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authorGlauber Costa <glommer@redhat.com>2010-05-11 12:17:39 -0400
committerAvi Kivity <avi@redhat.com>2010-05-19 11:40:59 +0300
commit424c32f1aa3112632a657d45698c8e7666668f78 (patch)
treec63fd6d83b6f2cbcb979b3f55c9a07425b13053f /arch/x86/kernel/pvclock.c
parentb69e8caef5b190af48c525f6d715e7b7728a77f6 (diff)
downloadop-kernel-dev-424c32f1aa3112632a657d45698c8e7666668f78.zip
op-kernel-dev-424c32f1aa3112632a657d45698c8e7666668f78.tar.gz
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/kernel/pvclock.c')
-rw-r--r--arch/x86/kernel/pvclock.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/arch/x86/kernel/pvclock.c b/arch/x86/kernel/pvclock.c
index 03801f2..f7fdd56 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));
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