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Commit dd2cb348 authored by Michael Kelley's avatar Michael Kelley Committed by Thomas Gleixner
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clocksource/drivers: Continue making Hyper-V clocksource ISA agnostic 



Continue consolidating Hyper-V clock and timer code into an ISA
independent Hyper-V clocksource driver.

Move the existing clocksource code under drivers/hv and arch/x86 to the new
clocksource driver while separating out the ISA dependencies. Update
Hyper-V initialization to call initialization and cleanup routines since
the Hyper-V synthetic clock is not independently enumerated in ACPI.

Update Hyper-V clocksource users in KVM and VDSO to get definitions from
the new include file.

No behavior is changed and no new functionality is added.

Suggested-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: default avatarMichael Kelley <mikelley@microsoft.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Reviewed-by: default avatarVitaly Kuznetsov <vkuznets@redhat.com>
Cc: "bp@alien8.de" <bp@alien8.de>
Cc: "will.deacon@arm.com" <will.deacon@arm.com>
Cc: "catalin.marinas@arm.com" <catalin.marinas@arm.com>
Cc: "mark.rutland@arm.com" <mark.rutland@arm.com>
Cc: "linux-arm-kernel@lists.infradead.org" <linux-arm-kernel@lists.infradead.org>
Cc: "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>
Cc: "linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>
Cc: "olaf@aepfle.de" <olaf@aepfle.de>
Cc: "apw@canonical.com" <apw@canonical.com>
Cc: "jasowang@redhat.com" <jasowang@redhat.com>
Cc: "marcelo.cerri@canonical.com" <marcelo.cerri@canonical.com>
Cc: Sunil Muthuswamy <sunilmut@microsoft.com>
Cc: KY Srinivasan <kys@microsoft.com>
Cc: "sashal@kernel.org" <sashal@kernel.org>
Cc: "vincenzo.frascino@arm.com" <vincenzo.frascino@arm.com>
Cc: "linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>
Cc: "linux-mips@vger.kernel.org" <linux-mips@vger.kernel.org>
Cc: "linux-kselftest@vger.kernel.org" <linux-kselftest@vger.kernel.org>
Cc: "arnd@arndb.de" <arnd@arndb.de>
Cc: "linux@armlinux.org.uk" <linux@armlinux.org.uk>
Cc: "ralf@linux-mips.org" <ralf@linux-mips.org>
Cc: "paul.burton@mips.com" <paul.burton@mips.com>
Cc: "daniel.lezcano@linaro.org" <daniel.lezcano@linaro.org>
Cc: "salyzyn@android.com" <salyzyn@android.com>
Cc: "pcc@google.com" <pcc@google.com>
Cc: "shuah@kernel.org" <shuah@kernel.org>
Cc: "0x7f454c46@gmail.com" <0x7f454c46@gmail.com>
Cc: "linux@rasmusvillemoes.dk" <linux@rasmusvillemoes.dk>
Cc: "huw@codeweavers.com" <huw@codeweavers.com>
Cc: "sfr@canb.auug.org.au" <sfr@canb.auug.org.au>
Cc: "pbonzini@redhat.com" <pbonzini@redhat.com>
Cc: "rkrcmar@redhat.com" <rkrcmar@redhat.com>
Cc: "kvm@vger.kernel.org" <kvm@vger.kernel.org>
Link: https://lkml.kernel.org/r/1561955054-1838-3-git-send-email-mikelley@microsoft.com
parent fd1fea68

arch/x86/entry/vdso/vma.c

+1 −1
Original line number Diff line number Diff line
@@ -22,7 +22,7 @@ 
#include <asm/page.h>

#include <asm/desc.h>

#include <asm/cpufeature.h>

#include <asm/mshyperv.h>

#include <clocksource/hyperv_timer.h>



#if defined(CONFIG_X86_64)

unsigned int __read_mostly vdso64_enabled = 1;

arch/x86/hyperv/hv_init.c

+3 −88
Original line number Diff line number Diff line
@@ -17,64 +17,13 @@ 
#include <linux/version.h>

#include <linux/vmalloc.h>

#include <linux/mm.h>

#include <linux/clockchips.h>

#include <linux/hyperv.h>

#include <linux/slab.h>

#include <linux/cpuhotplug.h>



#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;

}

EXPORT_SYMBOL_GPL(hv_get_tsc_page);



static u64 read_hv_clock_tsc(struct clocksource *arg)

{

	u64 current_tick = hv_read_tsc_page(tsc_pg);



	if (current_tick == U64_MAX)

		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 u64 read_hv_clock_msr(struct clocksource *arg)

{

	u64 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,

};

#include <clocksource/hyperv_timer.h>



void *hv_hypercall_pg;

EXPORT_SYMBOL_GPL(hv_hypercall_pg);

struct clocksource *hyperv_cs;

EXPORT_SYMBOL_GPL(hyperv_cs);



u32 *hv_vp_index;

EXPORT_SYMBOL_GPL(hv_vp_index);
@@ -343,42 +292,8 @@ void __init hyperv_init(void) 


	x86_init.pci.arch_init = hv_pci_init;



	/*

	 * Register Hyper-V specific clocksource.

	 */

#ifdef CONFIG_HYPERV_TSCPAGE

	if (ms_hyperv.features & HV_MSR_REFERENCE_TSC_AVAILABLE) {

		union hv_x64_msr_hypercall_contents tsc_msr;



		tsc_pg = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL);

		if (!tsc_pg)

			goto register_msr_cs;



		hyperv_cs = &hyperv_cs_tsc;



		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);



		hyperv_cs_tsc.archdata.vclock_mode = VCLOCK_HVCLOCK;



		clocksource_register_hz(&hyperv_cs_tsc, NSEC_PER_SEC/100);

		return;

	}

register_msr_cs:

#endif

	/*

	 * For 32 bit guests just use the MSR based mechanism for reading

	 * the partition counter.

	 */



	hyperv_cs = &hyperv_cs_msr;

	if (ms_hyperv.features & HV_MSR_TIME_REF_COUNT_AVAILABLE)

		clocksource_register_hz(&hyperv_cs_msr, NSEC_PER_SEC/100);



	/* Register Hyper-V specific clocksource */

	hv_init_clocksource();

	return;



remove_cpuhp_state:

arch/x86/include/asm/mshyperv.h

+11 −70
Original line number Diff line number Diff line
@@ -105,6 +105,17 @@ static inline void vmbus_signal_eom(struct hv_message *msg, u32 old_msg_type) 
#define hv_get_crash_ctl(val) \

	rdmsrl(HV_X64_MSR_CRASH_CTL, val)



#define hv_get_time_ref_count(val) \

	rdmsrl(HV_X64_MSR_TIME_REF_COUNT, val)



#define hv_get_reference_tsc(val) \

	rdmsrl(HV_X64_MSR_REFERENCE_TSC, val)

#define hv_set_reference_tsc(val) \

	wrmsrl(HV_X64_MSR_REFERENCE_TSC, val)

#define hv_set_clocksource_vdso(val) \

	((val).archdata.vclock_mode = VCLOCK_HVCLOCK)

#define hv_get_raw_timer() rdtsc_ordered()



void hyperv_callback_vector(void);

void hyperv_reenlightenment_vector(void);

#ifdef CONFIG_TRACING
@@ -133,7 +144,6 @@ static inline void hv_disable_stimer0_percpu_irq(int irq) {} 




#if IS_ENABLED(CONFIG_HYPERV)

extern struct clocksource *hyperv_cs;

extern void *hv_hypercall_pg;

extern void  __percpu  **hyperv_pcpu_input_arg;
@@ -387,73 +397,4 @@ static inline int hyperv_flush_guest_mapping_range(u64 as, 
}

#endif /* CONFIG_HYPERV */



#ifdef CONFIG_HYPERV_TSCPAGE

struct ms_hyperv_tsc_page *hv_get_tsc_page(void);

static inline u64 hv_read_tsc_page_tsc(const struct ms_hyperv_tsc_page *tsc_pg,

				       u64 *cur_tsc)

{

	u64 scale, offset;

	u32 sequence;



	/*

	 * The protocol for reading Hyper-V TSC page is specified in Hypervisor

	 * Top-Level Functional Specification ver. 3.0 and above. To get the

	 * reference time we must do the following:

	 * - READ ReferenceTscSequence

	 *   A special '0' value indicates the time source is unreliable and we

	 *   need to use something else. The currently published specification

	 *   versions (up to 4.0b) contain a mistake and wrongly claim '-1'

	 *   instead of '0' as the special value, see commit c35b82ef0294.

	 * - ReferenceTime =

	 *        ((RDTSC() * ReferenceTscScale) >> 64) + ReferenceTscOffset

	 * - READ ReferenceTscSequence again. In case its value has changed

	 *   since our first reading we need to discard ReferenceTime and repeat

	 *   the whole sequence as the hypervisor was updating the page in

	 *   between.

	 */

	do {

		sequence = READ_ONCE(tsc_pg->tsc_sequence);

		if (!sequence)

			return U64_MAX;

		/*

		 * Make sure we read sequence before we read other values from

		 * TSC page.

		 */

		smp_rmb();



		scale = READ_ONCE(tsc_pg->tsc_scale);

		offset = READ_ONCE(tsc_pg->tsc_offset);

		*cur_tsc = rdtsc_ordered();



		/*

		 * Make sure we read sequence after we read all other values

		 * from TSC page.

		 */

		smp_rmb();



	} while (READ_ONCE(tsc_pg->tsc_sequence) != sequence);



	return mul_u64_u64_shr(*cur_tsc, scale, 64) + offset;

}



static inline u64 hv_read_tsc_page(const struct ms_hyperv_tsc_page *tsc_pg)

{

	u64 cur_tsc;



	return hv_read_tsc_page_tsc(tsc_pg, &cur_tsc);

}



#else

static inline struct ms_hyperv_tsc_page *hv_get_tsc_page(void)

{

	return NULL;

}



static inline u64 hv_read_tsc_page_tsc(const struct ms_hyperv_tsc_page *tsc_pg,

				       u64 *cur_tsc)

{

	BUG();

	return U64_MAX;

}

#endif

#endif

arch/x86/include/asm/vdso/gettimeofday.h

+1 −1
Original line number Diff line number Diff line
@@ -18,7 +18,7 @@ 
#include <asm/unistd.h>

#include <asm/msr.h>

#include <asm/pvclock.h>

#include <asm/mshyperv.h>

#include <clocksource/hyperv_timer.h>



#define __vdso_data (VVAR(_vdso_data))

arch/x86/kvm/x86.c

+1 −0
Original line number Diff line number Diff line
@@ -67,6 +67,7 @@ 
#include <asm/mshyperv.h>

#include <asm/hypervisor.h>

#include <asm/intel_pt.h>

#include <clocksource/hyperv_timer.h>



#define CREATE_TRACE_POINTS

#include "trace.h"