RE: [PATCH 1/2] hyperv: implement hv_get_tsc_page()

[Stephen Hemminger]

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@xxxxxxxxxx] 
Sent: Thursday, February 9, 2017 6:11 AM
To: x86@xxxxxxxxxx; Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>; Ingo Molnar <mingo@xxxxxxxxxx>; H. Peter Anvin <hpa@xxxxxxxxx>; KY Srinivasan <kys@xxxxxxxxxxxxx>; Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>; Stephen Hemminger <sthemmin@xxxxxxxxxxxxx>; Dexuan Cui <decui@xxxxxxxxxxxxx>; linux-kernel@xxxxxxxxxxxxxxx; devel@xxxxxxxxxxxxxxxxxxxxxx; virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx
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@xxxxxxxxxx>
---
 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