Commit 4ad1aa57 authored by Anirudh Rayabharam's avatar Anirudh Rayabharam Committed by Wei Liu
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clocksource/drivers/hyperv: add data structure for reference TSC MSR 



Add a data structure to represent the reference TSC MSR similar to
other MSRs. This simplifies the code for updating the MSR.

Signed-off-by: default avatarAnirudh Rayabharam <anrayabh@linux.microsoft.com>
Reviewed-by: default avatarMichael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20221027095729.1676394-2-anrayabh@linux.microsoft.com


Signed-off-by: default avatarWei Liu <wei.liu@kernel.org>
parent 99632e3d

drivers/clocksource/hyperv_timer.c

+15 −14
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ 
#include <linux/interrupt.h>

#include <linux/irq.h>

#include <linux/acpi.h>

#include <linux/hyperv.h>

#include <clocksource/hyperv_timer.h>

#include <asm/hyperv-tlfs.h>

#include <asm/mshyperv.h>
@@ -395,25 +396,25 @@ static u64 notrace read_hv_sched_clock_tsc(void) 


static void suspend_hv_clock_tsc(struct clocksource *arg)

{

	u64 tsc_msr;

	union hv_reference_tsc_msr tsc_msr;



	/* Disable the TSC page */

	tsc_msr = hv_get_register(HV_REGISTER_REFERENCE_TSC);

	tsc_msr &= ~BIT_ULL(0);

	hv_set_register(HV_REGISTER_REFERENCE_TSC, tsc_msr);

	tsc_msr.as_uint64 = hv_get_register(HV_REGISTER_REFERENCE_TSC);

	tsc_msr.enable = 0;

	hv_set_register(HV_REGISTER_REFERENCE_TSC, tsc_msr.as_uint64);

}





static void resume_hv_clock_tsc(struct clocksource *arg)

{

	phys_addr_t phys_addr = virt_to_phys(&tsc_pg);

	u64 tsc_msr;

	union hv_reference_tsc_msr tsc_msr;



	/* Re-enable the TSC page */

	tsc_msr = hv_get_register(HV_REGISTER_REFERENCE_TSC);

	tsc_msr &= GENMASK_ULL(11, 0);

	tsc_msr |= BIT_ULL(0) | (u64)phys_addr;

	hv_set_register(HV_REGISTER_REFERENCE_TSC, tsc_msr);

	tsc_msr.as_uint64 = hv_get_register(HV_REGISTER_REFERENCE_TSC);

	tsc_msr.enable = 1;

	tsc_msr.pfn = HVPFN_DOWN(phys_addr);

	hv_set_register(HV_REGISTER_REFERENCE_TSC, tsc_msr.as_uint64);

}



#ifdef HAVE_VDSO_CLOCKMODE_HVCLOCK
@@ -495,7 +496,7 @@ static __always_inline void hv_setup_sched_clock(void *sched_clock) {} 


static bool __init hv_init_tsc_clocksource(void)

{

	u64		tsc_msr;

	union hv_reference_tsc_msr tsc_msr;

	phys_addr_t	phys_addr;



	if (!(ms_hyperv.features & HV_MSR_REFERENCE_TSC_AVAILABLE))
@@ -530,10 +531,10 @@ static bool __init hv_init_tsc_clocksource(void) 
	 * (which already has at least the low 12 bits set to zero since

	 * it is page aligned). Also set the "enable" bit, which is bit 0.

	 */

	tsc_msr = hv_get_register(HV_REGISTER_REFERENCE_TSC);

	tsc_msr &= GENMASK_ULL(11, 0);

	tsc_msr = tsc_msr | 0x1 | (u64)phys_addr;

	hv_set_register(HV_REGISTER_REFERENCE_TSC, tsc_msr);

	tsc_msr.as_uint64 = hv_get_register(HV_REGISTER_REFERENCE_TSC);

	tsc_msr.enable = 1;

	tsc_msr.pfn = HVPFN_DOWN(phys_addr);

	hv_set_register(HV_REGISTER_REFERENCE_TSC, tsc_msr.as_uint64);



	clocksource_register_hz(&hyperv_cs_tsc, NSEC_PER_SEC/100);

include/asm-generic/hyperv-tlfs.h

+9 −0
Original line number Diff line number Diff line
@@ -102,6 +102,15 @@ struct ms_hyperv_tsc_page { 
	volatile s64 tsc_offset;

} __packed;



union hv_reference_tsc_msr {

	u64 as_uint64;

	struct {

		u64 enable:1;

		u64 reserved:11;

		u64 pfn:52;

	} __packed;

};



/*

 * 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