From: Paolo Bonzini <pbonzini@redhat.com>
To: Naresh Kamboju <naresh.kamboju@linaro.org>
Cc: Sean Christopherson <seanjc@google.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
kvm list <kvm@vger.kernel.org>,
open list <linux-kernel@vger.kernel.org>,
lkft-triage@lists.linaro.org, regressions@lists.linux.dev
Subject: Re: [PATCH 3/4] KVM: x86: WARN and reject loading KVM if NX is supported but not enabled
Date: Wed, 7 Jul 2021 16:15:49 +0200 [thread overview]
Message-ID: <40623553-310a-68f7-2981-f8ea9c7bd5b0@redhat.com> (raw)
In-Reply-To: <CA+G9fYsrQo3FvtW1VhXocY2xkaPLNADA4S5f=fBM5uqa=C5LYg@mail.gmail.com>
On 07/07/21 14:09, Naresh Kamboju wrote:
> On Fri, 25 Jun 2021 at 14:35, Paolo Bonzini <pbonzini@redhat.com> wrote:
>>
>> On 25/06/21 00:33, Sean Christopherson wrote:
>>> On Tue, Jun 15, 2021, Sean Christopherson wrote:
>>>> WARN if NX is reported as supported but not enabled in EFER. All flavors
>>>> of the kernel, including non-PAE 32-bit kernels, set EFER.NX=1 if NX is
>>>> supported, even if NX usage is disable via kernel command line.
>>>
>>> Ugh, I misread .Ldefault_entry in head_32.S, it skips over the entire EFER code
>>> if PAE=0. Apparently I didn't test this with non-PAE paging and EPT?
>>>
>>> Paolo, I'll send a revert since it's in kvm/next, but even better would be if
>>> you can drop the patch :-) Lucky for me you didn't pick up patch 4/4 that
>>> depends on this...
>>>
>>> I'll revisit this mess in a few weeks.
>>
>> Rather, let's keep this, see if anyone complains and possibly add a
>> "depends on X86_PAE || X86_64" to KVM.
>
> [ please ignore if this is already reported ]
>
> The following kernel warning noticed while booting linus master branch and
> Linux next 20210707 tag on i386 kernel booting on x86_64 machine.
Ok, so the "depends on" is needed. Let's add it, I'm getting back to
KVM work and will send the patch today or tomorrow.
Paolo
next prev parent reply other threads:[~2021-07-07 14:15 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-15 16:45 [PATCH 0/4] KVM: x86: Require EFER.NX support unless EPT is on Sean Christopherson
2021-06-15 16:45 ` [PATCH 1/4] KVM: VMX: Refuse to load kvm_intel if EPT and NX are disabled Sean Christopherson
2021-06-15 22:26 ` Jim Mattson
2021-06-15 16:45 ` [PATCH 2/4] KVM: SVM: Refuse to load kvm_amd if NX support is not available Sean Christopherson
2021-06-15 22:30 ` Jim Mattson
2021-06-15 16:45 ` [PATCH 3/4] KVM: x86: WARN and reject loading KVM if NX is supported but not enabled Sean Christopherson
2021-06-15 22:39 ` Jim Mattson
2021-06-18 10:27 ` Paolo Bonzini
2021-06-24 22:33 ` Sean Christopherson
2021-06-25 9:04 ` Paolo Bonzini
2021-07-07 12:09 ` Naresh Kamboju
2021-07-07 12:09 ` Naresh Kamboju
2021-07-07 14:15 ` Paolo Bonzini [this message]
2021-06-15 16:45 ` [PATCH 4/4] KVM: x86: Simplify logic to handle lack of host NX support Sean Christopherson
2021-06-15 22:58 ` Jim Mattson
2021-06-15 23:33 ` Sean Christopherson
2021-06-18 10:31 ` Paolo Bonzini
2021-06-18 10:32 ` [PATCH 0/4] KVM: x86: Require EFER.NX support unless EPT is on Paolo Bonzini
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