Author: sephe
Date: Wed Jan  4 01:58:38 2017
New Revision: 311223
URL: https://svnweb.freebsd.org/changeset/base/311223

Log:
  MFC 310048,310101
  
  310048
      hyperv: Implement "enlightened" time counter, which is rdtsc based.
  
      Reviewed by:    kib
      Sponsored by:   Microsoft
      Differential Revision:  https://reviews.freebsd.org/D8763
  
  310101
      hyperv: Allow userland to ro-mmap reference TSC page
  
      This paves way to implement VDSO for the enlightened time counter.
  
      Reviewed by:    kib
      Sponsored by:   Microsoft
      Differential Revision:  https://reviews.freebsd.org/D8768

Modified:
  stable/10/include/Makefile
  stable/10/sys/dev/hyperv/include/hyperv.h
  stable/10/sys/dev/hyperv/vmbus/amd64/hyperv_machdep.c
  stable/10/sys/dev/hyperv/vmbus/hyperv_reg.h
Directory Properties:
  stable/10/   (props changed)

Modified: stable/10/include/Makefile
==============================================================================
--- stable/10/include/Makefile  Wed Jan  4 01:44:45 2017        (r311222)
+++ stable/10/include/Makefile  Wed Jan  4 01:58:38 2017        (r311223)
@@ -184,6 +184,9 @@ copies:
        ${INSTALL} -C -o ${BINOWN} -g ${BINGRP} -m 444 nand_dev.h \
            ${DESTDIR}${INCLUDEDIR}/dev/nand
 .endif
+       cd ${.CURDIR}/../sys/dev/hyperv/include; \
+       ${INSTALL} -C ${TAG_ARGS} -o ${BINOWN} -g ${BINGRP} -m 444 hyperv.h \
+           ${DESTDIR}${INCLUDEDIR}/dev/hyperv
        cd ${.CURDIR}/../sys/dev/hyperv/utilities; \
        ${INSTALL} -C ${TAG_ARGS} -o ${BINOWN} -g ${BINGRP} -m 444 
hv_snapshot.h \
            ${DESTDIR}${INCLUDEDIR}/dev/hyperv
@@ -287,6 +290,11 @@ symlinks:
                    ${DESTDIR}${INCLUDEDIR}/dev/nand; \
        done
 .endif
+       cd ${.CURDIR}/../sys/dev/hyperv/include; \
+       for h in hyperv.h; do \
+               ${INSTALL_SYMLINK} ${TAG_ARGS} 
../../../../sys/dev/hyperv/include/$$h \
+                   ${DESTDIR}${INCLUDEDIR}/dev/hyperv; \
+       done
        cd ${.CURDIR}/../sys/dev/hyperv/utilities; \
        for h in hv_snapshot.h; do \
                ${INSTALL_SYMLINK} ${TAG_ARGS} 
../../../../sys/dev/hyperv/utilities/$$h \

Modified: stable/10/sys/dev/hyperv/include/hyperv.h
==============================================================================
--- stable/10/sys/dev/hyperv/include/hyperv.h   Wed Jan  4 01:44:45 2017        
(r311222)
+++ stable/10/sys/dev/hyperv/include/hyperv.h   Wed Jan  4 01:58:38 2017        
(r311223)
@@ -31,10 +31,10 @@
 #ifndef _HYPERV_H_
 #define _HYPERV_H_
 
-#include <sys/param.h>
+#ifdef _KERNEL
 
-#include <vm/vm.h>
-#include <vm/pmap.h>
+#include <sys/param.h>
+#include <sys/systm.h>
 
 #define MSR_HV_TIME_REF_COUNT          0x40000020
 
@@ -45,6 +45,7 @@
 #define CPUID_HV_MSR_HYPERCALL         0x0020  /* MSR_HV_GUEST_OS_ID
                                                 * MSR_HV_HYPERCALL */
 #define CPUID_HV_MSR_VP_INDEX          0x0040  /* MSR_HV_VP_INDEX */
+#define CPUID_HV_MSR_REFERENCE_TSC     0x0200  /* MSR_HV_REFERENCE_TSC */
 #define CPUID_HV_MSR_GUEST_IDLE                0x0400  /* MSR_HV_GUEST_IDLE */
 
 #ifndef NANOSEC
@@ -53,14 +54,35 @@
 #define HYPERV_TIMER_NS_FACTOR         100ULL
 #define HYPERV_TIMER_FREQ              (NANOSEC / HYPERV_TIMER_NS_FACTOR)
 
+#endif /* _KERNEL */
+
+#define HYPERV_REFTSC_DEVNAME          "hv_tsc"
+
+/*
+ * Hyper-V Reference TSC
+ */
+struct hyperv_reftsc {
+       volatile uint32_t               tsc_seq;
+       volatile uint32_t               tsc_rsvd1;
+       volatile uint64_t               tsc_scale;
+       volatile int64_t                tsc_ofs;
+} __packed __aligned(PAGE_SIZE);
+#ifdef CTASSERT
+CTASSERT(sizeof(struct hyperv_reftsc) == PAGE_SIZE);
+#endif
+
+#ifdef _KERNEL
+
 struct hyperv_guid {
-       uint8_t         hv_guid[16];
+       uint8_t                         hv_guid[16];
 } __packed;
 
-#define HYPERV_GUID_STRLEN     40
+#define HYPERV_GUID_STRLEN             40
 
 int            hyperv_guid2str(const struct hyperv_guid *, char *, size_t);
 
 extern u_int   hyperv_features;        /* CPUID_HV_MSR_ */
 
+#endif /* _KERNEL */
+
 #endif  /* _HYPERV_H_ */

Modified: stable/10/sys/dev/hyperv/vmbus/amd64/hyperv_machdep.c
==============================================================================
--- stable/10/sys/dev/hyperv/vmbus/amd64/hyperv_machdep.c       Wed Jan  4 
01:44:45 2017        (r311222)
+++ stable/10/sys/dev/hyperv/vmbus/amd64/hyperv_machdep.c       Wed Jan  4 
01:58:38 2017        (r311223)
@@ -28,7 +28,52 @@
 __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
+#include <sys/conf.h>
+#include <sys/fcntl.h>
+#include <sys/kernel.h>
+#include <sys/systm.h>
+#include <sys/timetc.h>
+
+#include <machine/cpufunc.h>
+#include <machine/cputypes.h>
+#include <machine/md_var.h>
+#include <machine/specialreg.h>
+
+#include <vm/vm.h>
+
+#include <dev/hyperv/include/hyperv.h>
+#include <dev/hyperv/include/hyperv_busdma.h>
 #include <dev/hyperv/vmbus/hyperv_machdep.h>
+#include <dev/hyperv/vmbus/hyperv_reg.h>
+#include <dev/hyperv/vmbus/hyperv_var.h>
+
+struct hyperv_reftsc_ctx {
+       struct hyperv_reftsc    *tsc_ref;
+       struct hyperv_dma       tsc_ref_dma;
+};
+
+static d_open_t                        hyperv_tsc_open;
+static d_mmap_t                        hyperv_tsc_mmap;
+
+static struct timecounter      hyperv_tsc_timecounter = {
+       .tc_get_timecount       = NULL, /* based on CPU vendor. */
+       .tc_poll_pps            = NULL,
+       .tc_counter_mask        = 0xffffffff,
+       .tc_frequency           = HYPERV_TIMER_FREQ,
+       .tc_name                = "Hyper-V-TSC",
+       .tc_quality             = 3000,
+       .tc_flags               = 0,
+       .tc_priv                = NULL
+};
+
+static struct cdevsw           hyperv_tsc_cdevsw = {
+       .d_version              = D_VERSION,
+       .d_open                 = hyperv_tsc_open,
+       .d_mmap                 = hyperv_tsc_mmap,
+       .d_name                 = HYPERV_REFTSC_DEVNAME
+};
+
+static struct hyperv_reftsc_ctx        hyperv_ref_tsc;
 
 uint64_t
 hypercall_md(volatile void *hc_addr, uint64_t in_val,
@@ -41,3 +86,122 @@ hypercall_md(volatile void *hc_addr, uin
            "c" (in_val), "d" (in_paddr), "m" (hc_addr));
        return (status);
 }
+
+static int
+hyperv_tsc_open(struct cdev *dev __unused, int oflags, int devtype __unused,
+    struct thread *td __unused)
+{
+
+       if (oflags & FWRITE)
+               return (EPERM);
+       return (0);
+}
+
+static int
+hyperv_tsc_mmap(struct cdev *dev __unused, vm_ooffset_t offset,
+    vm_paddr_t *paddr, int nprot __unused, vm_memattr_t *memattr __unused)
+{
+
+       KASSERT(hyperv_ref_tsc.tsc_ref != NULL, ("reftsc has not been setup"));
+
+       /*
+        * NOTE:
+        * 'nprot' does not contain information interested to us;
+        * WR-open is blocked by d_open.
+        */
+
+       if (offset != 0)
+               return (EOPNOTSUPP);
+
+       *paddr = hyperv_ref_tsc.tsc_ref_dma.hv_paddr;
+       return (0);
+}
+
+#define HYPERV_TSC_TIMECOUNT(fence)                                    \
+static u_int                                                           \
+hyperv_tsc_timecount_##fence(struct timecounter *tc)                   \
+{                                                                      \
+       struct hyperv_reftsc *tsc_ref = hyperv_ref_tsc.tsc_ref;         \
+       uint32_t seq;                                                   \
+                                                                       \
+       while ((seq = tsc_ref->tsc_seq) != 0) {                         \
+               uint64_t disc, ret, tsc, scale;                         \
+               int64_t ofs;                                            \
+                                                                       \
+               __compiler_membar();                                    \
+               scale = tsc_ref->tsc_scale;                             \
+               ofs = tsc_ref->tsc_ofs;                                 \
+                                                                       \
+               fence();                                                \
+               tsc = rdtsc();                                          \
+                                                                       \
+               /* ret = ((tsc * scale) >> 64) + ofs */                 \
+               __asm__ __volatile__ ("mulq %3" :                       \
+                   "=d" (ret), "=a" (disc) :                           \
+                   "a" (tsc), "r" (scale));                            \
+               ret += ofs;                                             \
+                                                                       \
+               __compiler_membar();                                    \
+               if (tsc_ref->tsc_seq == seq)                            \
+                       return (ret);                                   \
+                                                                       \
+               /* Sequence changed; re-sync. */                        \
+       }                                                               \
+       /* Fallback to the generic timecounter, i.e. rdmsr. */          \
+       return (rdmsr(MSR_HV_TIME_REF_COUNT));                          \
+}                                                                      \
+struct __hack
+
+HYPERV_TSC_TIMECOUNT(lfence);
+HYPERV_TSC_TIMECOUNT(mfence);
+
+static void
+hyperv_tsc_tcinit(void *dummy __unused)
+{
+       uint64_t val, orig;
+
+       if ((hyperv_features &
+            (CPUID_HV_MSR_TIME_REFCNT | CPUID_HV_MSR_REFERENCE_TSC)) !=
+           (CPUID_HV_MSR_TIME_REFCNT | CPUID_HV_MSR_REFERENCE_TSC) ||
+           (cpu_feature & CPUID_SSE2) == 0)    /* SSE2 for mfence/lfence */
+               return;
+
+       switch (cpu_vendor_id) {
+       case CPU_VENDOR_AMD:
+               hyperv_tsc_timecounter.tc_get_timecount =
+                   hyperv_tsc_timecount_mfence;
+               break;
+
+       case CPU_VENDOR_INTEL:
+               hyperv_tsc_timecounter.tc_get_timecount =
+                   hyperv_tsc_timecount_lfence;
+               break;
+
+       default:
+               /* Unsupport CPU vendors. */
+               return;
+       }
+
+       hyperv_ref_tsc.tsc_ref = hyperv_dmamem_alloc(NULL, PAGE_SIZE, 0,
+           sizeof(struct hyperv_reftsc), &hyperv_ref_tsc.tsc_ref_dma,
+           BUS_DMA_WAITOK | BUS_DMA_ZERO);
+       if (hyperv_ref_tsc.tsc_ref == NULL) {
+               printf("hyperv: reftsc page allocation failed\n");
+               return;
+       }
+
+       orig = rdmsr(MSR_HV_REFERENCE_TSC);
+       val = MSR_HV_REFTSC_ENABLE | (orig & MSR_HV_REFTSC_RSVD_MASK) |
+           ((hyperv_ref_tsc.tsc_ref_dma.hv_paddr >> PAGE_SHIFT) <<
+            MSR_HV_REFTSC_PGSHIFT);
+       wrmsr(MSR_HV_REFERENCE_TSC, val);
+
+       /* Register "enlightened" timecounter. */
+       tc_init(&hyperv_tsc_timecounter);
+
+       /* Add device for mmap(2). */
+       make_dev(&hyperv_tsc_cdevsw, 0, UID_ROOT, GID_WHEEL, 0444,
+           HYPERV_REFTSC_DEVNAME);
+}
+SYSINIT(hyperv_tsc_init, SI_SUB_DRIVERS, SI_ORDER_FIRST, hyperv_tsc_tcinit,
+    NULL);

Modified: stable/10/sys/dev/hyperv/vmbus/hyperv_reg.h
==============================================================================
--- stable/10/sys/dev/hyperv/vmbus/hyperv_reg.h Wed Jan  4 01:44:45 2017        
(r311222)
+++ stable/10/sys/dev/hyperv/vmbus/hyperv_reg.h Wed Jan  4 01:58:38 2017        
(r311223)
@@ -57,6 +57,11 @@
 
 #define MSR_HV_VP_INDEX                        0x40000002
 
+#define MSR_HV_REFERENCE_TSC           0x40000021
+#define MSR_HV_REFTSC_ENABLE           0x0001ULL
+#define MSR_HV_REFTSC_RSVD_MASK                0x0ffeULL
+#define MSR_HV_REFTSC_PGSHIFT          12
+
 #define MSR_HV_SCONTROL                        0x40000080
 #define MSR_HV_SCTRL_ENABLE            0x0001ULL
 #define MSR_HV_SCTRL_RSVD_MASK         0xfffffffffffffffeULL
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