On 4/3/23 07:05, Lai Jiangshan wrote: > 2.3 #VE > ------- > > The approach for fixing the kernel mode #VE recursion issue is to just > NOT use IST for #VE although #VE is also considered to be one of the > super exceptions and had raised some worries: > https://lore.kernel.org/lkml/YCEQiDNSHTGBXBcj@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/ > https://lore.kernel.org/lkml/CALCETrU9XypKbj-TrXLB3CPW6=MZ__5ifLz0ckbB=c=Myegn9Q@xxxxxxxxxxxxxx/ > https://lore.kernel.org/lkml/1843debc-05e8-4d10-73e4-7ddce3b3eae2@xxxxxxxxx/ > > To remit the worries, SEPT_VE_DISABLE is forced used currently and > also disables its abilities (accept-on-demand or memory balloon which > is critical to lightweight VMs like Kata Containers): > https://lore.kernel.org/lkml/YCb0%2FDg28uI7TRD%2F@xxxxxxxxxx/ You don't need #VE for accept-on-demand. Pages go through _very_ well-defined software choke points before they get used *and* before they get ballooned. Thus: > https://lore.kernel.org/lkml/20230330114956.20342-3-kirill.shutemov@xxxxxxxxxxxxxxx/ BTW, _who_ considers #VE to be a "super exception"? Can you explain how it is any more "super" than #PF? #PF can recurse. You can take #PF in the entry paths. I kinda don't think you should be using TDX and #VE as part of the justification for this series.
