forked from torvalds/linux
-
Notifications
You must be signed in to change notification settings - Fork 23
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
clocksource: arm_arch_timer: Use pvtime LPT
Enable paravirtualized time to be used in a KVM guest if the host supports it. This allows the guest to derive a counter which is clocked at a persistent rate even when the guest is migrated. If we discover that the system supports SMCCC v1.1 then we probe to determine whether the hypervisor supports paravirtualized features and finally whether it supports "Live Physical Time" reporting. If so a shared structure is made available to the guest containing coefficients to calculate the derived clock. The guest kernel uses the coefficients to present a clock to user space that is always clocked at the same rate whenever the guest is running ('live'), even if the physical clock changes (due to the guest being migrated). The existing workaround framework for CNTVCT is used to trap user space accesses to the timer registers so we can present the derived clock. Signed-off-by: Steven Price <steven.price@arm.com> Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
- Loading branch information
1 parent
7cdd1e7
commit 47f3527
Showing
2 changed files
with
204 additions
and
34 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Oops, something went wrong.