KVM: nVMX: Precisely mark vAPIC and PID maps dirty when delivering nested PI

KVM: nVMX: Precisely mark vAPIC and PID maps dirty when delivering nested PI

Explicitly mark the vmcs12 vAPIC and PI descriptor pages as dirty when
delivering a nested posted interrupt instead of marking all vmcs12 pages
as dirty.  This will allow marking the APIC access page (and any future
 vmcs12 pages) as dirty in nested_mark_vmcs12_pages_dirty() without over-
dirtying in the nested PI case.  Manually marking the vAPIC and PID pages
as dirty also makes the flow a bit more self-documenting, e.g. it's not
obvious at first glance that vmx->nested.pi_desc is actually a host kernel
mapping of a vmcs12 page.

No functional change intended.

Link: https://patch.msgid.link/20251121223444.355422-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>