Commit 7d10001e authored by Vivek Thampi's avatar Vivek Thampi Committed by David S. Miller

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
......@@ -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>
......
......@@ -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
......@@ -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
// 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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