Commit 7d10001e authored by Vivek Thampi's avatar Vivek Thampi Committed by David S. Miller
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ptp: add VMware virtual PTP clock driver 



Add a PTP clock driver called ptp_vmw, for guests running on VMware ESXi
hypervisor. The driver attaches to a VMware virtual device called
"precision clock" that provides a mechanism for querying host system time.
Similar to existing virtual PTP clock drivers (e.g. ptp_kvm), ptp_vmw
utilizes the kernel's PTP hardware clock API to implement a clock device
that can be used as a reference in Chrony for synchronizing guest time with
host.

The driver is only applicable to x86 guests running in VMware virtual
machines with precision clock virtual device present. It uses a VMware
specific hypercall mechanism to read time from the device.

Reviewed-by: default avatarThomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: default avatarVivek Thampi <vithampi@vmware.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent a368e860

MAINTAINERS

+7 −0
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@@ -17852,6 +17852,13 @@ S: Supported 
F:	arch/x86/kernel/cpu/vmware.c

F:	arch/x86/include/asm/vmware.h













VMWARE VIRTUAL PTP CLOCK DRIVER













M:	Vivek Thampi <vithampi@vmware.com>













M:	"VMware, Inc." <pv-drivers@vmware.com>













L:	netdev@vger.kernel.org













S:	Supported













F:	drivers/ptp/ptp_vmw.c



























VMWARE PVRDMA DRIVER















M:	Adit Ranadive <aditr@vmware.com>















M:	VMware PV-Drivers <pv-drivers@vmware.com>

























drivers/ptp/Kconfig



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@@ -139,4 +139,16 @@ config PTP_1588_CLOCK_IDTCM













	  To compile this driver as a module, choose M here: the module















	  will be called ptp_clockmatrix.





























config PTP_1588_CLOCK_VMW













	tristate "VMware virtual PTP clock"













	depends on ACPI && HYPERVISOR_GUEST && X86













	depends on PTP_1588_CLOCK













	help













	  This driver adds support for using VMware virtual precision













	  clock device as a PTP clock. This is only useful in virtual













	  machines running on VMware virtual infrastructure.



























	  To compile this driver as a module, choose M here: the module













	  will be called ptp_vmw.





























endmenu
























drivers/ptp/Makefile



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@@ -14,3 +14,4 @@ ptp-qoriq-y				+= ptp_qoriq.o













ptp-qoriq-$(CONFIG_DEBUG_FS)		+= ptp_qoriq_debugfs.o















obj-$(CONFIG_PTP_1588_CLOCK_IDTCM)	+= ptp_clockmatrix.o















obj-$(CONFIG_PTP_1588_CLOCK_IDT82P33)	+= ptp_idt82p33.o













obj-$(CONFIG_PTP_1588_CLOCK_VMW)	+= ptp_vmw.o
























drivers/ptp/ptp_vmw.c
0 → 100644



+144
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// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause













/*













 * Copyright (C) 2020 VMware, Inc., Palo Alto, CA., USA













 *













 * PTP clock driver for VMware precision clock virtual device.













 */



























#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt



























#include <linux/acpi.h>













#include <linux/kernel.h>













#include <linux/module.h>













#include <linux/ptp_clock_kernel.h>













#include <asm/hypervisor.h>













#include <asm/vmware.h>



























#define VMWARE_MAGIC 0x564D5868













#define VMWARE_CMD_PCLK(nr) ((nr << 16) | 97)













#define VMWARE_CMD_PCLK_GETTIME VMWARE_CMD_PCLK(0)



























static struct acpi_device *ptp_vmw_acpi_device;













static struct ptp_clock *ptp_vmw_clock;









































static int ptp_vmw_pclk_read(u64 *ns)













{













	u32 ret, nsec_hi, nsec_lo, unused1, unused2, unused3;



























	asm volatile (VMWARE_HYPERCALL :













		"=a"(ret), "=b"(nsec_hi), "=c"(nsec_lo), "=d"(unused1),













		"=S"(unused2), "=D"(unused3) :













		"a"(VMWARE_MAGIC), "b"(0),













		"c"(VMWARE_CMD_PCLK_GETTIME), "d"(0) :













		"memory");



























	if (ret == 0)













		*ns = ((u64)nsec_hi << 32) | nsec_lo;













	return ret;













}



























/*













 * PTP clock ops.













 */



























static int ptp_vmw_adjtime(struct ptp_clock_info *info, s64 delta)













{













	return -EOPNOTSUPP;













}



























static int ptp_vmw_adjfreq(struct ptp_clock_info *info, s32 delta)













{













	return -EOPNOTSUPP;













}



























static int ptp_vmw_gettime(struct ptp_clock_info *info, struct timespec64 *ts)













{













	u64 ns;



























	if (ptp_vmw_pclk_read(&ns) != 0)













		return -EIO;













	*ts = ns_to_timespec64(ns);













	return 0;













}



























static int ptp_vmw_settime(struct ptp_clock_info *info,













			  const struct timespec64 *ts)













{













	return -EOPNOTSUPP;













}



























static int ptp_vmw_enable(struct ptp_clock_info *info,













			 struct ptp_clock_request *request, int on)













{













	return -EOPNOTSUPP;













}



























static struct ptp_clock_info ptp_vmw_clock_info = {













	.owner		= THIS_MODULE,













	.name		= "ptp_vmw",













	.max_adj	= 0,













	.adjtime	= ptp_vmw_adjtime,













	.adjfreq	= ptp_vmw_adjfreq,













	.gettime64	= ptp_vmw_gettime,













	.settime64	= ptp_vmw_settime,













	.enable		= ptp_vmw_enable,













};



























/*













 * ACPI driver ops for VMware "precision clock" virtual device.













 */



























static int ptp_vmw_acpi_add(struct acpi_device *device)













{













	ptp_vmw_clock = ptp_clock_register(&ptp_vmw_clock_info, NULL);













	if (IS_ERR(ptp_vmw_clock)) {













		pr_err("failed to register ptp clock\n");













		return PTR_ERR(ptp_vmw_clock);













	}



























	ptp_vmw_acpi_device = device;













	return 0;













}



























static int ptp_vmw_acpi_remove(struct acpi_device *device)













{













	ptp_clock_unregister(ptp_vmw_clock);













	return 0;













}



























static const struct acpi_device_id ptp_vmw_acpi_device_ids[] = {













	{ "VMW0005", 0 },













	{ "", 0 },













};



























MODULE_DEVICE_TABLE(acpi, ptp_vmw_acpi_device_ids);



























static struct acpi_driver ptp_vmw_acpi_driver = {













	.name = "ptp_vmw",













	.ids = ptp_vmw_acpi_device_ids,













	.ops = {













		.add = ptp_vmw_acpi_add,













		.remove	= ptp_vmw_acpi_remove













	},













	.owner	= THIS_MODULE













};



























static int __init ptp_vmw_init(void)













{













	if (x86_hyper_type != X86_HYPER_VMWARE)













		return -1;













	return acpi_bus_register_driver(&ptp_vmw_acpi_driver);













}



























static void __exit ptp_vmw_exit(void)













{













	acpi_bus_unregister_driver(&ptp_vmw_acpi_driver);













}



























module_init(ptp_vmw_init);













module_exit(ptp_vmw_exit);



























MODULE_DESCRIPTION("VMware virtual PTP clock driver");













MODULE_AUTHOR("VMware, Inc.");













MODULE_LICENSE("Dual BSD/GPL");


























































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