From: Vitaly Kuznetsov <vkuznets@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
Sean Christopherson <seanjc@google.com>
Cc: kvm@vger.kernel.org,
Anirudh Rayabharam <anrayabh@linux.microsoft.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>,
Maxim Levitsky <mlevitsk@redhat.com>,
linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 09/25] KVM: VMX: nVMX: Support TSC scaling and PERF_GLOBAL_CTRL with enlightened VMCS
Date: Mon, 01 Aug 2022 10:54:54 +0200 [thread overview]
Message-ID: <875yjc2vj5.fsf@redhat.com> (raw)
In-Reply-To: <62ac29cb-3270-a810-bad1-3692da448016@redhat.com>
Paolo Bonzini <pbonzini@redhat.com> writes:
> On 7/29/22 00:13, Sean Christopherson wrote:
>> The only flaw in this is if KVM gets handed a CPUID model that enumerates support
>> for 2025 (or whenever the next update comes) but not 2022. Hmm, though if Microsoft
>> defines each new "version" as a full superset, then even that theoretical bug goes
>> away. I'm happy to be optimistic for once and give this a shot. I definitely like
>> that it makes it easier to see the deltas between versions.
>
> Okay, I have queued the series but I still haven't gone through all the
> comments. So this will _not_ be in the 5.21 pull request.
>
> The first patch also needs a bit more thought to figure out the impact
> on userspace and whether we can consider syndbg niche enough to not care.
(Sorry for delayed replies here, I'm back from vacation now)
The first patch is not a requirement for the rest of the series, we can
discuss it separately. I, however, think that we can just keep checking
HV_FEATURE_DEBUG_MSRS_AVAILABLE in hv_check_msr_access() to be
compatible with existing QEMUs and make QEMU expose both
HV_FEATURE_DEBUG_MSRS_AVAILABLE and HV_ACCESS_DEBUG_MSRS unconditionally
when syndbg feature is enabled as we know that missing
HV_ACCESS_DEBUG_MSRS is just a bug. I don't think we actually need to
be so picky and support VMMs which want to set 'syndbg without access to
it' and 'access to syndbg without syndbg' use-cases. All-or-nothing is
likely good enough.
--
Vitaly
next prev parent reply other threads:[~2022-08-01 8:55 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-14 9:13 [PATCH v4 00/25] KVM: VMX: Support updated eVMCSv1 revision + use vmcs_config for L1 VMX MSRs Vitaly Kuznetsov
2022-07-14 9:13 ` [PATCH v4 01/25] KVM: x86: hyper-v: Expose access to debug MSRs in the partition privilege flags Vitaly Kuznetsov
2022-07-21 21:43 ` Sean Christopherson
2022-07-22 17:22 ` Paolo Bonzini
2022-08-01 8:16 ` Vitaly Kuznetsov
2022-07-14 9:13 ` [PATCH v4 02/25] x86/hyperv: Fix 'struct hv_enlightened_vmcs' definition Vitaly Kuznetsov
2022-07-14 9:13 ` [PATCH v4 03/25] x86/hyperv: Update " Vitaly Kuznetsov
2022-07-14 9:57 ` Maxim Levitsky
2022-07-14 9:13 ` [PATCH v4 04/25] KVM: VMX: Define VMCS-to-EVMCS conversion for the new fields Vitaly Kuznetsov
2022-07-14 9:13 ` [PATCH v4 05/25] KVM: nVMX: Support several new fields in eVMCSv1 Vitaly Kuznetsov
2022-07-14 9:13 ` [PATCH v4 06/25] KVM: x86: hyper-v: Cache HYPERV_CPUID_NESTED_FEATURES CPUID leaf Vitaly Kuznetsov
2022-07-14 9:59 ` Maxim Levitsky
2022-07-14 9:13 ` [PATCH v4 07/25] KVM: selftests: Add ENCLS_EXITING_BITMAP{,HIGH} VMCS fields Vitaly Kuznetsov
2022-07-14 9:20 ` Kai Huang
2022-07-14 9:13 ` [PATCH v4 08/25] KVM: selftests: Switch to updated eVMCSv1 definition Vitaly Kuznetsov
2022-07-14 10:07 ` Maxim Levitsky
2022-07-14 9:13 ` [PATCH v4 09/25] KVM: VMX: nVMX: Support TSC scaling and PERF_GLOBAL_CTRL with enlightened VMCS Vitaly Kuznetsov
2022-07-21 21:58 ` Sean Christopherson
2022-07-25 17:09 ` Paolo Bonzini
2022-07-25 18:18 ` Sean Christopherson
2022-07-28 21:52 ` Paolo Bonzini
2022-07-28 22:13 ` Sean Christopherson
2022-07-28 22:24 ` Paolo Bonzini
2022-07-28 22:35 ` Sean Christopherson
2022-08-01 8:54 ` Vitaly Kuznetsov [this message]
2022-08-02 13:03 ` Vitaly Kuznetsov
2022-07-14 9:13 ` [PATCH v4 10/25] KVM: selftests: Enable TSC scaling in evmcs selftest Vitaly Kuznetsov
2022-07-14 9:13 ` [PATCH v4 11/25] KVM: VMX: Get rid of eVMCS specific VMX controls sanitization Vitaly Kuznetsov
2022-07-14 10:04 ` Maxim Levitsky
2022-07-14 9:13 ` [PATCH v4 12/25] KVM: VMX: Check VM_ENTRY_IA32E_MODE in setup_vmcs_config() Vitaly Kuznetsov
2022-07-21 22:00 ` Sean Christopherson
2022-07-14 9:13 ` [PATCH v4 13/25] KVM: VMX: Check CPU_BASED_{INTR,NMI}_WINDOW_EXITING " Vitaly Kuznetsov
2022-07-21 22:01 ` Sean Christopherson
2022-07-14 9:13 ` [PATCH v4 14/25] KVM: VMX: Tweak the special handling of SECONDARY_EXEC_ENCLS_EXITING " Vitaly Kuznetsov
2022-07-21 22:11 ` Sean Christopherson
2022-08-02 12:52 ` Vitaly Kuznetsov
2022-07-14 9:13 ` [PATCH v4 15/25] KVM: VMX: Extend VMX controls macro shenanigans Vitaly Kuznetsov
2022-07-21 22:28 ` Sean Christopherson
2022-07-22 18:33 ` Sean Christopherson
2022-07-22 21:04 ` Nathan Chancellor
2022-07-22 21:38 ` Sean Christopherson
2022-07-23 1:06 ` Nathan Chancellor
2022-07-28 16:27 ` Paolo Bonzini
2022-07-14 9:13 ` [PATCH v4 16/25] KVM: VMX: Move CPU_BASED_CR8_{LOAD,STORE}_EXITING filtering out of setup_vmcs_config() Vitaly Kuznetsov
2022-07-21 22:30 ` Sean Christopherson
2022-07-14 9:13 ` [PATCH v4 17/25] KVM: VMX: Add missing VMEXIT controls to vmcs_config Vitaly Kuznetsov
2022-07-21 22:34 ` Sean Christopherson
2022-07-14 9:13 ` [PATCH v4 18/25] KVM: VMX: Add missing CPU based VM execution " Vitaly Kuznetsov
2022-07-21 22:39 ` Sean Christopherson
2022-07-14 9:13 ` [PATCH v4 19/25] KVM: VMX: Adjust CR3/INVPLG interception for EPT=y at runtime, not setup Vitaly Kuznetsov
2022-07-14 9:13 ` [PATCH v4 20/25] KVM: x86: VMX: Replace some Intel model numbers with mnemonics Vitaly Kuznetsov
2022-07-14 9:13 ` [PATCH v4 21/25] KVM: VMX: Move LOAD_IA32_PERF_GLOBAL_CTRL errata handling out of setup_vmcs_config() Vitaly Kuznetsov
2022-07-21 22:56 ` Sean Christopherson
2022-07-28 22:25 ` Paolo Bonzini
2022-07-28 22:34 ` Sean Christopherson
2022-07-14 9:13 ` [PATCH v4 22/25] KVM: nVMX: Always set required-1 bits of pinbased_ctls to PIN_BASED_ALWAYSON_WITHOUT_TRUE_MSR Vitaly Kuznetsov
2022-07-14 9:13 ` [PATCH v4 23/25] KVM: nVMX: Use sanitized allowed-1 bits for VMX control MSRs Vitaly Kuznetsov
2022-07-14 9:13 ` [PATCH v4 24/25] KVM: VMX: Cache MSR_IA32_VMX_MISC in vmcs_config Vitaly Kuznetsov
2022-07-21 23:06 ` Sean Christopherson
2022-08-02 16:11 ` Vitaly Kuznetsov
2022-08-02 16:28 ` Sean Christopherson
2022-07-14 9:13 ` [PATCH v4 25/25] KVM: nVMX: Use cached host MSR_IA32_VMX_MISC value for setting up nested MSR Vitaly Kuznetsov
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