[0/3] powerpc/kvm: Enable HV KVM guests to use prefixed instructions to access emulated MMIO

Message

Paul Mackerras March 8, 2023, 6:33 a.m. UTC

This series changes the powerpc KVM code so that HV KVM can fetch
prefixed instructions from the guest in those situations where there
is a need to emulate an instruction, which for HV KVM means emulating
loads and stores to emulated MMIO devices.  (Prefixed instructions
were introduced with POWER10 and Power ISA v3.1, and consist of two
32-bit words, called the prefix and the suffix.)

The instruction analysis code in arch/powerpc/lib/sstep.c has already
been extended to handle prefixed loads and stores, so all we have to
do in HV KVM is to fetch the suffix when necessary and pass it to
analyse_instr().

Since PR KVM doesn't yet handle prefixed instructions, we disable PR
KVM guests from using prefixed instructions (this is done using the
FSCR).

Paul.

 arch/powerpc/include/asm/kvm_host.h      |  4 ++--
 arch/powerpc/include/asm/kvm_ppc.h       | 37 +++++++++++++++++++++++---------
 arch/powerpc/include/asm/reg.h           |  1 +
 arch/powerpc/kvm/book3s.c                | 32 ++++++++++++++++++++++-----
 arch/powerpc/kvm/book3s_64_mmu_hv.c      | 26 ++++++++++++++++------
 arch/powerpc/kvm/book3s_hv.c             | 24 ++++++++++++++-------
 arch/powerpc/kvm/book3s_hv_rmhandlers.S  |  6 +++---
 arch/powerpc/kvm/book3s_paired_singles.c |  4 +++-
 arch/powerpc/kvm/book3s_pr.c             | 22 ++++++++++---------
 arch/powerpc/kvm/book3s_rmhandlers.S     |  1 +
 arch/powerpc/kvm/booke.c                 | 12 +++++++----
 arch/powerpc/kvm/bookehv_interrupts.S    |  2 +-
 arch/powerpc/kvm/e500_mmu_host.c         |  4 ++--
 arch/powerpc/kvm/emulate.c               |  8 ++++++-
 arch/powerpc/kvm/emulate_loadstore.c     |  8 +++----
 arch/powerpc/kvm/powerpc.c               |  4 ++--
 16 files changed, 136 insertions(+), 59 deletions(-)

Comments

Michael Ellerman April 6, 2023, 12:34 a.m. UTC | #1

On Wed, 08 Mar 2023 17:33:43 +1100, Paul Mackerras wrote:
> This series changes the powerpc KVM code so that HV KVM can fetch
> prefixed instructions from the guest in those situations where there
> is a need to emulate an instruction, which for HV KVM means emulating
> loads and stores to emulated MMIO devices.  (Prefixed instructions
> were introduced with POWER10 and Power ISA v3.1, and consist of two
> 32-bit words, called the prefix and the suffix.)
> 
> [...]

Applied to powerpc/topic/ppc-kvm.

[1/3] powerpc/kvm: Make kvmppc_get_last_inst() produce a ppc_inst_t
      https://git.kernel.org/powerpc/c/acf17878da680a0c11c0bcb8a54b4f676ff39c80
[2/3] powerpc/kvm: Fetch prefixed instructions from the guest
      https://git.kernel.org/powerpc/c/953e37397fb61be61f095d36972188bac5235021
[3/3] powerpc/kvm: Enable prefixed instructions for HV KVM and disable for PR KVM
      https://git.kernel.org/powerpc/c/a3800ef9c48c4497dafe5ede1b65d91d9ef9cf1e

cheers