[v2,0/8] KVM: x86: vcpu->arch.pio* cleanups

Message

Paolo Bonzini June 24, 2022, 5:18 p.m. UTC

These patches complete the job started by commit 3b27de271839 ("KVM:
x86: split the two parts of emulator_pio_in", 2021-10-22).  The commit
message eloquently said that emulator_pio_in_out "currently hardcodes
vcpu->arch.pio_data as the source/destination buffer, which sucks but
will be fixed after the more severe SEV-ES buffer overflow".  Some time
has passed and it's high time to do it.

After this series, in-kernel PIO does not use vcpu->arch.pio* anymore;
it is only used by complete_emulator_pio_in.

Paolo

v1->v2:
- split out "KVM: x86: complete fast IN directly with complete_emulator_pio_in()"
- remove WARN if emulated PIO performs successful in-kernel iterations before
  falling back to userspace, it is (unfortunately) valid if SRCU changes mid-loop.
- new patch 3 to handle unregistered devices mid-loop, dropping writes and reading
  as zero
- WARN if non-NULL data is passed to emulator_pio_in_out() before the code is
  ready to handle in-kernel PIO without vcpu->arch.pio*
- use "size" in SEV case instead of vcpu->arch.pio_size

Paolo Bonzini (8):
  KVM: x86: complete fast IN directly with complete_emulator_pio_in()
  KVM: x86: inline kernel_pio into its sole caller
  KVM: x86: drop PIO from unregistered devices
  KVM: x86: move all vcpu->arch.pio* setup in emulator_pio_in_out()
  KVM: x86: wean in-kernel PIO from vcpu->arch.pio*
  KVM: x86: wean fast IN from emulator_pio_in
  KVM: x86: de-underscorify __emulator_pio_in
  KVM: SEV-ES: reuse advance_sev_es_emulated_ins for OUT too

 arch/x86/kvm/trace.h |   2 +-
 arch/x86/kvm/x86.c   | 133 ++++++++++++++++++++-----------------------
 2 files changed, 62 insertions(+), 73 deletions(-)