On Wed, May 09, 2018 at 04:11:39PM +0100, Roger Pau Monné wrote: > On Wed, May 09, 2018 at 12:30:16PM +0100, Roger Pau Monné wrote: > > On Wed, May 09, 2018 at 11:56:40AM +0100, Andrew Cooper wrote: > > > On 09/05/18 11:21, Roger Pau Monne wrote: > > > I'm not sure that setting the default MTRR type is going to be a > > > clever idea in hindsight when we come to doing PCI Passthrough support. > > > > Setting the default type to WB is also set by hvmloader, it's just > > that hvmloader also sets some of the fixed and variable ranges to UC > > in order to cover the iomem areas. > > > > The expectations when doing pci-passthrough is that the guest will > > always use paging and PAT in order to set the appropriate cache > > attributes, or else the guest itself will have to program the UC MTRR > > ranges, I admit that's not very nice however. > > > > What about enabling the default MTRR type and setting it to WB in the > > toolstack for PVH? IMO doing it Xen itself would be wrong. > > I have the following patch to set the default MTRR type, but I think > if we go down this road then we will also have to set UC MTRRs for > MMIO areas, which again seems fine to me. >
Can you please document the default type(s) to pvh.markdown once the issue is resolved? Wei.
