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Date: Fri, 30 Dec 2016 13:35:59 -0800
From: kys@...hange.microsoft.com
To: gregkh@...uxfoundation.org, linux-kernel@...r.kernel.org,
devel@...uxdriverproject.org, olaf@...fle.de, apw@...onical.com,
vkuznets@...hat.com, jasowang@...hat.com,
leann.ogasawara@...onical.com, rkagan@...tuozzo.com,
x86@...nel.org, tglx@...utronix.de, hpa@...or.com
Cc: "K. Y. Srinivasan" <kys@...rosoft.com>
Subject: [PATCH 05/18] Drivers: hv: vmbus: Consolidate all Hyper-V specific clocksource code
From: K. Y. Srinivasan <kys@...rosoft.com>
As part of the effort to separate out architecture specific code,
consolidate all Hyper-V specific clocksource code to an architecture
specific code.
Signed-off-by: K. Y. Srinivasan <kys@...rosoft.com>
---
arch/x86/hyperv/hv_init.c | 104 +++++++++++++++++++++++++++++++++++++++
arch/x86/include/asm/mshyperv.h | 12 +++++
arch/x86/kernel/cpu/mshyperv.c | 23 ---------
drivers/hv/hv.c | 95 -----------------------------------
drivers/hv/hyperv_vmbus.h | 8 ---
5 files changed, 116 insertions(+), 126 deletions(-)
diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index b5c8e04..940a970 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -24,6 +24,79 @@
#include <linux/version.h>
#include <linux/vmalloc.h>
#include <linux/mm.h>
+#include <linux/clockchips.h>
+
+
+#ifdef CONFIG_X86_64
+
+static struct ms_hyperv_tsc_page *tsc_pg;
+
+static cycle_t read_hv_clock_tsc(struct clocksource *arg)
+{
+ cycle_t current_tick;
+
+ if (tsc_pg->tsc_sequence != 0) {
+ /*
+ * Use the tsc page to compute the value.
+ */
+
+ while (1) {
+ cycle_t tmp;
+ u32 sequence = tsc_pg->tsc_sequence;
+ u64 cur_tsc;
+ u64 scale = tsc_pg->tsc_scale;
+ s64 offset = tsc_pg->tsc_offset;
+
+ rdtscll(cur_tsc);
+ /* current_tick = ((cur_tsc *scale) >> 64) + offset */
+ asm("mulq %3"
+ : "=d" (current_tick), "=a" (tmp)
+ : "a" (cur_tsc), "r" (scale));
+
+ current_tick += offset;
+ if (tsc_pg->tsc_sequence == sequence)
+ return current_tick;
+
+ if (tsc_pg->tsc_sequence != 0)
+ continue;
+ /*
+ * Fallback using MSR method.
+ */
+ break;
+ }
+ }
+ rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
+ return current_tick;
+}
+
+static struct clocksource hyperv_cs_tsc = {
+ .name = "hyperv_clocksource_tsc_page",
+ .rating = 400,
+ .read = read_hv_clock_tsc,
+ .mask = CLOCKSOURCE_MASK(64),
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS,
+};
+#endif
+
+static cycle_t read_hv_clock_msr(struct clocksource *arg)
+{
+ cycle_t current_tick;
+ /*
+ * Read the partition counter to get the current tick count. This count
+ * is set to 0 when the partition is created and is incremented in
+ * 100 nanosecond units.
+ */
+ rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
+ return current_tick;
+}
+
+static struct clocksource hyperv_cs_msr = {
+ .name = "hyperv_clocksource_msr",
+ .rating = 400,
+ .read = read_hv_clock_msr,
+ .mask = CLOCKSOURCE_MASK(64),
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS,
+};
static void *hypercall_pg;
/*
@@ -31,6 +104,7 @@
* hypervisor has been detected.
*
* 1. Setup the hypercall page.
+ * 2. Register Hyper-V specific clocksource.
*/
void hyperv_init(void)
{
@@ -58,6 +132,36 @@ void hyperv_init(void)
hypercall_msr.enable = 1;
hypercall_msr.guest_physical_address = vmalloc_to_pfn(hypercall_pg);
wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
+
+ /*
+ * Register Hyper-V specific clocksource.
+ */
+#ifdef CONFIG_X86_64
+ if (ms_hyperv.features & HV_X64_MSR_REFERENCE_TSC_AVAILABLE) {
+ union hv_x64_msr_hypercall_contents tsc_msr;
+
+ tsc_pg = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL);
+ if (!tsc_pg)
+ clocksource_register_hz(&hyperv_cs_msr, NSEC_PER_SEC/100);
+ return;
+
+ rdmsrl(HV_X64_MSR_REFERENCE_TSC, tsc_msr.as_uint64);
+
+ tsc_msr.enable = 1;
+ tsc_msr.guest_physical_address = vmalloc_to_pfn(tsc_pg);
+
+ wrmsrl(HV_X64_MSR_REFERENCE_TSC, tsc_msr.as_uint64);
+ clocksource_register_hz(&hyperv_cs_tsc, NSEC_PER_SEC/100);
+ return;
+ }
+#endif
+ /*
+ * For 32 bit guests just use the MSR based mechanism for reading
+ * the partition counter.
+ */
+
+ if (ms_hyperv.features & HV_X64_MSR_TIME_REF_COUNT_AVAILABLE)
+ clocksource_register_hz(&hyperv_cs_msr, NSEC_PER_SEC/100);
}
/*
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index ed8e073..adfe8cc 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -26,6 +26,18 @@ struct ms_hyperv_info {
};
/*
+ * TSC page layout.
+ */
+
+struct ms_hyperv_tsc_page {
+ volatile u32 tsc_sequence;
+ u32 reserved1;
+ volatile u64 tsc_scale;
+ volatile s64 tsc_offset;
+ u64 reserved2[509];
+};
+
+/*
* The guest OS needs to register the guest ID with the hypervisor.
* The guest ID is a 64 bit entity and the structure of this ID is
* specified in the Hyper-V specification:
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 8b376f8..6afb517 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -133,26 +133,6 @@ static uint32_t __init ms_hyperv_platform(void)
return 0;
}
-static cycle_t read_hv_clock(struct clocksource *arg)
-{
- cycle_t current_tick;
- /*
- * Read the partition counter to get the current tick count. This count
- * is set to 0 when the partition is created and is incremented in
- * 100 nanosecond units.
- */
- rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
- return current_tick;
-}
-
-static struct clocksource hyperv_cs = {
- .name = "hyperv_clocksource",
- .rating = 400, /* use this when running on Hyperv*/
- .read = read_hv_clock,
- .mask = CLOCKSOURCE_MASK(64),
- .flags = CLOCK_SOURCE_IS_CONTINUOUS,
-};
-
static unsigned char hv_get_nmi_reason(void)
{
return 0;
@@ -185,9 +165,6 @@ static void __init ms_hyperv_init_platform(void)
}
#endif
- if (ms_hyperv.features & HV_X64_MSR_TIME_REF_COUNT_AVAILABLE)
- clocksource_register_hz(&hyperv_cs, NSEC_PER_SEC/100);
-
#ifdef CONFIG_X86_IO_APIC
no_timer_check = 1;
#endif
diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
index 11388d3..607d477 100644
--- a/drivers/hv/hv.c
+++ b/drivers/hv/hv.c
@@ -87,56 +87,6 @@ static int query_hypervisor_info(void)
return max_leaf;
}
-#ifdef CONFIG_X86_64
-static cycle_t read_hv_clock_tsc(struct clocksource *arg)
-{
- cycle_t current_tick;
- struct ms_hyperv_tsc_page *tsc_pg = hv_context.tsc_page;
-
- if (tsc_pg->tsc_sequence != 0) {
- /*
- * Use the tsc page to compute the value.
- */
-
- while (1) {
- cycle_t tmp;
- u32 sequence = tsc_pg->tsc_sequence;
- u64 cur_tsc;
- u64 scale = tsc_pg->tsc_scale;
- s64 offset = tsc_pg->tsc_offset;
-
- rdtscll(cur_tsc);
- /* current_tick = ((cur_tsc *scale) >> 64) + offset */
- asm("mulq %3"
- : "=d" (current_tick), "=a" (tmp)
- : "a" (cur_tsc), "r" (scale));
-
- current_tick += offset;
- if (tsc_pg->tsc_sequence == sequence)
- return current_tick;
-
- if (tsc_pg->tsc_sequence != 0)
- continue;
- /*
- * Fallback using MSR method.
- */
- break;
- }
- }
- rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
- return current_tick;
-}
-
-static struct clocksource hyperv_cs_tsc = {
- .name = "hyperv_clocksource_tsc_page",
- .rating = 425,
- .read = read_hv_clock_tsc,
- .mask = CLOCKSOURCE_MASK(64),
- .flags = CLOCK_SOURCE_IS_CONTINUOUS,
-};
-#endif
-
-
/*
* hv_init - Main initialization routine.
*
@@ -171,29 +121,7 @@ int hv_init(void)
if (!hypercall_msr.enable)
return -ENOTSUPP;
-#ifdef CONFIG_X86_64
- if (ms_hyperv.features & HV_X64_MSR_REFERENCE_TSC_AVAILABLE) {
- union hv_x64_msr_hypercall_contents tsc_msr;
- void *va_tsc;
-
- va_tsc = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL);
- if (!va_tsc)
- goto cleanup;
- hv_context.tsc_page = va_tsc;
-
- rdmsrl(HV_X64_MSR_REFERENCE_TSC, tsc_msr.as_uint64);
-
- tsc_msr.enable = 1;
- tsc_msr.guest_physical_address = vmalloc_to_pfn(va_tsc);
-
- wrmsrl(HV_X64_MSR_REFERENCE_TSC, tsc_msr.as_uint64);
- clocksource_register_hz(&hyperv_cs_tsc, NSEC_PER_SEC/100);
- }
-#endif
return 0;
-
-cleanup:
- return -ENOTSUPP;
}
/*
@@ -204,29 +132,6 @@ int hv_init(void)
void hv_cleanup(bool crash)
{
-#ifdef CONFIG_X86_64
- union hv_x64_msr_hypercall_contents hypercall_msr;
- /*
- * Cleanup the TSC page based CS.
- */
- if (ms_hyperv.features & HV_X64_MSR_REFERENCE_TSC_AVAILABLE) {
- /*
- * Crash can happen in an interrupt context and unregistering
- * a clocksource is impossible and redundant in this case.
- */
- if (!oops_in_progress) {
- clocksource_change_rating(&hyperv_cs_tsc, 10);
- clocksource_unregister(&hyperv_cs_tsc);
- }
-
- hypercall_msr.as_uint64 = 0;
- wrmsrl(HV_X64_MSR_REFERENCE_TSC, hypercall_msr.as_uint64);
- if (!crash) {
- vfree(hv_context.tsc_page);
- hv_context.tsc_page = NULL;
- }
- }
-#endif
}
/*
diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h
index 0948526..947455d 100644
--- a/drivers/hv/hyperv_vmbus.h
+++ b/drivers/hv/hyperv_vmbus.h
@@ -416,14 +416,6 @@ struct hv_context {
extern struct hv_context hv_context;
-struct ms_hyperv_tsc_page {
- volatile u32 tsc_sequence;
- u32 reserved1;
- volatile u64 tsc_scale;
- volatile s64 tsc_offset;
- u64 reserved2[509];
-};
-
struct hv_ring_buffer_debug_info {
u32 current_interrupt_mask;
u32 current_read_index;
--
1.7.4.1
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