From dd2cb348613b44f9d948b068775e159aad298599 Mon Sep 17 00:00:00 2001 From: Michael Kelley Date: Mon, 1 Jul 2019 04:26:06 +0000 Subject: 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: Marc Zyngier Signed-off-by: Michael Kelley Signed-off-by: Thomas Gleixner Reviewed-by: Vitaly Kuznetsov Cc: "bp@alien8.de" Cc: "will.deacon@arm.com" Cc: "catalin.marinas@arm.com" Cc: "mark.rutland@arm.com" Cc: "linux-arm-kernel@lists.infradead.org" Cc: "gregkh@linuxfoundation.org" Cc: "linux-hyperv@vger.kernel.org" Cc: "olaf@aepfle.de" Cc: "apw@canonical.com" Cc: "jasowang@redhat.com" Cc: "marcelo.cerri@canonical.com" Cc: Sunil Muthuswamy Cc: KY Srinivasan Cc: "sashal@kernel.org" Cc: "vincenzo.frascino@arm.com" Cc: "linux-arch@vger.kernel.org" Cc: "linux-mips@vger.kernel.org" Cc: "linux-kselftest@vger.kernel.org" Cc: "arnd@arndb.de" Cc: "linux@armlinux.org.uk" Cc: "ralf@linux-mips.org" Cc: "paul.burton@mips.com" Cc: "daniel.lezcano@linaro.org" Cc: "salyzyn@android.com" Cc: "pcc@google.com" Cc: "shuah@kernel.org" Cc: "0x7f454c46@gmail.com" <0x7f454c46@gmail.com> Cc: "linux@rasmusvillemoes.dk" Cc: "huw@codeweavers.com" Cc: "sfr@canb.auug.org.au" Cc: "pbonzini@redhat.com" Cc: "rkrcmar@redhat.com" Cc: "kvm@vger.kernel.org" Link: https://lkml.kernel.org/r/1561955054-1838-3-git-send-email-mikelley@microsoft.com --- drivers/clocksource/hyperv_timer.c | 139 +++++++++++++++++++++++++++++++++++++ 1 file changed, 139 insertions(+) (limited to 'drivers/clocksource') diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c index 68a28af31561..ba2c79e6a0ee 100644 --- a/drivers/clocksource/hyperv_timer.c +++ b/drivers/clocksource/hyperv_timer.c @@ -14,6 +14,8 @@ #include #include #include +#include +#include #include #include #include @@ -198,3 +200,140 @@ void hv_stimer_global_cleanup(void) hv_stimer_free(); } EXPORT_SYMBOL_GPL(hv_stimer_global_cleanup); + +/* + * Code and definitions for the Hyper-V clocksources. Two + * clocksources are defined: one that reads the Hyper-V defined MSR, and + * the other that uses the TSC reference page feature as defined in the + * TLFS. The MSR version is for compatibility with old versions of + * Hyper-V and 32-bit x86. The TSC reference page version is preferred. + */ + +struct clocksource *hyperv_cs; +EXPORT_SYMBOL_GPL(hyperv_cs); + +#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 notrace read_hv_sched_clock_tsc(void) +{ + u64 current_tick = hv_read_tsc_page(tsc_pg); + + if (current_tick == U64_MAX) + hv_get_time_ref_count(current_tick); + + return current_tick; +} + +static u64 read_hv_clock_tsc(struct clocksource *arg) +{ + return read_hv_sched_clock_tsc(); +} + +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 notrace read_hv_sched_clock_msr(void) +{ + 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. + */ + hv_get_time_ref_count(current_tick); + return current_tick; +} + +static u64 read_hv_clock_msr(struct clocksource *arg) +{ + return read_hv_sched_clock_msr(); +} + +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, +}; + +#ifdef CONFIG_HYPERV_TSCPAGE +static bool __init hv_init_tsc_clocksource(void) +{ + u64 tsc_msr; + phys_addr_t phys_addr; + + if (!(ms_hyperv.features & HV_MSR_REFERENCE_TSC_AVAILABLE)) + return false; + + tsc_pg = vmalloc(PAGE_SIZE); + if (!tsc_pg) + return false; + + hyperv_cs = &hyperv_cs_tsc; + phys_addr = page_to_phys(vmalloc_to_page(tsc_pg)); + + /* + * The Hyper-V TLFS specifies to preserve the value of reserved + * bits in registers. So read the existing value, preserve the + * low order 12 bits, and add in the guest physical address + * (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. + */ + hv_get_reference_tsc(tsc_msr); + tsc_msr &= GENMASK_ULL(11, 0); + tsc_msr = tsc_msr | 0x1 | (u64)phys_addr; + hv_set_reference_tsc(tsc_msr); + + hv_set_clocksource_vdso(hyperv_cs_tsc); + clocksource_register_hz(&hyperv_cs_tsc, NSEC_PER_SEC/100); + + /* sched_clock_register is needed on ARM64 but is a no-op on x86 */ + sched_clock_register(read_hv_sched_clock_tsc, 64, HV_CLOCK_HZ); + return true; +} +#else +static bool __init hv_init_tsc_clocksource(void) +{ + return false; +} +#endif + + +void __init hv_init_clocksource(void) +{ + /* + * Try to set up the TSC page clocksource. If it succeeds, we're + * done. Otherwise, set up the MSR clocksoruce. At least one of + * these will always be available except on very old versions of + * Hyper-V on x86. In that case we won't have a Hyper-V + * clocksource, but Linux will still run with a clocksource based + * on the emulated PIT or LAPIC timer. + */ + if (hv_init_tsc_clocksource()) + return; + + if (!(ms_hyperv.features & HV_MSR_TIME_REF_COUNT_AVAILABLE)) + return; + + hyperv_cs = &hyperv_cs_msr; + clocksource_register_hz(&hyperv_cs_msr, NSEC_PER_SEC/100); + + /* sched_clock_register is needed on ARM64 but is a no-op on x86 */ + sched_clock_register(read_hv_sched_clock_msr, 64, HV_CLOCK_HZ); +} +EXPORT_SYMBOL_GPL(hv_init_clocksource); -- cgit v1.2.3