diff options
| author | Glauber Costa <glommer@redhat.com> | 2010-05-11 20:17:39 +0400 |
|---|---|---|
| committer | Avi Kivity <avi@redhat.com> | 2010-05-19 12:40:59 +0400 |
| commit | 424c32f1aa3112632a657d45698c8e7666668f78 (patch) | |
| tree | c63fd6d83b6f2cbcb979b3f55c9a07425b13053f /arch/x86 | |
| parent | b69e8caef5b190af48c525f6d715e7b7728a77f6 (diff) | |
| download | linux-424c32f1aa3112632a657d45698c8e7666668f78.tar.xz | |
x86, paravirt: Enable pvclock flags in vcpu_time_info structure
This patch removes one padding byte and transform it into a flags
field. New versions of guests using pvclock will query these flags
upon each read.
Flags, however, will only be interpreted when the guest decides to.
It uses the pvclock_valid_flags function to signal that a specific
set of flags should be taken into consideration. Which flags are valid
are usually devised via HV negotiation.
Signed-off-by: Glauber Costa <glommer@redhat.com>
CC: Jeremy Fitzhardinge <jeremy@goop.org>
Acked-by: Zachary Amsden <zamsden@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/include/asm/pvclock-abi.h | 3 | ||||
| -rw-r--r-- | arch/x86/include/asm/pvclock.h | 1 | ||||
| -rw-r--r-- | arch/x86/kernel/pvclock.c | 9 |
3 files changed, 12 insertions, 1 deletions
diff --git a/arch/x86/include/asm/pvclock-abi.h b/arch/x86/include/asm/pvclock-abi.h index 6d93508f2626..ec5c41ac4bef 100644 --- a/arch/x86/include/asm/pvclock-abi.h +++ b/arch/x86/include/asm/pvclock-abi.h @@ -29,7 +29,8 @@ struct pvclock_vcpu_time_info { u64 system_time; u32 tsc_to_system_mul; s8 tsc_shift; - u8 pad[3]; + u8 flags; + u8 pad[2]; } __attribute__((__packed__)); /* 32 bytes */ struct pvclock_wall_clock { diff --git a/arch/x86/include/asm/pvclock.h b/arch/x86/include/asm/pvclock.h index 53235fd5f8ce..cd02f324aa6b 100644 --- a/arch/x86/include/asm/pvclock.h +++ b/arch/x86/include/asm/pvclock.h @@ -6,6 +6,7 @@ /* some helper functions for xen and kvm pv clock sources */ cycle_t pvclock_clocksource_read(struct pvclock_vcpu_time_info *src); +void pvclock_set_flags(u8 flags); unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src); void pvclock_read_wallclock(struct pvclock_wall_clock *wall, struct pvclock_vcpu_time_info *vcpu, diff --git a/arch/x86/kernel/pvclock.c b/arch/x86/kernel/pvclock.c index 03801f2f761f..f7fdd56bc0ab 100644 --- a/arch/x86/kernel/pvclock.c +++ b/arch/x86/kernel/pvclock.c @@ -31,8 +31,16 @@ struct pvclock_shadow_time { u32 tsc_to_nsec_mul; int tsc_shift; u32 version; + u8 flags; }; +static u8 valid_flags __read_mostly = 0; + +void pvclock_set_flags(u8 flags) +{ + valid_flags = flags; +} + /* * Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction, * yielding a 64-bit result. @@ -91,6 +99,7 @@ static unsigned pvclock_get_time_values(struct pvclock_shadow_time *dst, dst->system_timestamp = src->system_time; dst->tsc_to_nsec_mul = src->tsc_to_system_mul; dst->tsc_shift = src->tsc_shift; + dst->flags = src->flags; rmb(); /* test version after fetching data */ } while ((src->version & 1) || (dst->version != src->version)); |