On Mon, Apr 27, 2020 at 11:12:35AM +0100, Wei Liu wrote: > On Thu, Apr 23, 2020 at 06:33:49PM +0200, Jan Beulich wrote: > > On 23.04.2020 16:56, Roger Pau Monne wrote: > > > Introduce a specific flag to request a HVM guest linear TLB flush, > > > which is an ASID/VPID tickle that forces a guest linear to guest > > > physical TLB flush for all HVM guests. > > > > > > This was previously unconditionally done in each pre_flush call, but > > > that's not required: HVM guests not using shadow don't require linear > > > TLB flushes as Xen doesn't modify the pages tables the guest runs on > > > in that case (ie: when using HAP). Note that shadow paging code > > > already takes care of issuing the necessary flushes when the shadow > > > page tables are modified. > > > > > > In order to keep the previous behavior modify all shadow code TLB > > > flushes to also flush the guest linear to physical TLB if the guest is > > > HVM. I haven't looked at each specific shadow code TLB flush in order > > > to figure out whether it actually requires a guest TLB flush or not, > > > so there might be room for improvement in that regard. > > > > > > Also perform ASID/VPID flushes when modifying the p2m tables as it's a > > > requirement for AMD hardware. Finally keep the flush in > > > switch_cr3_cr4, as it's not clear whether code could rely on > > > switch_cr3_cr4 also performing a guest linear TLB flush. A following > > > patch can remove the ASID/VPID tickle from switch_cr3_cr4 if found to > > > not be necessary. > > > > > > Signed-off-by: Roger Pau Monné <roger....@citrix.com> > > > > Reviewed-by: Jan Beulich <jbeul...@suse.com> > > > > Tim, ICYMI, this patch needs your ack.
Let me put Tim on the To: field, more likely to raise attention. Roger.
