x86/hyper-v: Use cheaper HVCALL_FLUSH_VIRTUAL_ADDRESS_{LIST,SPACE} hypercalls when possible

While working on Hyper-V style PV TLB flush support in KVM I noticed that
real Windows guests use TLB flush hypercall in a somewhat smarter way:

  When the flush needs to be performed on a subset of first 64 vCPUs or on
  all present vCPUs Windows avoids more expensive hypercalls which support
  sparse CPU sets and uses their 'cheap' counterparts.

This means that HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED name is actually a
misnomer: EX hypercalls (which support sparse CPU sets) are "available",
not "recommended". This makes sense as they are actually harder to parse.

Nothing stops us from being equally 'smart' in Linux too. Switch to doing
cheaper hypercalls whenever possible.

Signed-off-by: Vitaly Kuznetsov <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Michael Kelley <[email protected]>
Cc: "K. Y. Srinivasan" <[email protected]>
Cc: Haiyang Zhang <[email protected]>
Cc: Stephen Hemminger <[email protected]>
Cc: "Michael Kelley (EOSG)" <[email protected]>
Cc: Tianyu Lan <[email protected]>
Cc: [email protected]
Cc: "H. Peter Anvin" <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

0 files changed, 0 insertions, 0 deletions