mirror of https://lore.kernel.org/lkml/
 help / color / mirror / Atom feed
From: Paolo Bonzini <pbonzini@redhat.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: kbusch@kernel.org, chang.seok.bae@intel.com
Subject: [PATCH 00/10] KVM: emulate: enable AVX moves
Date: Thu, 13 Nov 2025 19:36:23 -0500	[thread overview]
Message-ID: <20251114003633.60689-1-pbonzini@redhat.com> (raw)

Over a year ago, Keith Busch posted an RFC patch to enable VMOVDQA
and VMOVDQU instructions in the KVM emulator.  The reason to do so
is that people are using QEMU to emulate fancy devices whose drivers
use those instructions with BARs that, on real hardware, would
presumably support write combining.  These same people obviously
would appreciate being able to use KVM instead of emulation, hence
the request.

The original patch was not bad at all, but missed a few details:

- checking in XCR0 if AVX is enabled (which also protects against
  *hosts* with AVX disabled)

- 32-bit support

- clearing the high bytes of AVX registers if VEX.L=0

- checking some invalid prefix combinations

The ugly parts are in patch 7, which has to juggle the fact that the
same instruction can decode to SSE and AVX, and we only know which are
valid after all the groups are handled.

While at it I also included a small refactoring taken out of the
APX series, by Chang S. Bae, some cleanups, and an extra MOVNTDQ
instruction.

Paolo

Chang S. Bae (1):
  KVM: x86: Refactor REX prefix handling in instruction emulation

Paolo Bonzini (9):
  KVM: emulate: add MOVNTDQA
  KVM: emulate: move Src2Shift up one bit
  KVM: emulate: improve formatting of flags table
  KVM: emulate: move op_prefix to struct x86_emulate_ctxt
  KVM: emulate: share common register decoding code
  KVM: emulate: add get_xcr callback
  KVM: emulate: add AVX support to register fetch and writeback
  KVM: emulate: decode VEX prefix
  KVM: emulate: enable AVX moves

 arch/x86/kvm/emulate.c     | 320 ++++++++++++++++++++++++++-----------
 arch/x86/kvm/fpu.h         |  62 +++++++
 arch/x86/kvm/kvm_emulate.h |  20 ++-
 arch/x86/kvm/x86.c         |   9 ++
 4 files changed, 311 insertions(+), 100 deletions(-)

-- 
2.43.5


             reply	other threads:[~2025-11-14  0:36 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-11-14  0:36 Paolo Bonzini [this message]
2025-11-14  0:36 ` [PATCH 01/10] KVM: emulate: add MOVNTDQA Paolo Bonzini
2025-11-14  0:36 ` [PATCH 02/10] KVM: emulate: move Src2Shift up one bit Paolo Bonzini
2025-11-17 19:51   ` Chang S. Bae
2025-11-14  0:36 ` [PATCH 03/10] KVM: emulate: improve formatting of flags table Paolo Bonzini
2025-11-17 19:53   ` Chang S. Bae
2025-11-14  0:36 ` [PATCH 04/10] KVM: emulate: move op_prefix to struct x86_emulate_ctxt Paolo Bonzini
2025-11-17 19:54   ` Chang S. Bae
2025-11-14  0:36 ` [PATCH 05/10] KVM: emulate: share common register decoding code Paolo Bonzini
2025-11-17 19:55   ` Chang S. Bae
2025-11-14  0:36 ` [PATCH 06/10] KVM: emulate: add get_xcr callback Paolo Bonzini
2025-11-17 19:56   ` Chang S. Bae
2025-11-14  0:36 ` [PATCH 07/10] KVM: emulate: add AVX support to register fetch and writeback Paolo Bonzini
2025-11-14 17:06   ` kernel test robot
2025-11-14 20:10   ` kernel test robot
2025-11-14  0:36 ` [PATCH 08/10] KVM: x86: Refactor REX prefix handling in instruction emulation Paolo Bonzini
2025-11-17 19:56   ` Chang S. Bae
2025-11-14  0:36 ` [PATCH 09/10] KVM: emulate: decode VEX prefix Paolo Bonzini
2025-11-14  0:36 ` [PATCH 10/10] KVM: emulate: enable AVX moves Paolo Bonzini
2025-11-14  0:51 ` [PATCH 00/10] " Keith Busch
2025-11-17 19:57 ` Chang S. Bae
2025-11-21 18:55 ` Sean Christopherson

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20251114003633.60689-1-pbonzini@redhat.com \
    --to=pbonzini@redhat.com \
    --cc=chang.seok.bae@intel.com \
    --cc=kbusch@kernel.org \
    --cc=kvm@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox

all inboxes | Powered by JetHome®