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* [PATCH 0/4] KVM: TDX: Cleanup the kvm_x86_ops structure for vmx/tdx
@ 2025-03-13 19:30 Vishal Verma
  2025-03-13 19:30 ` [PATCH 1/4] KVM: TDX: Move apicv_pre_state_restore to posted_intr.c Vishal Verma
                   ` (3 more replies)
  0 siblings, 4 replies; 8+ messages in thread
From: Vishal Verma @ 2025-03-13 19:30 UTC (permalink / raw)
  To: Sean Christopherson, Paolo Bonzini
  Cc: kvm, linux-kernel, Rick Edgecombe, Vishal Verma

This is a cleanup that should follow the initial TDX base support (i.e.
not an immediate fix needed for kvm-coco-queue).

In [1], Sean points out that the kvm_x86_ops structure and its
associated helpers and wrappers can be cleaned up a lot by -

1. Putting the wrappers under CONFIG_KVM_INTEL_TDX, and
2. Defining the helpers with macros that switch between the tdx and
   non-tdx case, as well as NULL out the TDX-only stubs when needed.

This cleans up the generated code by completely removing trampolines
that would otherwise be left behind in the CONFIG_KVM_INTEL_TDX=n case.

[1]: https://lore.kernel.org/kvm/Z6v9yjWLNTU6X90d@google.com/

For example, looking at vt_refresh_apicv_exec_ctrl(), before this cleanup,
when CONFIG_KVM_INTEL_TDX=n, the following asm is generated:

0000000000036490 <vt_refresh_apicv_exec_ctrl>:
   36490:       f3 0f 1e fa             endbr64
   36494:       e8 00 00 00 00          call   36499 <vt_refresh_apicv_exec_ctrl+0x9>
                        36495: R_X86_64_PLT32   __fentry__-0x4
   36499:       e9 00 00 00 00          jmp    3649e <vt_refresh_apicv_exec_ctrl+0xe>
                        3649a: R_X86_64_PLT32   vmx_refresh_apicv_exec_ctrl-0x4
   3649e:       66 90                   xchg   %ax,%ax

But with these patches, it goes away completely.

These patches have been tested with TDX kvm-unit-tests, booting a Linux
TD, TDX enhanced KVM selftests, and building and examining the generated
assembly (or lack thereof) with both CONFIG_KVM_INTEL_TDX=y and
CONFIG_KVM_INTEL_TDX=n

Based on a patch by Sean Christopherson <seanjc@google.com>

Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
---
Vishal Verma (4):
      KVM: TDX: Move apicv_pre_state_restore to posted_intr.c
      KVM: VMX: Move x86_ops wrappers under CONFIG_KVM_INTEL_TDX
      KVM: VMX: Make naming consistent for kvm_complete_insn_gp via define
      KVM: VMX: Clean up and macrofy x86_ops

 arch/x86/kvm/vmx/posted_intr.h |   1 +
 arch/x86/kvm/vmx/tdx.h         |   2 +-
 arch/x86/kvm/vmx/x86_ops.h     |  68 +-------------
 arch/x86/kvm/vmx/main.c        | 204 ++++++++++++++++++++---------------------
 arch/x86/kvm/vmx/posted_intr.c |   8 ++
 5 files changed, 113 insertions(+), 170 deletions(-)
---
base-commit: 85c9490bbed74b006a614e542da404a55ff5938f
change-id: 20250311-vverma7-cleanup_x86_ops-c62e50e47126

Best regards,
-- 
Vishal Verma <vishal.l.verma@intel.com>


^ permalink raw reply	[flat|nested] 8+ messages in thread

end of thread, other threads:[~2025-03-14 15:47 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2025-03-13 19:30 [PATCH 0/4] KVM: TDX: Cleanup the kvm_x86_ops structure for vmx/tdx Vishal Verma
2025-03-13 19:30 ` [PATCH 1/4] KVM: TDX: Move apicv_pre_state_restore to posted_intr.c Vishal Verma
2025-03-14  2:36   ` Binbin Wu
2025-03-13 19:30 ` [PATCH 2/4] KVM: VMX: Move x86_ops wrappers under CONFIG_KVM_INTEL_TDX Vishal Verma
2025-03-14  2:42   ` Binbin Wu
2025-03-14 15:47     ` Verma, Vishal L
2025-03-13 19:30 ` [PATCH 3/4] KVM: VMX: Make naming consistent for kvm_complete_insn_gp via define Vishal Verma
2025-03-13 19:30 ` [PATCH 4/4] KVM: VMX: Clean up and macrofy x86_ops Vishal Verma

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