On 05/27/2010 06:02 AM, Glauber Costa wrote:
On Thu, May 27, 2010 at 11:15:43AM +0300, Avi Kivity wrote:
On 05/26/2010 09:04 PM, Glauber Costa wrote:
This patch adds a file that documents the usage of KVM-specific
MSRs.
Looks good. A few comments:
+
+Custom MSR list
+--------
+
+The current supported Custom MSR list is:
+
+MSR_KVM_WALL_CLOCK: 0x11
+
+ data: physical address of a memory area.
Which must be in guest RAM (i.e., don't point it somewhere random
and expect the hypervisor to allocate it for you).
Must be aligned to 4 bytes (we don't enforce it though).
I don't see the reason for it.
If this is a requirement, our own implementation
is failing to meet it.
It's so the atomic write actually is atomic. Stating a 4 -byte
alignment requirement prevents the wall clock from crossing a page boundary.
Zach
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