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From: Paolo Bonzini <pbonzini@redhat.com>
To: Sean Christopherson <seanjc@google.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	Xiaoyao Li <xiaoyao.li@intel.com>,
	Reiji Watanabe <reijiw@google.com>
Subject: Re: [PATCH 00/15] KVM: x86: RDPID/RDTSCP fixes and uret MSR cleanups
Date: Wed, 5 May 2021 10:51:49 +0200	[thread overview]
Message-ID: <dbd2b720-632a-0e03-a000-bb52168f6c24@redhat.com> (raw)
In-Reply-To: <20210504171734.1434054-1-seanjc@google.com>

On 04/05/21 19:17, Sean Christopherson wrote:
> This is a continuation of a less ambitious effort to unify MSR_TSC_AUX
> handling across SVM and VMX.  Reiji pointed out that MSR_TSC_AUX exists if
> RDTSCP *or* RDPID is supported, and things went downhill from there.
> 
> The first half of this series fixes a variety of RDTSCP and RDPID related
> bugs.
> 
> The second half of the series cleans up VMX's user return MSR framework
> and consolidates more of the uret logic into common x86.
> 
> The last two patches leverage the uret MSR cleanups to move MSR_TSC_AUX
> handling to common x86 and add sanity checks to guard against misreporting
> of RDPID and/or RDTSCP support.
> 
> This will conflict with my vCPU RESET/INIT cleanup series.  Feel free to
> punt the conflicts to me.
> 
> Other "fun" things to tackle:
> 
>   - The kernel proper also botches RDPID vs. RDTSCP, as MSR_TSC_AUX is
>     configured if RDTSCP is supported, but is consumed if RDPID is
>     supported.  I'll send this fix separately.
> 
>   - Commit 844d69c26d83 ("KVM: SVM: Delay restoration of host MSR_TSC_AUX
>     until return to userspace") unwittingly fixed a bug where KVM would
>     write MSR_TSC_AUX with the guest's value when svm->guest_state_loaded
>     is false, which could lead to running the host with the guest's value.
>     The bug only exists in 5.12 (maybe 5.11 too?), so crafting a fix for
>     stable won't be too awful.
> 
> Sean Christopherson (15):
>    KVM: VMX: Do not adverise RDPID if ENABLE_RDTSCP control is
>      unsupported
>    KVM: x86: Emulate RDPID only if RDTSCP is supported
>    KVM: SVM: Inject #UD on RDTSCP when it should be disabled in the guest
>    KVM: x86: Move RDPID emulation intercept to its own enum
>    KVM: VMX: Disable preemption when probing user return MSRs
>    KVM: SVM: Probe and load MSR_TSC_AUX regardless of RDTSCP support in
>      host
>    KVM: x86: Add support for RDPID without RDTSCP
>    KVM: VMX: Configure list of user return MSRs at module init
>    KVM: VMX: Use flag to indicate "active" uret MSRs instead of sorting
>      list
>    KVM: VMX: Use common x86's uret MSR list as the one true list
>    KVM: VMX: Disable loading of TSX_CTRL MSR the more conventional way
>    KVM: x86: Export the number of uret MSRs to vendor modules
>    KVM: x86: Move uret MSR slot management to common x86
>    KVM: x86: Tie Intel and AMD behavior for MSR_TSC_AUX to guest CPU
>      model
>    KVM: x86: Hide RDTSCP and RDPID if MSR_TSC_AUX probing failed
> 
>   arch/x86/include/asm/kvm_host.h |   9 +-
>   arch/x86/kvm/cpuid.c            |  18 ++-
>   arch/x86/kvm/emulate.c          |   2 +-
>   arch/x86/kvm/kvm_emulate.h      |   1 +
>   arch/x86/kvm/svm/svm.c          |  50 +++-----
>   arch/x86/kvm/vmx/vmx.c          | 217 ++++++++++++++++----------------
>   arch/x86/kvm/vmx/vmx.h          |  12 +-
>   arch/x86/kvm/x86.c              | 101 ++++++++++++---
>   8 files changed, 245 insertions(+), 165 deletions(-)
> 

Queued, thanks.

Paolo


      parent reply	other threads:[~2021-05-05  8:51 UTC|newest]

Thread overview: 68+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-04 17:17 Sean Christopherson
2021-05-04 17:17 ` [PATCH 01/15] KVM: VMX: Do not adverise RDPID if ENABLE_RDTSCP control is unsupported Sean Christopherson
2021-05-04 17:37   ` Jim Mattson
2021-05-04 17:53     ` Jim Mattson
2021-05-04 18:14       ` Sean Christopherson
2021-05-05  3:04   ` Reiji Watanabe
2021-05-10  8:03   ` Maxim Levitsky
2021-05-04 17:17 ` [PATCH 02/15] KVM: x86: Emulate RDPID only if RDTSCP is supported Sean Christopherson
2021-05-04 17:50   ` Jim Mattson
2021-05-05  3:51   ` Reiji Watanabe
2021-05-05  8:01     ` Paolo Bonzini
2021-05-10  8:08   ` Maxim Levitsky
2021-05-10 17:20     ` Sean Christopherson
2021-05-11 12:32       ` Maxim Levitsky
2021-05-04 17:17 ` [PATCH 03/15] KVM: SVM: Inject #UD on RDTSCP when it should be disabled in the guest Sean Christopherson
2021-05-04 21:45   ` Jim Mattson
2021-05-04 21:53     ` Sean Christopherson
2021-05-04 21:56       ` Jim Mattson
2021-05-04 22:10         ` Sean Christopherson
2021-05-04 22:24           ` Jim Mattson
2021-05-04 21:57       ` Paolo Bonzini
2021-05-04 21:58         ` Jim Mattson
2021-05-10  8:08           ` Maxim Levitsky
2021-05-10 16:56             ` Sean Christopherson
2021-05-11 12:34               ` Maxim Levitsky
2021-05-18 10:59               ` Paolo Bonzini
2021-05-18 19:24                 ` Sean Christopherson
2021-05-05  4:26   ` Reiji Watanabe
2021-05-10  8:08   ` Maxim Levitsky
2021-05-04 17:17 ` [PATCH 04/15] KVM: x86: Move RDPID emulation intercept to its own enum Sean Christopherson
2021-05-04 23:24   ` Jim Mattson
2021-05-10  8:14   ` Maxim Levitsky
2021-05-04 17:17 ` [PATCH 05/15] KVM: VMX: Disable preemption when probing user return MSRs Sean Christopherson
2021-05-04 23:36   ` Jim Mattson
2021-05-10  8:18   ` Maxim Levitsky
2021-05-04 17:17 ` [PATCH 06/15] KVM: SVM: Probe and load MSR_TSC_AUX regardless of RDTSCP support in host Sean Christopherson
2021-05-10  8:20   ` Maxim Levitsky
2021-05-04 17:17 ` [PATCH 07/15] KVM: x86: Add support for RDPID without RDTSCP Sean Christopherson
2021-05-10  8:20   ` Maxim Levitsky
2021-05-04 17:17 ` [PATCH 08/15] KVM: VMX: Configure list of user return MSRs at module init Sean Christopherson
2021-05-10  8:23   ` Maxim Levitsky
2021-05-10 15:13     ` Sean Christopherson
2021-05-11 12:34       ` Maxim Levitsky
2021-05-11 20:10         ` Sean Christopherson
2021-05-04 17:17 ` [PATCH 09/15] KVM: VMX: Use flag to indicate "active" uret MSRs instead of sorting list Sean Christopherson
2021-05-08  3:31   ` Reiji Watanabe
2021-05-10 16:43     ` Sean Christopherson
2021-05-10 17:55       ` Reiji Watanabe
2021-05-10  8:25   ` Maxim Levitsky
2021-05-04 17:17 ` [PATCH 10/15] KVM: VMX: Use common x86's uret MSR list as the one true list Sean Christopherson
2021-05-10  8:25   ` Maxim Levitsky
2021-05-04 17:17 ` [PATCH 11/15] KVM: VMX: Disable loading of TSX_CTRL MSR the more conventional way Sean Christopherson
2021-05-05  8:49   ` Paolo Bonzini
2021-05-05 15:36     ` Sean Christopherson
2021-05-05 15:50       ` Paolo Bonzini
2021-05-10  8:26   ` Maxim Levitsky
2021-05-04 17:17 ` [PATCH 12/15] KVM: x86: Export the number of uret MSRs to vendor modules Sean Christopherson
2021-05-10  8:27   ` Maxim Levitsky
2021-05-04 17:17 ` [PATCH 13/15] KVM: x86: Move uret MSR slot management to common x86 Sean Christopherson
2021-05-10  8:28   ` Maxim Levitsky
2021-05-04 17:17 ` [PATCH 14/15] KVM: x86: Tie Intel and AMD behavior for MSR_TSC_AUX to guest CPU model Sean Christopherson
2021-05-10  8:29   ` Maxim Levitsky
2021-05-10 16:50     ` Sean Christopherson
2021-05-10 17:11       ` Jim Mattson
2021-05-11 12:34         ` Maxim Levitsky
2021-05-04 17:17 ` [PATCH 15/15] KVM: x86: Hide RDTSCP and RDPID if MSR_TSC_AUX probing failed Sean Christopherson
2021-05-10  8:29   ` Maxim Levitsky
2021-05-05  8:51 ` Paolo Bonzini [this message]

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