[0/2] x86/vmx: Don't crash guests when there is no model-specific LBRs available

Message

Andrew Cooper Jan. 9, 2023, 12:08 p.m. UTC

This is the minimum bodge required to stop guests crashing on Sapphire Rapids
hardware.

Note that both Arch LBR and safely (in terms of migration) enumerating
PDCM/MSR_PERF_CAPS depend on improved MSR levelling support which is still not
yet complete.

i.e. We cannot do the second half (enumerating LBR_FORMAT=0x3f) yet because
we'll make it more likely for VMs to crash in migrate.

Andrew Cooper (2):
  x86/vmx: Calculate model-specific LBRs once at start of day
  x86/vmx: Support for CPUs without model-specific LBR

 xen/arch/x86/hvm/vmx/vmx.c | 307 +++++++++++++++++++++++----------------------
 1 file changed, 155 insertions(+), 152 deletions(-)