clocksource/drivers: Continue making Hyper-V clocksource ISA agnostic
authorMichael Kelley <mikelley@microsoft.com>
Mon, 1 Jul 2019 04:26:06 +0000 (04:26 +0000)
committerThomas Gleixner <tglx@linutronix.de>
Wed, 3 Jul 2019 09:00:59 +0000 (11:00 +0200)
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 <marc.zyngier@arm.com>
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Vitaly 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
arch/x86/entry/vdso/vma.c
arch/x86/hyperv/hv_init.c
arch/x86/include/asm/mshyperv.h
arch/x86/include/asm/vdso/gettimeofday.h
arch/x86/kvm/x86.c
drivers/clocksource/hyperv_timer.c
drivers/hv/hv_util.c
include/clocksource/hyperv_timer.h

index 8db1f594e8b1f7aee34cf2aa46718f97d66a53cf..349a61d8bf3490199c5d8ae911f4d48ab44cdb2d 100644 (file)
@@ -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;
index 1608050e9df95755ed369b1fe024a2e5bd818746..0e033ef11a9f73c6ae0ecf2c4a077bbb5e4fcc44 100644 (file)
 #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:
index cc60e617931cb5a56b3641247258dda5336cba60..f4fa8a9d5d0baa1fbf4aa2256756c47d0ccf06a5 100644 (file)
@@ -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
index a14039a59abdfa0c4f693c0eb4d68113130b0330..ae91429129a6411b8cd324f911ec1b5b57085365 100644 (file)
@@ -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))
 
index 8ec67602936585fc2b5d1b3afc57232db3284542..5e1db26b5e1512c22ec623537577763750308b86 100644 (file)
@@ -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"
index 68a28af3156109169fecceced45b1b573c7f3b93..ba2c79e6a0ee74d5a9a48278dfb561c978e81356 100644 (file)
@@ -14,6 +14,8 @@
 #include <linux/percpu.h>
 #include <linux/cpumask.h>
 #include <linux/clockchips.h>
+#include <linux/clocksource.h>
+#include <linux/sched_clock.h>
 #include <linux/mm.h>
 #include <clocksource/hyperv_timer.h>
 #include <asm/hyperv-tlfs.h>
@@ -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);
index 7d3d31f099ea124042ab424081c0c248bf0b62a8..e32681ee7b9f6a3119610eef0578e46a153656be 100644 (file)
@@ -17,6 +17,7 @@
 #include <linux/hyperv.h>
 #include <linux/clockchips.h>
 #include <linux/ptp_clock_kernel.h>
+#include <clocksource/hyperv_timer.h>
 #include <asm/mshyperv.h>
 
 #include "hyperv_vmbus.h"
index 0cd73f7bc9928a7e889f2eb9a11374c245d0a0ed..a821deb8ecb28c6c09bb2b4e80ea785498b29e3e 100644 (file)
 #ifndef __CLKSOURCE_HYPERV_TIMER_H
 #define __CLKSOURCE_HYPERV_TIMER_H
 
+#include <linux/clocksource.h>
+#include <linux/math64.h>
+#include <asm/mshyperv.h>
+
 #define HV_MAX_MAX_DELTA_TICKS 0xffffffff
 #define HV_MIN_DELTA_TICKS 1
 
@@ -24,4 +28,80 @@ extern void hv_stimer_cleanup(unsigned int cpu);
 extern void hv_stimer_global_cleanup(void);
 extern void hv_stimer0_isr(void);
 
+#if IS_ENABLED(CONFIG_HYPERV)
+extern struct clocksource *hyperv_cs;
+extern void hv_init_clocksource(void);
+#endif /* CONFIG_HYPERV */
+
+#ifdef CONFIG_HYPERV_TSCPAGE
+extern struct ms_hyperv_tsc_page *hv_get_tsc_page(void);
+
+static inline notrace 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 = hv_get_raw_timer();
+
+               /*
+                * 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 notrace 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 /* CONFIG_HYPERV_TSC_PAGE */
+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)
+{
+       return U64_MAX;
+}
+#endif /* CONFIG_HYPERV_TSCPAGE */
+
 #endif