On 19/2/25 10:51, Jason Gunthorpe wrote:
On Wed, Feb 19, 2025 at 10:35:28AM +1100, Alexey Kardashevskiy wrote:
With in-place conversion, we could map the entire guest once in the HV IOMMU
and control the Cbit via the guest's IOMMU table (when available). Thanks,
Isn't it more complicated than that? I understood you need to have a
IOPTE boundary in the hypervisor at any point where the guest Cbit
changes - so you can't just dump 1G hypervisor pages to cover the
whole VM, you have to actively resize ioptes?
When the guest Cbit changes, only AMD RMP table requires update but not
necessaryly NPT or IOPTEs.
(I may have misunderstood the question, what meaning does "dump 1G
pages" have?).
This was the whole motivation to adding the page size override kernel
command line.
Jason
--
Alexey
