[PATCH v3 0/7] KVM: x86: Add CMCI and UCNA emulation

[Jue Wang <juew@google.com>]

This patch series implement emulation for Corrected Machine Check
Interrupt (CMCI) signaling and UnCorrectable No Action required (UCNA)
error injection.

UCNA errors signaled via CMCI allow a guest to be notified as soon as
uncorrectable memory errors get detected by some background threads,
e.g., threads that migrate guest memory across hosts or threads that
constantly scan system memory for errors [1].

Upon receiving UCNAs, guest kernel isolates the poisoned pages which may
still be free, preventing future accesses that may cause fatal MCEs.

1. https://lore.kernel.org/linux-mm/8eceffc0-01e8-2a55-6eb9-b26faa9e3caf@intel.com/t/


Patch 1-3 clean up KVM APIC LVT logic.

Patch 4 adds CMCI emulation to lapic.

Patch 5 updates the allocation of mce_array to use array allocation api:
kcalloc.

Patch 6 adds emulation for the per-bank MSR_IA32_MCx_CTL2 MSRs that
controls CMCI signaling.

Patch 7 enables MCG_CMCI_P on x86 and handles injected UCNA errors.


v3 changes
- Incorporate feedback from Sean Christopherson <seanjc@google.com>
- Split clean up to KVM APIC LVT logic to 3 patches.
- Put the clean up of mce_array allocation in a separate patch.
- Base the MCi_CTL2 register emulation on Sean's clean up and fix
series [2]
- Fix bugs around MCi_CTL2 register offset validation and the free of
mci_ctl2_banks array.
- Rewrite the change log with more details in architectural information
about CMCI, UCNA and MCG_CMCI_P.
- Fix various comments and wrapping style.

2. https://lore.kernel.org/lkml/20220512222716.4112548-1-seanjc@google.com/T/


v2 chanegs
- Incorporate feedback from Sean Christopherson <seanjc@google.com>
- Split the single patch into 4:
  1). clean up KVM APIC LVT logic
  2). add CMCI emulation to lapic
  3). add emulation of MSR_IA32_MCx_CTL2
  4). enable MCG_CMCI_P and handle injected UCNAs
- Fix various style issues.

Jue Wang (7):
  KVM: x86: Make APIC_VERSION capture only the magic 0x14UL.
  KVM: x86: Fill apic_lvt_mask with enums / explicit entries.
  KVM: x86: Add APIC_LVTx() macro.
  KVM: x86: Add Corrected Machine Check Interrupt (CMCI) emulation to
    lapic.
  KVM: x86: Use kcalloc to allocate the mce_banks array.
  KVM: x86: Add emulation for MSR_IA32_MCx_CTL2 MSRs.
  KVM: x86: Enable MCG_CMCI_P and handle injected UCNAs.

 arch/x86/include/asm/kvm_host.h |   1 +
 arch/x86/kvm/lapic.c            |  58 +++++++---
 arch/x86/kvm/lapic.h            |  15 ++-
 arch/x86/kvm/vmx/vmx.c          |   1 +
 arch/x86/kvm/x86.c              | 182 +++++++++++++++++++++++++-------
 5 files changed, 200 insertions(+), 57 deletions(-)

-- 
2.36.0.550.gb090851708-goog