vmx: fix save/restore issue with apicv

vmx: fix save/restore issue with apicv

This patch fixes two issues:

1. Interrupts on PIR are lost during save/restore. Syncing the PIR
into IRR during save will fix it.

2. EOI exit bitmap doesn't set up correctly after restore. Here we
will construct the eoi exit bitmap via (IRR | ISR). Though it may cause
unnecessary eoi exit of the interrupts that pending in IRR or ISR during
save/restore, each pending interrupt only causes one vmexit. The
subsequent interrupts will adjust the eoi exit bitmap correctly. So
the performance hurt can be ignored.

Signed-off-by: Yang Zhang <yang.z.zhang@Intel.com>
Signed-off-by: Olaf Hering <olaf@aepfle.de>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>