Linux Virtualization - Feb 2017 - [PATCH 1/2] hyperv: implement hv_get_tsc_page()

The actual code looks fine, but the style police will not like you.
{ should be at start of line on functions.
And #else should be at start of line,

But maybe this was just more of exchange mangling the mail.

-----Original Message-----
From: Vitaly Kuznetsov [mailto:vkuznets at redhat.com] 
Sent: Thursday, February 9, 2017 6:11 AM
To: x86 at kernel.org; Andy Lutomirski <luto at amacapital.net>
Cc: Thomas Gleixner <tglx at linutronix.de>; Ingo Molnar <mingo at
redhat.com>; H. Peter Anvin <hpa at zytor.com>; KY Srinivasan <kys
at microsoft.com>; Haiyang Zhang <haiyangz at microsoft.com>; Stephen
Hemminger <sthemmin at microsoft.com>; Dexuan Cui <decui at
microsoft.com>; linux-kernel at vger.kernel.org; devel at
linuxdriverproject.org; virtualization at lists.linux-foundation.org
Subject: [PATCH 1/2] hyperv: implement hv_get_tsc_page()

To use Hyper-V TSC page clocksource from vDSO we need to make tsc_pg available.
Implement hv_get_tsc_page() and add CONFIG_HYPERV_TSCPAGE to make #ifdef-s
simple.

Signed-off-by: Vitaly Kuznetsov <vkuznets at redhat.com>
---
 arch/x86/hyperv/hv_init.c       | 9 +++++++--
 arch/x86/include/asm/mshyperv.h | 8 ++++++++
 drivers/hv/Kconfig              | 3 +++
 3 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c index
b371d0e..0ce8485 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -27,10 +27,15 @@
 #include <linux/clockchips.h>
 
 
-#ifdef CONFIG_X86_64
+#ifdef CONFIG_HYPERV_TSCPAGE
 
 static struct ms_hyperv_tsc_page *tsc_pg;
 
+struct ms_hyperv_tsc_page *hv_get_tsc_page(void) {
+	return tsc_pg;
+}
+
 static u64 read_hv_clock_tsc(struct clocksource *arg)  {
 	u64 current_tick;
@@ -136,7 +141,7 @@ void hyperv_init(void)
 	/*
 	 * Register Hyper-V specific clocksource.
 	 */
-#ifdef CONFIG_X86_64
+#ifdef CONFIG_HYPERV_TSCPAGE
 	if (ms_hyperv.features & HV_X64_MSR_REFERENCE_TSC_AVAILABLE) {
 		union hv_x64_msr_hypercall_contents tsc_msr;
 
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index f8dc370..14dd92c 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -173,4 +173,12 @@ void hyperv_report_panic(struct pt_regs *regs);  bool
hv_is_hypercall_page_setup(void);  void hyperv_cleanup(void);  #endif
+#ifdef CONFIG_HYPERV_TSCPAGE
+struct ms_hyperv_tsc_page *hv_get_tsc_page(void); #else static inline 
+struct ms_hyperv_tsc_page *hv_get_tsc_page(void) {
+	return NULL;
+}
+#endif
 #endif
diff --git a/drivers/hv/Kconfig b/drivers/hv/Kconfig index 0403b51..c29cd53
100644
--- a/drivers/hv/Kconfig
+++ b/drivers/hv/Kconfig
@@ -7,6 +7,9 @@ config HYPERV
 	  Select this option to run Linux as a Hyper-V client operating
 	  system.
 
+config HYPERV_TSCPAGE
+       def_bool HYPERV && X86_64
+
 config HYPERV_UTILS
 	tristate "Microsoft Hyper-V Utilities driver"
 	depends on HYPERV && CONNECTOR && NLS
--
2.9.3

On Thu, 9 Feb 2017, Stephen Hemminger wrote:
> The actual code looks fine, but the style police will not like you.
> { should be at start of line on functions.
> And #else should be at start of line,
> 
> But maybe this was just more of exchange mangling the mail.
Looks like.
> +struct ms_hyperv_tsc_page *hv_get_tsc_page(void) {
> +	return tsc_pg;
> +}
> +
That's how it reads in a proper mail client connected to a proper mail
server:
> +struct ms_hyperv_tsc_page *hv_get_tsc_page(void)
> +{
> +       return tsc_pg;
> +}
:)

On Thu, 9 Feb 2017 21:14:25 +0100 (CET)
Thomas Gleixner <tglx at linutronix.de> wrote:
> On Thu, 9 Feb 2017, Stephen Hemminger wrote:
> 
> > The actual code looks fine, but the style police will not like you.
> > { should be at start of line on functions.
> > And #else should be at start of line,
> > 
> > But maybe this was just more of exchange mangling the mail.  
> 
> Looks like.
> 
> > +struct ms_hyperv_tsc_page *hv_get_tsc_page(void) {
> > +	return tsc_pg;
> > +}
> > +  
> 
> That's how it reads in a proper mail client connected to a proper mail
> server:
> 
> > +struct ms_hyperv_tsc_page *hv_get_tsc_page(void)
> > +{
> > +       return tsc_pg;
> > +}  
> 
> :)

Yup. it looks like the mail server is trying to be "helpful" by
eliminating extra white space.