Implement PTP clock ops that set time and frequency of the underlying
clock. On supported versions of VMware precision clock virtual device,
new commands can adjust its time and frequency, allowing time transfer
from a virtual machine to the underlying hypervisor.
In case of error, vmware_hypercall doesn't return Linux defined errno,
converting it to -EIO.
Cc: Shubham Gupta <shubham-sg.gupta@broadcom.com>
Cc: Nick Shi <nick.shi@broadcom.com>
Tested-by: Karen Wang <karen.wang@broadcom.com>
Tested-by: Hari Krishna Ginka <hari-krishna.ginka@broadcom.com>
Signed-off-by: Ajay Kaher <ajay.kaher@broadcom.com>
---
drivers/ptp/ptp_vmw.c | 39 +++++++++++++++++++++++++++++----------
1 file changed, 29 insertions(+), 10 deletions(-)
diff --git a/drivers/ptp/ptp_vmw.c b/drivers/ptp/ptp_vmw.c
index 20ab05c4d..7d117eee4 100644
--- a/drivers/ptp/ptp_vmw.c
+++ b/drivers/ptp/ptp_vmw.c
@@ -1,6 +1,7 @@
// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
/*
- * Copyright (C) 2020 VMware, Inc., Palo Alto, CA., USA
+ * Copyright (C) 2020-2023 VMware, Inc., Palo Alto, CA., USA
+ * Copyright (C) 2024-2025 Broadcom Ltd.
*
* PTP clock driver for VMware precision clock virtual device.
*/
@@ -16,20 +17,36 @@
#define VMWARE_CMD_PCLK(nr) ((nr << 16) | 97)
#define VMWARE_CMD_PCLK_GETTIME VMWARE_CMD_PCLK(0)
+#define VMWARE_CMD_PCLK_SETTIME VMWARE_CMD_PCLK(1)
+#define VMWARE_CMD_PCLK_ADJTIME VMWARE_CMD_PCLK(2)
+#define VMWARE_CMD_PCLK_ADJFREQ VMWARE_CMD_PCLK(3)
static struct acpi_device *ptp_vmw_acpi_device;
static struct ptp_clock *ptp_vmw_clock;
+/*
+ * Helpers for reading and writing to precision clock device.
+ */
-static int ptp_vmw_pclk_read(u64 *ns)
+static int ptp_vmw_pclk_read(int cmd, u64 *ns)
{
u32 ret, nsec_hi, nsec_lo;
- ret = vmware_hypercall3(VMWARE_CMD_PCLK_GETTIME, 0,
- &nsec_hi, &nsec_lo);
+ ret = vmware_hypercall3(cmd, 0, &nsec_hi, &nsec_lo);
if (ret == 0)
*ns = ((u64)nsec_hi << 32) | nsec_lo;
- return ret;
+
+ return ret != 0 ? -EIO : 0;
+}
+
+static int ptp_vmw_pclk_write(int cmd, u64 in)
+{
+ u32 ret, unused;
+
+ ret = vmware_hypercall5(cmd, 0, 0, in >> 32, in & 0xffffffff,
+ &unused);
+
+ return ret != 0 ? -EIO : 0;
}
/*
@@ -38,19 +55,19 @@ static int ptp_vmw_pclk_read(u64 *ns)
static int ptp_vmw_adjtime(struct ptp_clock_info *info, s64 delta)
{
- return -EOPNOTSUPP;
+ return ptp_vmw_pclk_write(VMWARE_CMD_PCLK_ADJTIME, (u64)delta);
}
static int ptp_vmw_adjfine(struct ptp_clock_info *info, long delta)
{
- return -EOPNOTSUPP;
+ return ptp_vmw_pclk_write(VMWARE_CMD_PCLK_ADJFREQ, (u64)delta);
}
static int ptp_vmw_gettime(struct ptp_clock_info *info, struct timespec64 *ts)
{
u64 ns;
- if (ptp_vmw_pclk_read(&ns) != 0)
+ if (ptp_vmw_pclk_read(VMWARE_CMD_PCLK_GETTIME, &ns) != 0)
return -EIO;
*ts = ns_to_timespec64(ns);
return 0;
@@ -59,7 +76,9 @@ static int ptp_vmw_gettime(struct ptp_clock_info *info, struct timespec64 *ts)
static int ptp_vmw_settime(struct ptp_clock_info *info,
const struct timespec64 *ts)
{
- return -EOPNOTSUPP;
+ u64 ns = timespec64_to_ns(ts);
+
+ return ptp_vmw_pclk_write(VMWARE_CMD_PCLK_SETTIME, ns);
}
static int ptp_vmw_enable(struct ptp_clock_info *info,
@@ -71,7 +90,7 @@ static int ptp_vmw_enable(struct ptp_clock_info *info,
static struct ptp_clock_info ptp_vmw_clock_info = {
.owner = THIS_MODULE,
.name = "ptp_vmw",
- .max_adj = 0,
+ .max_adj = 999999999,
.adjtime = ptp_vmw_adjtime,
.adjfine = ptp_vmw_adjfine,
.gettime64 = ptp_vmw_gettime,
--
2.40.4On 22/10/2025 11:51, Ajay Kaher wrote:
> Implement PTP clock ops that set time and frequency of the underlying
> clock. On supported versions of VMware precision clock virtual device,
> new commands can adjust its time and frequency, allowing time transfer
> from a virtual machine to the underlying hypervisor.
>
> In case of error, vmware_hypercall doesn't return Linux defined errno,
> converting it to -EIO.
>
> Cc: Shubham Gupta <shubham-sg.gupta@broadcom.com>
> Cc: Nick Shi <nick.shi@broadcom.com>
> Tested-by: Karen Wang <karen.wang@broadcom.com>
> Tested-by: Hari Krishna Ginka <hari-krishna.ginka@broadcom.com>
> Signed-off-by: Ajay Kaher <ajay.kaher@broadcom.com>
> ---
> drivers/ptp/ptp_vmw.c | 39 +++++++++++++++++++++++++++++----------
> 1 file changed, 29 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/ptp/ptp_vmw.c b/drivers/ptp/ptp_vmw.c
> index 20ab05c4d..7d117eee4 100644
> --- a/drivers/ptp/ptp_vmw.c
> +++ b/drivers/ptp/ptp_vmw.c
> @@ -1,6 +1,7 @@
> // SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
> /*
> - * Copyright (C) 2020 VMware, Inc., Palo Alto, CA., USA
> + * Copyright (C) 2020-2023 VMware, Inc., Palo Alto, CA., USA
> + * Copyright (C) 2024-2025 Broadcom Ltd.
> *
> * PTP clock driver for VMware precision clock virtual device.
> */
> @@ -16,20 +17,36 @@
>
> #define VMWARE_CMD_PCLK(nr) ((nr << 16) | 97)
> #define VMWARE_CMD_PCLK_GETTIME VMWARE_CMD_PCLK(0)
> +#define VMWARE_CMD_PCLK_SETTIME VMWARE_CMD_PCLK(1)
> +#define VMWARE_CMD_PCLK_ADJTIME VMWARE_CMD_PCLK(2)
> +#define VMWARE_CMD_PCLK_ADJFREQ VMWARE_CMD_PCLK(3)
>
> static struct acpi_device *ptp_vmw_acpi_device;
> static struct ptp_clock *ptp_vmw_clock;
>
> +/*
> + * Helpers for reading and writing to precision clock device.
> + */
>
> -static int ptp_vmw_pclk_read(u64 *ns)
> +static int ptp_vmw_pclk_read(int cmd, u64 *ns)
> {
> u32 ret, nsec_hi, nsec_lo;
>
> - ret = vmware_hypercall3(VMWARE_CMD_PCLK_GETTIME, 0,
> - &nsec_hi, &nsec_lo);
> + ret = vmware_hypercall3(cmd, 0, &nsec_hi, &nsec_lo);
> if (ret == 0)
> *ns = ((u64)nsec_hi << 32) | nsec_lo;
> - return ret;
> +
> + return ret != 0 ? -EIO : 0;
> +}
Why do you need to introduce this change? VMWARE_CMD_PCLK_GETTIME is
the only command used in read() in both patches of this patchset.
On Wed, Oct 22, 2025 at 4:43 PM Vadim Fedorenko
<vadim.fedorenko@linux.dev> wrote:
>
> On 22/10/2025 11:51, Ajay Kaher wrote:
> > Implement PTP clock ops that set time and frequency of the underlying
> > clock. On supported versions of VMware precision clock virtual device,
> > new commands can adjust its time and frequency, allowing time transfer
> > from a virtual machine to the underlying hypervisor.
> >
> > In case of error, vmware_hypercall doesn't return Linux defined errno,
> > converting it to -EIO.
> >
> > Cc: Shubham Gupta <shubham-sg.gupta@broadcom.com>
> > Cc: Nick Shi <nick.shi@broadcom.com>
> > Tested-by: Karen Wang <karen.wang@broadcom.com>
> > Tested-by: Hari Krishna Ginka <hari-krishna.ginka@broadcom.com>
> > Signed-off-by: Ajay Kaher <ajay.kaher@broadcom.com>
> > ---
> > drivers/ptp/ptp_vmw.c | 39 +++++++++++++++++++++++++++++----------
> > 1 file changed, 29 insertions(+), 10 deletions(-)
> >
> > diff --git a/drivers/ptp/ptp_vmw.c b/drivers/ptp/ptp_vmw.c
> > index 20ab05c4d..7d117eee4 100644
> > --- a/drivers/ptp/ptp_vmw.c
> > +++ b/drivers/ptp/ptp_vmw.c
> > @@ -1,6 +1,7 @@
> > // SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
> > /*
> > - * Copyright (C) 2020 VMware, Inc., Palo Alto, CA., USA
> > + * Copyright (C) 2020-2023 VMware, Inc., Palo Alto, CA., USA
> > + * Copyright (C) 2024-2025 Broadcom Ltd.
> > *
> > * PTP clock driver for VMware precision clock virtual device.
> > */
> > @@ -16,20 +17,36 @@
> >
> > #define VMWARE_CMD_PCLK(nr) ((nr << 16) | 97)
> > #define VMWARE_CMD_PCLK_GETTIME VMWARE_CMD_PCLK(0)
> > +#define VMWARE_CMD_PCLK_SETTIME VMWARE_CMD_PCLK(1)
> > +#define VMWARE_CMD_PCLK_ADJTIME VMWARE_CMD_PCLK(2)
> > +#define VMWARE_CMD_PCLK_ADJFREQ VMWARE_CMD_PCLK(3)
> >
> > static struct acpi_device *ptp_vmw_acpi_device;
> > static struct ptp_clock *ptp_vmw_clock;
> >
> > +/*
> > + * Helpers for reading and writing to precision clock device.
> > + */
> >
> > -static int ptp_vmw_pclk_read(u64 *ns)
> > +static int ptp_vmw_pclk_read(int cmd, u64 *ns)
> > {
> > u32 ret, nsec_hi, nsec_lo;
> >
> > - ret = vmware_hypercall3(VMWARE_CMD_PCLK_GETTIME, 0,
> > - &nsec_hi, &nsec_lo);
> > + ret = vmware_hypercall3(cmd, 0, &nsec_hi, &nsec_lo);
> > if (ret == 0)
> > *ns = ((u64)nsec_hi << 32) | nsec_lo;
> > - return ret;
> > +
> > + return ret != 0 ? -EIO : 0;
> > +}
>
> Why do you need to introduce this change? VMWARE_CMD_PCLK_GETTIME is
> the only command used in read() in both patches of this patchset.
>
Vadim, thanks for looking into patches.
I have added ptp_vmw_pclk_write() where cmd has been passed as argument.
Keeping the same format for ptp_vmw_pclk_read() as well, also may be useful
in future.
Let me know if you think it's better to keep ptp_vmw_pclk_read() as it
is. I will
revert in v3.
-Ajay
On 22/10/2025 18:27, Ajay Kaher wrote:
> On Wed, Oct 22, 2025 at 4:43 PM Vadim Fedorenko
> <vadim.fedorenko@linux.dev> wrote:
>>
>> On 22/10/2025 11:51, Ajay Kaher wrote:
>>> Implement PTP clock ops that set time and frequency of the underlying
>>> clock. On supported versions of VMware precision clock virtual device,
>>> new commands can adjust its time and frequency, allowing time transfer
>>> from a virtual machine to the underlying hypervisor.
>>>
>>> In case of error, vmware_hypercall doesn't return Linux defined errno,
>>> converting it to -EIO.
>>>
>>> Cc: Shubham Gupta <shubham-sg.gupta@broadcom.com>
>>> Cc: Nick Shi <nick.shi@broadcom.com>
>>> Tested-by: Karen Wang <karen.wang@broadcom.com>
>>> Tested-by: Hari Krishna Ginka <hari-krishna.ginka@broadcom.com>
>>> Signed-off-by: Ajay Kaher <ajay.kaher@broadcom.com>
>>> ---
>>> drivers/ptp/ptp_vmw.c | 39 +++++++++++++++++++++++++++++----------
>>> 1 file changed, 29 insertions(+), 10 deletions(-)
>>>
>>> diff --git a/drivers/ptp/ptp_vmw.c b/drivers/ptp/ptp_vmw.c
>>> index 20ab05c4d..7d117eee4 100644
>>> --- a/drivers/ptp/ptp_vmw.c
>>> +++ b/drivers/ptp/ptp_vmw.c
>>> @@ -1,6 +1,7 @@
>>> // SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
>>> /*
>>> - * Copyright (C) 2020 VMware, Inc., Palo Alto, CA., USA
>>> + * Copyright (C) 2020-2023 VMware, Inc., Palo Alto, CA., USA
>>> + * Copyright (C) 2024-2025 Broadcom Ltd.
>>> *
>>> * PTP clock driver for VMware precision clock virtual device.
>>> */
>>> @@ -16,20 +17,36 @@
>>>
>>> #define VMWARE_CMD_PCLK(nr) ((nr << 16) | 97)
>>> #define VMWARE_CMD_PCLK_GETTIME VMWARE_CMD_PCLK(0)
>>> +#define VMWARE_CMD_PCLK_SETTIME VMWARE_CMD_PCLK(1)
>>> +#define VMWARE_CMD_PCLK_ADJTIME VMWARE_CMD_PCLK(2)
>>> +#define VMWARE_CMD_PCLK_ADJFREQ VMWARE_CMD_PCLK(3)
>>>
>>> static struct acpi_device *ptp_vmw_acpi_device;
>>> static struct ptp_clock *ptp_vmw_clock;
>>>
>>> +/*
>>> + * Helpers for reading and writing to precision clock device.
>>> + */
>>>
>>> -static int ptp_vmw_pclk_read(u64 *ns)
>>> +static int ptp_vmw_pclk_read(int cmd, u64 *ns)
>>> {
>>> u32 ret, nsec_hi, nsec_lo;
>>>
>>> - ret = vmware_hypercall3(VMWARE_CMD_PCLK_GETTIME, 0,
>>> - &nsec_hi, &nsec_lo);
>>> + ret = vmware_hypercall3(cmd, 0, &nsec_hi, &nsec_lo);
>>> if (ret == 0)
>>> *ns = ((u64)nsec_hi << 32) | nsec_lo;
>>> - return ret;
>>> +
>>> + return ret != 0 ? -EIO : 0;
>>> +}
>>
>> Why do you need to introduce this change? VMWARE_CMD_PCLK_GETTIME is
>> the only command used in read() in both patches of this patchset.
>>
>
> Vadim, thanks for looking into patches.
>
> I have added ptp_vmw_pclk_write() where cmd has been passed as argument.
> Keeping the same format for ptp_vmw_pclk_read() as well, also may be useful
> in future.
>
> Let me know if you think it's better to keep ptp_vmw_pclk_read() as it
> is. I will
> revert in v3.
I do believe it's better to keep code as is until you have real use of
new feature. And I'm not quite sure which command you can use to do
another read?
On Thu, Oct 23, 2025 at 3:47 AM Vadim Fedorenko
<vadim.fedorenko@linux.dev> wrote:
>
> On 22/10/2025 18:27, Ajay Kaher wrote:
> > On Wed, Oct 22, 2025 at 4:43 PM Vadim Fedorenko
> > <vadim.fedorenko@linux.dev> wrote:
> >>
> >> On 22/10/2025 11:51, Ajay Kaher wrote:
> >>> Implement PTP clock ops that set time and frequency of the underlying
> >>> clock. On supported versions of VMware precision clock virtual device,
> >>> new commands can adjust its time and frequency, allowing time transfer
> >>> from a virtual machine to the underlying hypervisor.
> >>>
> >>> In case of error, vmware_hypercall doesn't return Linux defined errno,
> >>> converting it to -EIO.
> >>>
> >>> Cc: Shubham Gupta <shubham-sg.gupta@broadcom.com>
> >>> Cc: Nick Shi <nick.shi@broadcom.com>
> >>> Tested-by: Karen Wang <karen.wang@broadcom.com>
> >>> Tested-by: Hari Krishna Ginka <hari-krishna.ginka@broadcom.com>
> >>> Signed-off-by: Ajay Kaher <ajay.kaher@broadcom.com>
> >>> ---
> >>> drivers/ptp/ptp_vmw.c | 39 +++++++++++++++++++++++++++++----------
> >>> 1 file changed, 29 insertions(+), 10 deletions(-)
> >>>
> >>> diff --git a/drivers/ptp/ptp_vmw.c b/drivers/ptp/ptp_vmw.c
> >>> index 20ab05c4d..7d117eee4 100644
> >>> --- a/drivers/ptp/ptp_vmw.c
> >>> +++ b/drivers/ptp/ptp_vmw.c
> >>> @@ -1,6 +1,7 @@
> >>> // SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
> >>> /*
> >>> - * Copyright (C) 2020 VMware, Inc., Palo Alto, CA., USA
> >>> + * Copyright (C) 2020-2023 VMware, Inc., Palo Alto, CA., USA
> >>> + * Copyright (C) 2024-2025 Broadcom Ltd.
> >>> *
> >>> * PTP clock driver for VMware precision clock virtual device.
> >>> */
> >>> @@ -16,20 +17,36 @@
> >>>
> >>> #define VMWARE_CMD_PCLK(nr) ((nr << 16) | 97)
> >>> #define VMWARE_CMD_PCLK_GETTIME VMWARE_CMD_PCLK(0)
> >>> +#define VMWARE_CMD_PCLK_SETTIME VMWARE_CMD_PCLK(1)
> >>> +#define VMWARE_CMD_PCLK_ADJTIME VMWARE_CMD_PCLK(2)
> >>> +#define VMWARE_CMD_PCLK_ADJFREQ VMWARE_CMD_PCLK(3)
> >>>
> >>> static struct acpi_device *ptp_vmw_acpi_device;
> >>> static struct ptp_clock *ptp_vmw_clock;
> >>>
> >>> +/*
> >>> + * Helpers for reading and writing to precision clock device.
> >>> + */
> >>>
> >>> -static int ptp_vmw_pclk_read(u64 *ns)
> >>> +static int ptp_vmw_pclk_read(int cmd, u64 *ns)
> >>> {
> >>> u32 ret, nsec_hi, nsec_lo;
> >>>
> >>> - ret = vmware_hypercall3(VMWARE_CMD_PCLK_GETTIME, 0,
> >>> - &nsec_hi, &nsec_lo);
> >>> + ret = vmware_hypercall3(cmd, 0, &nsec_hi, &nsec_lo);
> >>> if (ret == 0)
> >>> *ns = ((u64)nsec_hi << 32) | nsec_lo;
> >>> - return ret;
> >>> +
> >>> + return ret != 0 ? -EIO : 0;
> >>> +}
> >>
> >> Why do you need to introduce this change? VMWARE_CMD_PCLK_GETTIME is
> >> the only command used in read() in both patches of this patchset.
> >>
> >
> > Vadim, thanks for looking into patches.
> >
> > I have added ptp_vmw_pclk_write() where cmd has been passed as argument.
> > Keeping the same format for ptp_vmw_pclk_read() as well, also may be useful
> > in future.
> >
> > Let me know if you think it's better to keep ptp_vmw_pclk_read() as it
> > is. I will
> > revert in v3.
>
> I do believe it's better to keep code as is until you have real use of
> new feature. And I'm not quite sure which command you can use to do
> another read?
Sure, I will revert the changes of ptp_vmw_pclk_read() in v3.
-Ajay
© 2016 - 2026 Red Hat, Inc.