[PATCH v8 00/10] x86/cpu: KVM: Clean up PAT and VMX macros

Sean Christopherson
2024-06-05T23:19:22Z

The primary goal of this series is to clean up the VMX MSR macros and their
usage in KVM.

The first half of the series touches memtype code that (obviously) impacts
areas well outside of KVM, in order to address several warts:

(a) KVM is defining VMX specific macros for the architectural memtypes
(b) the PAT and MTRR code define similar, yet different macros
(c) that the PAT code not only has macros for the types (well, enums),
it also has macros for encoding the entire PAT MSR that can be used
by KVM.

The memtype changes aren't strictly required for the KVM-focused changes in
the second half of the series, but splitting this into two series would
generating a number of conflicts that would be cumbersome to resolve after
the fact.

I would like to take this through the KVM tree, as I don't expect the PAT/MTRR
code to see much change in the near future, and IIRC the original motiviation
of the VMX MSR cleanups was to prepare for KVM feature enabling (FRED maybe?).

Based on:

https://github.com/kvm-x86/linux next

v8:
- Collect more reviews.
- Call out opportunistic change in patch 4. [Xiaoyao]
- Hopefully actually Cc the x86 maintainers to get Acks on the PAT changes.

v7:
- https://lore.kernel.org/all/20240520175925.1217334-1-seanjc@google.com
- Collect reviews.
- Fix an Author misattribution issue. [Xiaoyao]
- Add vmx_basic_encode_vmcs_info() to avoid ending up with a mix of open-coded
shift/masks and #defined shift/masks. [Xiaoyao]
- Remove an "#undef PAT" that got left behind. [Kai]

v6:
- https://lore.kernel.org/all/20240309012725.1409949-1-seanjc@google.com
- Add all the PAT/memtype patches.
- Split the VMX changes into more appropriately sized chunks.
- Multiple minor modifications to make the macro mess more maintainable
(and yes, I edited that sentence to use "modifications" specifically
for alliteration purposes).

v5:
* https://lore.kernel.org/all/20240206182032.1596-1-xin3.li@intel.com
* Do not split VMX_BASIC bit definitions across multiple files (Kai
Huang).
* Put some words to the changelog to justify changes around memory
type macros (Kai Huang).
* Remove a leftover ';' (Kai Huang).

v4:
* Remove vmx_basic_vmcs_basic_cap() (Kai Huang).
* Add 2 macros VMX_BASIC_VMCS12_SIZE and VMX_BASIC_MEM_TYPE_WB to
avoid keeping 2 their bit shift macros (Kai Huang).

v3:
* Simply save the full/raw value of MSR_IA32_VMX_BASIC in the global
vmcs_config, and then use the helpers to extract info from it as
needed (Sean Christopherson).
* Move all VMX_MISC related changes to the second patch (Kai Huang).
* Commonize memory type definitions used in the VMX files, as memory
types are architectural.

v2:
* Don't add field shift macros unless it's really needed, extra layer
of indirect makes it harder to read (Sean Christopherson).
* Add a static_assert() to ensure that VMX_BASIC_FEATURES_MASK doesn't
overlap with VMX_BASIC_RESERVED_BITS (Sean Christopherson).
* read MSR_IA32_VMX_BASIC into an u64 rather than 2 u32 (Sean
Christopherson).
* Add 2 new functions for extracting fields from VMX basic (Sean
Christopherson).
* Drop the tools header update (Sean Christopherson).
* Move VMX basic field macros to arch/x86/include/asm/vmx.h.

Sean Christopherson (5):
x86/cpu: KVM: Add common defines for architectural memory types (PAT,
MTRRs, etc.)
x86/cpu: KVM: Move macro to encode PAT value to common header
KVM: x86: Stuff vCPU's PAT with default value at RESET, not creation
KVM: nVMX: Add a helper to encode VMCS info in MSR_IA32_VMX_BASIC
KVM VMX: Move MSR_IA32_VMX_MISC bit defines to asm/vmx.h

Xin Li (5):
KVM: VMX: Move MSR_IA32_VMX_BASIC bit defines to asm/vmx.h
KVM: VMX: Track CPU's MSR_IA32_VMX_BASIC as a single 64-bit value
KVM: nVMX: Use macros and #defines in vmx_restore_vmx_basic()
KVM: VMX: Open code VMX preemption timer rate mask in its accessor
KVM: nVMX: Use macros and #defines in vmx_restore_vmx_misc()

arch/x86/include/asm/msr-index.h | 34 ++++++++++--------
arch/x86/include/asm/vmx.h | 40 +++++++++++++++------
arch/x86/kernel/cpu/mtrr/mtrr.c | 6 ++++
arch/x86/kvm/vmx/capabilities.h | 10 +++---
arch/x86/kvm/vmx/nested.c | 62 +++++++++++++++++++++-----------
arch/x86/kvm/vmx/nested.h | 2 +-
arch/x86/kvm/vmx/vmx.c | 30 ++++++++--------
arch/x86/kvm/x86.c | 4 +--
arch/x86/kvm/x86.h | 3 +-
arch/x86/mm/pat/memtype.c | 36 ++++++-------------
10 files changed, 132 insertions(+), 95 deletions(-)

base-commit: af0903ab52ee6d6f0f63af67fa73d5eb00f79b9a
--
2.45.1.467.gbab1589fc0-goog