From: Paolo Bonzini <pbonzini@redhat.com>
To: David Matlack <dmatlack@google.com>
Cc: "kvm list" <kvm@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"Jim Mattson" <jmattson@google.com>,
"Radim Krčmář" <rkrcmar@redhat.com>
Subject: Re: [PATCH 3/4] KVM: nVMX: accurate emulation of MSR_IA32_CR{0,4}_FIXED1
Date: Wed, 23 Nov 2016 23:11:52 +0100 [thread overview]
Message-ID: <ebbe99dc-9725-4a34-467c-ccbbcd1c55d7@redhat.com> (raw)
In-Reply-To: <CALzav=dGsDjhN3JV9onGbUE9Ge0+spH454GenUxb5S30vS7uxQ@mail.gmail.com>
On 23/11/2016 23:07, David Matlack wrote:
> A downside of this scheme is we'd have to remember to update
> nested_vmx_cr4_fixed1_update() before giving VMs new CPUID bits. If we
> forget, a VM could end up with different values for CR{0,4}_FIXED0 for
> the same CPUID depending on which version of KVM you're running on.
If userspace doesn't obey KVM_GET_SUPPORTED_CPUID, all bets are off
anyway, so I don't think it's a big deal. However, if you want to make
it generated by userspace, that would be fine as well! That would
simply entail removing this patch, wouldn't it?
Paolo
> Hm, now I'm thinking you were right in the beginning. Userspace should
> generate CR{0,4}_FIXED1, not the kernel. And KVM should allow
> userspace to save/restore them.
next prev parent reply other threads:[~2016-11-23 22:14 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-23 1:14 [PATCH 0/4] VMX Capability MSRs David Matlack
2016-11-23 1:14 ` [PATCH 1/4] KVM: nVMX: support restore of VMX capability MSRs David Matlack
2016-11-23 11:44 ` Paolo Bonzini
2016-11-28 21:11 ` David Matlack
2016-11-28 22:48 ` Paolo Bonzini
2016-11-28 22:57 ` David Matlack
2016-11-29 8:01 ` Paolo Bonzini
2016-11-29 17:42 ` David Matlack
2016-11-23 1:14 ` [PATCH 2/4] KVM: nVMX: fix checks on CR{0,4} during virtual VMX operation David Matlack
2016-11-23 11:31 ` Paolo Bonzini
2016-11-28 19:51 ` David Matlack
2016-11-23 1:14 ` [PATCH 3/4] KVM: nVMX: accurate emulation of MSR_IA32_CR{0,4}_FIXED1 David Matlack
2016-11-23 9:06 ` Paolo Bonzini
2016-11-23 19:16 ` David Matlack
2016-11-23 19:24 ` Paolo Bonzini
2016-11-23 22:07 ` David Matlack
2016-11-23 22:11 ` Paolo Bonzini [this message]
2016-11-23 23:28 ` David Matlack
2016-11-28 21:51 ` David Matlack
2016-11-23 1:14 ` [PATCH 4/4] KVM: nVMX: load GUEST_EFER after GUEST_CR0 during emulated VM-entry David Matlack
2016-11-23 11:45 ` [PATCH 0/4] VMX Capability MSRs Paolo Bonzini
2016-11-28 17:44 ` David Matlack
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