER_VIRT_PPI) + ptp_counter = ARM_PTP_VIRT_COUNTER; + else + ptp_counter = ARM_PTP_PHY_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); + *cycle = (u64)hvc_res.a2 << 32 | hvc_res.a3; + *cs = &clocksource_counter; + + return 0; +} +EXPORT_SYMBOL_GPL(kvm_arch_ptp_get_crosststamp); diff --git a/drivers/ptp/Kconfig b/drivers/ptp/Kconfig index 942f72d8151d..677c7f696b70 100644 --- a/drivers/ptp/Kconfig +++ b/drivers/ptp/Kconfig @@ -106,7 +106,7 @@ 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 699a4e4d19c2..9fa5ede44b2b 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..2212827c0384 --- /dev/null +++ b/drivers/ptp/ptp_kvm_arm.c @@ -0,0 +1,44 @@ +// 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 <linux/kernel.h> +#include <linux/err.h> +#include <asm/hypervisor.h> +#include <linux/module.h> +#include <linux/psci.h> +#include <linux/arm-smccc.h> +#include <linux/timecounter.h> +#include <linux/sched/clock.h> +#include <asm/arch_timer.h> +#include <asm/hypervisor.h> + +int kvm_arch_ptp_init(void) +{ + int ret; + + ret = kvm_arm_hyp_service_available(ARM_SMCCC_KVM_FUNC_KVM_PTP); + if (ret <= 0) + return -EOPNOTSUPP; + + return 0; +} + +int kvm_arch_ptp_get_clock(struct timespec64 *ts) +{ + ktime_t ktime; + struct arm_smccc_res hvc_res; + + arm_smccc_1_1_invoke(ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID, + ARM_PTP_NONE_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); + + return 0; +}
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 envirenment, 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 precison 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. Signed-off-by: Jianyong Wu <jianyong.wu@arm.com> --- drivers/clocksource/arm_arch_timer.c | 28 ++++++++++++++++++ drivers/ptp/Kconfig | 2 +- drivers/ptp/Makefile | 1 + drivers/ptp/ptp_kvm_arm.c | 44 ++++++++++++++++++++++++++++ 4 files changed, 74 insertions(+), 1 deletion(-) create mode 100644 drivers/ptp/ptp_kvm_arm.c