Re: [PATCH v2 6/7] don't compute pvclock adjustments if we trustthe tsc

From: Avi Kivity
Date: Wed May 05 2010 - 04:28:20 EST


On 05/03/2010 06:52 PM, Glauber Costa wrote:
If the HV told us we can fully trust the TSC, skip any
correction


Signed-off-by: Glauber Costa<glommer@xxxxxxxxxx>
---
arch/x86/include/asm/kvm_para.h | 5 +++++
arch/x86/include/asm/pvclock-abi.h | 1 +
arch/x86/kernel/kvmclock.c | 3 +++
arch/x86/kernel/pvclock.c | 4 ++++
4 files changed, 13 insertions(+), 0 deletions(-)

diff --git a/arch/x86/include/asm/kvm_para.h b/arch/x86/include/asm/kvm_para.h
index f019f8c..6f1b878 100644
--- a/arch/x86/include/asm/kvm_para.h
+++ b/arch/x86/include/asm/kvm_para.h
@@ -21,6 +21,11 @@
*/
#define KVM_FEATURE_CLOCKSOURCE2 3

+/* The last 8 bits are used to indicate how to interpret the flags field
+ * in pvclock structure. If no bits are set, all flags are ignored.
+ */
+#define KVM_FEATURE_CLOCKSOURCE_STABLE_TSC 24

This needs documentation (in cpuid.txt). The flag doesn't mean the TSC is stable, rather it means the pvclock tsc stable bit is valid.


--
error compiling committee.c: too many arguments to function

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