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KVM: x86: reorganize pvclock_gtod_data members
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We will need a copy of tk->offs_boot in the next patch.  Store it and
cleanup the struct: instead of storing tk->tkr_xxx.base with the tk->offs_boot
included, store the raw value in struct pvclock_clock and sum it in
do_monotonic_raw and do_realtime.   tk->tkr_xxx.xtime_nsec also moves
to struct pvclock_clock.

While at it, fix a (usually harmless) typo in do_monotonic_raw, which
was using gtod->clock.shift instead of gtod->raw_clock.shift.

Fixes: 53fafdb ("KVM: x86: switch KVMCLOCK base to monotonic raw clock")
Cc: stable@vger.kernel.org
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Paolo Bonzini committed Feb 5, 2020
1 parent 33aabd0 commit 917f947
Showing 1 changed file with 12 additions and 17 deletions.
29 changes: 12 additions & 17 deletions arch/x86/kvm/x86.c
Original file line number Diff line number Diff line change
Expand Up @@ -1610,6 +1610,8 @@ struct pvclock_clock {
u64 mask;
u32 mult;
u32 shift;
u64 base_cycles;
u64 offset;
};

struct pvclock_gtod_data {
Expand All @@ -1618,22 +1620,15 @@ struct pvclock_gtod_data {
struct pvclock_clock clock; /* extract of a clocksource struct */
struct pvclock_clock raw_clock; /* extract of a clocksource struct */

u64 boot_ns_raw;
u64 boot_ns;
u64 nsec_base;
ktime_t offs_boot;
u64 wall_time_sec;
u64 monotonic_raw_nsec;
};

static struct pvclock_gtod_data pvclock_gtod_data;

static void update_pvclock_gtod(struct timekeeper *tk)
{
struct pvclock_gtod_data *vdata = &pvclock_gtod_data;
u64 boot_ns, boot_ns_raw;

boot_ns = ktime_to_ns(ktime_add(tk->tkr_mono.base, tk->offs_boot));
boot_ns_raw = ktime_to_ns(ktime_add(tk->tkr_raw.base, tk->offs_boot));

write_seqcount_begin(&vdata->seq);

Expand All @@ -1643,20 +1638,20 @@ static void update_pvclock_gtod(struct timekeeper *tk)
vdata->clock.mask = tk->tkr_mono.mask;
vdata->clock.mult = tk->tkr_mono.mult;
vdata->clock.shift = tk->tkr_mono.shift;
vdata->clock.base_cycles = tk->tkr_mono.xtime_nsec;
vdata->clock.offset = tk->tkr_mono.base;

vdata->raw_clock.vclock_mode = tk->tkr_raw.clock->archdata.vclock_mode;
vdata->raw_clock.cycle_last = tk->tkr_raw.cycle_last;
vdata->raw_clock.mask = tk->tkr_raw.mask;
vdata->raw_clock.mult = tk->tkr_raw.mult;
vdata->raw_clock.shift = tk->tkr_raw.shift;

vdata->boot_ns = boot_ns;
vdata->nsec_base = tk->tkr_mono.xtime_nsec;
vdata->raw_clock.base_cycles = tk->tkr_raw.xtime_nsec;
vdata->raw_clock.offset = tk->tkr_raw.base;

vdata->wall_time_sec = tk->xtime_sec;

vdata->boot_ns_raw = boot_ns_raw;
vdata->monotonic_raw_nsec = tk->tkr_raw.xtime_nsec;
vdata->offs_boot = tk->offs_boot;

write_seqcount_end(&vdata->seq);
}
Expand Down Expand Up @@ -2126,10 +2121,10 @@ static int do_monotonic_raw(s64 *t, u64 *tsc_timestamp)

do {
seq = read_seqcount_begin(&gtod->seq);
ns = gtod->monotonic_raw_nsec;
ns = gtod->raw_clock.base_cycles;
ns += vgettsc(&gtod->raw_clock, tsc_timestamp, &mode);
ns >>= gtod->clock.shift;
ns += gtod->boot_ns_raw;
ns >>= gtod->raw_clock.shift;
ns += ktime_to_ns(ktime_add(gtod->raw_clock.offset, gtod->offs_boot));
} while (unlikely(read_seqcount_retry(&gtod->seq, seq)));
*t = ns;

Expand All @@ -2146,7 +2141,7 @@ static int do_realtime(struct timespec64 *ts, u64 *tsc_timestamp)
do {
seq = read_seqcount_begin(&gtod->seq);
ts->tv_sec = gtod->wall_time_sec;
ns = gtod->nsec_base;
ns = gtod->clock.base_cycles;
ns += vgettsc(&gtod->clock, tsc_timestamp, &mode);
ns >>= gtod->clock.shift;
} while (unlikely(read_seqcount_retry(&gtod->seq, seq)));
Expand Down

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