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From: Paolo Bonzini <pbonzini@redhat.com>
To: Jim Mattson <jmattson@google.com>
Cc: "David Woodhouse" <dwmw@amazon.co.uk>,
	"Radim Krčmář" <rkrcmar@redhat.com>,
	LKML <linux-kernel@vger.kernel.org>,
	"kvm list" <kvm@vger.kernel.org>,
	"KarimAllah Ahmed" <karahmed@amazon.de>,
	"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org
Subject: Re: [PATCH 7/9] KVM/VMX: Emulate MSR_IA32_ARCH_CAPABILITIES
Date: Mon, 19 Feb 2018 14:10:11 +0100	[thread overview]
Message-ID: <a4693ca3-face-e1f5-b619-74fc59870ce9@redhat.com> (raw)
In-Reply-To: <CALMp9eQQ-94g=fNanvwpr6b2pmH87RPGr6s9gOv43dUDABFuhw@mail.gmail.com>

On 16/02/2018 17:29, Jim Mattson wrote:
> On Fri, Feb 16, 2018 at 6:18 AM, Paolo Bonzini <pbonzini@redhat.com> wrote:
> 
>> Uhm, taking contents from the hardware is wrong (guess why---live
>> migration).  I'll send a revert of those two lines.
> 
> Hardware seems like a reasonable place to get the default value (cf.
> the VMX capability MSRs).

There are some differences:

- a zero value for ARCH_CAPABILITIES should be safe, while a zero value
for VMX capabilities doesn't really make sense.  On the contrary, a
nonzero value for ARCH_CAPABILITIES is not safe across live migration.

- VMX doesn't support live migration; before adding that support we will
probably have Tom's patches to retrieve MSR capabilities.

Thanks,

Paolo

> Should these two lines just be moved to
> vmx_create_cpu?
> 

  parent reply	other threads:[~2018-02-19 13:10 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-02-06 17:29 [STABLE 4.9.y PATCH 0/9] Backport of KVM Speculation Control support David Woodhouse
2018-02-06 17:29 ` [PATCH 1/9] KVM: nVMX: vmx_complete_nested_posted_interrupt() can't fail David Woodhouse
2018-02-06 17:29 ` [PATCH 2/9] KVM: nVMX: mark vmcs12 pages dirty on L2 exit David Woodhouse
2018-02-06 17:29 ` [PATCH 3/9] KVM: nVMX: Eliminate vmcs02 pool David Woodhouse
2018-02-06 17:29 ` [PATCH 4/9] KVM: VMX: introduce alloc_loaded_vmcs David Woodhouse
2018-02-06 17:29 ` [PATCH 5/9] KVM: VMX: make MSR bitmaps per-VCPU David Woodhouse
2018-02-06 17:29 ` [PATCH 6/9] KVM/x86: Add IBPB support David Woodhouse
2018-02-06 17:29 ` [PATCH 7/9] KVM/VMX: Emulate MSR_IA32_ARCH_CAPABILITIES David Woodhouse
2018-02-16 14:18   ` Paolo Bonzini
2018-02-16 16:29     ` Jim Mattson
2018-02-16 16:33       ` David Woodhouse
2018-02-19 13:10       ` Paolo Bonzini [this message]
2018-02-19 13:35         ` David Woodhouse
2018-02-19 14:07           ` Paolo Bonzini
2018-02-06 17:29 ` [PATCH 8/9] KVM/VMX: Allow direct access to MSR_IA32_SPEC_CTRL David Woodhouse
2018-02-16  4:02   ` Jim Mattson
2018-02-16  4:16   ` Jim Mattson
2018-02-06 17:29 ` [PATCH 9/9] KVM/SVM: " David Woodhouse
2018-02-06 18:01 ` [STABLE 4.9.y PATCH 0/9] Backport of KVM Speculation Control support Paolo Bonzini
2018-02-06 21:05   ` Woodhouse, David
2018-02-08  2:49     ` Greg KH
2018-02-08  2:49       ` Greg KH
2018-02-08 17:14       ` Greg KH
2018-02-08 17:14         ` Greg KH
2018-02-08 17:42         ` Paolo Bonzini
2018-02-08 17:57           ` Greg KH
2018-02-08 17:57             ` Greg KH
2018-02-09  7:58             ` Greg KH
2018-02-09  7:58               ` Greg KH
2018-02-15 10:15 ` Thomas Voegtle
2018-02-15 10:23   ` Greg KH
2018-02-15 10:49     ` Thomas Voegtle
2018-02-15 13:57       ` Greg KH

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