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Groups > linux.kernel > #1291833

RE: [PATCH RESEND 09/27] drivers:hv: Export the API to invoke a hypercall on Hyper-V

From KY Srinivasan <kys@microsoft.com>
Newsgroups linux.kernel
Subject RE: [PATCH RESEND 09/27] drivers:hv: Export the API to invoke a hypercall on Hyper-V
Date 2015-12-15 05:20 +0100
Message-ID <qFPfI-7sb-7@gated-at.bofh.it> (permalink)
References <qFJN1-3NK-19@gated-at.bofh.it> <qFJN1-3NK-17@gated-at.bofh.it> <qFJWF-3Ss-9@gated-at.bofh.it> <qFO9Y-6I0-1@gated-at.bofh.it>
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> -----Original Message-----
> From: Greg KH [mailto:gregkh@linuxfoundation.org]
> Sent: Monday, December 14, 2015 7:08 PM
> To: KY Srinivasan <kys@microsoft.com>
> Cc: linux-kernel@vger.kernel.org; devel@linuxdriverproject.org;
> olaf@aepfle.de; apw@canonical.com; vkuznets@redhat.com;
> jasowang@redhat.com; Jake Oshins <jakeo@microsoft.com>
> Subject: Re: [PATCH RESEND 09/27] drivers:hv: Export the API to invoke a
> hypercall on Hyper-V
> 
> On Mon, Dec 14, 2015 at 04:01:40PM -0800, K. Y. Srinivasan wrote:
> > From: Jake Oshins <jakeo@microsoft.com>
> >
> > This patch exposes the function that hv_vmbus.ko uses to make hypercalls.
> This
> > is necessary for retargeting an interrupt when it is given a new affinity.
> >
> > Since we are exporting this API, rename the API as it will be visible outside
> > the hv.c file.
> >
> > Signed-off-by: Jake Oshins <jakeo@microsoft.com>
> > Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
> > ---
> >  drivers/hv/hv.c           |   20 ++++++++++----------
> >  drivers/hv/hyperv_vmbus.h |    2 +-
> >  include/linux/hyperv.h    |    1 +
> >  3 files changed, 12 insertions(+), 11 deletions(-)
> >
> > diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
> > index 6341be8..7a06933 100644
> > --- a/drivers/hv/hv.c
> > +++ b/drivers/hv/hv.c
> > @@ -89,9 +89,9 @@ static int query_hypervisor_info(void)
> >  }
> >
> >  /*
> > - * do_hypercall- Invoke the specified hypercall
> > + * hv_do_hypercall- Invoke the specified hypercall
> >   */
> > -static u64 do_hypercall(u64 control, void *input, void *output)
> > +u64 hv_do_hypercall(u64 control, void *input, void *output)
> >  {
> >  	u64 input_address = (input) ? virt_to_phys(input) : 0;
> >  	u64 output_address = (output) ? virt_to_phys(output) : 0;
> > @@ -132,6 +132,7 @@ static u64 do_hypercall(u64 control, void *input,
> void *output)
> >  	return hv_status_lo | ((u64)hv_status_hi << 32);
> >  #endif /* !x86_64 */
> >  }
> > +EXPORT_SYMBOL_GPL(hv_do_hypercall);
> >
> >  #ifdef CONFIG_X86_64
> >  static cycle_t read_hv_clock_tsc(struct clocksource *arg)
> > @@ -315,7 +316,7 @@ int hv_post_message(union hv_connection_id
> connection_id,
> >  {
> >
> >  	struct hv_input_post_message *aligned_msg;
> > -	u16 status;
> > +	u64 status;
> >
> >  	if (payload_size > HV_MESSAGE_PAYLOAD_BYTE_COUNT)
> >  		return -EMSGSIZE;
> > @@ -329,11 +330,10 @@ int hv_post_message(union hv_connection_id
> connection_id,
> >  	aligned_msg->payload_size = payload_size;
> >  	memcpy((void *)aligned_msg->payload, payload, payload_size);
> >
> > -	status = do_hypercall(HVCALL_POST_MESSAGE, aligned_msg, NULL)
> > -		& 0xFFFF;
> > +	status = hv_do_hypercall(HVCALL_POST_MESSAGE, aligned_msg,
> NULL);
> >
> >  	put_cpu();
> > -	return status;
> > +	return status & 0xFFFF;
> >  }
> >
> >
> > @@ -343,13 +343,13 @@ int hv_post_message(union hv_connection_id
> connection_id,
> >   *
> >   * This involves a hypercall.
> >   */
> > -u16 hv_signal_event(void *con_id)
> > +int hv_signal_event(void *con_id)
> >  {
> > -	u16 status;
> > +	u64 status;
> >
> > -	status = (do_hypercall(HVCALL_SIGNAL_EVENT, con_id, NULL) &
> 0xFFFF);
> > +	status = hv_do_hypercall(HVCALL_SIGNAL_EVENT, con_id, NULL);
> >
> > -	return status;
> > +	return status & 0xFFFF;
> 
> This "feels" odd, as the return value isn't the traditional 0 or -ERROR,
> right?  Why are you masking off the top bits?
> 
> And, no one ever does anything with the return value of
> hv_signal_event(), so why have it return anything anyway?
> 
> I'll take this, but please fix up the area, it's messy...

Thanks Greg. Will do.

K. Y
> 
> greg k-h
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Thread

[PATCH RESEND 01/27] Drivers: hv: util: Increase the timeout for util services "K. Y. Srinivasan" <kys@microsoft.com> - 2015-12-14 23:30 +0100
  [PATCH RESEND 02/27] Drivers: hv: utils: run polling callback always in interrupt context "K. Y. Srinivasan" <kys@microsoft.com> - 2015-12-14 23:30 +0100
  [PATCH RESEND 03/27] tools: hv: report ENOSPC errors in hv_fcopy_daemon "K. Y. Srinivasan" <kys@microsoft.com> - 2015-12-14 23:30 +0100
  [PATCH RESEND 06/27] Drivers: hv: utils: use memdup_user in hvt_op_write "K. Y. Srinivasan" <kys@microsoft.com> - 2015-12-14 23:30 +0100
  [PATCH RESEND 04/27] tools: hv: remove repeated HV_FCOPY string "K. Y. Srinivasan" <kys@microsoft.com> - 2015-12-14 23:30 +0100
  [PATCH RESEND 10/27] drivers:hv: Define the channel type for Hyper-V PCI Express pass-through "K. Y. Srinivasan" <kys@microsoft.com> - 2015-12-14 23:40 +0100
  [PATCH RESEND 09/27] drivers:hv: Export the API to invoke a hypercall on Hyper-V "K. Y. Srinivasan" <kys@microsoft.com> - 2015-12-14 23:40 +0100
    Re: [PATCH RESEND 09/27] drivers:hv: Export the API to invoke a  hypercall on Hyper-V Greg KH <gregkh@linuxfoundation.org> - 2015-12-15 04:10 +0100
      RE: [PATCH RESEND 09/27] drivers:hv: Export the API to invoke a  hypercall on Hyper-V KY Srinivasan <kys@microsoft.com> - 2015-12-15 05:20 +0100
  [PATCH RESEND 14/27] Drivers: hv: vmbus: Get rid of the unused macro "K. Y. Srinivasan" <kys@microsoft.com> - 2015-12-14 23:40 +0100
  [PATCH RESEND 20/27] Drivers: hv: vmbus: channge vmbus_connection.channel_lock to mutex "K. Y. Srinivasan" <kys@microsoft.com> - 2015-12-14 23:40 +0100
  [PATCH RESEND 26/27] Drivers: hv: utils: Invoke the poll function after handshake "K. Y. Srinivasan" <kys@microsoft.com> - 2015-12-14 23:40 +0100
  [PATCH RESEND 05/27] Drivers: hv: util: catch allocation errors "K. Y. Srinivasan" <kys@microsoft.com> - 2015-12-14 23:40 +0100
  [PATCH RESEND 08/27] drivers:hv: Export a function that maps Linux CPU num onto Hyper-V proc num "K. Y. Srinivasan" <kys@microsoft.com> - 2015-12-14 23:40 +0100
  [PATCH RESEND 07/27] drivers/hv: cleanup synic msrs if vmbus connect failed "K. Y. Srinivasan" <kys@microsoft.com> - 2015-12-14 23:40 +0100
  [PATCH RESEND 22/27] tools/hv: Use include/uapi with __EXPORTED_HEADERS__ "K. Y. Srinivasan" <kys@microsoft.com> - 2015-12-14 23:40 +0100
    Re: [PATCH RESEND 22/27] tools/hv: Use include/uapi with  __EXPORTED_HEADERS__ Greg KH <gregkh@linuxfoundation.org> - 2015-12-15 04:20 +0100
      Re: [PATCH RESEND 22/27] tools/hv: Use include/uapi with  __EXPORTED_HEADERS__ Kamal Mostafa <kamal@canonical.com> - 2015-12-15 19:20 +0100
        [PATCH v2] tools/hv: Use include/uapi with __EXPORTED_HEADERS__ Kamal Mostafa <kamal@canonical.com> - 2015-12-15 19:30 +0100
          Re: [PATCH v2] tools/hv: Use include/uapi with __EXPORTED_HEADERS__ Greg KH <gregkh@linuxfoundation.org> - 2015-12-15 19:50 +0100
  [PATCH RESEND 25/27] Drivers: hv: vmbus: Force all channel messages to be delivered on CPU 0 "K. Y. Srinivasan" <kys@microsoft.com> - 2015-12-14 23:40 +0100
  [PATCH RESEND 21/27] drivers:hv: Allow for MMIO claims that span ACPI _CRS records "K. Y. Srinivasan" <kys@microsoft.com> - 2015-12-14 23:40 +0100
  [PATCH RESEND 24/27] drivers/hv: correct tsc page sequence invalid value "K. Y. Srinivasan" <kys@microsoft.com> - 2015-12-14 23:40 +0100
  [PATCH RESEND 11/27] Drivers: hv: vss: run only on supported host versions "K. Y. Srinivasan" <kys@microsoft.com> - 2015-12-14 23:40 +0100
  [PATCH RESEND 27/27] tools: hv: vss: fix the write()'s argument: error -> vss_msg "K. Y. Srinivasan" <kys@microsoft.com> - 2015-12-14 23:40 +0100
  [PATCH RESEND 16/27] Drivers: hv: vmbus: serialize process_chn_event() and vmbus_close_internal() "K. Y. Srinivasan" <kys@microsoft.com> - 2015-12-14 23:40 +0100
  [PATCH RESEND 18/27] Drivers: hv: vmbus: fix rescind-offer handling for device without a driver "K. Y. Srinivasan" <kys@microsoft.com> - 2015-12-14 23:40 +0100
  [PATCH RESEND 19/27] Drivers: hv: vmbus: release relid on error in vmbus_process_offer() "K. Y. Srinivasan" <kys@microsoft.com> - 2015-12-14 23:40 +0100
  [PATCH RESEND 23/27] Drivers: hv: vmbus: Fix a Host signaling bug "K. Y. Srinivasan" <kys@microsoft.com> - 2015-12-14 23:40 +0100
  [PATCH RESEND 17/27] Drivers: hv: vmbus: do sanity check of channel state in vmbus_close_internal() "K. Y. Srinivasan" <kys@microsoft.com> - 2015-12-14 23:50 +0100
  [PATCH RESEND 13/27] Drivers: hv: vmbus: Use uuid_le_cmp() for comparing GUIDs "K. Y. Srinivasan" <kys@microsoft.com> - 2015-12-14 23:50 +0100
  [PATCH RESEND 12/27] Drivers: hv: vmbus: Use uuid_le type consistently "K. Y. Srinivasan" <kys@microsoft.com> - 2015-12-14 23:50 +0100
  [PATCH RESEND 15/27] Drivers: hv: vmbus: Get rid of the unused irq variable "K. Y. Srinivasan" <kys@microsoft.com> - 2015-12-14 23:50 +0100

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