linux-kernel - Re: [GIT PULL] KVM: x86: Misc changes for 6.20

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Message-ID: <CABgObfatae4rtioViKGueFG9=Qm=qEmvXQp=8LWhZnUMML7_9w@mail.gmail.com>
Date: Mon, 9 Feb 2026 18:56:55 +0100
From: Paolo Bonzini <pbonzini@...hat.com>
To: Sean Christopherson <seanjc@...gle.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [GIT PULL] KVM: x86: Misc changes for 6.20

On Sat, Feb 7, 2026 at 5:10 AM Sean Christopherson <seanjc@...gle.com> wrote:
>  - Add WARNs to guard against modifying KVM's CPU caps outside of the intended
>    setup flow, as nested VMX in particular is sensitive to unexpected changes
>    in KVM's golden configuration.

Possible follow-up: does it make sense to sync kvm_caps.supported_xss
by calling kvm_setup_xss_caps() from kvm_finalize_cpu_caps()?

In the meanwhile I've pulled this of course---thanks!

Paolo

>  - Add a quirk to allow userspace to opt-in to actually suppress EOI broadcasts
>    when the suppression feature is enabled by the guest (currently limited to
>    split IRQCHIP, i.e. userspace I/O APIC).  Sadly, simply fixing KVM to honor
>    Suppress EOI Broadcasts isn't an option as some userspaces have come to rely
>    on KVM's buggy behavior (KVM advertises Supress EOI Broadcast irrespective
>    of whether or not userspace I/O APIC supports Directed EOIs).
>
>  - Minor cleanups.
>
> ----------------------------------------------------------------
> Jun Miao (1):
>       KVM: x86: align the code with kvm_x86_call()
>
> Khushit Shah (1):
>       KVM: x86: Add x2APIC "features" to control EOI broadcast suppression
>
> Sean Christopherson (6):
>       KVM: x86: Disallow setting CPUID and/or feature MSRs if L2 is active
>       KVM: x86: Return "unsupported" instead of "invalid" on access to unsupported PV MSR
>       KVM: x86: Enforce use of EXPORT_SYMBOL_FOR_KVM_INTERNAL
>       KVM: x86: Ignore -EBUSY when checking nested events from vcpu_block()
>       KVM: x86: Drop WARN on INIT/SIPI being blocked when vCPU is in Wait-For-SIPI
>       KVM: x86: Harden against unexpected adjustments to kvm_cpu_caps
>
> Vasiliy Kovalev (1):
>       KVM: x86: Add SRCU protection for reading PDPTRs in __get_sregs2()
>
> Xiaoyao Li (1):
>       KVM: x86: Don't read guest CR3 when doing async pf while the MMU is direct
>
> Zhao Liu (4):
>       KVM: x86: Advertise MOVRS CPUID to userspace
>       KVM: x86: Advertise AMX CPUIDs in subleaf 0x1E.0x1 to userspace
>       KVM: x86: Advertise AVX10.2 CPUID to userspace
>       KVM: x86: Advertise AVX10_VNNI_INT CPUID to userspace
>
>  Documentation/virt/kvm/api.rst     | 28 ++++++++++++-
>  arch/x86/include/asm/cpufeatures.h |  1 +
>  arch/x86/include/asm/kvm_host.h    |  9 +++++
>  arch/x86/include/uapi/asm/kvm.h    |  6 ++-
>  arch/x86/kvm/Makefile              | 49 +++++++++++++++++++++++
>  arch/x86/kvm/cpuid.c               | 75 +++++++++++++++++++++++++++++------
>  arch/x86/kvm/cpuid.h               | 12 +++++-
>  arch/x86/kvm/ioapic.c              |  2 +-
>  arch/x86/kvm/lapic.c               | 77 +++++++++++++++++++++++++++++++-----
>  arch/x86/kvm/lapic.h               |  2 +
>  arch/x86/kvm/mmu/mmu.c             | 11 +++---
>  arch/x86/kvm/pmu.c                 |  2 +-
>  arch/x86/kvm/reverse_cpuid.h       | 19 +++++++++
>  arch/x86/kvm/svm/svm.c             |  4 +-
>  arch/x86/kvm/vmx/vmx.c             |  4 +-
>  arch/x86/kvm/x86.c                 | 81 +++++++++++++++++++++++---------------
>  arch/x86/kvm/x86.h                 | 15 ++++++-
>  17 files changed, 328 insertions(+), 69 deletions(-)
>