From: Paolo Bonzini <pbonzini@redhat.com>
To: Jim Mattson <jmattson@google.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
kvm list <kvm@vger.kernel.org>,
bdas@redhat.com, David Matlack <dmatlack@google.com>
Subject: Re: [PATCH 6/6] KVM: nVMX: support RDRAND and RDSEED exiting
Date: Tue, 14 Mar 2017 10:55:49 +0100 [thread overview]
Message-ID: <d930d842-6283-f271-b6b1-60c245b69bff@redhat.com> (raw)
In-Reply-To: <CALMp9eT4NYDbtgPLtyERch-4XiBD3Lj9x=AQaO=X7JOE06S6Jg@mail.gmail.com>
On 13/03/2017 19:27, Jim Mattson wrote:
> I would expect that any reasonable CPU will support "RDRAND exiting"
> iff it supports RDRAND (i.e. CPUID.01H:ECX.RDRAND[bit 30]).
> Similarly, any reasonable CPU will support "RDSEED exiting" iff it
> supports RDSEED (i.e. CPUID.(EAX=07H, ECX=0H):EBX.RDSEED[bit 18]).
>
> Shouldn't there be some code in vmx_cpuid_update to adjust the
> vmx->nested.nested_vmx_secondary_ctls_high bits for "RDRAND exiting"
> and "RDSEED exiting," as there already is for "enable RDTSCP"?
Enable RDTSCP is a bit different in that the instruction itself is
disabled rather than the VMEXIT, still it would probably be a good idea.
One thing to be careful about is any conflicts with David Matlack's work
to customize the MSRs for processor models, since there's no prescribed
ordering of KVM_SET_CPUID2 and KVM_SET_MSR. Maybe
nested_vmx_setup_ctls_msrs can save the "default" nested_*_ctls_*; then
vmx_restore_control_msr can refer to those in order to check the written
value against the supported bits.
Paolo
next prev parent reply other threads:[~2017-03-14 9:55 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-08 18:03 [PATCH 0/6] KVM: nVMX: nested EPT improvements and A/D bits, RDRAND and RDSEED exits Paolo Bonzini
2017-03-08 18:03 ` [PATCH 1/6] KVM: nVMX: we support 1GB EPT pages Paolo Bonzini
2017-03-09 10:34 ` David Hildenbrand
2017-03-08 18:03 ` [PATCH 2/6] KVM: VMX: cleanup check for invalid EPT violation Paolo Bonzini
2017-03-09 10:43 ` David Hildenbrand
2017-03-09 10:50 ` David Hildenbrand
2017-03-28 10:09 ` Paolo Bonzini
2017-03-08 18:03 ` [PATCH 3/6] kvm: x86: MMU support for EPT accessed/dirty bits Paolo Bonzini
2017-03-08 18:03 ` [PATCH 4/6] kvm: nVMX: support " Paolo Bonzini
2017-03-08 18:03 ` [PATCH 5/6] KVM: VMX: add missing exit reasons Paolo Bonzini
2017-03-09 9:27 ` David Hildenbrand
2017-03-08 18:03 ` [PATCH 6/6] KVM: nVMX: support RDRAND and RDSEED exiting Paolo Bonzini
2017-03-13 18:27 ` Jim Mattson
2017-03-14 9:55 ` Paolo Bonzini [this message]
2017-03-30 9:55 [PATCH v2 0/6] KVM: nVMX: nested EPT improvements and A/D bits, RDRAND and RDSEED exits Paolo Bonzini
2017-03-30 9:55 ` [PATCH 6/6] KVM: nVMX: support RDRAND and RDSEED exiting Paolo Bonzini
2017-03-30 16:54 ` Jim Mattson
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