Message ID | cover.1569833766.git.hongyax@amazon.com (mailing list archive) |
---|---|
Headers | show |
Series | Switch to domheap for Xen PTEs | expand |
On Mon, Sep 30, 2019 at 11:32:52AM +0100, Hongyan Xia wrote: > This series is mostly Wei's effort to switch from xenheap to domheap for > Xen page tables. In addition, I have also merged several bug fixes from > my "Remove direct map from Xen" series [1]. As the title suggests, this > series switches from xenheap to domheap for Xen PTEs. > > This is needed to achieve the ultimate goal of removing the > always-mapped direct map from Xen. To work without an always-mapped > direct map, Xen PTE manipulations themselves must not rely on it. > Unfortunately, PTE APIs currently use the xenheap that does not work > without the direct map. By switching to domheap APIs, it is much easier > for us to break the reliance on the direct map later on, not only for > PTEs but for all other memory allocations as well. > > I have broken down the direct map removal series into two. This series > is the first batch. The patches change the life cycle of Xen PTEs from > alloc-free to alloc-map-unmap-free, which means PTEs must be explicitly > mapped and unmapped. This also makes sense to be the first batch from a > stability PoV, since this is just an API change and the direct map has > not been actually removed. Further, the map and unmap in the release > build use the direct map as a fast path, so there is also no performance > degredation in a release build. > > I have tested both debug and release build on bare-metal and nested > virtualisation. I am able to run PV and HVM guests and XTF tests without > crashes so far on x86. I am able to build on AArch64. > > This series is at https://xenbits.xen.org/git-http/people/hx242/xen.git, > xen_pte_map branch. > > --- > Changed since v1: > - squash some commits > - merge bug fixes into this first batch > - rebase against latest master FYI in the future it is better to rebase against staging. Wei.