Re: [PATCH] kvmclock: Ensure time in migration never goes backward

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 




On 06.05.14 01:31, Marcelo Tosatti wrote:
On Mon, May 05, 2014 at 08:23:43PM -0300, Marcelo Tosatti wrote:
Hi Alexander,

On Mon, May 05, 2014 at 03:51:22PM +0200, Alexander Graf wrote:
When we migrate we ask the kernel about its current belief on what the guest
time would be.
KVM_GET_CLOCK which returns the time in "struct kvm_clock_data".

However, I've seen cases where the kvmclock guest structure
indicates a time more recent than the kvm returned time.
This should not happen because the value returned by KVM_GET_CLOCK
(get_kernel_ns() + kvmclock_offset) should be relatively in sync
with what is seen in the guest via kvmclock read.


Yes, and it isn't. Any ideas why it's not? This patch really just uses the guest visible kvmclock time rather than the host view of it on migration.

There is definitely something very broken on the host's side since it does return a smaller time than the guest exposed interface indicates.


Alex

--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html




[Index of Archives]     [KVM ARM]     [KVM ia64]     [KVM ppc]     [Virtualization Tools]     [Spice Development]     [Libvirt]     [Libvirt Users]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite Questions]     [Linux Kernel]     [Linux SCSI]     [XFree86]
  Powered by Linux